Megafossils And Stratigraphy Of The Late Precambrian Strata In Eastern Margin Of The North China Platform

This thesis is resulted from the synthetical studies of the LatePrecambrian strata and megafossils in eastern margin of the North ChinaPlatform(including southern Eastern Liaoning Peninsula, Northern Anhuiand Jiangsu Provinces). The author has reinterpreted the geologicalrecords such as sequences and sedimentary environments of the strata, megafossils, geochemical data, paleogeomagnetic materials,chronostratigraphic and biostratigraphic data and made the firstmicroscopic observation of the megafossils from the Late Precambrianstrata under a fluoromicroscope.The succession of various lithostratigraphic formations of the Neo-proterozoic strata in the south Liaoning Province and Xuzhou-Huainanarea has been confirmed and revised after paying particular attention tothe field markers of outcrop sequence stratigraphy and megafossilsdistribution. A new scheme of biostratigraphic correlation has beenproposed from the view-point of the four evolution stage of themegafossils (including macroscopic algae, paramedusoid, vermes) subdividedas follows: (1) Liulaobei-Diaoyutai and Nanfen-Luotuoling period withthe character of some large macroscopic algae fossils; (2) Jiuliqiao-Changlingzi and Nanguanling peroid flourishing various vermes fossilsaccompanied by some macroscopic algae fossils; (3) Jiudingshan, Zhangquand Weiji-Yinchengzi, Shisanlitai and Majiatun period emerging a largenumber of macroscopic algae fossils distributed in the thin blackcarbonic rocks mostly belongs to CS sector after transgressive systemstract; (4) Wangshan-Xingmingcun period with enormous paramedusoidmetazoans in Xingmingcun Formation floating on sea basin far away fromoffshore.By means of analysing the microscopic characteristic of themegafossils under transmissive-light and fluorescent-light microscopes,the author has proposed some ideas explained as follows: (1) themegafossils of Late Precambrian in this area were almost multicellularorganism fossils; (2) a portion of the chuaria fossils might group tovolvox algae of green alga because of the characteristic of tiny ballsimilar to multicellular feature; (3) the thin sections of themacroscopic algae fossils show small polygon net shape mostly similar tothe pseudofilm character of brown alga; (4) worms and paramedusoidssections appear some approaching circle morph of cellular level might bemulticellular morph of the metazoans.