摘要
在华北地台北缘内蒙地轴及胶辽台隆之上,发现原被划为太古代、元古代的地层与我国北方地槽区古生代早期温都尔庙群相同,为蛇绿岩套,在辽北称清河镇群。本文着重论述了在清河镇群的上部硅质岩中所发现的小壳化石。蛇绿岩套沿华北地台北缘东西延展近千公里,15个地点产小壳化石,层位稳定。文中描述了4类型,7属(其中5新属),10种(其中8新种,1新亚种),称清河镇动物群。动物化石特点是:壳体形态简单,个体小最长不超过4 mm,有明显的壳壁与壳饰,壳体等结构与我国南方梅树村动物群中某些属种的特点有可比性,但与梅树村期小壳化石不同的是门类单调,生态环境有明显差异,两个动物群可能同属早寒武世同一演化阶段,在不周地区并行发展的动物群。清河镇动物群的存在说明我国北部地槽区早古生代早期的一次重大生物事件。清河镇动物群将会对我国寒武纪动物群,生物地理区及华北地台北缘大地构造性质等一系列基础地质及找矿问题,产生新的认识和深远的影响。
Relicts of ancient ocean crust found in the Inner Mongolia axis and Jiaoliao anticlise along the margin of the North China Platform in the last two years have been named the Qinghezhen Group of Early Palaeozoic age. They were originally assigned to the Liaohe Group. But apparently this group is very similar to the early Palaeozoic Ondor Sum Group, so thus named.Microfossils were discovered in 15 localities from the siliceous rocks in the upper part of the Qinghezhen Group over a distance of nearly 1000 km in Liaoning and Hebei provinces. The fossils making up the Qinghezhen fauna comprise 4 types, 8 genera (7 new), and 15 species (13 new and 1 indetermined). They are of small skeletal fossils characterized by a size less than 4 mm and are biologically similar to certain fossils of the Early Cambrian Meishucun fauna of South China, though less diversified than the latter.Owing to the difference in tectonic settings, the Qinghezhen fauna differs in its biological content from the Meishucun fauna, but as both show certain similar characteristics, it is inferred that they experienced parallel development in different regions but belonged to the same evolutionary stage. The discovery of the Qinghezhen fauna shows that during the Early Palaeozoic there occurred a significant event in the North China geosyncline. This event is significant for solving basic problems concerning the Cambrian biogeographic provinces, the geotectonic nature of the northern margin of the North China platform and mineral prospecting.
出处
《地质学报》
EI
CAS
CSCD
北大核心
1990年第2期170-183,T003,共15页
Acta Geologica Sinica
基金
地质矿产部行业基金
定向基金
国家重点攻关项目资金的资助
