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The Characteristics And Origin Of South Ordos Basin Chang7 Margin Facies

Posted on:2017-12-23Degree:MasterType:Thesis
Country:ChinaCandidate:J LiFull Text:PDF
GTID:2310330482498576Subject:Mineralogy, petrology, ore deposits
Abstract/Summary:PDF Full Text Request
In recent years,with the increase in the difficulty of oil-gas exploration and development,accelerate the process of science and technology and the rapid development,continental lake basin research come into a new and higher stage at home and abroad.The southern margin of Ordos basin is located in transition zone between the stable Ordos Basin and Qinling Qilian orogenic belt,the research of the characteristics of sedimentary facies distribution about Ordos Basin and palaeo lacustrine basin margin tectonic evolution has always been paid attention.Especially for the sedimentary facies and basin boundary,there has been controversial.This is a certain restriction to the tectonic evolution and the exploration and development of the resources in Ordos Basin.In this study we search the stratigraphic data of the southern margin of Ordos Basin and its adjacent areas,observations of the typical field profile,and collect data of the lithology in the field,combined with the theory of sedimentology and geophysical,we discuss the Late Triassic southern margin of Ordos Basin maximum Lake flooding period is also a Chang 7 lacustrine basin margin facies characteristics and provenance,meanwhile combined with the tectonic activity of Late Triassic southern margin of Ordos Basin,we analysed the cause of marginal facies of southern margin.By searching and analysing for the marginal sedimentary facies we think that it mainly developed alluvial fan depositional system,fan delta depositional system,braided river systems and braided river delta sedimentary system in the southern margin of Ordos Basin in Chang7 period.Because of that Chang7 period is the large range of lake transgression period,so that basin evolution effect the marginal depositional system.Combine with the tectonic activity,we analysis the origin of the basin margin facise.From the study we can see tectonic stress and stratigraphic distribution characteristics mainly effect the formation of the margin facise.Tethys stress from the south of the basin is the important reason for the asymmetric structure and non-equilibrium deposition process of the basin and make the northeast wing of the basin width slow,southwest wing of the basin steep dip.Different tectonic attributes make the component of the basin different and make the settlement center of Chang7 period deviation to southwest.
Keywords/Search Tags:Ordos Basin, Marginal facies, Sedimentary characteristics
PDF Full Text Request
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