Excluding fossils, McSween says, a quartz-rich sandstone is probably one of the most Earth-specific rocks imaginable—creating one would require plate tectonics, erosion, and water.

麦克斯温说，除去化石，富含石英的砂岩可能是我们所能想象到的最具地球特色的岩石之一——要想形成这样的砂岩，需要板块构造、侵蚀和水的作用。