【摘要】 滦平盆地张家沟侏罗—白垩系界线上下为连续沉积的滨浅湖—半深湖序列,介形类和叶肢介类化石丰富,是中国陆相J\K界线理想的层型候选剖面。通过晚侏罗世和早白垩世介形类、叶肢介生物组合及沉积学与成因地层学的综合研究,认为陆相侏罗—白垩系生物地层界线以介形类大个体滦平介Luanpingella的消失、女星介Cypridea的出现,叶肢介Nestoria、Pseudograpta及Keratestheria等的消失以及Eosestheria的始现,扇三角洲平原或前缘亚相或等同亚、微相带的结束为标志。陆相界线层型研究和定义异于海相盆地,陆相环境生物化石的自然缺欠可以通过地层格架建立及沉积亚微相序列高精度地划分、对比予以弥补,并应纳入陆相界线层型的定义中。更多还原

【Abstract】 The Jurassic-Cretaceous Dabeigou and Dadianzi Fms ,in Luanping basin,is typical and no hia-tus non-marine depositional succession,within it Jehol fauna is founded,around the northern Hebei and western Liaoning.Dabeigou and Dadianzi Fms at Zhangjiagou of Luanping basin is characterized by contin-uning terrestrial lake deposition from beach to deep lake subfacies,which is considered as an ideal candidate section for stratotype and ostracoda and conchostracans are prevailing biota within it.On the basis of sedi-mentary facies and successions ,ostracoda and conchostracans biota,herein is given a conclusion to the Jurassic-Cretaceous biostratigraphical boundary and stratotype.The boundary is marked by the disappear of Luanpingella,Nestoria?Pseudograpta and Keratestheria,and first occurrence of Cypridea and Eosestheria,and the top part of fan-delta front subfacies is also another marker for the boundary.更多还原