Early Paleozoic Stratigraphic Division And Contradistinction Study In Zhongwei And Around Areas

Zhongwei of Ningxia and its adjacent areas locate in the Giant north and Southtectonic belt in central and Western China，lies between North China Craton andAlashan，locate in the triangle among Alashan, Erdos and Qilian-Qaidam massif. It isa part of China’s East and West tectonic, the northern end of the stratigraphic andgeomorphic demarcation line，and thickness changed rapidly with geophysical crustal.It has a unique feature on the direction of the structure, sedimentary formation andstrong tectonic movement.（1）On the basis of previous studies, Zhongwei in Ningxia and its adjacent areasare divided in the paper. It reviewed on the controversial issue, established divisionand comparison scheme of Zhongwei and its adjacent areas of Early Paleozoic strata.The Cambrian strata according to the International Stratigraphic years stablepublished in2012，changed the3division scheme before into4division series of10order. Meanwhile, the Xiangshan group are put under the Cambrian third series andFurongian. Some abandoned group name are no longer used. It compared with theErdos stratigraphic region partition. There are some indication on the affinity of plate.Ordovician strata refer to issue of the international stratigraphic years representativepublished in2012，using3series7stages divideing. The peper analysised theOrdovician strata in the study area systemativily，compared with the Erdosstratigraphic area partition. On the basis of above, the paper has completed the leozoicstrata comparison scheme of Zhongwei and its adjacent areas.（2）The paper selects the typical section of research area, based on existingregional geological data and former research, combined geological investigation infield、Early Paleozoic lithologic identification under the microscope slices、comprehensive analysis of indoor、Zhongwei and the surrounding areas of Paleozoic strata profile measured，drawed3paintings of Zhongwei and its adjacent areas of fieldmeasured stratigraphic section column（1:2000）。（3）The paper establishes correlation paleobiological strata in Zhongwei andneighboring areas，thus it can be seen：①The middle section of Helan mountain areahas Yangtze and North China in the Early Cambrian;②Biology in middle Cambrianof Helan mountain area has characteristics of an affinity for North China and Qilian;the Helan mountains in the early Ordovician biological pro-North Chinacharacteristics;③Biology in Helan mountain area of Early Ordovician biological hascharacteristics of an affinity for North China.④Biology in Helan mountain area ofMiddle Ordovician has characteristics of an affinity for creatures with North Chinaand Yangtze；Biology in Helan mountain area of the late Ordovician hascharacteristics of an affinity for Yangtze. Helan mountain area of Middle Ordoviciancreatures with North China and Yangtze affinity characteristics（4）Ordovician source mainly Neoproterozoic and early Paleozoic geologicalbody In the study area，Early Paleozoic zircons mainly came from the northern area ofQilian, The Neoproterozoic components mainly from Alashan area，almost nocontemporaneous north western margin of Erdos Miboshan formation stable zirconage distribution。（5）Detrital zircon age the ancient biological affinity indicate：Early Mesozoicprovenance comes from the North Qilian orogenic belt，the Neoproterozoicprovenance from the Alashan micro-block；at this moment，the North Qilian orogenicbelt (ARC) is closed to the Alashan micro-blockduring the basin graduallydisappear.In addition to phylogenetic distribution of the study area the tillite on platealso has a certain instruction significance.