A New Fauna—Qinghezhen Fauna—from the Northern Margin of the North China Platform

Abstract

Abstract In the Inner Mongolia axis and Jiaoliao anteclise along the northern margin of the North China Platform, it has been found that the strata formerly considered as Archaean and Proterozoic are in fact an ophiolite suite similar to the Early Palaeozoic Ondor Sum Group in the Northern Geosyncline region of China. The strata have been named in northern Liaoning as the Qinghezhen Group. The emphasis of this paper is on the discussion of the small shelly fossils found in the siliceous rocks in the upper part of the Qinghezhen Group. This ophiolite suite stretches in an E‐W direction for about 1000 km along the northern margin of the North China Platform, in which 15 fossil localities with stable stratigraphic horizons have been discovered. In this paper. 4 types. 7 genera (including 5 new ones) and 10 species (including 8 new ones and 1 new subspecies) are described, which are collectively referred to as the Qinghezhen Fauna. The characteristics of these fossils are: shell form simple, the maximum length not exceeding 4 mm, with obvious shell wall and wall ornaments. The Qinghezhen Fauna is comparable in shell structure of some genera and species with the Meishucun Fauna in South China, but differs from the latter in having only monotonous fossil groups developed in a distinctly varied ecological environment. The two faunas may belong to the same evolutionary stage of the Early Cambrian but have developed parallelly in different regions. The existence of the Qinghezhen Fauna represents an important biological event in the Early Cambrian in the Northern Geosyncline region of China. The discovery of the Qinghezhen Fauna will bring new knowledge and profound influence to a series of problems on basic geology and mineral deposit prospecting such as the Cambrian faunas, biogeographical povincialism in China and the geotectonic features of the northern margin of the North China Platform.