福建大田崆峒山晚二叠世和早三叠世介形类

OSTRACODES FROM THE UPPER PERMIAN AND LOWER TRIASSIC AT THE KONGTONGSHAN SECTION OF DATIAN, FUJIAN

报道福建大田崆峒山晚二叠世大隆组、长兴组及早三叠世溪口组介形类 35属 6 7种 ,其中描述 8属 9种 (包括 5新种 )。产自长兴组的介形类化石被划分为 3个组合 ,自下而上分别是 :Polytylitesmagnituberosus Or thobairdiameishanensis Pustulobairdiamailinensis组合 ,Bairdiaurodeloformis Orthobairdiaexilimarginata Bairdiasubcontracta组合和Petasobairdiabicornuta Neoamphissitescostatus Kegelitesdatianensis组合。大田崆峒山介形类动物群在二叠 三叠系界线上下具有明显的突变性质 ,这与世界其它地区一样 ,是遭受二叠纪末期的生物大灭绝事件重创所致。根据介形类化石组合特征 ,并参考共生或共存化石的内容 ,福建大田地区长兴组大致相当于浙江煤山长兴组的中、上部 ,长兴灰岩下伏的海相碎屑岩应划归长兴阶。大隆组、长兴组及溪口组的岩性和化石组合特征 ,显示古环境从滨海沼泽开始 ,经历浅海盆地→浅水碳酸盐台地→浅海近岸环境的演化过程。

The paper reports the ostracoda fossils of the Dalong Formation and Changhsing Formation (Latest Permian), and the Xikou Formation (Earlist Triassic) collected from the Kongtongshan in Datian of Fujian Province. This ostracoda fauna has 67 species and 35 genus, including 5 new species. The ostracodes from the Changhsing Formation can be divided into three assemblages in ascending order:1.Polytylites magnituberosus-Orthobairdia meishanensis-Pustulobairdia mailinensis Assemblage, 2.Bairdia urodeloformis-Orthobairdia exilimarginata-Bairdia subcontracta Assemblage, 3.Petasobairdia bicornuta-Neoamphissites costatus-Kegelites datianensis Assemblage. The evolutionary features around displays of the ostracoda assemblages at Kongtongshan in Datian are analysed and discussed in detail. And the author concluded that the ostracoda fauna around the P-T boundary at Kongtongshan in Datian displays “sudden change” characters in the microscopic view and “gradual change”relationships in the macrocosmic view, and that the Changhsing Formation in Datian County is approximately equivalent to the middle-upper parts of the Changhsing Formation in Meishan of Zhejiang Province, and that the marine detrial rock under the limestone of Changhsing Formation should belong to the Changhsingian. The nature of sedmentary facies and the character of fossils show that the environment from the Late Permian to Early Triassic went through coastal swamp, basin of shallow sea, shallow carbonate platform, and coastall shallow sea.