摘要
我国东部下第三系发育齐全、分布广泛、沉积巨厚,蕴藏着丰富的石油及天然气矿藏。正确地认识、划分与对比第三系,对石油普查勘探有重要意义。本文涉及的范围大致为大兴安岭、太行山、巫山、雪峰山以东的广大地区,包括我国部分海域。台湾的古新世海相沉积,由于资料少,没有列入。
Abstract
The Paleocene Epoch was important in the evolution history of the mam-mal and vice-versa,the later is important to the division of the former.ButCenozoic basins in Eastern China are always rich in microfossils while mammalscould seldom be found,that is why the study of micropaleontological assem-blages has become the key point to the stratigraphic division and correlation.Nanxiong Basin,Guangdong Province,is not only rich in mammal fossils,but also has plentiful microfossils.The Shanghu Formation,as the representa-tive of the Middle-Lower Paleocene,and known in rich Bemalambda assemblage,is associated with ostracods mainly represented by , taizhouensis and with radial sulcus.These ostracods,with some mem-bers of the make up a transitional type of the Meso-Cenozoic Porpocy-pris-- assemblage;while in the Nongshan Formation,therepresentative of the Upper Paleocene,the extinct Bemalambda are replaced bythe development of Archaeolambda,Phenacolophus and Arclostylops associated with largely breading - chanzhouensis- assemblage of Cenozoic ostracods.The formal transitional to later predominant featuresof ostracods evolution is fit well for that of charophytes and sporo-pollen.Based on the correlation mentioned above,the disputed strata which contain microfossils only are studied in this paper,i.e.the Taizhou Formation of Su-bei Basin,except containing the same micrafossil assemblage as the Shanghu Formation,having more fossils with enormous surface varieties,justthe same as charophytcs and sporo-pollen,constitutes a distinctive transitionalzone quite different from that of Cretaceous;the ostracods of the Dalangshan Formation,Sanshui Basin,characterized with the Shanghu and Taizhou For-mations,mainly belongs to transitional assemblage.So it is appropriate to con-sider both the Taizhou and Dalangshan Formations to be the Lower-Middle Paleocene.The 3rd and 4th members of the Funing Formation in Subei Basin,though contain more new species,yet ,, and in the strata are all important members of the Nong-shan Formation,they may thus be correlated each other.
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