The Response Of Elemental Geochemistry To Depositional Environment And Its Petroleum Geological Significance:the Lower Cambrian In Kalpin,Tarim Basin

There are relatively few studies on the Lower Cambrian depositional environment in Kalpin area of Tarim Basin and whether where growth conditions of source rock exists from the perspective of elemental geochemical,and currently,it is still in dispute over whether the Xiaoerbulak Formation is a potential source rock.Based on analysis of test results of elemental geochemistry?trace elements,REE and carbon-oxygen isotopes?to recover sedimentary environment factor,this paper analyses its geological significance combined with experimental measurement data of TOC and micro-animal fossil identification.Having studying the changes in the content of elements,preliminary understanding obtained is as follows:?1?Non-correlation between trace elements and REE,?¹³C and?¹⁸O indicates that the sample is less affected by diagenesis,and the data can reflect the real environment during the deposition period.?2??LREE/?HREE reflects that change of LREE content determines change of total REE.?La/Yb?_N,?La/Sm?_N,?Gd/Yb?_N and Chondrite standardization model diagram reflect high inclination of standard curve.Obviously,the curve is right-trending,and Eu is"V"type,which is negative anomaly.?3?Yuertus Formation,the Lower Section of Xiaoerbulak Formation,experienced the whole process of regressions and retrogressions,and it was in sea salt water environment where the climate is gradually dry and hot,ancient productivity was on higher level and Oxygen is scarce.?4?Based on environment factors,combining with TOC and micropaleontology data,rock in the Yuertus Formation can be recognized as high quality source rock,and the Lower Section of Xiaoerbulak Formation,potential source rock.Literally,Kalpin area can be as fine hydrocarbon potential zone.Vertically,source rock in the central part of Yuertus Formation is better than which in the upper part of the Lower Section of Xiaoerbulak Formation.