冀北承德盆地奥陶纪冶里组叠层石的发现及沉积环境  

Discovery of Stromatolites from the Ordovician Yeli Formation and Its Sedimentary Environment in Chengde Basin,Hebei Province

作　　者：关秀宇[1] 郭杰 陈海燕[1] 修迪[1] 张运强[1] Guan Xiuyu;Guo Jie;Chen Haiyan;Xiu Di;Zhang Yunqiang(Hebei Institute of Regional Geological and Mineral Resource Survey, Langfang Hebei 065000, China;China Petrolenm Engineering Coltd HuaBei Branch, Renqiu Hebei 062552, China)

机构地区：[1]河北省区域地质矿产调查研究所,河北廊坊065000 [2]中国石油集团工程设计有限公司华北分公司,河北任丘062552

出　　处：《地球科学进展》2018年第5期545-553,共9页Advances in Earth Science

基　　金：中国地质调查局基础地质调查项目"河北1:5万新杖子;承德幅区域地质矿产调查"(编号:1212011220486)资助~~

摘　　要：通过1∶5万区域地质调查,在冶里组中发现了叠层石,识别为雅库特叠层石Jacutophyton,颈状叠层石Collumnacollenia,卡塔夫叠层石Katavia f.和拟锥叠层石Paraconophyton,填补了区域上冶里组生物地层该项空白,丰富了奥陶纪生物地层内容。叠层石的形态特征说明其主要生长在潮下带中下部能量较低的环境中,有时转变成潮下带中上部能量较高的环境,可能代表了由下而上由深而浅的副层序模式。结合岩性岩相和基本层序分析,冶里组整体相序特征为:浅海陆棚相页岩→缓坡相含海绿石砂屑灰岩→潮下—潮间带亮晶生屑鲕粒砂屑灰岩、亮晶团块灰岩、叠层石灰岩→潮间带白云石化泥晶灰岩,构成向上水体变浅的沉积序列,推断冶里组沉积环境整体为浅海陆棚至潮间带环境。这一结论与根据冶里组岩性岩相及基本层序得出的沉积环境的结论吻合较好。On the basis of our regional geological survey report of Chengde Basin on the scale of 1 ： 50000, it was the first time to discover the stromatolites in Yeli-Formation with stratigraphic determination techniques and iso- tope analysis techniques. It is well known that Yell Formation is consisted of gray-green thin limestone with yellowish-green and gray-black shale. The bottom of Yeli Formation is thick black limestone with pyrite nodules. According to the characteristics of lithology, structure, sedimentary structure and microscopic microfacies, Yeli Formation can be divided into shale facies and limestone facies. Yeli Formation can be identified into six kinds of basic sequence according to the limestone assemblage, lithological facies characteristics and phase sequence rule. The ingredient of these stromatolites was recognized as Jacutophyton, Colloumnacollenia, Katavia and Paraconophyton. The discovery of stromatolites as shown in Chengde Basin amplitude regional geological survey report has filled the gap in the biogenic strata of the Yell Formation. Besides, the contents of Ordovician biostragraphy have been enriched according to our regional geological survey of Chengde Basin. The growing environment of stromatolites was mainly in the lower tidal zone with the lower energy environment, sometime transformed the upper tidal zone with the upper energy environment. The growing environment of stromatolites can be concluded through the morphology of stromatolites. From the morphology of stromatolites, it also revealed that Ordovician biostragraphy belongs to vicesequence stratum deposition mode from bottom up, deep and shallow. Combination of lithological facies and basic sequence analysis, the overall phase sequence characteristics of Yeli-Formation can be described as follows ： Shales in shelf facies→glauconite sandstone in ramp facies→sparite spergenite, lump sparite, laminated limestone in subtidal-intertidal belt→dolomitization-micrite in intertical belt. The shallowing upwards sedimentary sequenc

关 键 词：叠层石 沉积环境 冶里组 承德盆地 

分 类 号：P534.42[天文地球—古生物学与地层学] P588.2[天文地球—地质学]