| 中国西南及其邻区生物礁的分布与沉积相古构造的关系 |
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| 引用本文： | 江宗龙,李钟模.中国西南及其邻区生物礁的分布与沉积相古构造的关系[J].化工矿产地质,1993(1). |
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| 作者姓名： | 江宗龙 李钟模 |
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| 作者单位： | 化工部化学矿产地质研究院
(江宗龙)，化工部化学矿产地质研究院(李钟模) |
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| 摘 要： | 中国西南及其邻区晚震旦世晚期、早寒武世、早奥陶世、早志留世、中泥盆世、早、晚二叠世、中三叠世为主要成礁期,生物礁的分布与沉积相、古构造相关,其主要受成礁期同生断裂控制。
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| 关 键 词： | 生物礁 沉积相 古构造 中国西南地区 |
RELATION OF DISTRIBUTION OF BIOHERMS TO SDEIMENTARY FACIES AND PALAEOTECTONICS IN SOUTHWEST CHINA AND ITS NEIGHBOURING AREAS |
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| Abstract: | Bioherms are widespread in the marine sequences of the studied area;the reef-forming periods mainly include Dengying Stage(Z_d),Early Cambrian,EarlyOrdovician,Early Silurian,Middle Devonian,Late Permian,and Middle Triassic.Although in the recent twenty years,a number of experts have applied the newtheory about carbonatite,with reference to modern reefs,to researches on thebioherms in the studied area with remarkable achievements,a few problems stillremain unsolved,such as how to combine the reef-forming aspects with the reef-forming periods in this area so that a systematic study and summary of them ismake.The purpose of the present paper is to expound the character and regularity inthe distribution of bioherms in this area according to palaeogeography,sedimentary facies,palaeotectonics and reef-forming process.Form Figs.1-8(showing paleogeography of main reef-forming periods anddistribution of deep faults in the studied area),it may be concluded that:1.In this area the back-reef sedimentary facies is generally semirestrictedplatform facies,sometimes developed with evaporite facies,while the reef-frontsedimentary facies is usually basin facies or platformal basin facies.2.The distribution of the reefs often shows very strong orientation.3.The reefs are always situated at or nearby places where the thickness of stratachanges strongly.4.These reefs tend to occur in the conjoining zone between paleotectonic“units”with obvious difference in activity or along the tectonized deep fracture.The above facts suggest that the type and distribution of the reefs are mainlycontrolled by synsedimentary faults,besides“palaeo-uplifts”and sedimentary facies.Based on this understanding,to make a deepgoing study of the new problemabout the reefs,(for example,why the distributions of the reefs may be the same andalso different in different reef-forming periods)would inevitally get into researcheson the synsedimentary fault.The monement of synsedimentary fault,according to a great amount of data,hasits own regularity:the active period of synsedimentary fault is subordinate to certaintectohic stage or substage;for example,the active period of the northeastwardZhenyuan Nandan synsedimentary fault is limited to Early Palaeozoic,while that ofthe northwestward Ziyun-Duan synsedimentary fault is in the Late Palaeozoic.So,we have arrived at another understanding that is the formation anddistribution of reefs in reef-forming periods belonging to the same tectonic stage canreflect similar features,such as the reefs formed in the Dengying stage,EarlyCambrian and Early Ordovician.When the tectonization of the studied area entered into another new tectonicstage or substage,the synsedimentary fault belonging to an earlier tectonic stage orsubstage had become a“dead”one,with no controlling effect on the reefs.Insteadanother strikingly different synsedimentary fault would play an unnegligible role incontrolling the distribution of these reefs,such as those of the Middle Devonian. |
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