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Sedimentary Facies And Sequence Palaeogeography Research Of Xujiahe Formation In Western Sichuan Depression

Posted on:2012-07-12Degree:MasterType:Thesis
Country:ChinaCandidate:X H ChenFull Text:PDF
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Sedimentary facies and paleogeographic of upper Triassic Xujiahe Formation is researched in this dissertation. On the basis of research results of previous studies, make full use of outcrops, Drilling cores, Well logging, on the guiding of sedimentology, tectonics, and the principle of basin analysis, Stratigraphic classification and contrast, characteristic of sedimentary system, characteristic and evolution of paleogeographic is analysed detailedly. The thesis has gained the followinig achievements:1. Merging and dividing the stratigraphy of late Triassic, and name unitedly Xujiahe Formation which is divided five sections. After researching the sequence interface type and characteristcs, Xujiahe Formation is divided into threee tectonic sequence which is divided by the most pan of lakes or seas surfaces. All of the tectonic sequence can be divided into two system tracts which are basin expansion system tracts and basin contraction system tracts.2. Studies suggest that six sedimentary system has been recognized, that is alluvial system, lak system, lak deltas, the sea land transition system, a barrier coast and carbonate platform. The characteristic of all sedimentary facies is discussed detailedly.3. Xujiahe Formation tectonic sequence lithofacies-paleogeographic diagram is systematically created using the systems tracts of tectonic sequence as compilation unit in this dissertation. The results show that sedimentary facies distribution and paleogeographic evolution of each sedimentary period of upper Triassic Xujiahe Formation in Western Sichuan Depression is closely related to regional tectonic movement. In the process of transformation form Passive Continental Margin to foreland basins, the sedimentary enviornment is changed from marine to continental by the sea land transition. With different strength of tectonic movements, the sedimentary facies of the differential development type and plane exhibition is a different response cloth. TS1-BE(Maantang Formation)is marin, TS1-BW(Xiaotangzi Formation) is sea land transition, TS2-BE~BW (second and third section,T3x2-3) is sea land transition, TS3-BE~BW (fourth and fiveth section,T3x4-5) is continental, Anxian Tectonic Movement is the key period of marin convert to continental.
Keywords/Search Tags:Western Sichuan Depression, Xujiahe Formation, Sedimentary facies, Palaeogeography
PDF Full Text Request
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