华北地台区东部晚古生代小有孔虫动物群发育特征

本文研究了华北地台区东部辽宁、山东、山西、河南和安徽太原组地层中的小有孔虫37属127种,进行了群落分析。从沉积学角度,华北的石炭——二叠系可大致划分5个沉积体系,其中的潮坪—海湾体系和滨岸浅海体系,构成了小有孔虫繁衍发育的主要场所。从群落的角度讲,这也就是华北地台晚石炭世至早二叠小有孔虫动物群的两大生态底域位置,分别称为局限海湾生态域G和正常浅海生态域SH。自晚石炭世至早二叠世,局限海湾生态域先后孕育了小有孔虫群落G-Ia-G-M;正常浅海生态域先后孕育了小有孔虫群落SH-Ia—SH-V。群落组成受生态与演化双重因素控制,正成分描述时,参考了前人资料,建议并使用了如下术语:（1）特征分子,包括窄时分子和窄相分子;（2）遍布分子,包括广时分子和广相分子;（3）递变分子,包括异地分子或孑遗分子;（4）优势分子。本文还分析了华北地区晚石炭世至早二叠世小有孔虫演化的5个阶段。

PALAEOZOIC SMALLER FORAMINIFERA FAUNAS ON THE EAST PART OF NORTH CHINA PLATFORM

In the six field investigations, carbonate rock samples were collected from Liaoning, - Shandong, Shanxi, Henan and Anhui provinces. A total of 2500 thin sections made from this samples were studied. 127 species belonging to 37 genera of smaller foram-inifera were identified.All of the fossils studied in this paper were collected from the Taiyuan Formation deposited from Late Carboniferous to Early Permian. Five assemblage zones of smaller foraminifera are established and named as zone 1 to zone V in ascending order. The. evolutionary characters of each zone are reflected by the combination of the natures of each community which lived in different environments contemporaneously. So the nature of communities will be taken as the key to understand the characters of the zones. From the sedimentologic point of view, the deposit of Late Carboniferous and Early Permian on the north China Platform can be divided into five sedimentary systems. Among which the tide-gulf system and the littoral-shelf sea system provide two main kinds of area for foraminifera, in the sense of ecology, two major benthic ecological positions of foraminifera. One is limited gulf ecologic position simply called G, the other is normal shallow water ecological position simply called SH. During Late Carboniferous to Early Permian the foraminiferal communities G-Ia to G-V1 w'ere brecded in G and the SH-Ia to SH-V in SH.The following terms are used to describe the characters of communielement; ties: (l) Characteristic element; (2) Intergrading (3) Ubiquitors elements (4) Dominant element.Six revolutionary stages can be recognized. Foraminifera communities SH-Ia, G-Ia and SH-Ib, G-lb developed in Moscovian, SH-n, G-n in Gzehlian. During Asselian-Sakmarian three other revolutionary stages can be distinguished. The representative communities are SH-III and G-III, SH-IV and G-IV, SH-Vand G-V, G-VI respectively.