Re-study On 'Shuiyougou Biota' From Neoproterozoic Shales Of The Ruyang Group In Western Henan

'Shuiyougou Biota' is well exposed in the Beidajian and Baicaoping Formations of Ruyang Group in western Henan,and rich in acritarchs with complex ornament.This Biota has been studied for several years,in which a lot of results were made by predecessors.However,it was not studied thoroughly in paleontology,stratigraphy and isotope chronology,resulting that we have not yet found a fossil assemblage can be compared with the 'Shuiyougou Biota' in the world.Furthermore,the geological age of the 'Shuiyougou Biota' has not been solved,which is due to the lack of precise isotopic age data.Therefore,we chose to study the "shuiyougou" in western Henan province in this dissertation.We did a systematic geological survey,during which we collected all kinds of specimens that we thought might be connected with this study.We first did a series of optics-and electron-microscopic observation of these fossils.Detrital zircon LA-ICPMS U-Pb dating and biomarker-research were also carried out simultaneously.Through all these studies,we hope to get some new evidences about the geochronology and paleo-environmental background of the biota.In this dissertation,we present these several new findings as follows.1.'Shuiyougou Biota',however,has been only obtained from Shuiyougou section in Yongji County,Shanxi province and Maijingou section in Mianchi County,Henan province.Recently,it was found from the shales of Baicaoping Formation at Luoquancun section in Ruzhou,Henan province.This discovery not only expands the range of their distribution,but also provides new materials for paleogeographic environment study.2.Using the scanning electron microscope(SEM),with the traditional optical microscope,the author systematically studied the 'Shuiyougou Biota':?re-combing the Genus Shuiyousphaeridium,and established a new species Shuiyousphaeridium bicrurium sp.nov.;?The diagnosis of Dictyosphaera delicata was amended,that the wall on the face of membrane shell is composed of polygon ridges and film;? Through the comparative study of the fossil specimens under the scanning electron microscope(SEM)and the optical microscope observation,it appears that Dictyosphaera delicata is likely to be the Shuiyousphaeridium,from which the processes are completely off;?The author used petrological thin sections for the first time in the area,which filled the blank of paleontological research methods of this region.3.This paper carried out the measure on detrital zircon age from the Ruyang Group.The youngest age is 978±Ma,which reflects the depositional age.And the author compared the'Shuiyougou Biota' with the similar fossil assemblage from the Torridon Group,NW Scotland,It shows the depositional age may be the early Neoproterozoic.4.The author firstly attempted to use the distribution and characteristics of biomarkers to explore the depositional environment of 'Shuiyougou Biota'.The results of the organic geochemical analysis and the content of the element B,show the depositional environment of Ruyang Group is a marine depositional setting.