福建大田东坑晚二叠世晚期及早三叠世早期介形类动物群

Ostracoda Fauna of Late Late Permian and Early Early Triassic in Dongkeng Area of Datian County, Fujian Province

摘要本文记述了大田东坑晚二叠世长兴组和早三叠世溪口组介形类化石24属55种(包括3个新种),在长兴组自下而上建立了3个介形类组合:1.Polytylites magnituberosus-Orthobairdia meishanensis-Acratia zhongyingensis 组合;2.Bairdia subcontracta-Orothobairdiaexilimarginata-Bairdia urodeloformis-Silenis acuta组合;3.Petasobairdia bicornuta-Bairdia subleguminoides-Pseudobythocyprischangxingensis组合。并详细分析了各组合的特点及它们彼此间的关系。根据介形类化石的分布规律,笔者认为大田东坑长兴组仅大致相当于浙江煤山长兴组的中、上部,而长兴组灰岩下伏的海相碎屑岩应划归长兴阶。

This paper reports on the ostracoda fossils of the Changhsing Formation (Late Permian) and theXikou Formation (Early Triassic)collected from the Dongkeng area of Datian County, Fujian Province.This ostracoda fauna has 55 species and 24 genera, including 3 new species. Based on the ostracoda distributionand lithological characters, the ostraeodes from the Changhsing Formation can be divided intothree assemblages from bottom to top. They are; 1. Polytylites magnituberosus-Orthobairdia meishanensis-Acratia zhongyinggensis assemblage; 2. Bairdia subcontracta-Orthobairdia exilimarginata-Bairdia urodeloformis-Silenisacuta assemblage; 3. Petasobairdia bicornuta-Bairdia subleguminoides-Pseudobythocyprischangxingensis assemblage. After analyzing the features and relations of the ostraeoda assemblages in detail,the author concluded that the Changhsing Formation in Dongkeng of Datian County is approximatelyequivalent to the middle-upper parts of the Changhsing Formation in Meishan of Zhejiang Provinceand that the marine detrial rock under the limestone of Changhsing Formation should belong to theChanghsingian.