安徽巢湖地区早寒武世小壳化石

EARLY CAMBRIAN SMALL SHELLY FOSSILS FROM CHAOHU AREA, ANHUI

安徽巢湖地区冷泉王组底都及灯影组顶部发现了Anabarites, Allatheca, Actinothcea, Protoconus, Stephaconus, Anhuiconus等小壳化石,它们中有一些是西南地区梅树村期动物群的成员,也有一些是淮南雨台山组小壳化石组合的分子。因此,它们的层位高於西南地区Anabarites-Protohertzina组合,巢湖地区的Anabarites为我国已知时代最新的Anabarites。这些小壳化石的发现,使冷泉王组归入下寒武统有了可靠的生物依据,证明了传统的冷泉王组与灯影组之间的岩性界线是穿时的,确切的寒武-震旦系界线应划在灯影组顶部。 本文描述了Protoconus sp.,Stephaconus sp.,Anhuiconus sp.,of. Sacciconus sacciformis Jiang,monoplacophoran gen. et sp. indet. A, monoplacophoran gen. et sp. indet. B, Circolheca(?) sp., Allatheca of. nanjiangensis Yang et He, Aclinotheca dolioformis Xiao et Zhou, Anabarites sp., Tiksilheca (?) sp., Spinulilheca (?) sp., Lapworthella sp., "Fomitchella "(?) sp.,Olivooides(?)sp. 及biconical shell,它们分属于单板型、软舌螺型、海绵型及其它分类地位未定的小壳化石。

In recent years, Anabarites, Lapworthella, Anhuiconus, Allatheca, Actinotheca and other small shelly fossils have been found from the top of the Tongying Formation and the base of the Lengquanwang Formation in the Chaohu area, Anhui Province, among which Anabarites is most abundant and characteristic. Some of the fossils are members of the Meishucun Fauna in SW China, such as Anabarites, Spinulitheca, Stephaconus and Protoconus, while the others are also found from the middle Early Cambrian Yutaishan Formation in Huainan and Huoqiu of Anhui Province, such as Actinotheca dolioformis and Anhuiconus. Anabarites of the Chaohu area may be the latest forms in China, and the Lengquanwang Formation may be assigned to the Lower Cambrian. The exact Precambrian-Cambrian boundary in the Chaohu area is tentatively put at the top of the Tongying Formation, roughly between the Lengquanwang Formation and the Tongying Formation.Here described are Protoconus sp., Stephaconus sp., Anhuiconus sp., cf. Sacciconus sacciformis Jiang, Monoplacophoran gen. et sp. indet. Forms A and B, Circotheca(?) sp., Allatheca cf. nanjiangensis Yang et He, Actinotheca dolioformis Xiao et Zhou, Anabarites sp., Tiksitheca(?) sp., Spinulitheca(?) sp., Lapworthella sp., 'Formitchella' (?)sp., Olivooides(?) sp. and biconical shells, which belong to monoplacophorans, hyolithids, sponges and skeletal Problematic fossils respectively.