浙江桐庐早二叠世船山组介形类化石

OSTRACODES FROM THE CHUANSHAN FORMATION AT THE SHENCUN SECTION OF TONGLU, ZHEJIANG

研究报道的介形类化石系采自浙江省桐庐县瑶林镇沈村剖面早二叠世船山组,计14 属4 亚属22 种,包括4新种和4未定种。其中12属4亚属和19种产自船山组第三段,并被归为Hollinella(Praehollinella) ema ciata Basslerella ola 组合,代表早二叠世船山世隆林期。牙形刺化石主要产自船山组第一段,带化石Streptogna thodus elegantulus 及其共生的其它牙形刺化石,指明船山组第一段的时代为中、晚卡西莫夫期到早格泽里期。根据介形类动物群生态组合和岩石特征,推测船山组第三段是在温暖的近岸浅水且为低能的开阔海环境下沉积的。

The fossil ostracodes studied in the present paper were collected from the Chuanshan Formation at the Shencun section of Tonglu, Zhejiang, including 14 genera, 4 subgenera and 22 species. Of them, 4 species are described as new and 4 species are dealt with under open nomenclature. Among the above-mentioned ostracodes, 19 species are obtained from the Third Member of the Chuanshan Formation and the rest (Chamishaella qilianshanensis, Paraparchites sp. cf. P. distortus and Healdianella sp.1) are only known from the First or Second Member of the Chuanshan Formation. The Hollinella (Praehollinella) emaciata-Basslerella ola assemblage is proposed in this paper for those ostracodes from the Third Member and represents the Longlingian (of the Chuanshanian of Early Permian). The conodonts are mainly discovered in the base of the First Member of the Chuanshan Formation, including Streptognathodus elegantulus, S. oppletus, S. cancellosus, Idiognathodus lobulatus, etc. These conodonts indicate that the First Member, especially its base is middle-late Kasimovian to late Gzhelian in age (Late Carboniferous). The Third Member of the Chuanshan Formation might be deposited in a nearshore, shallow water and open marine environment with lower energy based on the ostracode ecoassemblage and lithological features.