新疆阿克苏地区康克林组腕足动物群     

王成文 《吉林大学学报(地球科学版)》1995,(1)

记述康克林组腕足动物４５属６４种，描述９个新种。其时代为阿舍尔期。古生物地理区划属特提斯大区，欧洲－华夏区。  相似文献   

石炭纪海相碳酸盐岩的锶同位素演化及其意义   总被引：4，自引：0，他引：4  

卢武长  崔秉荃 《矿物岩石》1992,12(2):86-93

本文从马角坝剖面石炭系海相碳酸盐岩和腕足化石的锶同位素变化出发,讨论了锶同位素地层曲线的地质意义,并且指出海相碳酸盐岩和腕足化石的锶同位素组成可作为了解地球构造演化的工具。  相似文献   

碳酸盐岩氧、碳稳定同位素地球化学研究目前面临的几个问题   总被引：17，自引：1，他引：16  

李心清  万国江 《地球科学进展》1999,14(3):252-268

碳酸盐岩氧,碳同位素的研究是地球化学重要的示踪手段之一。它可以为认识地质历史时期的地质过程,地球表面的气候过程和海洋环境过程等提供定量依据。４０多年的研究结果,尤其是进入８０年代方解石质的腕足化石壳体和早期成岩胶结物等特殊样品的应用,取得了若干重大研究进展,但同时也发现了一些新的问题。  相似文献   

Nonlinear relationship between preservation of microstructure and geochemical composition of Pleistocene brachiopod shells from the Ryukyu Islands,southwestern Japan          下载免费PDF全文

Kazuyuki Yamamoto  Hideko Takayanagi  Ryuji Asami  Yasufumi Iryu 《Island Arc》2017,26(6)

Stable carbon and oxygen isotope composition of fossilized brachiopod shells serves as an important source to delineate Earth's paleoenvironmental evolution in the Phanerozoic. However, the original isotopic composition is potentially modified by various kinds of diagenesis. To evaluate the extent to which the original isotopic composition of fossilized brachiopod shells is modified by meteoric diagenesis, microstructure, cathodoluminescence (CL) images, and carbon and oxygen isotope composition of fossilized Kikaithyris hanzawai (rhynchonellate brachiopod) shells were examined. The shells were collected from Pleistocene shallow marine carbonates exposed on the Ryukyu Islands, southwestern Japan. The extent of diagenetic alteration is quantitatively evaluated here as both the preservation state of the original shell microstructure and the luminescence/non‐luminescence of shells. Although altered fibers were commonly observed in the brachiopod shells, the original isotopic composition was almost retained. There are no significant differences in the isotopic composition between the luminescent and non‐luminescent shells. There is no direct relationship between the preservation state of the original shell microstructure and the luminescence/non‐luminescence of shells at three of four horizons, indicating that CL images are not necessarily useful for the detection of diagenetic alteration of shells or shell portions. Applying multiple criteria to assessing diagenetic alteration and cross‐checking them are required to distinguish between diagenetically altered and unaltered brachiopod shells.  相似文献   

几种凉水型腕足动物的分布特征   总被引：1，自引：0，他引：1  

张松梅  王成文 《地球科学进展》2004,(Z1)

腕足动物的分布主要受温度—纬度控制,凉水型分子的地理分布、迁移与古气候的变化关系十分密切,向赤道方向的进退则代表了古气候的冷暖变化。通过兴蒙造山带中二叠世哲斯几个凉水型腕足动物属的地理分布特征分析,Yakovlevia具两极分布的特征,为典型凉水分子。  相似文献   

内蒙古准格尔旗晚石炭世－早二叠世早期腕足类动物多样性与沉积环境   总被引：1，自引：0，他引：1  

曾勇 《古地理学报》2007,9(5):513-518

文章以定性与定量相结合的研究方法，对内蒙古准格尔旗晚石炭世－早二叠世早期的腕足类物种多样性、沉积环境进行了综合研究，指出本区海进序列的腕足类物种多样性远高于海退序列；规模较大、具有一定水深的海进序列是腕足类动物辐射、分异、物种多样性升高的重要环境体系；本区腕足类辐射起步于晚石炭世早期之初，物种多样性出现了3次峰值（晚石炭世早期之中期、晚石炭世早期之晚期、晚石炭世晚期之中期），其中晚石炭世早期之晚期是本区腕足类物种多样性的顶峰期。  相似文献   

西藏申扎地区晚石炭世-早二叠世冈瓦纳相腕足类动物群再研究   总被引：3，自引：3，他引：3  

詹立培姚建新  纪占胜武桂春 《地质通报》2007,26(1):54-72

西藏申扎地区德日昂玛-下拉剖面永珠组中上部和昂杰组的腕足类动物群可以与国内、外冈瓦纳相和亲冈瓦纳相地区的腕足类动物群进行对比,但又显示出其独特的一面。将其自下而上划分为4个组合,永珠组中上部为Reedoconcha xizangensis-Spinomartinia xainzaensis组合、Cimmeriella mucronata-Reedoconcha excellens组合和Trigonotreta magnifica-Bandoproductus in-termedia组合,昂杰组为Aulosteges ingens-Punctocyrtella nagmargensis组合。按照国内、外冈瓦纳相、亲冈瓦纳相地区及华夏特提斯地区腕足类的时代意见,永珠组中部腕足类组合的时代为晚石炭世巴斯基尔期,上部2个腕足类组合分别为早二叠世萨克马尔早期—萨克马尔晚期,昂杰组的腕足类组合的时代为早二叠世亚丁斯克期。  相似文献   

辽东太子河流域石炭系下部红层腕足动物群研究     

范炳恒  何锡麟  沈树忠 《地质通报》1998,(1)

早石炭世晚期至晚石炭世早期,太子河流域发育了一套红层沉积,泥岩中含有丰富的腕足动物化石,共计２１属３９种。系统分析了腕足动物群性质;结合围岩和地球化学特征等,识别出ＬｉｎｏｐｒｏｄｕｃｔｕｓＯｖａｔｉａ群落,它生活在与广海相连的浅水海湾低潮线附近地带;对同期腕足动物群进行了比较和讨论,提出当时研究区属于天山—辽吉腕足动物生物地理分区的观点。  相似文献   

大庆中央拗陷区早二叠世腕足动物群的发现及其地层意义          下载免费PDF全文

廖卓庭  万伟彪 《地质学报》2002,76(1):50-54

位于大庆中央拗陷区腹部的杜101井，在1700余米井下，首次发现保存完好的腕足类等多门类化石，经研究确认：腕足动物群属于天山-兴安沉积区早二叠世广泛分布的北山类群。从而肯定了大庆探区大面积中新生界之下存在正常沉积的海相下二叠统，说明松辽盆地北部盆地的基底为海西期浅层褶皱基底。这一发现不仅对松辽盆地二叠纪构造与生物古地理变迁机制等理论问题的深入研究有重要意义，也对大庆探区开展深部油气勘探，寻找新的油气接替层位提供了实际依据，应引起有关方面的重视。  相似文献   

PROBLEMS IN STUDIES ON CARBON AND OXYGEN STABLE ISOTOPES IN CARBONATES     

LI Xinqing  WAN Guojiang 《地球科学进展》1999,14(3):262-268

Carbon and Oxygen stable isotopes in carbonates have long been the important geochemical tracers. Studies on the isotopic compositions can provide insights into the paleoclimatic processes, the paleoceanic environmental processes and the geological processes as well. Researches of more than four decades in the field, especially from the early 1980s on, during which the analysis of the isotopes in fossil brachiopods and early diagenetic cements has contributed much to the knowledge, achieved appreciable progress. However, problems still remained with how to explain the data that already existed on the isotopic compositions of carbonates, on which there is a dichotomy between those who advocate that the data represent the original characteristics of the isotopes and those who argue that the data have been altered diagenetically; with how to select the samples of carbonate for analysis of the isotopic ratios, which has a set of criteria, namely, the microstructure, the Cathodoluminescence and trace elements, for tests of the sample preservations; with whether the fossil brachiopods′shells have vital effects on the isotopic compositions, on which there is a tendency toward the existence in recent years; with to what extent the living environment variations of the fossil affect their carbon and oxygen isotopic ratios and with the utilization of early diagenetic cement as analyzing samples. Along with the problem raising, this paper reviewed the
methods on, and new developing trends toward, the problem-solvings, as well as the up-to-date advances of studies on each problem.  相似文献