| 单词 | igneous |
| 例句 | His latest album, “Ancestral Recall,” is a highlight, throwing Scott’s blistering trumpet and Saul Williams’s equally igneous poetry into conversation with pounding ancient rhythms, all swathed in a foreboding digital soundscape. 12 Pop, Rock and Jazz Concerts to Check Out in N.Y.C. This Weekend 2020-03-05T05:00:00Z Inside is yet another ring, dating back at least 2,000 years, made of so-called bluestones — igneous rocks, each weighing between two and four tons, not indigenous to the area. Hiking along Virginia’s Aquia Creek and finding history a stone’s throw from home 2021-04-01T04:00:00Z The landscape is carved by igneous intrusions, lava and ash from volcanic eruptions, and tectonic fracturing, uplift and erosion. Deep in the heart of Big Bend National Park 2015-04-30T04:00:00Z “They found him as a rock. . . . Cold, hard, igneous. But it was him.” ‘In a Word’: A poetic, rock-solid look at grief and loss by the Hub Theatre 2016-04-06T04:00:00Z There’s that little pause of Canadian restraint, as if to say, “I thought it was obvious,” before his devastating, “I’m sorry but of course we were looking for James Monroe/Liechtenstein/igneous rock.” Alex Trebek is asking the right question after his latest cancer setback 2019-10-08T04:00:00Z There's that little pause of Canadian restraint, as if to say, "I thought it was obvious," before his devastating, "I'm sorry but of course we were looking for James Monroe/Liechtenstein/igneous rock." Bidding a final, poignant adieu to "Jeopardy!" host Alex Trebek amidst our nation's chaos 2021-01-09T05:00:00Z The six-tonne Altar Stone had traditionally been grouped with the other, smaller, igneous bluestones, although when it arrived at Stonehenge is unclear. Stonehenge's Altar Stone is not Welsh, Aberystwyth University says 2023-10-17T04:00:00Z Some of Rum's igneous rocks have a very similar mineral and chemical content to those found in the Séítah Formation within the Jezero crater on Mars. Nasa collect Rum rocks ahead of Mars space mission 2023-07-28T04:00:00Z These ferocious fires are gifting scientists with an unparalleled look at the connective tissue between the igneous abyss below and the lava-licked landscape above. Iceland has entered a new volcanic era 2023-07-24T04:00:00Z Lithium is often found in igneous rocks—magma that crystallized in the crust or lava that cooled on the surface. Major U.S. geological survey aims to uncover minerals critical for batteries and microchips 2023-06-01T04:00:00Z That includes igneous rock to date the crater and sedimentary rock and clays that may contain biosignatures, perhaps even fossilized evidence of microbial life. NASA’s Perseverance Rover May Already Have Evidence of Ancient Martian Life 2023-04-05T04:00:00Z The hillsides consist of a mélange of sheared and metamorphosed sedimentary and igneous rocks, crisscrossed with faults that allow water to seep beneath and destabilize the slopes. In Big Sur, Living With Nature’s Beauty but Trapped by Its Fury 2023-02-04T05:00:00Z As lava cools, it crystallizes into igneous rock, freezing electrons within iron-bearing minerals into patterns that could reveal a magnetic field’s traits, such as its orientation. Mars rover digs up intriguing clues in the hunt for life beyond Earth 2022-11-23T05:00:00Z Heavy REEs—those with high atomic numbers, including dysprosium, yttrium, and terbium—are most commonly extracted from masses of clay formed through eons of weathering of igneous rocks such as granite. It’s electric! Technique could clean up mining of valuable rare earth elements 2022-11-01T04:00:00Z These igneous rocks contain radioactive elements such as uranium. Mars rover nears milestone in ambitious plan to to return first rocks from another planet 2022-09-20T04:00:00Z Collected in September 2021, the rover’s first sample is thought to be igneous rock from an ancient lava flow. NASA’s Perseverance Rover May Already Have Evidence of Ancient Martian Life 2023-04-05T04:00:00Z After landing farther away from the delta than scientists had hoped, it drove around Jezero’s floor, where it surprisingly found ‘igneous’ rocks formed directly from molten magma, or from volcanic activity. Perseverance Mars Rover Makes ‘Fantastic’ Find in Search for Past Life 2022-09-19T04:00:00Z These are both igneous rock, the term used for any rock that has cooled from a molten state. Astronomy 2016-10-13T00:00:00Z It is estimated that over the past 100 million years some of these igneous bodies have been uplifted in the order of 8,000 m. Physical Geology 2015-01-01T00:00:00Z Solid sedimentary, igneous, or metamorphic bedrock shakes less than unconsolidated sediments. An Introduction to Geology 2017-01-01T00:00:00Z The age estimates revealed that the ecosystem collapse coincided with the first rumblings of tremendous volcanic eruptions in a “large igneous province” known as the Siberian Traps, in what is now Russia. Toxic Slime Contributed to Earth’s Worst Mass Extinction—And It’s Making a Comeback 2022-07-06T04:00:00Z The granite was formed as intrusive igneous rock approximately 350 million years ago. In Barre, Vt., granite is a way of life — and beyond 2022-06-16T04:00:00Z Describe the differences among primitive, igneous, sedimentary, and metamorphic rock, and relate these differences to their origins. Astronomy 2016-10-13T00:00:00Z Subduction of oceanic crust at various locations along the west coast and within the accreted terranes prior to their arrival has produced massive volumes of intrusive igneous rocks within the Coast Range. Physical Geology 2015-01-01T00:00:00Z Felsic is the compositional term applied to continental igneous minerals and rocks that contain an abundance of orthoclase feldspar. An Introduction to Geology 2017-01-01T00:00:00Z Studies have consistently implicated the Siberian Traps igneous event as the ultimate instigator of the end-Permian mass extinction, in large part because of the composition of the rocks in the area. Toxic Slime Contributed to Earth’s Worst Mass Extinction—And It’s Making a Comeback 2022-07-06T04:00:00Z It spent many of its early months exploring the crater floor — which unexpectedly is made of igneous rocks, a type that forms as molten materials cool. NASA’s Perseverance Rover Begins Key Search for Life on Mars 2022-06-07T04:00:00Z The probes found that the rock in the landing areas is igneous, primarily basalts. Astronomy 2016-10-13T00:00:00Z Intrusive igneous rocks form at depths of several hundreds of metres to several tens of kilometres. Physical Geology 2015-01-01T00:00:00Z It is this magma that becomes the source for volcanoes and igneous rocks. An Introduction to Geology 2017-01-01T00:00:00Z But on Mars, many lake-deposited sediments were eroded from igneous rocks and can appear volcanic from space. Mars rover wraps survey of Jezero crater’s surprising volcanic floor 2022-03-09T05:00:00Z That was a scientific jackpot because scientists can date igneous rocks on the basis of the radioactive decay of their chemical elements. NASA’s Perseverance Rover Begins Key Search for Life on Mars 2022-06-07T04:00:00Z Sedimentary rocks are made of fragments of igneous rock or the shells of living organisms deposited by wind or water and cemented together without melting. Astronomy 2016-10-13T00:00:00Z Over time, the igneous rock of the oceanic crust gets covered with layers of sediment, which eventually become sedimentary rock, including limestone, mudstone, chert, and turbidites. Physical Geology 2015-01-01T00:00:00Z This chapter will describe the classification of igneous rocks, the unique processes that form magmas, types of volcanoes and volcanic processes, volcanic hazards, and igneous landforms. An Introduction to Geology 2017-01-01T00:00:00Z Séítah rocks contained evenly distributed crystals of the mineral olivine, which coalesce as magma slowly cools, whereas Máaz rocks had small grains of pyroxene and plagioclase, interlocked in a way that indicated igneous formation. Mars rover wraps survey of Jezero crater’s surprising volcanic floor 2022-03-09T05:00:00Z “All of the rocks that we have confidently identified are igneous,” Farley says. What We Learned from the Perseverance Rover’s First Year on Mars 2022-02-17T05:00:00Z Terrestrial rocks can be classified as igneous, sedimentary, or metamorphic. Astronomy 2016-10-13T00:00:00Z Intrusive igneous rock typically crystallizes at depths of hundreds of metres to tens of kilometres below the surface. Physical Geology 2015-01-01T00:00:00Z These are known as fine-grained extrusive, or volcanic, igneous rocks. An Introduction to Geology 2017-01-01T00:00:00Z Those observations revealed large grains of olivine, an igneous mineral that can accumulate at the bottom of a large lava flow. On Mars, a NASA Rover and Helicopter’s Year of Surprise and Discovery 2022-02-15T05:00:00Z Produced volcanically, the igneous rocks on Jezero’s floor contain large olivine crystals that typically form near the bottoms of thick lava lakes and flows. What We Learned from the Perseverance Rover’s First Year on Mars 2022-02-17T05:00:00Z Molten rock rises from below to fill the space between the receding plates; this rock is basaltic lava, the kind of igneous rock that forms most of the ocean basins. Astronomy 2016-10-13T00:00:00Z To change its position in the rock cycle, intrusive igneous rock has to be uplifted and exposed by the erosion of the overlying rocks. Physical Geology 2015-01-01T00:00:00Z Figure 4.1: Half Dome, a mass of intrusive igneous rock in Yosemite National Park, now exposed by erosion. An Introduction to Geology 2017-01-01T00:00:00Z The research involved dunite, a coarse, dense type of igneous rock named after a mountain in New Zealand. Underground carbon-dioxide storage idea is cracked. And that’s actually good. 2022-02-13T05:00:00Z Perseverance’s already-collected igneous rock cores can be used to measure the strength of Mars’s ancient magnetic field and to precisely pin ages on the crater’s epochs. What We Learned from the Perseverance Rover’s First Year on Mars 2022-02-17T05:00:00Z The layers of rock at Salisbury Crags supported his belief that igneous rocks are formed from magma. Calls to allow people to return to Edinburgh's Radical Road 2022-02-01T05:00:00Z Virtually all of the igneous rocks that we see on Earth are derived from magmas that formed from partial melting of existing rock, either in the upper mantle or the crust. Physical Geology 2015-01-01T00:00:00Z These are known as coarse-grained intrusive, or plutonic, igneous rocks. An Introduction to Geology 2017-01-01T00:00:00Z Before cooling and forming igneous rocks, molten lava is made of metal and oxygen-containing glasses that are not only tolerant of heat, but also flow when heated. New lava-like coating can stop fires in their tracks 2022-01-06T05:00:00Z “If you’ve got any rock that you’re looking to categorize as igneous or sedimentary, I can help you out,” he joked on a video call. For Muhammad Ali’s grandson, family legacy extends beyond the ring 2021-12-10T05:00:00Z Scholars have identified limestone, igneous and sedimentary rocks. Saint Francis had a vision. Or was it just a dream? This makes it unique among the minerals that are common in igneous rocks. Physical Geology 2015-01-01T00:00:00Z This relationship between cooling rates and grain sizes of the solidified minerals in igneous rocks is important for interpreting the rock’s geologic history. An Introduction to Geology 2017-01-01T00:00:00Z "Some of these rocks could have a composition that makes it look igneous, when they could be sedimentary or igneous rocks," Siebach said. Mars' weird geology is making Perseverance's job more complicated 2021-08-26T04:00:00Z This happened when the drill bored into structurally flimsy sedimentary rock, though—not anything igneous. Crumbly Mars Rock, Not Hardware Flaws, Scuttled Perseverance's First Sample Attempt 2021-08-12T04:00:00Z Those eruptions, forming what we call “large igneous provinces,” are associated with some of the worst extinction events in Earth history. Opinion | NASA is planning to return to Venus. It’s about time. 2021-06-09T04:00:00Z In most cases, this is sedimentary or igneous rock, but metamorphic rock that reaches the surface and is then reburied can also be considered a parent rock. Physical Geology 2015-01-01T00:00:00Z Cooling history is also related to changes that can occur to the composition of igneous rocks. An Introduction to Geology 2017-01-01T00:00:00Z Basalts are igneous, or volcanic, rocks that are common on Mars as well as Earth. Perseverance Mars Rover Records Sound of Rock-Zapping Laser 2021-03-11T05:00:00Z Percy may be directed back to this spot to try and grab some igneous rocks in the future, Farley says. Crumbly Mars Rock, Not Hardware Flaws, Scuttled Perseverance's First Sample Attempt 2021-08-12T04:00:00Z These volcanic events, which leave deposits called large igneous provinces, produce at least 100,000 cubic kilometers of lava over one million years. Model Suggests Toxic Transformation on Venus 2020-08-07T04:00:00Z The Bowen reaction series is one of the results of his work, and even a century later, it is an important basis for our understanding of igneous rocks. Physical Geology 2015-01-01T00:00:00Z The slow cooling process allows crystals to grow large, giving the intrusive igneous rock a coarse-grained or phaneritic texture. An Introduction to Geology 2017-01-01T00:00:00Z Zircon, a mineral commonly found in igneous rocks, proves particularly useful. How Do Scientists Determine the Ages of Human Ancestors, Fossilized Dinosaurs and Other Organisms? 2020-08-04T04:00:00Z This land is made of igneous rock fissured with gold. The Fight for the Reindeer 2019-11-18T05:00:00Z The region, northwest of the much-visited Four Corners, includes a stunning variety of topography — flat-topped mesas and expansive valleys, sloping igneous mountains and towering sandstone cliffs. What remains of Bears Ears The diagram in Figure 3.16 can be used to help classify igneous rocks by their mineral composition. Physical Geology 2015-01-01T00:00:00Z When lava is extruded onto the surface, or intruded into shallow fissures near the surface and cools, the resulting igneous rock is called extrusive or volcanic. An Introduction to Geology 2017-01-01T00:00:00Z Just the natural bits will do, which is why amethyst is so much more abundant in igneous than sedimentary rocks. The Origin of Amethysts May Leave You All Tingly 2019-03-03T05:00:00Z The igneous band formed from upwelling magma that cooled before reaching the surface. Ancient Earth's Weakened Magnetic Field May Have Driven Mass Extinction 2019-02-15T05:00:00Z It's not terribly surprising to find garnets in igneous rocks. The Astonishing Origin of Garnets in Rhyolite 2019-02-03T05:00:00Z It is not uncommon to see an intrusive igneous rock with crystals up to a centimetre long. Physical Geology 2015-01-01T00:00:00Z Extrusive igneous rocks have a fine-grained or aphanitic texture, in which the grains are too small to see with the unaided eye. An Introduction to Geology 2017-01-01T00:00:00Z The 300 million-year-old igneous rock on which the Eastern Seaboard is perched does not conduct electricity well. This NASA spacecraft is about to probe one of Earth’s scariest threats — the sun 2018-08-09T04:00:00Z Higher up, past the sound of running water, granite thumbs shoot into the air, the remarkable, distinctive igneous intrusions of the Black Hills. Debate ensues in South Dakota over meaning of Poet’s Table 2018-06-09T04:00:00Z The Spanish noun refers to the hollows in the igneous rock that, after a good rain, transform into watery cradles for tadpoles and fairy shrimp. You’re going where? El Paso, Texas 2018-05-16T04:00:00Z Metamorphism can also take place if cold rock near the surface is intruded and heated by a hot igneous body. Physical Geology 2015-01-01T00:00:00Z To avoid these complications, the following figure presents a simplified version of igneous rock nomenclature focusing on the four main groups, which is adequate for an introductory student. An Introduction to Geology 2017-01-01T00:00:00Z Pebbles caught up in this ancient martian river are causing us to rethink our view of how the underlying igneous crust and mantle of Mars formed. Curiosity rover: 2,000 days on Mars 2018-03-22T04:00:00Z Sites such as Bear's House — composed of igneous rock, the solid core of what was likely once a volcano — are therefore charged places. What you say can be used in an Edgar Heap of Birds painting: The artist on his way with words 2018-02-14T05:00:00Z Finally, there is the large group of other twentieth-century geoscientists who quantified the theory of plate tectonics by using magnetic reversals recorded in igneous and sedimentary rocks. How the planet’s poles keep trading places 2018-01-29T05:00:00Z In order to use the K-Ar dating technique, we need to have an igneous or metamorphic rock that includes a potassium-bearing mineral. Physical Geology 2015-01-01T00:00:00Z Therefore, most landforms and rock groups that owe their origin to igneous rocks are intrusive bodies. An Introduction to Geology 2017-01-01T00:00:00Z Petford, N. Controls on primary porosity and permeability development in igneous rocks. Primordial clays on Mars formed beneath a steam or supercritical atmosphere 2017-12-05T05:00:00Z The answer is a resounding yes when CO2 is injected into the igneous rock basalt, says Matter. Emissions: We have the technology : Nature : Nature Research 2017-10-10T04:00:00Z One idea is that when igneous or metamorphic rocks are under stress, their molecular bonds break and release ionized oxygen that travels through the rock. What caused the mysterious lights in the night sky after Mexico’s earthquake? 2017-09-15T04:00:00Z Of the consolidated rocks, well-fractured volcanic rocks and limestone that has cavernous openings produced by dissolution have the highest potential porosity, while intrusive igneous and metamorphic rocks, which formed under great pressure, have the lowest. Physical Geology 2015-01-01T00:00:00Z This section will focus on the common igneous bodies which are found in many places within the bedrock of Earth. An Introduction to Geology 2017-01-01T00:00:00Z Now the researchers hope to locate a large igneous province—a vast swath of hardened lava—that would date back to the time of the extinction. Volcanoes May Have Triggered the Last Unexplained Mass Extinction 2017-08-08T04:00:00Z Then the three main rock types are presented: igneous, sedimentary, and metamorphic. Rocks: A Handy Book for Tiny Geologists 2017-07-29T04:00:00Z These are tough igneous rocks of the Cascade mountains. Bad Signs 2017-06-04T04:00:00Z Fractured igneous and metamorphic rocks, and especially fractured volcanic rocks, can be highly permeable, as can limestone that has been dissolved along fractures and bedding planes to create solutional openings. Physical Geology 2015-01-01T00:00:00Z This explains the wide variety of resulting igneous rocks that are found all over Earth. An Introduction to Geology 2017-01-01T00:00:00Z You may recall from your high school geology class that natural stone falls into one of three basic geological classifications: metamorphic, sedimentary and igneous. Seven tips for cleaning natural stone | Provided By Seal Team One 2017-05-15T04:00:00Z Today, the granular, igneous rock is less popular than engineered stone, commonly referred to as quartz. With countertops, quartz has supplanted granite as the people’s choice 2017-01-19T05:00:00Z “Magnetite is typically something that geologists expect in igneous rocks. To find it in an animal is a bio-chemical anomaly.” Maverick scientist thinks he has discovered a magnetic sixth sense in humans 2016-06-23T04:00:00Z An aquitard is a body that does not allow transmission of a significant amount of water, such as a clay, a till, or a poorly fractured igneous or metamorphic rock. Physical Geology 2015-01-01T00:00:00Z Note that there are exceptions to this generalized layout of volcano types and igneous rock composition. An Introduction to Geology 2017-01-01T00:00:00Z Most of the “meteorwrongs” are actually masses of iron, glassy byproducts from smelting ore called slags, or igneous rocks with small cavities called vesicular rocks. Some Meteorites Are Million-Dollar Finds, Others Are ‘Meteorwrongs’ 2016-04-20T04:00:00Z The stones are volcanic and igneous rocks with precise geological signatures that match the inner horseshoe of smaller rocks at Stonehenge. New Discovery Solves One Mystery of Stonehenge’s Construction 2015-12-07T05:00:00Z For a start, it would mean the igneous ocean crust is far more variable in thickness and in structure than previously recognised. Bid to drill deep inside Earth - BBC News 2015-11-30T05:00:00Z Metamorphic rocks form when either igneous or sedimentary rocks are heated and squeezed to the point where some of their minerals are unstable and new minerals form to create a different type of rock. Physical Geology 2015-01-01T00:00:00Z Cross-cutting igneous rocks and sills can be used to bracket the ages of affected, older sedimentary rocks. An Introduction to Geology 2017-01-01T00:00:00Z Obsidian is an igneous rock that forms when molten material cools so rapidly that atoms are unable to arrange themselves into a crystalline structure. Strange Skills: The Flintknapper 2015-11-07T05:00:00Z Second, they want igneous rocks, which can be dated on Earth and can help scientists understand the way that Mars formed. Mars scientists tap ancient river deltas and hot springs as promising targets for 2020 rover 2015-08-06T04:00:00Z The textbook explanation is that the Moho draws the line between the crust and the mantle: a demarcation between familiar igneous surface rocks - such as granites, basalts and gabbros - and those of the interior peridotites. Bid to drill deep inside Earth - BBC News 2015-11-30T05:00:00Z These high-temperature feldspars are likely to be found only in volcanic rocks because intrusive igneous rocks cool slowly enough to low temperatures for the feldspars to change into one of the lower-temperature forms. Physical Geology 2015-01-01T00:00:00Z This is not to be confused with the igneous texture porphyritic, although the name is derived from the porphyritic texture that is nearly always present in the igneous rocks in a porphyry deposit. An Introduction to Geology 2017-01-01T00:00:00Z The palm-like Pandanus candelabrum apparently prefers soil rich in kimberlite — a type of igneous rock that forms in the Earth's crust in huge vertical columns. Rare African plant points the way to diamonds 2015-05-07T04:00:00Z The digital model was a computer simulation of cooling igneous rock. Volcanic Activity, Not Giant Bears, Created Enigmatic Devils Tower 2015-03-10T04:00:00Z We see different igneous rock types, sedimentary rock types... this is a very complex meteorite. Meteorite 'is oldest chunk of Mars' 2013-11-21T02:29:38Z In classifying intrusive igneous rocks, the first thing to consider is the percentage of ferromagnesian silicates. Physical Geology 2015-01-01T00:00:00Z Mica minerals are usually found in igneous and metamorphic rocks, while clay minerals are more often found in sedimentary rocks. An Introduction to Geology 2017-01-01T00:00:00Z It doesn’t look like anywhere else controlled by Israel: an igneous formation, the Golan’s stone is no shade of the limestone that sheaths Jerusalem; it’s black. Why Israel Fears Syria's War 2013-09-19T08:20:26Z They are actually the edges of roughly hexagonal columns of igneous rock, similar to other geometric landmarks such as Ireland's Giant's Causeway or Devils Postpile in California. Volcanic Activity, Not Giant Bears, Created Enigmatic Devils Tower 2015-03-10T04:00:00Z The trouble is that different isotopic tracers yield wildly different dates for the most common variety of Martian meteorites, hunks of igneous rock called shergottites. Solved: The Mystery of the Martian Meteorites 2013-07-26T18:45:00.760Z The textures of volcanic rocks will be discussed in Chapter 4, so here we’ll only look at the different textures of intrusive igneous rocks. Physical Geology 2015-01-01T00:00:00Z Note the unweathered igneous rock in the center. An Introduction to Geology 2017-01-01T00:00:00Z An X-ray analysis by CheMin showed that the ground-up rock comprised mostly igneous minerals such as feldspar, pyroxene, olivine and magnetite. Mars Rover Finds Evidence of Ancient Habitability 2013-03-13T19:45:00.600Z "It's igneous," Gellert said, referring to rock formed from molten material. NASA's Mars rover finds rock with Earth-like chemistry 2012-10-12T01:31:36Z As I sit on a fragment of igneous rock and look around me, I indeed feel that "the singer is less than his themes." Australian Pictures Drawn with Pen and Pencil 2012-04-02T02:00:28.873Z The minerals that make up igneous rocks crystallize at a range of different temperatures. Physical Geology 2015-01-01T00:00:00Z Aluminum concentrates in soils as feldspar and ferromagnesian minerals in igneous and metamorphic rocks undergo chemical weathering processes. An Introduction to Geology 2017-01-01T00:00:00Z He seems to have regarded the soul as composed of igneous matter, and so approximates the orthodox Pythagorean doctrine of the central fire, or Hestia, to the more detailed theories of Heraclitus. Encyclopaedia Britannica, 11th Edition, Volume 13, Slice 5 "Hinduism" to "Home, Earls of" 2012-03-25T02:00:05.717Z Scientists found the rock lacks magnesium and iron - elements found in igneous rock examined by previous Mars rovers Spirit and Opportunity. NASA's Mars rover finds rock with Earth-like chemistry 2012-10-12T01:31:36Z It is a common constituent of granite and of various igneous rocks. Webster's Unabridged Dictionary 2012-03-24T02:00:23.513Z Rocks are made up of mixtures of minerals and can form though igneous, sedimentary, or metamorphic processes. Physical Geology 2015-01-01T00:00:00Z First, the mineral grains containing the isotope formed at the same time as the rock, such as minerals in an igneous rock that crystallized from magma. An Introduction to Geology 2017-01-01T00:00:00Z A variety of pyroxene, usually of a black or dark green color, occurring in igneous rocks, such as basalt; Ð also used instead of the general term pyroxene. Webster's Unabridged Dictionary (2nd 100 Pages) 2012-03-24T02:00:19.387Z From diabases, basalts, andesites and other igneous rocks a third type of hornfels is produced. Encyclopaedia Britannica, 11th Edition, Volume 13, Slice 6 "Home, Daniel" to "Hortensius, Quintus" 2012-03-15T02:00:32.250Z A mineral of the feldspar family, commonly occurring in small glassy crystals, also a constituent of some igneous rocks. Webster's Unabridged Dictionary 2012-03-24T02:00:23.513Z The second most important goal is to find igneous rocks that could be dated by radioisotope analysis to get a better idea of the ages of rocks on Mars. Mars Scientists Propose Landing Sites for Future Rovers 2012-03-01T23:15:03.017Z Note the unweathered igneous rock in the center. An Introduction to Geology 2017-01-01T00:00:00Z The Flume, on Star Island, is a fine specimen of the intrusion of igneous rock among the harder formation. Nooks and Corners of the New England Coast 2012-02-22T03:00:25.113Z The original porphyritic, fluidal, vesicular or fragmental structures of the igneous rock are clearly visible in the less advanced stages of hornfelsing, but become less evident as the alteration progresses. Encyclopaedia Britannica, 11th Edition, Volume 13, Slice 6 "Home, Daniel" to "Hortensius, Quintus" 2012-03-15T02:00:32.250Z The igneous rocks of the Vosges, and those of the Alps, Corsica, &c., and the subject of metamorphism occupied his attention. Encyclopaedia Britannica, 11th Edition, Volume 7, Slice 10 "David, St" to "Demidov" 2012-02-17T03:00:33.923Z There are twigs of driftwood, and igneous pebbles, and a few coconuts, but they're far outnumbered by the shrapnel of debris. The great escape of bath toys in the Pacific 2012-02-12T00:05:21Z Phosphorus is an essential element that occurs in the mineral apatite, which is found in trace amounts in common igneous rocks. An Introduction to Geology 2017-01-01T00:00:00Z The first point to be achieved is, of course, to procure the meat, and then to see that the “igneous element,” as Mr. Dryden learnedly calls fire, has attained a sufficient degree of heat. Antigua and the Antiguans, Volume II (of 2) A full account of the colony and its inhabitants from the time of the Caribs to the present day 2012-02-09T03:00:13.500Z Green and dark-green are the prevalent tints of the hornfelses produced by the alteration of igneous rocks. Encyclopaedia Britannica, 11th Edition, Volume 13, Slice 6 "Home, Daniel" to "Hortensius, Quintus" 2012-03-15T02:00:32.250Z The northern coast range is formed by the oldest rocks in the island, consisting chiefly of limestones and marbles with occasional masses of igneous rock. Encyclopaedia Britannica, 11th Edition, Volume 7, Slice 8 "Cube" to "Daguerre, Louis" 2012-01-31T03:00:17.257Z The igneous rocks will be described under the various groups of Granitic, Trappean, and Volcanic. Early Days in North Queensland 2012-01-24T03:00:29.987Z Within the cooling magma, the mineral crystals continue to grow until they solidify into igneous rock. An Introduction to Geology 2017-01-01T00:00:00Z All these forms are found in vitreous igneous rocks. Encyclopaedia Britannica, 11th Edition, Volume 7, Slice 7 "Crocoite" to "Cuba" 2012-01-22T03:00:24.397Z Granite, gran′it, n. an igneous crystalline rock, composed of grains of quartz, feldspar, and mica, and of a whitish, grayish, or reddish colour.—adj. Chambers's Twentieth Century Dictionary (part 2 of 4: E-M) 2012-01-11T03:00:23.770Z The Pliocene is of marine origin, and rests unconformably upon all the older beds, including the Post-oligocene igneous rocks, thus proving that the final folding and the last volcanic outbursts were approximately of Miocene age. Encyclopaedia Britannica, 11th Edition, Volume 7, Slice 8 "Cube" to "Daguerre, Louis" 2012-01-31T03:00:17.257Z The assemblage is not a perfectly homogeneous one but includes both igneous and sedimentary rocks, but the former preponderate. Encyclopaedia Britannica, 11th Edition, Volume 12, Slice 7 "Gyantse" to "Hallel" 2011-12-26T03:00:11.613Z They are usually found in igneous rocks, such as granite, rhyolite, and basalt as well as metamorphic rocks and detrital sedimentary rocks. An Introduction to Geology 2017-01-01T00:00:00Z They are common constituents of microcrystalline igneous rocks, and often occur as inclusions in larger crystals of other substances. Encyclopaedia Britannica, 11th Edition, Volume 7, Slice 7 "Crocoite" to "Cuba" 2012-01-22T03:00:24.397Z Hornblende, horn′blend, n. a mineral of various colours, found in granite and other igneous rocks that contain quartz. Chambers's Twentieth Century Dictionary (part 2 of 4: E-M) 2012-01-11T03:00:23.770Z These lowest rocks are frequently called "igneous," in contradistinction to the stratified rocks nearer the surface, which have been obviously deposited under water. Harper's New Monthly Magazine Vol. IV, No. 19, Dec 1851 2011-12-25T03:00:11.297Z The structure of igneous rocks, also, is exactly that which would be produced from alluvial deposits subjected during these cyclical movements to the enormous pressure and consequent heating caused by superimposed material. The Energy System of Matter A Deduction from Terrestrial Energy Phenomena 2011-12-21T03:00:36.570Z He noticed that in igneous rocks, certain minerals always occur together and these mineral assemblages exclude other minerals. An Introduction to Geology 2017-01-01T00:00:00Z Black thought that he might be able to lay hold of this "igneous matter" supposed to be taken by the limestone from the fire; but he found that limestone loses weight when changed into quicklime. Heroes of Science Chemists 2011-12-09T03:00:21.047Z The other kinds of rocks are known as igneous rocks, which have been melted under the action of heat and become solid on cooling. Cornwall 2011-12-05T03:00:38.530Z The popular local belief that the quartzite is of igneous origin is without the slightest warrant. The Geography of the Region about Devils Lake and the Dalles of the Wisconsin 2011-11-29T03:00:17.347Z This was near a geological frontier where the igneous and sedimentary rocks joined, and the neighbourhood was highly mineralized, there being iron, coal, and gold within a short distance. The Inhabitants of the Philippines 2011-11-23T03:00:21.653Z Curious as to why, and with the hypothesis in mind that it had to do with the temperature at which the rocks cooled, he set about conducting experiments on igneous rocks in the early 1900s. An Introduction to Geology 2017-01-01T00:00:00Z The Saxon granulites are apparently for the most part igneous and correspond in composition to granites and porphyries. Encyclopaedia Britannica, 11th Edition, Volume 12, Slice 3 "Gordon, Lord George" to "Grasses" 2011-11-13T03:00:13.177Z There are as well intrusive veins of igneous rocks. Cornwall 2011-12-05T03:00:38.530Z Were this the fact, igneous rock should be found about it. The Geography of the Region about Devils Lake and the Dalles of the Wisconsin 2011-11-29T03:00:17.347Z Alt-na-blashy.—The aqueous and igneous agencies seem to be combined in these quarters, for since the rain we hear of a great increase of burns. Mr. Punch in the Highlands 2011-11-01T02:00:23.677Z He conducted experiments on igneous rock—grinding combinations of rocks into powder, sealing the powders into metal capsules, heating them to various temperatures, and then cooling them. An Introduction to Geology 2017-01-01T00:00:00Z More conclusive, however, is the chemical composition of these rocks, which often is such as no igneous masses possess, but resembles that of many impure argillaceous sediments. Encyclopaedia Britannica, 11th Edition, Volume 12, Slice 2 "Gloss" to "Gordon, Charles George" 2011-10-31T02:00:28.703Z The oldest known rocks, those of the Archean era, contain so much igneous matter that many students have assumed that they show that the entire earth was once liquid. Climatic Changes Their Nature and Causes 2011-10-28T02:00:24.840Z Thus, when Dr Johnson defines fire, he tells us it is the igneous element. Deformities of Samuel Johnson, Selected from his Works 2011-10-18T02:00:19.057Z Augite, aw′jīt, n. one of the Pyroxene group of minerals, closely allied to hornblende, usually of a greenish colour, occurring crystallised in prisms, and forming an essential component of many igneous rocks.—adj. Chambers's Twentieth Century Dictionary (part 1 of 4: A-D) 2011-10-11T02:01:08.990Z The results of many of these experiments, conducted at different temperatures over a period of several years, showed that the common igneous minerals crystallize from magma at different temperatures. An Introduction to Geology 2017-01-01T00:00:00Z These have very much the same composition as acid igneous rocks such as granite, aplite, hornblende granite, or intermediate rocks such as syenite and quartz diorite. Encyclopaedia Britannica, 11th Edition, Volume 12, Slice 2 "Gloss" to "Gordon, Charles George" 2011-10-31T02:00:28.703Z The formation of these particular sedimentary rocks by weathering of igneous rocks involves only a little carbon dioxide and water. Climatic Changes Their Nature and Causes 2011-10-28T02:00:24.840Z This variety of igneous rock was met with principally at Pemmican Rock, western inlet of Bellot Strait. In the Arctic Seas A Narrative of the Discovery of the Fate of Sir John Franklin and his Companions 2011-10-10T02:00:18.377Z Clink′stone, a greenish-gray or brownish compact, or very finely crystalline igneous rock, splitting into slabs, which give a metallic clink when struck by a hammer. Chambers's Twentieth Century Dictionary (part 1 of 4: A-D) 2011-10-11T02:01:08.990Z The unmelted country rocks within an igneous rock mass are called xenoliths. An Introduction to Geology 2017-01-01T00:00:00Z This intermixture of igneous and sedimentary material may take place on the finest scale and in the most intricate manner. Encyclopaedia Britannica, 11th Edition, Volume 12, Slice 2 "Gloss" to "Gordon, Charles George" 2011-10-31T02:00:28.703Z It is now considered that they merely indicate igneous activity of great magnitude. Climatic Changes Their Nature and Causes 2011-10-28T02:00:24.840Z With the magnetic anomaly data it is possible to distinguish some types of igneous rocks, particularly basalts, against the background of less magnetic material, particularly sediments. Scientist at Work Blog: Scooping Up Arctic Seafloor Data in an Expedition's Homestretch 2011-10-05T17:01:36Z These cliffs were of solid rock of an igneous formation chiefly, but marked here and there with veins of what appeared to be quartz. The Island of Gold A Sailor's Yarn 2011-10-03T02:00:28.483Z The rock cycle shows that both igneous and sedimentary rocks can become metamorphic rocks. An Introduction to Geology 2017-01-01T00:00:00Z It is composed chiefly of disintegrating quartzite, flanked on the west by igneous rocks. Climbing in The British Isles, Vol. II Wales and Ireland 2011-09-23T02:00:23.653Z Many of the characters of igneous rocks have been reproduced experimentally by fusing together their minerals, or the constituents of their minerals, in the proper proportion. Encyclopaedia Britannica, 11th Edition, Volume 11, Slice 6 "Geodesy" to "Geometry" 2011-09-19T02:00:10.473Z So it is with Neptunists, the Vaishnavas: then, of course, of aqueous, in lieu of igneous, reference. Cultus Arborum Phallic Tree Worship 2011-09-12T02:00:27.807Z Very often a mass of normal gabbro with typical igneous character passes at its margins or along localized zones into foliated rocks of this kind, and every transition can be found between the different types. Encyclopaedia Britannica, 11th Edition, Volume 11, Slice 4 "G" to "Gaskell, Elizabeth" 2011-08-24T02:00:20.690Z These crystalline changes create identifying textures, which is shown in the figure below comparing the phaneritic texture of igneous granite with the foliated texture of metamorphic gneiss. An Introduction to Geology 2017-01-01T00:00:00Z Lava streams and other signs of volcanic action abound, but there has been no igneous activity since the Spaniards took possession. Encyclopaedia Britannica, 11th Edition, Volume 11, Slice 3 "Frost" to "Fyzabad" 2011-08-15T02:00:28.473Z Massive igneous rocks can be observed to have undergone intense crushing and cleavage, and to have ultimately assumed a crystalline foliated character. Encyclopaedia Britannica, 11th Edition, Volume 11, Slice 6 "Geodesy" to "Geometry" 2011-09-19T02:00:10.473Z After lunch they conjugate “aburrir” or memorize the differences between igneous, sedimentary and metamorphic rock. To students, it?s all about the (boring) content 2011-08-14T15:47:26Z It is a gated fortress built of gray igneous rock in northern Sana, in a neighborhood called Hasaba. Magazine Preview: Yemen on the Brink of Hell 2011-07-21T01:01:35Z Fluids-activated metamorphism is frequently involved in creating economically important mineral deposits that are located next to igneous intrusions of magma bodies. An Introduction to Geology 2017-01-01T00:00:00Z The soil of the grass-lands is of an igneous clay formation—magnesian clay, formed by disintegration of the plutonic rocks, whose upheaval in two successive stages brought the Nicobars into existence. In the Andamans and Nicobars The Narrative of a Cruise in the Schooner "Terrapin" 2011-06-30T02:00:24.487Z From this arrangement they have been termed “stratified,” in contrast to the unstratified or igneous series. Encyclopaedia Britannica, 11th Edition, Volume 11, Slice 6 "Geodesy" to "Geometry" 2011-09-19T02:00:10.473Z Three small islands gem its surface, one of which, from its columnar appearance, seems to be of volcanic or igneous formation. Fifty Years In The Northwest With An Introduction And Appendix Containing Reminiscences, Incidents And Notes 2011-06-13T02:00:27.317Z Ultramafics are igneous rocks — formed volcanically — that become capable of carrying electrical current when they are melted back down into magma. Scientists Discover Magma Ocean on Jupiter's Moon Io 2011-06-08T11:20:00Z The lighter colored layers are interpreted to be the result of the separation of a felsic igneous melt from the adjacent highly metamorphosed darker layers, or injection of a felsic melt from some distance away. An Introduction to Geology 2017-01-01T00:00:00Z Ultramafics are igneous rocks — those formed volcanically — which become capable of carrying electrical current when they are melted back down to magma. Scientists discover Magma ocean on Jupiter's moon Io 2011-05-17T09:00:00Z As the sedimentary rocks have for the most part been laid down under water, and more especially on the sea-floor, they are often spoken of as “aqueous,” in contradistinction to the igneous rocks. Encyclopaedia Britannica, 11th Edition, Volume 11, Slice 6 "Geodesy" to "Geometry" 2011-09-19T02:00:10.473Z Notwithstanding the igneous character of the formation there is much excellent farming land on plains and intervales, while the more abrupt and rocky portions are rich in iron and the precious metals. Fifty Years In The Northwest With An Introduction And Appendix Containing Reminiscences, Incidents And Notes 2011-06-13T02:00:27.317Z A blurred, half-naked, grisly monster sprawled on its loathsome haunches before them,—a thing topped with a blood-mottled, hideous head, made frightful by two luridly igneous, horrible eyes. The Red Debt Echoes from Kentucky 2011-05-08T02:00:04.810Z These are common around intrusive igneous bodies and are hard to identify. An Introduction to Geology 2017-01-01T00:00:00Z The rocks of Labrador are largely metamorphic, but include ancient igneous intrusions, and are hard and resistant. North America 2011-05-05T02:00:20.027Z Sills, or intrusive sheets, are bed-like masses which have been thrust between the planes of sedimentary or even of igneous rocks. Encyclopaedia Britannica, 11th Edition, Volume 11, Slice 6 "Geodesy" to "Geometry" 2011-09-19T02:00:10.473Z The geological formation consists largely of primitive or igneous rocks, trappean, basaltic and granite, and the scenery has a peculiarly grand and sombre appearance. Fifty Years In The Northwest With An Introduction And Appendix Containing Reminiscences, Incidents And Notes 2011-06-13T02:00:27.317Z His observations on the geology of South America were given in a masterly essay, and these and subsequent researches threw much light on igneous and metamorphic phenomena and on the resulting changes in rock-formations. Encyclopaedia Britannica, 11th Edition, Volume 10, Slice 6 "Foraminifera" to "Fox, Edward" 2011-04-22T02:00:08.637Z Along this route, the degree of metamorphism gradually increases from sedimentary parent rock to low-grade metamorphic rock, then higher-grade metamorphic rock, and eventually the igneous core. An Introduction to Geology 2017-01-01T00:00:00Z Segregated and fissure veins occur in either igneous, sedimentary, or metamorphic terranes, but are more commonly of economic importance in the metamorphic rocks than elsewhere, and will be referred to again in that connection. North America 2011-05-05T02:00:20.027Z They present in addition other structures which have been superinduced upon them, and which they share with the unstratified or igneous rocks. Encyclopaedia Britannica, 11th Edition, Volume 11, Slice 6 "Geodesy" to "Geometry" 2011-09-19T02:00:10.473Z Felspar is one of the principal constituents of almost all igneous rocks, such as granite, diorite, and basalt. The New Gresham Encyclopedia Volume 4, Part 3: Estremoz to Felspar 2011-04-14T02:00:59.373Z Diabase, originally an equivalent of diorite; then used for chloritic igneous rocks of the Intermediate series of various grain; and now usually for a type of dolerite in which the felspar is embedded in augite. The New Gresham Encyclopedia Volume 4, Part 1: Deposition to Eberswalde 2011-04-14T02:00:57.977Z Principle of Cross-Cutting Relationships: Deformation events like folds, faults and igneous intrusions that cut across rocks are younger than the rocks they cut across. An Introduction to Geology 2017-01-01T00:00:00Z Most of the iron in igneous rocks is contained in mineral, usually silicates, and would be difficult to separate. North America 2011-05-05T02:00:20.027Z Hence he attached but little importance to them, and did not include in his system of rocks any division of volcanic or igneous materials. Encyclopaedia Britannica, 11th Edition, Volume 11, Slice 6 "Geodesy" to "Geometry" 2011-09-19T02:00:10.473Z Felsite, or Felstone, a hard, compact igneous rock of somewhat flinty appearance, composed usually of quartz and orthoclase felspar intimately mixed, but sometimes of less highly siliceous minerals. The New Gresham Encyclopedia Volume 4, Part 3: Estremoz to Felspar 2011-04-14T02:00:59.373Z Diop�side, a calcium magnesium silicate, of the pyroxene series, occurring in igneous rocks and altered limestones, with a vitreous lustre, and of a pale-green, or a greenish- or yellowish-white colour. The New Gresham Encyclopedia Volume 4, Part 1: Deposition to Eberswalde 2011-04-14T02:00:57.977Z In the lowest parts of the Grand Canyon are the oldest sedimentary formations, with igneous and metamorphic rocks at the bottom. An Introduction to Geology 2017-01-01T00:00:00Z When exposed to the air and to percolating water, the iron-bearing minerals of the igneous or other rocks decay and the iron enters into various new combinations. North America 2011-05-05T02:00:20.027Z An igneous mass will stand out as a bold hill from amidst the more decomposable strata through which it has risen. Encyclopaedia Britannica, 11th Edition, Volume 11, Slice 6 "Geodesy" to "Geometry" 2011-09-19T02:00:10.473Z We were still besieged by the igneous element—as completely confined within the circumscribed boundaries of the glade, as if encompassed by a hostile army of twenty times our number—indeed, more so. Osceola the Seminole The Red Fawn of the Flower Land 2011-03-22T02:00:20.123Z The land is of recent geological formation, the principal ranges being composed of igneous rock, and showing traces of much volcanic disturbance. Encyclopaedia Britannica, 11th Edition, Volume 10, Slice 3 "Fenton, Edward" to "Finistere" 2011-03-14T03:01:00.580Z The photo of the Grand Canyon here show strata that were originally deposited in a flat layer on top of older igneous and metamorphic “basement” rocks, per the original horizontality principle. An Introduction to Geology 2017-01-01T00:00:00Z When the heat which produced certain phases of metamorphism is sufficiently increased, greater freedom of molecular and chemical changes occur 327 and the material acted on passes to the condition of an igneous magma. North America 2011-05-05T02:00:20.027Z This substance has been detected in all igneous rocks, especially among the granites, in quantity sufficient, according to the Hon. R.J. Encyclopaedia Britannica, 11th Edition, Volume 11, Slice 6 "Geodesy" to "Geometry" 2011-09-19T02:00:10.473Z In the speculation respecting the igneous origin of trap or granite, the fact does not admit of direct proof, that those substances have been actually subjected to intense heat. A System of Logic: Ratiocinative and Inductive 7th Edition, Vol. II 2011-03-01T03:00:40.557Z I must acknowledge, however, that all these arguments fail of convincing a few geologists of the doctrine of internal igneous fluidity, to the extent above described. The Religion of Geology and Its Connected Sciences 2011-02-28T03:00:28.890Z A nonconformity occurs when sedimentary rock is deposited on top of igneous and metamorphic rocks as is the case with the contact between the strata and basement rocks at the bottom of the Grand Canyon. An Introduction to Geology 2017-01-01T00:00:00Z The rocks referred to have been changed without fusion from a previous condition, during which they were either sedimentary beds or cooled and crystallized igneous magma. North America 2011-05-05T02:00:20.027Z Some of them can be readily recognized as altered igneous masses; others are as manifestly of sedimentary origin; while of many it is difficult to decide what may have been their pristine character. Encyclopaedia Britannica, 11th Edition, Volume 11, Slice 6 "Geodesy" to "Geometry" 2011-09-19T02:00:10.473Z The zeolites occur very commonly in cavities in igneous rocks, and also in mineral veins. Geology 2011-02-20T03:00:12.660Z To prove the original igneous fluidity of the globe, we might have adopted another course of argument. The Religion of Geology and Its Connected Sciences 2011-02-28T03:00:28.890Z Metamorphic processes tend to reset the clocks and smear the igneous rock’s original date. An Introduction to Geology 2017-01-01T00:00:00Z In the case of several of these mines, igneous rock is near at hand, and the ores are believed to owe their concentration largely to the action of heated waters. North America 2011-05-05T02:00:20.027Z It is among igneous rocks that the progressive stages of metamorphism can be most easily traced. Encyclopaedia Britannica, 11th Edition, Volume 11, Slice 6 "Geodesy" to "Geometry" 2011-09-19T02:00:10.473Z What is the nature of the jointing in igneous rocks? Geology 2011-02-20T03:00:12.660Z The unstratified class are all colored red, to indicate their igneous origin. The Religion of Geology and Its Connected Sciences 2011-02-28T03:00:28.890Z However, scientists can use igneous events to date sedimentary sequences. An Introduction to Geology 2017-01-01T00:00:00Z They are probably solid, but in a potentially plastic condition, and become fused and may be forced upward through fissures in the condition of igneous magmas when pressure is relieved. North America 2011-05-05T02:00:20.027Z There is another type of alteration termed “contact-metamorphism,” which is developed around masses of igneous rock, especially where these have been intruded in large bosses among stratified formations. Encyclopaedia Britannica, 11th Edition, Volume 11, Slice 6 "Geodesy" to "Geometry" 2011-09-19T02:00:10.473Z What is the nature of the beds of breccia, conglomerate, ash, and tuff, with which contemporaneous igneous rocks are often associated? Geology 2011-02-20T03:00:12.660Z Tuffs, basalts and other igneous rocks appear also in Montana, Wyoming, California, Oregon, Washington, Idaho, Colorado; also in Central America, the Antillean region and S. America. Encyclopaedia Britannica, 11th Edition, Volume 9, Slice 6 "English Language" to "Epsom Salts" 2011-02-19T03:00:59.807Z Forces involved in tectonic processes as well as gravity and igneous pluton emplacement produce strains in rocks that include folds, fractures, and faults. An Introduction to Geology 2017-01-01T00:00:00Z Economic Importance of the Igneous Terranes.—The igneous rocks, as previously noted, are such as have cooled from fusion. North America 2011-05-05T02:00:20.027Z From their mode of origin this great class of rocks has been called “igneous” or “eruptive.” Encyclopaedia Britannica, 11th Edition, Volume 11, Slice 6 "Geodesy" to "Geometry" 2011-09-19T02:00:10.473Z What is the origin of the vesicular structure in igneous rocks? Geology 2011-02-20T03:00:12.660Z Relevant to our study is the apparent continuation of a distinctive belt of igneous rocks — known as rapakivi granites, which are notable for their texture, mineralogy and chemistry — between North America and Antarctica. Scientist at Work: Answering Questions About Antarctica 2011-01-22T16:00:18Z These requirements place some constraints on the kinds of rock suitable for dating, with the igneous rock being the best. An Introduction to Geology 2017-01-01T00:00:00Z Under the influence of percolating, heated waters, new minerals are formed in sedimentary or igneous rocks, and rocks once metamorphosed may undergo additional changes. North America 2011-05-05T02:00:20.027Z The textures of igneous rocks likewise comprise a wide series of varieties. Encyclopaedia Britannica, 11th Edition, Volume 11, Slice 6 "Geodesy" to "Geometry" 2011-09-19T02:00:10.473Z How may granite be at one and the same time a metamorphic and igneous rock? Geology 2011-02-20T03:00:12.660Z The contemporaneous igneous rocks include olivine basalts, andesites, trachytes, rhyolites and tuffs, which are pierced by the microgranite of the Black Hill and by several vents filled with agglomerate, as near Swanston. Encyclopaedia Britannica, 11th Edition, Volume 8, Slice 10 "Echinoderma" to "Edward" 2011-01-19T03:00:19.027Z Happily, we collected a variety of igneous and metamorphic rocks that will help fill in the hole left by several other unproductive sites. Scientist at Work: Rocks, Zircon Zapping and a Big Shrimp 2011-01-07T21:02:35Z The exceptions, where metamorphosed rocks do not occur beneath sedimentary or volcanic beds, are when igneous intrusions or ancient lava-flows are present at a depth. North America 2011-05-05T02:00:20.027Z Though the igneous rocks occupy extensive areas in some countries, they nevertheless cover a much smaller part of the whole surface of the land than is taken up by the second division or stratified rocks. Encyclopaedia Britannica, 11th Edition, Volume 11, Slice 6 "Geodesy" to "Geometry" 2011-09-19T02:00:10.473Z Fragmental Igneous Rocks.—All the igneous rocks briefly described above are more or less distinctly crystalline in texture. Geology 2011-02-20T03:00:12.660Z The intrusive igneous rocks forming prominent features in the county are divisible into two main groups, which are separated from each other by a considerable interval of time. Encyclopaedia Britannica, 11th Edition, Volume 8, Slice 10 "Echinoderma" to "Edward" 2011-01-19T03:00:19.027Z The deposits at Mount Sirius sit on top of a mesa of Ferrar dolerite igneous rocks, which weather to form curious patterns. Scientist at Work: Rocks, Zircon Zapping and a Big Shrimp 2011-01-07T21:02:35Z While this scheme of classification is based on the succession of sedimentary beds, igneous and metamorphic rocks have a place in it, providing their age can be determined. North America 2011-05-05T02:00:20.027Z Its members are specially distinguished by a prevailing fissile, or schistose, structure which they did not at first possess, and which differs from anything found in unaltered igneous or sedimentary rocks. Encyclopaedia Britannica, 11th Edition, Volume 11, Slice 6 "Geodesy" to "Geometry" 2011-09-19T02:00:10.473Z How do we distinguish the two groups into which igneous rocks are subdivided? Geology 2011-02-20T03:00:12.660Z According to Strabo, it obtained its high estimation amongst the Persians, who were worshippers of fire, from its igneous qualities; and perhaps those virtues for which it hath been styled “the first of stones.” Shorter Novels, Eighteenth Century The History of Rasselas, Prince of Abyssinia; The Castle of Otranto, a Gothic Story; Vathek, an Arabian Tale 2010-12-29T03:00:31.850Z Near faster ice streams, like Byrd Glacier, we found a rich assortment of igneous and metamorphic rocks, probably eroded from the upstream craton, even though the local nunatak geology exposes only Beacon and Ferrar. Scientist at Work: Rocks, Zircon Zapping and a Big Shrimp 2011-01-07T21:02:35Z Although igneous rocks do contain gold, silver, copper, etc., and a large variety of the rarer metals, they are widely disseminated. North America 2011-05-05T02:00:20.027Z The igneous rocks present a considerable range of composition. Encyclopaedia Britannica, 11th Edition, Volume 11, Slice 6 "Geodesy" to "Geometry" 2011-09-19T02:00:10.473Z What are some of the appearances relied upon for distinguishing metamorphic from igneous granite? Geology 2011-02-20T03:00:12.660Z Some of the clasts, literally boulders, show the same kind of complexity that we see in outcrop, with veins of igneous material cutting across older, deformed gneisses. Scientist at Work: Unraveling the History Beneath the Ice 2010-12-28T21:28:12Z His attention was now largely directed to the study of the artificial production of minerals, to the metamorphism of rocks, and to the genesis of igneous rocks. Encyclopaedia Britannica, 11th Edition, Volume 8, Slice 8 "Dubner" to "Dyeing" 2010-12-26T03:00:17.840Z Although the igneous rocks sometimes contain valuable ores, they are in many, if not all instances, due to secondary enrichment and are not a result of primary crystallization from fusion. North America 2011-05-05T02:00:20.027Z They include those masses of mineral matter which, unlike the igneous rocks, can be traced back to a definite origin on the surface of the earth. Encyclopaedia Britannica, 11th Edition, Volume 11, Slice 6 "Geodesy" to "Geometry" 2011-09-19T02:00:10.473Z Define what is meant by contemporaneous and subsequent or intrusive igneous rocks. Geology 2011-02-20T03:00:12.660Z Metamorphic and igneous rocks here show extremely complex structure, which represents a geologic history told in many chapters. Scientist at Work: Unraveling the History Beneath the Ice 2010-12-28T21:28:12Z In the Sanquhar basin there are small outliers of lavas probably of this age and several vents filled with agglomerate from which these igneous materials in the Thornhill basin may have been derived. Encyclopaedia Britannica, 11th Edition, Volume 8, Slice 8 "Dubner" to "Dyeing" 2010-12-26T03:00:17.840Z The igneous rocks themselves furnish desirable building stones, such as granite, diorite, porphyry, diabase, etc. North America 2011-05-05T02:00:20.027Z Yet they included granite, gneiss, basalt, porphyry and serpentine, which, even in his own day, were by many observers correctly regarded as of igneous origin. Encyclopaedia Britannica, 11th Edition, Volume 11, Slice 6 "Geodesy" to "Geometry" 2011-09-19T02:00:10.473Z How does a contemporaneous igneous rock affect the beds upon which it rests? Geology 2011-02-20T03:00:12.660Z From moraine sites near the Miller Range, we sampled an abundance of igneous and high-grade metamorphic rocks, not unlike those found locally in the Nimrod Group. Scientist at Work: Unraveling the History Beneath the Ice 2010-12-28T21:28:12Z But from a cursory inspection I should imagine this particular specimen to be of an igneous nature. The Lighter Side of School Life 2010-12-24T03:00:31.150Z There are extensive regions throughout which the rocks have been changed in a manner similar to the alterations commonly found adjacent to igneous intrusions which, in general, have been brought about in some other way. North America 2011-05-05T02:00:20.027Z In volcanic rocks, and in nearly all other kinds of igneous rocks with the exception of granite, biotite occurs to the exclusion of the muscovite. Encyclopaedia Britannica, 11th Edition, Volume 3, Slice 7 "Bible" to "Bisectrix" 2010-12-20T17:12:05.780Z How are the axes of the prisms in a columnar igneous rock arranged? Geology 2011-02-20T03:00:12.660Z You pass towering, desolate mountains of black and brown igneous rock. Is Yemen the Next Afghanistan? 2010-07-07T00:34:00Z In addition, all the Martian meteorites consist of hard igneous rock; the more fragile sedimentary rock, which is most likely to contain sign of life, falls apart before reaching Earth. NASA team cites new evidence that meteorites from Mars contain ancient fossils 2010-05-04T04:00:00Z The basal portion of the continent, with the exception of certain areas where igneous rocks occur, is formed of metamorphosed terranes. North America 2011-05-05T02:00:20.027Z It dwarfs the Deccan traps, a large igneous province in west-central India. Rise of dinos linked to volcanism 2010-03-23T05:05:00Z A spheroidal structure is occasionally met with amongst some igneous rocks. Geology 2011-02-20T03:00:12.660Z The materials yielding these fossils are embedded in a course volcanic agglomerate which gives rise to crags and is pierced by acid and basic igneous rocks. Encyclopaedia Britannica, 11th Edition, Volume 2, Slice 6 "Armour Plates" to "Arundel, Earls of" The intrusive igneous rocks belonging to this period are widely distributed and form conspicuous features. Encyclopaedia Britannica, 11th Edition, Volume 2, Slice 5 "Arculf" to "Armour, Philip" In this series of mountains built by igneous agencies belongs the great volcanic piles of the Cascade region, of which Mounts Baker, Rainier, Adams, Hood, Jefferson, Mazama, Shasta, etc., are among the leading examples. North America 2011-05-05T02:00:20.027Z In the Mesaba district of Minnesota the Archean consists of a complex of more or less foliated igneous rocks mostly basic in character. Encyclopaedia Britannica, 11th Edition, Volume 2, Slice 4 "Aram, Eugene" to "Arcueil" It is probably both igneous and metamorphic, however. Geology 2011-02-20T03:00:12.660Z Batholite, a mass of igneous rock having no visible floor, and presumed to pass down into some region of the earth's crust where molten rocks at one time prevailed over all others. The New Gresham Encyclopedia. Vol. 1 Part 3 Atrebates to Bedlis It occurs principally in igneous rocks, particularly diorites. The New Gresham Encyclopedia. Vol. 1 Part 2 Amiel to Atrauli In this same connection certain interesting general conclusions have been reached in reference to igneous activity. North America 2011-05-05T02:00:20.027Z Anorthite is an essential constituent of many basic igneous rocks, such as gabbro and basalt, also of some meteoric stones. Encyclopaedia Britannica, 11th Edition, Volume 2, Slice 2 "Anjar" to "Apollo" Lava, basalt, and obsidian are characteristic types of this group of igneous rocks. Geology 2011-02-20T03:00:12.660Z Lava, which flows hot and fluid, from a volcano, and cooling becomes a sheet of solid rock, is an igneous rock. The Geological Story of the Isle of Wight The lowest cretaceous rocks yet found are composed of an arkose, derived in large part from the original igneous mass. The History of Cuba, vol. 1 Such sheets of intruded material cutting across the bedding of stratified rocks, or traversing older igneous or metamorphic terranes, are of common occurrence and are frequently abundant in deeply eroded regions. North America 2011-05-05T02:00:20.027Z In igneous rocks of all kinds it is invariably present in small amounts as minute acicular crystals, and was one of the first constituents of the rock to crystallize out from the magma. Encyclopaedia Britannica, 11th Edition, Volume 2, Slice 2 "Anjar" to "Apollo" Some geologists consider it to be invariably an igneous rock; but, as just stated, it sometimes passes into gneiss in such a way as to lead us to infer its metamorphic origin. Geology 2011-02-20T03:00:12.660Z Some igneous rocks solidify under ground under great pressure, and become crystalline rocks such as granite. The Geological Story of the Isle of Wight It is manifest indeed that the effluvia are destroyed by flame and igneous * heat; and therefore they attract neither flame nor bodies very near a flame. On the magnet, magnetick bodies also, and on the great magnet the earth a new physiology, demonstrated by many arguments & experiments The rocks are mainly crystalline schist, gneiss, granite, etc., together with igneous intrusions, all of which have been intensely folded, crumpled, and broken. North America 2011-05-05T02:00:20.027Z A third group of breccias is due to movement in a partly consolidated igneous rock, and may be called “fluxion-breccias.” Encyclopaedia Britannica, 11th Edition, Volume 4, Slice 4 "Bradford, William" to "Brequigny, Louis" Granite, however, also occurs as an igneous rock. Geology 2011-02-20T03:00:12.660Z Basalt , a dark brown or black igneous rock. Unexplored! As now used by road builders, it embraces a large variety of igneous rocks, chiefly those of fine crystalline structure and of dark-blue, gray, and green colors. The Future of Road-making in America The rocks exposed in the mountains are largely of sedimentary origin, but a characteristic feature is the geology, especially to the west, in the presence of extensive volcanic areas and lofty mountains of igneous rocks. North America 2011-05-05T02:00:20.027Z Of this range the central feature is the mountain of Kinabalu, which is composed of porphyritic granite and igneous rocks and attains to a height of 13,698 ft. Encyclopaedia Britannica, 11th Edition, Volume 4, Slice 3 "Borgia, Lucrezia" to "Bradford, John" Syenite, like granite, is recognised as an igneous as well as a metamorphic rock. Geology 2011-02-20T03:00:12.660Z As this igneous rock weathered with time, the rain and the streams washed it into the ocean. Unexplored! The igneous period of the eruption having terminated on the evening of the 27th, the ashes, lapilli, and projectiles became a little more abundant, whilst the roaring noises of the craters apparently became greater. The Eruption of Vesuvius in 1872 CHARNOCKITE, a series of foliated igneous rocks of wide distribution and great importance in India, Ceylon, Madagascar and Africa. Encyclopaedia Britannica, 11th Edition, Volume 5, Slice 8 "Chariot" to "Chatelaine" The igneous rocks are chiefly granite; and granite is formed of orthoclase-feldspar, mica, and quartz. Nature's Miracles, Volume 1 Familiar Talks on Science—World-Building and Life. Earth, Air and Water. In the British Islands, and many other non-volcanic regions, we find besides crystalline igneous rocks, abundant traces of loose ejectamenta, which clearly prove the former presence of volcanoes. Geology 2011-02-20T03:00:12.660Z Subsequent denudation has removed the sedimentary covering and exposed the igneous core. Encyclopaedia Britannica, 11th Edition, Volume 5, Slice 5 "Cat" to "Celt" Granite, porphyry, and other igneous rocks supposed to have consolidated from a melted state at a great depth from the surface. Principles of Geology or, The Modern Changes of the Earth and its Inhabitants Considered as Illustrative of Geology These are dark slates and thin-bedded grits with enormous masses of interbedded igneous rocks, lavas and ashes, the product of contemporaneous volcanoes. Encyclopaedia Britannica, 11th Edition, Volume 5, Slice 3 "Capefigue" to "Carneades" The metamorphic rocks were primarily igneous and are changed somewhat in their structure by the lapse of time. Nature's Miracles, Volume 1 Familiar Talks on Science—World-Building and Life. Earth, Air and Water. True igneous rocks occur either in beds or as irregular amorphous masses. Geology 2011-02-20T03:00:12.660Z Near the northern foot of the Caucasus, especially in the neighbourhood of the hot mineral springs of Pyatigorsk, a group of hills of igneous rocks rises above the plain. Encyclopaedia Britannica, 11th Edition, Volume 5, Slice 5 "Cat" to "Celt" A group, whether of alluvial deposits, sedimentary strata, or igneous rocks, referred to a common origin or period. Principles of Geology or, The Modern Changes of the Earth and its Inhabitants Considered as Illustrative of Geology They contain a great variety of sediments and igneous rocks. Encyclopaedia Britannica, 11th Edition, Volume 5, Slice 2 "Camorra" to "Cape Colony" The igneous rocks, then, are the lowest of all; then come the metamorphic rocks; and as before stated, on top of metamorphic rock begins the first evidence of life in its lowest form. Nature's Miracles, Volume 1 Familiar Talks on Science—World-Building and Life. Earth, Air and Water. Occasionally they appear to have been the feeders of the great sheets of igneous rock which here and there occur in their vicinity. Geology 2011-02-20T03:00:12.660Z Throughout, the rocks are crystalline and include gneiss, schist, and marble--the metamorphosed equivalents of a large variety of ancient sedimentary and igneous rocks. Drainage Modifications and Glaciation in the Danbury Region Connecticut State of Connecticut State Geological and Natural History Survey Bulletin No. 30 A simple mineral, generally of a deep red color, crystallized; most commonly met with in mica slate, but also in granite and other igneous rocks. Principles of Geology or, The Modern Changes of the Earth and its Inhabitants Considered as Illustrative of Geology The rocks have been greatly changed by pressure in most cases and by the intrusion of great masses of igneous material, the Namaqualand schists and Malmesbury beds being most altered. Encyclopaedia Britannica, 11th Edition, Volume 5, Slice 2 "Camorra" to "Cape Colony" At the period in question the internal temperature of the earth was probably vastly greater than at present, and perhaps the whole interior of the globe may have been in a state of igneous fluidity. The Origin of the World According to Revelation and Science The alteration effected by igneous rocks is generally greatest in the case of intrusive masses. Geology 2011-02-20T03:00:12.660Z The Housatonic, however, instead of choosing the broad lowland in the limestone formation, spread invitingly before it, turns aside and flows through a narrow gorge cut in resistant gneiss, schist, and igneous intrusives. Drainage Modifications and Glaciation in the Danbury Region Connecticut State of Connecticut State Geological and Natural History Survey Bulletin No. 30 The great agents of change in the inorganic world may be divided into two principal classes, the aqueous and the igneous. Principles of Geology or, The Modern Changes of the Earth and its Inhabitants Considered as Illustrative of Geology In Bohemia, North America and Canada igneous rocks have been observed. Encyclopaedia Britannica, 11th Edition, Volume 5, Slice 1 "Calhoun" to "Camoens" I have said that the Bible, which informs us of a universal ocean preceding the existence of land, also gives indications of a still earlier period of igneous fluidity or gaseous expansion. The Origin of the World According to Revelation and Science Chemical changes also take place in the case of many igneous rocks, the result being that a weathered 'crust' forms wherever such rocks are exposed to the action of the atmosphere. Geology 2011-02-20T03:00:12.660Z Contemporary igneous outbursts are extremely common in some of the ancient formations, and add, by their resistance to atmospheric erosion, to the extreme ruggedness of the scenery. Encyclopaedia Britannica, 11th Edition, Volume 9, Slice 4 "England" to "English Finance" The country around Naples, so named by the Greeks, from the traces of igneous action everywhere visible. Principles of Geology or, The Modern Changes of the Earth and its Inhabitants Considered as Illustrative of Geology In the Ardennes the system is represented by grits and sandstones, shales, slates and quartz schists, and includes also whet slates and some igneous rocks. Encyclopaedia Britannica, 11th Edition, Volume 5, Slice 1 "Calhoun" to "Camoens" The form of the earth is just that which an igneous liquid mass would assume if thrown into an orbit with an axial revolution similar to that of our earth. Caxton's Book: A Collection of Essays, Poems, Tales, and Sketches. These form the Fragmental group of igneous rocks. Geology 2011-02-20T03:00:12.660Z Mid Wales is built up, for the most part, of Silurian or Ordovician rocks, practically free from igneous intrusions except in the south-west. Encyclopaedia Britannica, 11th Edition, Volume 9, Slice 4 "England" to "English Finance" "We may recognize, therefore," says Leibnitz, "a double origin of primitive masses, the one by refrigeration from igneous fusion, the other by concretion from aqueous solution." Principles of Geology or, The Modern Changes of the Earth and its Inhabitants Considered as Illustrative of Geology It is superfluous to cite localities for them as they are among the commonest of igneous rocks. Encyclopaedia Britannica, 11th Edition, Volume 8, Slice 6 "Dodwell" to "Drama" It is also an essential constituent of some pyroxene-granites, diorites and a few other igneous rocks, but the characteristic pyroxene of this class of rocks is augite. Encyclopaedia Britannica, 11th Edition, Volume 8, Slice 5 "Dinard" to "Dodsworth" But, for sake of clearness, we have reserved special account of the structure and mode of occurrence of metamorphic and igneous rocks to this place. Geology 2011-02-20T03:00:12.660Z As regards igneous rocks, the Charnwood Forest quarries of Leicestershire, and those of Cornwall, are particularly noted for their granite. Encyclopaedia Britannica, 11th Edition, Volume 9, Slice 4 "England" to "English Finance" So insignificant is the aggregate force exerted by man, when contrasted with the ordinary operations of aqueous or igneous agents in the natural world. Principles of Geology or, The Modern Changes of the Earth and its Inhabitants Considered as Illustrative of Geology They are very remarkable, one part for masses of sheer precipices descending in columns to the sea, the other for the extraordinary contortions which the rocks have undergone from igneous action and huge compressing forces. The Life of William Ewart Gladstone (Vol 2 of 3) Volcanic activity was in abeyance in Europe and in much of Asia, but in America there were many eruptions and intrusions of igneous rock towards the close of the period. Encyclopaedia Britannica, 11th Edition, Volume 7, Slice 6 "Coucy-le-Château" to "Crocodile" There is generally, also, some discoloration both in the pavement of rock upon which the igneous mass lies, and in the under portions of the latter itself. Geology 2011-02-20T03:00:12.660Z Mountains of the Secondary Age were often made of Primary sedimentary rocks, or of Primary igneous rocks, so much changed that geologists call them metamorphic rocks. The Boy With the U.S. Miners It is scarcely necessary to observe, that the control which man can obtain over the igneous agents is less even than that which he may exert over the aqueous. Principles of Geology or, The Modern Changes of the Earth and its Inhabitants Considered as Illustrative of Geology The color was about right, and he knew datolite was found in igneous rocks of volcanic origin. The Flaming Mountain The igneous period of eruption having terminated, the ashes, lapilli, and projectiles became more abundant, accompanied by thunder and lightning. Volcanoes: Past and Present When the igneous rock itself is examined, its upper portions are often observed to be scoriaceous or cinder-like, and the under portions likewise frequently exhibit a similar appearance. Geology 2011-02-20T03:00:12.660Z Even to his relatively untrained eye, this was a place where a volcanic fissure had opened ages ago, allowing igneous rock to thrust sharply upward through the sedimentary layers of the older ground. The Blue Ghost Mystery It has long been a favorite conjecture, that the whole of our planet was originally in a state of igneous fusion, and that the central parts still retain a great portion of their primitive heat. Principles of Geology or, The Modern Changes of the Earth and its Inhabitants Considered as Illustrative of Geology It could be igneous or sedimentary in origin. The Flaming Mountain It is a convenient name for use in the field when doubt occurs as to the real nature of an igneous rock. Volcanoes: Past and Present Not unfrequently, however, an igneous rock will preserve the same texture throughout. Geology 2011-02-20T03:00:12.660Z On the steep slope of igneous rock no grass had managed to get hold, although a few hardy weeds clung to it. The Blue Ghost Mystery Man observes the annual decomposition of crystalline and igneous rocks, and may sometimes see their conversion into stratified deposits; but he cannot witness the reconversion of the sedimentary into the crystalline by subterranean fire. Principles of Geology or, The Modern Changes of the Earth and its Inhabitants Considered as Illustrative of Geology In the form of isolated grains the mineral is a characteristic constituent of ultrabasic igneous rocks, namely the peridotites and the serpentines which have resulted from their alteration. Encyclopaedia Britannica, 11th Edition, Volume 6, Slice 3 "Chitral" to "Cincinnati" Let it be observed, in the first place, that there is no hard and fast line between the varieties of igneous and volcanic rocks. Volcanoes: Past and Present It will be noticed that the contemporaneous igneous rocks form a series of escarpments rising one above the other. Geology 2011-02-20T03:00:12.660Z Except for the igneous outcropping in which the mine is located, this whole valley is sedimentary rock, probably for a depth of several hundred feet. The Blue Ghost Mystery The inclined strata A are the disturbed formations of the Apennines, into which the ancient igneous rocks a are supposed to have intruded themselves. Principles of Geology or, The Modern Changes of the Earth and its Inhabitants Considered as Illustrative of Geology Many altered igneous rocks owe their green colour to the presence of secondary chlorite. Encyclopaedia Britannica, 11th Edition, Volume 6, Slice 3 "Chitral" to "Cincinnati" Lithologically they are crystalline schists, together with granite, diorite, gabbro and other igneous rocks. Encyclopaedia Britannica, 11th Edition, Volume 6, Slice 2 "Chicago, University of" to "Chiton" Contemporaneous igneous rocks are frequently associated with more or less regular beds of breccia, conglomerate, ash, tuff, &c. Geology 2011-02-20T03:00:12.660Z This marked the end of the igneous outcropping in which the lead mine was located, Rick guessed. The Blue Ghost Mystery But we must shut our eyes to the whole economy of the existing causes, aqueous, igneous, and organic, if we fail to perceive that such in not the plan of Nature. Principles of Geology or, The Modern Changes of the Earth and its Inhabitants Considered as Illustrative of Geology Much discussion had centred about fire or the “igneous principle.” Encyclopaedia Britannica, 11th Edition, Volume 6, Slice 1 "Châtelet" to "Chicago" Through the Mesozoic beds are intruded granitic and other igneous rocks of Tertiary age, and upon the folded Mesozoic foundation rise the volcanic cones of Tertiary and later date. Encyclopaedia Britannica, 11th Edition, Volume 6, Slice 2 "Chicago, University of" to "Chiton" The strata are bent down towards the central plug of igneous rock, and are generally more or less altered at the line of junction. Geology 2011-02-20T03:00:12.660Z Great rents had been formed, igneous rocks had boiled up through them; and then in a grand, titanic effort the fire had forced its way up. Silver and Gold A Story of Luck and Love in a Western Mining Camp The small area of volcanic regions may appear, at first view, to present an objection to these views, but not so when we include earthquakes among the effects of igneous agency. Principles of Geology or, The Modern Changes of the Earth and its Inhabitants Considered as Illustrative of Geology It does not occur in distinct crystals with definite outlines, but only as lamellar masses in deep-seated igneous rocks, principally gabbro, of which it is an essential constituent. Encyclopaedia Britannica, 11th Edition, Volume 8, Slice 3 "Destructors" to "Diameter" In all the wide bowl of the great crater top was nothing but dead ashes of fires gone long centuries before, coarse, igneous rock—nothing to set the little nerves of one's spine to tingling. Two Thousand Miles Below Limestones weather much more rapidly than clay-rocks; and augitic igneous rocks, as a rule, disintegrate more readily than the more highly silicated species. Geology 2011-02-20T03:00:12.660Z When we pass from the agency termed igneous, to aqueous and atmospheric agencies, we see the like ever-growing complications of effects. Essays: Scientific, Political, & Speculative, Vol. I Several pieces of shale lay exposed under a fold of igneous rock. The Long Voyage Contemporaneous igneous rocks are generally absent in the American Devonian, but in Nova Scotia and New Brunswick there appear to be some. Encyclopaedia Britannica, 11th Edition, Volume 8, Slice 3 "Destructors" to "Diameter" He had descended a thousand feet, he was estimating, when the black igneous rocks blazed blindingly with a reflected light like that of a thousand suns. The Finding of Haldgren What is the general structure of a contemporaneous igneous rock? Geology 2011-02-20T03:00:12.660Z When the exposed land consists of several unlike kinds of sedimentary strata, or igneous rocks, or both, denudation produces changes proportionably more heterogeneous. Essays: Scientific, Political, & Speculative, Vol. I Rocks may be igneous, which have cooled from a melted condition; or sedimentary, which are made of layers spread one upon another by water currents or waves, or by winds. Boy Scouts Handbook The First Edition, 1911 It was surrounded by huge blocks of orange rock, the igneous rock which is the outstanding feature of the Martian desert landscape. The Martian Cabal Many varieties of rocks are to be found among the gravel pebbles, but the rocks of igneous origin and possessing a considerable degree of hardness generally predominate. American Rural Highways What is the general texture of a contemporaneous igneous rock? Geology 2011-02-20T03:00:12.660Z And finding that igneous action, to which sundry earlier geologists had ascribed basaltic rocks, was in countless places a cause of disturbance, he taught that from it resulted these periodic convulsions. Essays: Scientific, Political, & Speculative, Vol. I Some igneous rocks, especially lavas, are glassy; others are so fine grained that the crystals cannot be seen. Boy Scouts Handbook The First Edition, 1911 A hard skeleton of igneous rock, with clayey soil for flesh, riven and seamed and pitted, crumbling and dusty in the sun, ever disintegrating with wind and water and frost. Rimrock Trail The harder limestones, some sandstones, pebbles from many of the gravel deposits and practically all of the igneous rocks make satisfactory aggregates for the concrete road. American Rural Highways What relation do they occasionally bear to sheets of igneous rock? Geology 2011-02-20T03:00:12.660Z Again, it is fast becoming an acknowledged truth that igneous rock, of whatever kind, is the product of sedimentary strata which have been completely melted. Essays: Scientific, Political, & Speculative, Vol. I Every metal deprived of this igneous principle is immediately reduced to a calx, and thus deprived of its splendour, fusibility, and other properties, until restored again by the readmission of its phlogiston. A Treatise on Foreign Teas Abstracted From An Ingenious Work, Lately Published, Entitled An Essay On the Nerves These vividly green hillocks are probably the craters of long extinct volcanoes, as we were now in the line, and near the centre, of that wide igneous action mentioned in a former chapter. Rambles in the Islands of Corsica and Sardinia with Notices of their History, Antiquities, and Present Condition. The Ceylon sapphires are found in the streams, but originate in rock of igneous origin. A Text-Book of Precious Stones for Jewelers and the Gem-Loving Public What is a neck of intrusive igneous rock, and how have the strata surrounding it been affected? Geology 2011-02-20T03:00:12.660Z It is an established geological doctrine, that sedimentary strata are liable to be changed, more or less profoundly, by igneous action. Essays: Scientific, Political, & Speculative, Vol. I The trap rocks themselves may have been formed in a similar manner, by upward pressure of the igneous fluid beneath, through the veins and fissures formed on the breaking of the solid crust. The American Quarterly Review, No. 17, March 1831 The name is applied in America to a round piece of basic igneous rock. Austral English A dictionary of Australasian words, phrases and usages with those aboriginal-Australian and Maori words which have become incorporated in the language, and the commoner scientific words that have had their origin in Australasia One is tempted to suspect that these stones are of aqueous origin and that sapphires, and beryl, other than emerald, are more likely of igneous origin. A Text-Book of Precious Stones for Jewelers and the Gem-Loving Public Mention some of the contrasts between intrusive and contemporaneous igneous rocks. Geology 2011-02-20T03:00:12.660Z Nature's obvious reply is—They have been destroyed by that igneous action to which so great a part of our oldest-known strata owe their fusion or metamorphosis. Essays: Scientific, Political, & Speculative, Vol. I The conversion of the igneous liquid surface into solid matter, could only have taken place in successive shells or concentric layers; hence would arise a stratified character. The American Quarterly Review, No. 17, March 1831 In the speculation respecting the igneous origin of trap or granite, the fact does not admit of direct proof that those substances have been actually subjected to intense heat. A System Of Logic, Ratiocinative And Inductive More reliable figures for the relative abundance of the minerals are available for each of the two classes of rocks, igneous and sedimentary. The Economic Aspect of Geology But both contortion and faulting may be due, on a small scale, to local causes, such as the intrusion of igneous rocks, the consolidation of strata, the falling in of old water-courses, &c. Geology 2011-02-20T03:00:12.660Z The conception of igneous action has been rationalized, as the conception of aqueous action had previously been. Essays: Scientific, Political, & Speculative, Vol. I But we, even to the present day, occasionally see the igneous fluid from beneath forced up to the surface, and spreading from volcanic craters over great regions. The American Quarterly Review, No. 17, March 1831 Many granitic and volcanic landscapes are variegated in places by accidental beds of sedimentary rock; and conversely occasional sedimentary landscapes are set off by intrusions of igneous rocks. The Book of the National Parks The weathering of sedimentary rocks proceeds along lines already indicated for the igneous rocks. The Economic Aspect of Geology Subdivisions.—In their chemical and mineralogical composition, igneous rocks offer great variety; but they all agree in having felspar for their base. Geology 2011-02-20T03:00:12.660Z Crystals are found as a rarity in the amygdaloidal cavities of igneous rocks. Encyclopaedia Britannica, 11th Edition, Volume 3, Part 1, Slice 3 "Banks" to "Bassoon" The metamorphic sediments have been pierced by acid and basic igneous intrusions, partly before and partly after the folding and metamorphism of the strata. Encyclopaedia Britannica, 11th Edition, Volume 3, Part 1, Slice 2 "Baconthorpe" to "Bankruptcy" The principal one of many igneous rocks, it is liquefied under intense heat and afterward cooled under pressure. The Book of the National Parks An ore formed directly by igneous processes has been called primary, while an ore formed by enrichment of such primary ore by later processes has been called secondary. The Economic Aspect of Geology Granite is recognised as an igneous as well as a metamorphic rock. Geology 2011-02-20T03:00:12.660Z In current usage the term includes a large variety of types of igneous rock belonging to the basic subdivision, dark in colour weathering to brown, and comparatively rich in magnesia and iron. Encyclopaedia Britannica, 11th Edition, Volume 3, Part 1, Slice 3 "Banks" to "Bassoon" In ten years he is proved utterly wrong by that microscopist who has detected animal remains in an igneous rock. The Voyage Alone in the Yawl "Rob Roy" Basalt is an igneous rock composed largely of augite and felspar, which are silicate crystals of calcium, potassium, alumina, etc., of which the Moonstone is a variety. Second Sight A study of Natural and Induced Clairvoyance Or a sulphide deposit originating through igneous agencies may undergo two or three successive enrichments, each successive one secondary to the preceding, but primary to the one following. The Economic Aspect of Geology There has been much difference of opinion as to the origin of granite—some holding it to be an igneous rock, others maintaining its metamorphic origin. Geology 2011-02-20T03:00:12.660Z On the other side, a black and terrible cloud, bursting with an igneous serpentine vapor, darted out a long train of fire, resembling, but much larger than the flashes of lightning. Complete Story of the San Francisco Horror At the other side a black and dreadful cloud, bursting with an igneous serpentine vapor, darted out a long train of fire, resembling flashes of lightning, but much larger.... Historic Tales, Volume 11 (of 15) The Romance of Reality There are no proofs that the igneous rocks were produced more abundantly at remote periods. The World's Greatest Books — Volume 15 — Science The magnetite crystals of these deposits interpenetrate with the other constituents of an igneous rock, commonly of a gabbro type, and the deposits themselves are essentially igneous rocks. The Economic Aspect of Geology Metamorphic granite, then, graduates, as a rule, almost imperceptibly into rocks which are clearly of aqueous origin; while on the contrary the junction-line between igneous granite and the surrounding rocks is always well marked. Geology 2011-02-20T03:00:12.660Z Scientists have advanced many theories concerning the primary causes of volcanoes, and many explanations relating to the igneous matter discharged from their craters. Complete Story of the San Francisco Horror Then volcanoes burst forth; the igneous rocks sent up mountains of liquid flame, and the paste of the streaming porphyry and basalt began to congeal. Bouvard and Pécuchet A Tragi-comic Novel of Bourgeois Life We shall now consider the igneous agents that act on the earth's surface. The World's Greatest Books — Volume 15 — Science The minerals of these deposits are derived from the weathering and erosion of land surfaces, either igneous or sedimentary. The Economic Aspect of Geology Occasionally we meet with igneous rocks which are more or less vesicular and amygdaloidal throughout their entire mass. Geology 2011-02-20T03:00:12.660Z For two hundred years the igneous forces beneath Krakatoa remained dormant; but in September, 1880, premonitory shocks of earthquake were heard in the neighborhood. Complete Story of the San Francisco Horror Traces of it are found in practically all igneous and most sedimentary rocks. Commercial Geography A Book for High Schools, Commercial Courses, and Business Colleges II.—Changes in the Inorganic World now in Progress The great agents of change in the inorganic world may be divided into two principal classes—the aqueous and the igneous. The World's Greatest Books — Volume 15 — Science We can only speculate as to causes of the occurrence of valuable minerals in certain igneous rocks and not in others. The Economic Aspect of Geology Captain DeCastros had withdrawn to a level outcropping of igneous rock and sat staring at the nothing where the greenish-black sky met the pale gray horizon. The Marooner However that may be, metals were brought up with the igneous rocks, and one of these metals is copper. Diggers in the Earth Many caves pierce the igneous rock of the Hawaiian group, some with entrances below the ocean level, and discovered only by accident. Myths & Legends of our New Possessions & Protectorate To the aqueous belong rain, rivers, springs, currents, and tides, and the action of frost and snow; to the igneous, volcanoes and earthquakes. The World's Greatest Books — Volume 15 — Science The common rocks and minerals develop in a general sequence, starting with igneous processes, and passing through stages of weathering, erosion, sedimentary processes, and alterations beneath the surface. The Economic Aspect of Geology It is, in fact, a true igneous rock. Chambers's Edinburgh Journal, No. 458 Volume 18, New Series, October 9, 1852 They are called "igneous" rocks, from the Latin word ignis meaning "fire." Diggers in the Earth Some diseases, he averred, require earthy remedies, others aqueous or atmospheric, and still others, igneous. Primitive Psycho-Therapy and Quackery Whatever the original shape of our planet, it must in time have become spheroidal by the gradual operation of centrifugal force acting on yielding materials brought successively within its action by aqueous and igneous causes. The World's Greatest Books — Volume 15 — Science Mineral products formed by weathering from common igneous rocks include soils, clay, bauxite, and certain iron, chromite, and nickel ores. The Economic Aspect of Geology The volcanic fires have been more active there; and though that may have been thousands of years ago, the igneous rocks in many places look as if freshly upheaved. The Scalp Hunters When the igneous rocks were thrown up to the surface of the earth, they brought various metals with them. Diggers in the Earth How could the facts of geology be recollected, or how, indeed, could they constitute a science without reference to some real or supposed bond of union, some aqueous or igneous theory? Blackwood's Edinburgh Magazine, No. CCCXXXVI. October, 1843. Vol. LIV. The principal discharge is from an orifice thirty feet broad, opening beneath a ledge of igneous rocks, nearly on a level with the bottom of the ravine. The Continental Monthly, Vol. 6, No 3, September 1864 Devoted To Literature And National Policy The deposition of ores of igneous source in the country rock into which the igneous rocks are intruded is a phase of contact metamorphism. The Economic Aspect of Geology "This stone was a brown, igneous rock, its longest axis about eight feet, and on the eastern face, which had an angle of about forty-five degrees, was the deep-cut inscription." The Book of the Damned The Malutis consist of beds of sandstone and shale, overlaid by an outflow of igneous rock from two to five thousand feet thick. Impressions of South Africa The stone formation bears the usual indications of aqueous and igneous deposits, but more of the former than the latter. Official Report of the Niger Valley Exploring Party Poetry of the second degree is like the secondary rocks of modern geology,—a still, gentle, alluvial formation: the igneous glow of primary genius brings forth ideas like the primeval granite, simple, astounding, and alone. Harvard Classics Volume 28 Essays English and American The great deposits of Rio Tinto, Spain, which produce about half of the world's pyrite, were formed by replacement of slates by heated solutions from nearby igneous rocks. The Economic Aspect of Geology It is to the metamorphic formation that the abundance of mineral ores is due, and the igneous rocks which have given rise thereto—the granites, basalts, diorites, porphyries, and others. Mexico Its Ancient and Modern Civilisation, History, Political Conditions, Topography, Natural Resources, Industries and General Development The summit of Machacha is composed of a dark igneous rock, apparently a sort of amygdaloidal trap, with white and greenish calcareous crystals scattered through it. Impressions of South Africa Near the base of the volcanic series intrusive igneous rocks of Carboniferous age appear in the form of sills and bosses, as, for instance, the oval mass of olivine-basalt on Suidhe Hill. Encyclopaedia Britannica, 11th Edition, Volume 4, Part 4 "Bulgaria" to "Calgary" His observations on the igneous rocks of south Tirol compared with those of Christiania afford much information on the relations of the granitic and basic rocks. Encyclopaedia Britannica, 11th Edition, Volume 4, Part 3 "Brescia" to "Bulgaria" Granite and basalt as technically defined are very common igneous rocks,—so common that the names are sometimes used to classify igneous rocks in general into two great groups, the granitic and the basaltic. The Economic Aspect of Geology The igneous theory assault the aqueous theory with the greatest heat; while the aqueous theorists pour cold water, in torrents, upon the igneous men. Fables of Infidelity and Facts of Faith Being an Examination of the Evidences of Infidelity Chrysor was the great igneous power of Nature, and Baal and Malakarth representations of the Sun and Moon, the latter word, in Hebrew, meaning Queen. Morals and Dogma of the Ancient and Accepted Scottish Rite of Freemasonry It is a common product of alteration in igneous rocks, and frequently occurs as well-developed crystals in association with zeolites lining the amygdaloidal cavities of basaltic and other rocks. Encyclopaedia Britannica, 11th Edition, Volume 4, Part 4 "Bulgaria" to "Calgary" The crystals are found attached to the walls of cavities in decomposed igneous rocks and crystalline schists; it is also found as minute isolated crystals in many sedimentary rocks. Encyclopaedia Britannica, 11th Edition, Volume 4, Part 3 "Brescia" to "Bulgaria" It has been estimated that about 65 per cent of the igneous rocks are of the granitic group and 35 per cent of the basaltic group. The Economic Aspect of Geology Thousands of miles of the earth's surface must once have presented the lurid glow of a vast furnace full of igneous rocks. Fables of Infidelity and Facts of Faith Being an Examination of the Evidences of Infidelity Agriculture by the hand, then, and absolute refusal or banishment of unnecessary igneous force, are the first conditions of a school of art in any country. Lectures on Art Delivered before the University of Oxford in Hilary term, 1870 Like labradorite and anorthite, it is a common constituent of basic igneous rocks, such as gabbro and basalt. Encyclopaedia Britannica, 11th Edition, Volume 4, Part 4 "Bulgaria" to "Calgary" Like an igneous phantom, a witch flame, it rose, higher, higher, higher, to what I adjudged to be some twelve feet or more from the ground. The Devil Doctor Pegmatites are closely related to igneous after-effects, discussed under the next heading. The Economic Aspect of Geology Basalt is a brown rock of igneous origin. A Journey to the Centre of the Earth Shouldn't have known where to look for you either, after this storm among the aqueous or the igneous rocks. Melbourne House We can not well believe that water could have formed a part of the deeper earth in the old days of original igneous fusion. Outlines of the Earth's History A Popular Study in Physiography It exhibits extraordinary signs of commotion and vicissitude; the lowest rocks indicating a previous condition of igneous fusion; those above them of aqueous solution. An Expository Outline of the "Vestiges of the Natural History of Creation" With a Notice of the Author's "Explanations:" A Sequel to the Vestiges As a whole, the mineral products formed directly in igneous rocks constitute a much less important class than mineral products formed in other ways, as described below. The Economic Aspect of Geology Iron, lead, or any mineral, in a state of igneous solution, will run, has the same inclination to run as water, or any other liquid. Lectures on Language As Particularly Connected with English Grammar. The Catoctin Belt itself may be described as a broad area of igneous rocks bordered by two lines of Lower Cambrian sandstones and slates. History and Comprehensive Description of Loudoun County, Virginia We had reached the village of Hassané, opposite to a conical hill named Chisulwé, which is on the south side of the river, and evidently of igneous origin. The Last Journals of David Livingstone, in Central Africa, from 1865 to His Death, Volume I (of 2), 1866-1868 There were mountains everywhere—huge, rugged mountains, erected in the igneous fury of world-making, long since calmed. The Furnace of Gold These become deposited in openings in adjacent rocks, or replace them, or are deposited in previously hardened portions of the parent igneous mass itself. The Economic Aspect of Geology Haloes are not found in the younger igneous rocks. The Birth-Time of the World and Other Scientific Essays Over the surface of the igneous rocks are scattered occasional outliers of the Lower Cambrian slate; but far the greater part of the surface of the belt is covered by the igneous rocks. History and Comprehensive Description of Loudoun County, Virginia Mica schist crowned some of the heights on the watershed, then gneiss, and now, as we descend further, we have igneous rocks of more recent eruption, porphyry and gneiss, with hornblende. The Last Journals of David Livingstone, in Central Africa, from 1865 to His Death, Volume I (of 2), 1866-1868 When we pass from the agency which geologists term igneous, to aqueous and atmospheric agencies, we see the like ever growing complications of effects. Essays on Education and Kindred Subjects Everyman's Library Among the valuable minerals of the igneous after-effect class are ores of gold, silver, copper, iron, antimony, mercury, zinc, lead, and others. The Economic Aspect of Geology Keeping the figures to round numbers we find that this amount of sodium involves the denudation of about 80 x 1016 tonnes of average igneous rock to 53 x 1016 tonnes of average sediment. The Birth-Time of the World and Other Scientific Essays The igneous rocks have also been much folded and crumpled, but on account of their lack of distinctive beds the details of folds can not well be traced among them. History and Comprehensive Description of Loudoun County, Virginia As at Chilolé hill, we have igneous rocks, apparently trap, capped with masses of beautiful white dolomite. The Last Journals of David Livingstone, in Central Africa, from 1865 to His Death, Volume I (of 2), 1866-1868 When the exposed land consists of several unlike formations, sedimentary and igneous, the denudation produces changes proportionably more heterogeneous. Essays on Education and Kindred Subjects Everyman's Library The same weathering processes described above for igneous rocks cause considerable changes of economic significance in deposits formed as igneous after-effects. The Economic Aspect of Geology The viscous movements of siliceous materials, and the out-pouring of igneous rocks which often attend mountain elevation, would find an explanation in such temperatures. The Birth-Time of the World and Other Scientific Essays The formation, though developed in the Piedmont plain, bears upon the history of the Catoctin Belt by throwing light on the periods of degradation, deposition, igneous injection, and deformation that have involved them both. History and Comprehensive Description of Loudoun County, Virginia As we come down from the watershed towards Tanganyika we enter an area of the earth's surface still disturbed by internal igneous action. The Last Journals of David Livingstone, in Central Africa, from 1865 to His Death, Volume I (of 2), 1866-1868 The whole region is as certainly of igneous origin, and was the centre of as violent fiery action, as the vicinity of Naples. Roman Mosaics Or, Studies in Rome and Its Neighbourhood The former term is also applied to less profound changes in connection with igneous intrusions, which result merely in cementation without mashing. The Economic Aspect of Geology The exotic materials may be dolomites, limestones, schists, sandstones, or rocks of igneous origin. The Birth-Time of the World and Other Scientific Essays The metamorphism of the igneous rocks is regional in nature and has the same increase from west to east as the sediments. History and Comprehensive Description of Loudoun County, Virginia Is there any such thing as an igneous fluid? The Atlantic Monthly, Volume 13, No. 78, April, 1864 It was laid down close to the igneous Archaean rocks when Mother Earth was in her girlhood and water first began to flow. Among the Forces The phase of metamorphism dealing with the constructive changes in rocks, due to cementation, dynamic movements, and igneous influences, is called anamorphism. The Economic Aspect of Geology The earliest mountains arose as purely igneous or volcanic elevations, but the generations of the hills soon originated in the collection of the _débris_, under the law of gravity, in the hollow places. The Birth-Time of the World and Other Scientific Essays Reverse a portion, and give an igneous rock. St. Nicholas, Vol. 5, No. 5, March, 1878 |
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