山东惠民凹陷东营组尾花介科化石的发现及其意义  

Discovery and Significance of Cytheruridae Fossils in the Oligocene Dongying Formation of the Huimin Depression, Shandong Province

作　　者：费安玮[1] 

机构地区：[1]石油大学地球科学系,北京102200

出　　处：《地质论评》2001年第6期596-601,T001,共7页Geological Review

基　　金：国家教委博士点基金

摘　　要：在山东惠民凹陷渐新统东营组二段发现了浪花介超科尾花介科Recticytherura ualisicosta gen.etsp.nov.——U形脊直尾花介(新属、新种),化石产于该段近底部含生物砂质灰岩中。这是本区乃至渤海湾盆地下第三系尾花介科化石的首次发现。对该新属、新种进行了描述并据铰合构造、尾突、放射毛细管及壳壁构造等特征判断其为海相介形类。与之共生的介形类的组合特征、壳壁的元素组成特征及围岩的碳、氧同位素特征反映了微咸一半咸水的沉积环境,并由古湖泊的扩张和古气候分析认为东营组二段沉积初期在惠民凹陷发生了一次短暂海泛。Recticytherura ualisicosta gen. et sp. nov. , referred to the Cytheruridae of the Cytheracea, was found in the basal sandy limestone of Member I of the Oligocene Dongying Formation in the Huimin Depression, Shandong Province. This is the first discovery of Cytheruridae fossils from the Eogene in the depression ,even in the Bohai Gulf Basin. In this paper Recticytherura ualisicosta gen. et sp. nov. was described and inferred to be a marine ostracoda based on the characteristics of its hinge, caudal process, radial pore canals and shell wall etc. The assemblage of paragenetic ostracods, the elementary compositions of their shell walls and the carbon oxygen isotopic characteristics of their wall rocks indicate a sedimentary environment of brackish water body. It is inferred according to the spreading of the palaeolake and palaeoclimate that a marining occurred during the early depositional period of Member I of the Dongying Formation in the Huimin Dpression.Description of New Genus and Species Subclass OSTRACODA Latreille, 1806 Order PODOCOPIDA Muller,1894 Suborder PODOCOPINA Sars, 1866 Superfamily CYTHERACEA Baird, 1850 Family CYTHERURIDAE Muller, 1894Recticytherura gen.nov.Etymology: From the Latin recti,straight,and the genus Cytherura, indicating the straight subrectangular caudal process and the resemblance to Cytherura Sars, 1866.Type species; Recticytherura ualisicosta gen. et sp. nov.Diagnosis; Carapace small, subrectangled in lateral view. Dorsal and ventral margins relatively straight and nearly parallel to each other. Anterior end broadly rounded, posterior end with a subrectangular caudal process which is situated centrally to dorsally. Right valve larger. Surface ornamented with ridges and reticulations. Hinge amphidont. Anterior tooth in right valve triangular. Posterior tooth elongate, crenulate. Median element consists of an anteromedian short split socket and a posteromedian fine crenulate groove. Left valve with complementary elements. No vestibula present. Pore canal zone wide. Radial pore canals

关 键 词：尾花介科 早第三纪 沉积环境 介形类化石群 渐新世 东营组 山东 惠民凹陷 

分 类 号：Q914[天文地球—古生物学与地层学]