甘肃宝积山盆地中侏罗统两种真叶肢介化石  

TWO MIDDLE JURASSIC Euestheria SPECIES FOSSILS IN BAOJISHAN BASIN, GANSU PROVINCE

作　　者：彭琳[1,2] 杨涛[1,2] 刘军[1,2] 陈应权[1,2] PENG Lin YANG Tao LIU Jun CHEN Ying-quan(School of Earth Sciences, Lanzhou University, Lanzhou 730000, China Key Laboratory of Mineral Resources in Western China （ Gansu Province ）, Lanzhou University, Lanzhou 730000, China)

机构地区：[1]兰州大学地质科学与矿产资源学院,甘肃兰州730000 [2]甘肃省西部矿产资源重点实验室,甘肃兰州730000

出　　处：《甘肃地质》2016年第4期1-6,49,共7页Gansu Geology

基　　金：国家自然科学基金(41272026)

摘　　要：本文研究了采自甘肃宝积山盆地中侏罗统新河组的叶肢介化石,经室内鉴定为椭圆真叶肢介(Euestheria fabiformis)和靖远真叶肢介(Euestheria jingyuanensis),两者均为我国中侏罗世自流井真叶肢介(Euestheria ziliujingensis)动物群的重要分子。椭圆真叶肢介主要特征为壳瓣小,长椭圆形,腹缘呈宽弧状拱曲,生长带窄而密集,后端在壳顶之后依次与背缘明显相交,交角相对较大,生长带上具有较小的不规则的网孔状装饰。而靖远真叶肢介主要特征为壳瓣中等大小,呈不规则的卵形,生长带后端与背缘相汇于一点,靠近腹缘的生长带较窄,有线状装饰,其他部位的生长带有不规则的网孔状装饰。甘肃宝积山盆地叶肢介化石的研究,进一步补充了研究区中侏罗世叶肢介的化石记录,表明中侏罗世时期沉积环境有利于叶肢介的生长。Two species, Euestheria fabiformis and Euestheria jingyuanensis, aredescribed in this paper. The fossils are collected from the Middle Jurassic Xinhe Formation in the Baojishan Basin, Gansu Province. Both the two species are important componentsof Euestheria ziliujingensis fauna in the Middle Jurassic. The main characteristics of Euestheria fabiformis are smallin in size, long elliptic, ventral margin rounded, growth lines at dorsal area form a large postero-dorsal angle, growth bands narrow and dense, growth bands ornamented with irregular small reticulations. Euestheria jingyuanensis are median in size, ovoid in outline; growth lines at ventral area gather at postero-dorsal end; growth bands relatively narrow and dense near the ventral margin, and bear some linear decoration, while irregular ornamented reticulations seen in the other parts. The occurrence of the conchostracan fossils in the Baojishan Basin, Gansu Province enriched the fossil materials of conchostracan in the region. And it is shown that the palaeoenvironment of the Middle Jurassic contributes to the growth of Euestheria.

关 键 词：宝积山盆地 中侏罗统 新河组 真叶肢介 

分 类 号：P534.52[天文地球—古生物学与地层学] Q915[天文地球—地质学]