Structural characterister of a huge Paleoproterozoic stromatolite in Mt. Wutai, and its genetic implication
五台山古元古代巨型叠层石的结构特征及成因意义

The Paleoproterozoic Hutuo Group in Mt. Wutai of Shanxi Province yields various types of stromatolite with different size and morphology. Recently a huge stromatolite was discovered in the stratas of Dongye Subgroup there. After morphologic and ultra-structural morphologic characteristic analysis, geological profile measured and relative growing environment analysis, the "domal" stromatolite in macroscopic view is actually a bioherm composed of large amounts of columnar stromatolites which radially grew on the surface of an initial sediment. The round salients and long-strip-shaped ridges on surface are cross and inclined sections of the stromatolite columns. Microcrystalline calcites composing the columns as well as filling space among columnsand are observed in sections under polarizing microscope, so are the remains of tenuous filamentous microorganisms which interweave together to form up the dark layers. The huge architectural mass requires basically a long-period stable environment with deep water. The well-crystallized microcrystalline calcites indicate that the growing environment was warm shallow sea with weak hydrodynamic condition and high deposition rate, perhaps the subtidal zone.