[南京地质古生物研究所]为深入研究伊朗与中国二叠系及其生物群的对比关系，中科院南京古生物所专家沈树忠、王伟、张以春于日前赴伊朗，与该国USB（University of Sistan and Baluchestan）大学的专家Mohammad Gorgij小组开展合作，对...[南京地质古生物研究所]为深入研究伊朗与中国二叠系及其生物群的对比关系，中科院南京古生物所专家沈树忠、王伟、张以春于日前赴伊朗，与该国USB（University of Sistan and Baluchestan）大学的专家Mohammad Gorgij小组开展合作，对伊朗中部地区的海相和陆相二叠系剖面进行了联合考察，并采集了大量样品。展开更多
Carbon and oxygen isotope records for Shangsi Section in Northwest Sichuan Basin, South China can help investigating depositional environments and processes, including the burial rate and possible contribution of hydr...Carbon and oxygen isotope records for Shangsi Section in Northwest Sichuan Basin, South China can help investigating depositional environments and processes, including the burial rate and possible contribution of hydrothermal events. Samples from the lower Chihsian Formation show δ13CPDB and δ18OPDB values close to those of typical marine limestone. However, the overlying Permian middle-upper Chihsian, Wujiaping, and Maokou Formation samples reveal negative δ18OSMOW values and strong positive δ13CPDB values. These indicate high biological productivity and rapid burial of organic carbon. Samples from the Dalong Formation present both negative δ13CPDB and negative δ18OPDB values, which are quite different from the underlying Permian strata. These abnormal carbon and oxygen isotope characteristics in the Dalong Formation may suggest that hydrothermal processes contributed to deposition.展开更多
文摘[南京地质古生物研究所]为深入研究伊朗与中国二叠系及其生物群的对比关系，中科院南京古生物所专家沈树忠、王伟、张以春于日前赴伊朗，与该国USB（University of Sistan and Baluchestan）大学的专家Mohammad Gorgij小组开展合作，对伊朗中部地区的海相和陆相二叠系剖面进行了联合考察，并采集了大量样品。
文摘在江西修水四都镇东岭村发现了一个连续的、出露完好的二叠纪-三叠纪界线地层剖面。在剖面中有一段厚约2.1m 的地层具有指示海平面下降的岩石组构。这段地层的底部为红色的碳酸盐颗粒岩。红色是颗粒表面的红色铁染,成分为褐铁矿,是出露地表风化形成的。这层红色颗粒岩之上有约2.0 m 的去白云石化灰岩,其中保留了原来粉晶白云石的晶形。去白云石化作用是白云岩受淡水影响而发生的,指示海平面下降事件。这段地层之上是厚1m 的颗粒岩和灰泥岩,代表浅水潮下环境。其上是二叠系-三叠系的界线。这段地层之下的地层中生物丰富多样,并且有复(蜒)、钙藻等大绝灭前的生物。这段地层及其以上的地层中生物种类很少,(蜓)、钙藻等已经消失,表明集群绝灭事件开始于这段地层之下,生物大绝灭的发生与海平面下降事件的发生是基本同时的。由此认为,可能是海平面下降有关的环境剧变事件引发了二叠纪末的集群绝灭事件。
基金国家科技重大专项(编号:2016ZX05004-004,2016ZX05004006-006),国家自然科学基金项目(编号:41372121,41502004)联合资助.[Co-Funded by the Major National Science-Technology Projects of China(Nos.2016ZX05004-004,2016ZX05004006-006),and the National Natural Science Foundation of China(No.4137
基金financially supported by the Key Project of the Natural Science Foundation of Hubei Province (2008CDA095)the SINOPEC project (G0800-06-ZS-319)
文摘Carbon and oxygen isotope records for Shangsi Section in Northwest Sichuan Basin, South China can help investigating depositional environments and processes, including the burial rate and possible contribution of hydrothermal events. Samples from the lower Chihsian Formation show δ13CPDB and δ18OPDB values close to those of typical marine limestone. However, the overlying Permian middle-upper Chihsian, Wujiaping, and Maokou Formation samples reveal negative δ18OSMOW values and strong positive δ13CPDB values. These indicate high biological productivity and rapid burial of organic carbon. Samples from the Dalong Formation present both negative δ13CPDB and negative δ18OPDB values, which are quite different from the underlying Permian strata. These abnormal carbon and oxygen isotope characteristics in the Dalong Formation may suggest that hydrothermal processes contributed to deposition.
