新疆巴楚中-晚奥陶世牙形刺生物地层和沉积环境研究  

CONODONT BIOSTRATIGRAPHY AND SEDIMENTOLOGY OF THE MIDDLE AND UPPER ORDOVICIAN IN BACHU, XINJIANG

作　　者：李越[1] 黄智斌[2] 王建坡[1] 王志浩[1] 薛耀松[1] 张俊明[1] 张元动[1] 樊隽轩[1] 张园园[1] 

机构地区：[1]中国科学院南京地质古生物研究所,江苏南京210008 [2]塔里木油田分公司勘探开发研究院,新疆库尔勒841000

出　　处：《地层学杂志》2009年第2期113-122,共10页Journal of Stratigraphy

基　　金：中国科学院创新工程方向性项目(KZCXZ-YW-122,KZCX2-YW-Q05-01);国家自然科学基金项目(No.40572069,40532009);科技部973课题(2006CB806402);中石油塔里木油田分公司专项研究课题资助

摘　　要：塔里木盆地中央隆起区的中—上奥陶统灰岩相地层露头分布在巴楚良里塔格地区的一间房—唐王城。以牙形刺动物群为依据厘定3个组的时代,从下至上为一间房组(Periodus flabellum层、Pygodus serra层,属达瑞威尔阶)、吐木休克组(Pygodus anserinus层、Baltoniodus alobatus带,属桑比阶)和良里塔格组(含B.confluens动物群层,属凯迪阶下部)。一间房组的开始标志了新一期的海进,此组下段发育1期藻丘,中段发育1期藻丘、1期瓶筐石礁丘和3—4期瓶筐石—棘屑滩,上段代表了海水加深至浪基面之下的过程;吐木休克组沉积过程中达到了海进最大值,为凝缩沉积;良里塔格组代表了逐渐海退的过程,由浅滩和3期藻丘建造组成。Mid-Upper Ordovician limestone sequences outcrop along the Lianglitag Hills of the Bachu County. This outcrop region belongs to the northwestern part of the Central High of the Tarim Block. Geochronology of these sequences is determined based on conodont biostratigraphy. The top Dapingian and Darriwilian Stage （upper Middle Ordovician）Yijianfang Formation is subdivided into the Periodus flabellure Bed and Pygodus serra Bed. The Sandbian Stage （lower Upper Ordovician）Tumuxiuke Formation includes the Pygodus anserinus Bed to the Baltoniodus alobatus Zone. Only the B. confluens Fauna is recognized from the Kaitian Stage （mid Upper Ordovician） Lianglitag Formation. A hiatus is inferred from a palaeokarst and conglomerate bed at the base of the Yijianfang Formation. This hiatus marks the base of the transgression tract from the Darriwilian onwards. Two phases of microbial-algal mounds occur within the lower part of the Yijianfang Formation, and the early phase of Calathium reef-mound contains 3-4 layers of coarser bioclastic shoals from the middle part. Deepening successions continued upward in the upper part of the formation and probably reached the depth below the wave-base regime. The condensed red limestone in the Tumuxiuke Formation represents the acme of the sea-level high-stand during the Sandbian interval, and it was deposited in a out-shelf setting. The Lianglitag Formation represents a regression tract with shallow shoals and three phases of microbial-algal mounds occurring in the shallow marine belt during the early Katian time interval.

关 键 词：牙形刺 生物地层 沉积环境 一间房组 吐木休克组 良里塔格组 中-上奥陶统 巴楚 新疆 

分 类 号：P534.42[天文地球—古生物学与地层学]