Mirror symmetry of petroleum occurrences is due to multistage-accumulation and remigration.

油气地球化学特徵性相似性与成藏多期性及油气运移对称性密切相关。

The observed deltas are highly two-dimensional in planform, adopting palmated structures which retain throughout their evolution a high degree of mirror symmetry.

实验观察到的三角洲，为一高度二维蹼狀发展且镜面对称的构造。