| 北京西山及邻区下古生界白云石化与层序地层 |
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| 关键词:dolomitization Cambrian Ordovician Western Hills Beijing and Its adjacent areas |
| 基金项目:国家科学技术部“九五”攀登计划专项(95-专-04) |
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| Lower Paleozoic Dolomitization in Western Hills of Beijing and Its Adjacent Areas and Its Relationship with Sequence Stratigraphy |
| During the study of the Lower Paleozoic sequence stratigraphy in Western Hills of Beijing and its adjacent areas in the last decade,the authors studied dolomitization, its relation to sedimentary environments and sequence stratigraphy. Four new considerations are obtained as follows: ①According to the dolomitization in mud-stripe limestone, micrite limestone and grainstone,the existence of clay minerals(muds) was an important accelerant in dolomitization. ②The formation of the “abnormal debric like limestone” in the lower part of Changping Formation in Western Hills of Beijing is related to dolomitization. ③Trace fossils in bioturbited limestone have been heavily reformed by dolomitization. ④Rudaceous structure and discontinuous ribbon strutucres in rudaceous oolite limestone are not necessarily primary structures and some of the "gravels" are products of penecontemporaneous dolomitization. According to the formation condition of dolomite, the authors have reached the following conclusions:①In the cycle of thick bedded algae lamellar limestone bioturbited limestone dolomitic limestone dolomite in Majiagou Formation,dolomite constitutes the top of this kind of parasequence. ②The upper part of Sanshanzi dolomite was formed during late HST at the end of Cambrian, and its correlated stratum, the micrite mound located along Beijing Laiyuan Hunyuan, is the sediment of LST.This suggests that when regression took place at the end of Cambrian, the areas where micrite mound is now located were sea areas, whereas the areas where Sanshanzi dolomite is now located were not sea areas. These viewpoints are valuable in studying sediment environments and sequence stratigraphy. |
| PENG Yang,ZHANG Yu-xu.2000.Lower Paleozoic Dolomitization in Western Hills of Beijing and Its Adjacent Areas and Its Relationship with Sequence Stratigraphy[J].Acta Geoscientica Sinica,21(1):78-85. |
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