黑龙江省东部Aucellina(双壳类)的发现

Discovery of Aucellina (bivalve) in eastern Heilongjiang

黑龙江省东部的龙爪沟群分布在虎林、密山、宝清和饶河县境内,鸡西群见于鸡西、穆 棱、勃利、双鸭山、绥滨和集贤等盆地 中。虎林地区的龙爪沟群从下自上分 为裴德组、七虎林组、下云山组、上云 山组(包括曙光组)和珠山组,鸡西盆 地的鸡西群分为滴道组。

Recent study has recognized 2 Aucellina beds from the Upper Yunshan Formation of Longzhaogou Group in Yunshan area, Hulin prefecture and the lower Chengzihe Formation of Jixi Group in 79-132 bore-hole of Ronghua-Pingyang area, Jixi basin.1, Aucellina caucasic a-Aucellina aptlensis-Aucellina jeletzfyi beds, characterized by the three index species (Text-fig.1 A--F), occur in the lower parts of both Upper Yunshan and Chengzihe Formations.In lower Upper Yunshan Formation, the beds also contain Aucellina cf.apiculaia, A.sp..Entolium sp, and Inoccrunius sp.nov.(Text-fig.2 A--E).2.Aucellina cf.caucasic a-Aucellina cf.aptiensis beds, only found in upper Upper Yunshan Formation, overlie the A, caucasica-A.aptiensis-A.jeletzfa'i beds.The beds are characterized by those Auceltina (Text-fig.1 G-I) resembling A.caucasica-A.aptiensis-A.jeletzkji group (Text-fig.1 A-F) except that they lack radial riblets on shell surface.A.caucasica-A.aptiensis-A.jeletzkii association is widespread in northern hemisphere (Text-fig.3), mainly from upper middle Barremian--upper Aptian confirmed by ammonites.In Eastern Heilongjiang province, although there are A, cf.caucasica-A.cf.ap-tiensis beds overlying the A.caucasica-A.aptiensn-A.jeletzfyi beds, there is neither middle-upper AI-bian Aucellina such as A.gryphaeoides, A.nassibinazi, A.uerpmanni nor other typical middle-upper Albian index fossils in the beds.Subsequently, the age of these two Aucellina beds of Upper Yunshan Formation of Longzhaogou Group in Yunshan, Hiding prefecture and Chengzihe Formation of Jixi Group of borehole 79-132 of Ronghua-Pmgyang, Jixi basin is mainly Barremian-upper Aptian and probably extends into lower Albian, and based on which, it could be proposed that at least some strata of Longzhaogou and Jixi Groups are of Early Cretaceous age when some coal-bearing measures were deposited in Eastern Heilongjiang province and even Northeastern China.