陕西宜君晚三叠世延长组长7段鲎虫化石的发现及意义  

LATE TRIASSIC TRIOPS FROM CHANG 7 MEMBER,YANCHANG FORMATION OF YIJUN COUNTY,SHAANXI PROVINCE AND ITS SCIENTIFIC SIGNIFICANCE

作　　者：解古巍[1,2] 叶美芳 冯胜斌[1,2] 袁效奇[1,2] 贺静[1,2] 

机构地区：[1]中国石油长庆油田分公司勘探开发研究院,西安710018 [2]低渗透油气田勘探开发国家工程实验室,西安710018 [3]西安地质调查中心,西安710054

出　　处：《古生物学报》2015年第3期381-386,共6页Acta Palaeontologica Sinica

基　　金：国家重点基础研究发展计划(973)(2014CB239003)资助

摘　　要：鲎虫从早石炭世延续至今,它的分类特征没有发生明显变化,被认为是"一个演化呆滞的类群"。笔者在陕西宜君地区马庄剖面发现了延长组长7段底部地层中保存的鲎虫化石,新标本保存了较好的小颚腺凸起结构,其为鲎虫的排泄器官,鉴于前人对哈萨克虫的研究定义,小颚腺可以作为鉴别鲎虫的重要特征。鲎虫的生存特性,结合同层位发现的膜翅类昆虫化石和底栖宏观藻类化石,都证明鄂尔多斯盆地南部宜君地区延长组长7段沉积初期水体深度很浅,为淡水环境。长7段是延长组沉积的最大湖泛期,在盆地南部宜君地区湖盆面积的扩张和水体的加深在长7段沉积初期尚未开始。本研究的发现对评估长7段湖泛期水体深度、水域面积和烃源岩分布范围具有重要意义。We found some Triops in the bottom of the Chang 7 member of the Triassic Yanchang Formation in the Mazhuang section, Yijun County, Shaanxi Province. these new fossils, Comparing with t Maxillary gland which is the exc he Kazacharthra, was found in retory organs. the maxillary gland is the distinguishing feature for Triops. Some insects of the order hymenoptera and benthic macroalga were found from the same location with Triops, which indicates shallow fresh water. The Chang 7 member was deposited during the lake flooding stage, but the lake basin expansion didn＇t reach the research area in its initial stage. The new fossil records may affect the evaluation of the depth of water, the water area and the distribution of source rocks.

关 键 词：小颚腺 鲎虫 延长组 三叠系 鄂尔多斯盆地 

分 类 号：Q915.2[天文地球—古生物学与地层学]