Abstract:

Most people usually pay more attention to the gravitative compaction when they study the compaction of carbonatesediments than to the compaction from side pressure. By studying algal oolites in algal oolitic grainstone of Middle-Upper Devonian, Gan Dong Zi, Tian Lin, Guang Xi, this article thinks that the changes in shape and direction of algal oolites are caused not by the gravitative compaction but by Yin Zhi (Yan Shan )movement after Middle Triassic The factors controlling the changes in shape and direction of algal oolites are tectonic compaction，early cementation，composition of grains，gravitative compaction，and dissolution-filling etc.，of which the tectonic compaction，early cementation and composition of grains are main factors.

Key words: Algal oolitic grainstone, Changes in shape and direction of algal oolites, Tectonic compaction, Carbonate rocks, Petrology, Middle-Uppeer Devonian