辽西建昌盆地下白垩统义县组的划分及其介形类化石  

DIVISION OF THE LOWER CRETACEOUS YIXIAN FORMATION AND ITS OSTRACOD FOSSILS IN JIANCHANG BASIN,WESTERN LIAONING

作　　者：张立君[1,2] 张立东[1] 杨雅军[1] 郭胜哲[1] 王五力[1] 郑月娟[1] 丁秋红[1] 成龙[1] 

机构地区：[1]沈阳地质矿产研究所,辽宁沈阳110034 [2]沈阳师范大学古生物研究所,辽宁沈阳110034

出　　处：《地质与资源》2012年第1期81-92,共12页Geology and Resources

基　　金：中国地质调查局工作项目"辽西义县组-冀北大店子组火山-沉积地层对比研究"(编号1212010811056)成果之一

摘　　要：以要路沟上平房-青石岩、上白庙-罗家沟和小郎家沟-三门店剖面为代表的建昌盆地义县组,自下而上分为5段:第一段主要为砂砾岩(要路沟层);第二段为砂泥岩、页岩夹凝灰岩,其中包括上白庙层含Cypridea(C.)biventricostata-Yumenia luojiagouensis介形类亚组合带,罗家沟层产介形类Cypridea(C.)luanpingensis-Yumenia unidorsalta-Djungarica camarata亚组合带以及爬行类和鸟类等多门类化石,后狮沟里层以鱼类和介甲类化石为主;第三段岩性是中酸熔岩及其火山碎屑岩;第四段亦称前狮子沟层,以砂页岩为主,夹安山岩,含介形类Yumenia luojiagouensis-Jianchangella dorsicostata亚组合带;第五段为酸性火山岩.上述各层介形类亚组合统归该盆地义县组Cypridea(C.)biventricostata-Yumenia luojiagouensis-Djungarica camarata组合带,其时代属早白垩世早期.文中描述了介形类化石1新属7新种.The Yixian Formation of Jianchang Basin, represented by the Shangpingfang-Qingshiyan, Shangbaimiao- Luojiagou and Xiaolangjiagou-Sanmendian stratigraphic sections in Yaolugou area, may be subdivided into five members. The first member is characterized mainly by sandy conglomerate （Yaolugou layer）. The second member is composed of sandy mudstone and shale intercalated with tuff, including the ostracod Cypridea （C.） biventricostata-Yumenia luojiagouensis assemblage subzone （in Shangbaimiao layer）, Cypridea （ C. ） luanpingensis-Yumenia unidorsalta-Djungarica camarata assemblage subzone （in Luojiagou layer）, and the fossil birds and reptiles etc., but the Houshigouli layer contains mainly fossil fishes and conchostracas. The third member consists of acidic-intermediate lavas and its pyroclastic rocks. The fourth member, called Qianshizigou layer, is characteristic of sandshale intercalated by andesite, containing the ostracod Yumenia luojiagouensis-Jianchangella dorsicostata assemblage subzone. The fifth member is of acid volcanic rocks. All the above mentioned ostracod assemblage subzones are put under the Cypridea （C.） biventricostata-Yumenia luojiagouensis-Djungarica camarata assemblage zone of Yixian Formation in Jianchang Basin, to be the early stage of Early Cretaceous in age. This paper describes the fossil ostracods of one new genus and seven new species.

关 键 词：义县组 介形类化石 早白垩世 建昌盆地 辽西 

分 类 号：P535[天文地球—古生物学与地层学] Q915.2[天文地球—地质学]