检索结果-南通市图书馆

中国科学院地质与地球物理研究所2008学术年会

作者： yan detian~(1,2,*),chen daizhao~1,wang qingchen~1,wang jianguo~1 and chu yang~1 1 state key laboratory of lithospheric evolution,institute of geology and geophysics,chinese academy of sciences,beijing 100029 2 key laboratory of tectonics and petroleum resources,china university of geosciences, ministry of education,wuhan 430074

Extensive organic-matter(OM) rich facies(black shales) occur in the Ordo-Silurian boundary successions in the yangtze area,South *** investigate the redox changes of the yangtze Sea during the Ordo-Silurian transition,two OM sections(wangjiawan in Yichang,Hubei Province,and Sanjiaguan in Zhangjiajie,Hunan Province) straddling the Ordo-Silurian boundary are *** measurements finished in this study include contents of the total organic carbon(TOC), pyrite sulphur,and different species of Fe,including dithionite-extractable Fe(Fe),pyrite Fe(Fe), HCl-extractable Fe(Fe),and total Fe(Fe),in black shales,as well as other redox proxies,such as the S/C ratio,the ratio between highly reactive Fe(Fe= Fe+ Fe) and Fe,and the Fe/(Fe + Fe) ratio, known as the degree of pyritization(DOP).In the wangjiawan section,the Middle Ashgill sediments have high Fe/Fe ratios(0.20-0.77;avg.0.45),high DOP values(0.21-0.72;avg.0 54),and a relatively constant sulfur content independent of the organic carbor *** she contrast,the mid-early Hirnantian deposits generally have low Fe/Fe ratios(0.10-0.35;avg.0.21),low DOP values(0.11- 0.40;avg.0.28),and S/C values are clustering on the normal marine value(S/C = 0.36).The late Hirnantian and early Rhuddanian Jeposits,similar to those of the Middle Ashgill deposits,are characterized by high Fe/Ve ratios(0.32-0.49;avg.0.41),high DOP values(0.46-0.68;avg.0.53) and fairly constant sulfur mm *** data suggest the occurrences of marine anoxia on the yangtze Sea shelf during intervals of the Mid Ashgill,Late Hirnantian and Early Rhuddanian,and ventilated and oxygenated marine conditions during the mid-early Hirnantian *** mid-early Hirnantian ventilated event was concomitant with the global glacial period,likely resulted from the glacio-eustatic sea-level fall and subsequent circulation of cold,dense oxygenated waters upon the shelf seabed. Accordingly,the abrupt change from oxygenated to anoxic marine waters from the late Hirnan

关键词： oceanic anoxia water column stratification Fe-S geochemistry organic carbon Late Ordovician Early Silurian yangtze Sea South china

来源： cnki会议评论

在线全文

cnki会议

学校读者我要写书评

暂无评论

Environmental Redox Changes of the Ancient Sea in the yangtze Area during the Ordo-Silurian Transition

引用

Acta Geologica Sinica(English Edition) 2008年第3期82卷 679-689页

作者： yan detian chen daizhao wang qingchen wang jianguo chu yang state key laboratory of lithospheric evolution Institute of Geology and Geophysics Chinese Academy of Sciences Beijing 100029 key laboratory of tectonics and petroleum resources China University of Geosciences Ministry of Education Wuhan 430074

Extensive organic-matter （OM） rich facies （black shales） occur in the Ordo-Silurian boundary successions in the yangtze area, South china. To investigate the redox changes of the yangtze Sea during the Ordo-Silurian transition, two OM sections （wangjiawan in Yichang, Hubei Province, and Sanjiaguan in Zhangjiajie, Hunan Province） straddling the Ordo-Silurian boundary are studied. The measurements finished in this study include contents of the total organic carbon （TOC）, pyrite sulphur, and different species of Fe, including dithionite-extractable Fe （FED）, pyrite Fe （FeP）, HCl-extractable Fe （FeH）, and total Fe （FeT）, in black shales, as well as other redox proxies, such as the SIC ratio, the ratio between highly reactive Fe （FeHR = FeD ＋ FeP） and FeT, and the FeP/（FeP ＋ FeH） ratio, known as the degree of pyritization （DOP）. In the wangjiawan section, the Middle Ashgill sediments have high FeHR/FeT ratios （0.20-0.77; avg. 0.45）, high DOP values （0.21-0.72; avg. 0.54）, and a relatively constant sulfur content independent of the organic carbon content. By the contrast, the mid-early Hirnantian deposits generally have low FeHR/FeT ratios （0.10-0.35; avg. 0.21）, low DOP values （0.11- 0.40; avg. 0.28）, and SIC values are clustering on the normal marine value （SIC = 0.36）. The late Hirnantian and early Rhuddanian deposits, similar to those of the Middle Ashgill deposits, are characterized by high FeHR/FeT ratios （0.32-0.49; avg. 0.41）, high DOP values （0.46-0.68; avg. 0.53） and fairly constant sulfur contents. These data suggest the occurrences of marine anoxia on the yangtze Sea shelf during intervals of the Mid Ashgill, Late Hirnantian and Early Rhuddanian, and ventilated and oxygenated marine conditions during the mid-early Hirnantian time. The mid-early Hirnantian ventilated event was concomitant with the global glacial period, likely resulted from the glacio-eustatic sea-level fall and subsequent circulation of cold, dense oxygenated waters upon the shelf seabed. Acco

关键词： oceanic anoxia water column stratification Fe-S geochemistry organic carbon Late Ordovician Early Silurian yangtze Sea South china

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Geochemical changes across the Ordovician-Silurian transition on the yangtze Platform,South china

引用

Science china Earth sciences 2009年第1期52卷 38-54页

作者： yan detian chen daizhao wang qingchen wang jianguo key laboratory of tectonics and petroleum resources Ministry of EducationChina University of GeosciencesWuhan 430074China state key laboratory of lithospheric evolution Institute of Geology and GeophysicsChinese Academy of SciencesBeijing 100029China

The trace element and rare earth element(REE) variations across the Ordovician-Silurian succession are presented from two outcrop sections on the yangtze Platform:the Nanbazi section,Guizhou Province,deposited in a shallow platform interior setting,and the wangjiawan section,Hubei Province,deposited in a deeper basinal *** analysis of closely spaced samples through three intervals,the Wufeng,Guanyinqiao and Longmaxi,revealed vast palaeoceanographic *** geochemical proxies,including Th/U,Ni/Co,V/Cr,and V/(V+Ni) ratios,together with sedimentary facies and biotic data,indicate that an anoxic condition on the most of the yangtze Platform during the Wufeng and Longmaxi intervals,but an oxic condition during the Guanyinqiao *** shift of the anoxic to the oxic environment during the Guanyinqiao time coincided with a global sea-level lowstand,in parallel with the global *** Longmaxian anoxic environment was a result of a global sea-level rise,which may be synchronized with a mainly catastrophic event in the latest *** the two sections generally show similar variation patterns of trace and REE concentrations and some element ratios,a minor difference occurs between the wangjiawan and Nanbazi sections,likely reflecting a difference in depositional setting during the *** an oceanic oxygen-level variation may add a useful constraint to the current arguments on the cause and consequence of the latest Ordovician mass extinction.

关键词： rare earth elements trace elements paleo-redox proxies mass extinction Ordovician-Silurian boundary yangtze Platform

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

新特提斯洋俯冲起始的地质记录：土耳其南部蛇绿岩和变质底板

引用

岩石学报 2018年第11期34卷 3302-3314页

作者：陈晨苏本勋景揭俊肖燕林伟褚杨刘霞白洋中国科学院地质与地球物理研究所中国科学院矿产资源研究重点实验室北京100029 中国科学院大学北京100049 中国科学院地球科学研究院北京100029 中国科学院地质与地球物理研究所岩石圈演化国家重点实验室北京100029

在现行板块构造理论的框架下,板块的初始俯冲是岩浆活动和构造运动发生转变的重要过程,亦是理解板块运动的关键节点。在俯冲起始过程中,主要存在四个方面的地质记录,分别为一系列地球化学成分多样的岩浆活动、SSZ型蛇绿岩、变质底板和... 详细信息

在现行板块构造理论的框架下,板块的初始俯冲是岩浆活动和构造运动发生转变的重要过程,亦是理解板块运动的关键节点。在俯冲起始过程中,主要存在四个方面的地质记录,分别为一系列地球化学成分多样的岩浆活动、SSZ型蛇绿岩、变质底板和玻安岩及其对应的铬铁矿床。特提斯造山带作为公认的研究板块构造理论尤其是初始俯冲的关键场所,一直备受地学界的重视。而土耳其南部构造带作为特提斯造山带的重要组成部分,亦是确定亚欧板块和阿拉伯板块之间缝合线存在的重要标志。该南部构造带是研究新特提斯洋俯冲起始的理想场所,上述关于俯冲初始的四个地质记录均保存良好,且有如下方面的重要特点:1)不同地区的镁铁质岩石甚至同一地区的镁铁质岩石具有不同的地球化学特征,从似洋中脊玄武岩,到过渡型岩石类型和玻安质岩石均有发育; 2)大部分蛇绿岩具有完整的序列,各单元及变质底板岩石中普遍发育侵入的基性岩脉,产状多变,是多期岩浆事件的产物; 3)蛇绿岩下部通常发育一套角闪岩相变质底板,且其年龄与蛇绿岩的形成年龄基本一致; 4)蛇绿岩中普遍发育铬铁矿床,以高Cr型为主,部分蛇绿岩中还赋存高Al-高Cr的过渡型铬铁矿,均被认为是幔源岩浆与地幔橄榄岩反应的产物。因而,这些地质体完整记录了新特提斯洋形成-俯冲-消减的演化过程。

关键词：初始俯冲蛇绿岩变质底板铬铁矿床新特提斯洋

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：