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Ordovician graptolite-bearing strata in southern Jiangxi with a special reference to the Kwangsian Orogeny

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science China Earth sciences 2010年第11期53卷 1602-1610页

作者： Xu Chen YuanDong Zhang JunXuan Fan JunFeng Cheng QiJian Li Chinese Acad sci Nanjing Inst Geol & Palaeontol State Key Lab Palaeobiol & Stratig Nanjing 210008 Peoples R China

The Ordovician graptolite sequence of the Yongxin-Chongyi area in southern Jiangxi was suggested as a standard for the correlation of Ordovician in the Zhujiang region of South China. Based on a restudy of the Upper Ordovician graptolites, the Shikou and Huamianlong formations are recognized herein as a part of the Hanjiang Formation, corresponding only to the Dipla-canthograptus caudatus-Diplacanthograptus spiniferus Zone. Two graptolite zones in the Longxi Formation of Yongxin and Chongyi, the Nemagraptus gracilis Zone and Climacograptus bicornis Zone, are redefined here. A rapid replacement of facies from the typical deep-water graptolitic black shale of Longxi Formation to the rapidly-accumulated, shallow-water clastic deposits of Hanjiang Formation indicates the tectonic initiation of the Kwangsian Orogeny. The thick clastic deposits of the Han-jiang Formation are proposed to come from a nearby source area that rose during the Kwangsian Orogeny. The D. caudatus-D. spiniferus graptolite Zone of the Hanjiang Formation indicates the initiation time of this tectonic event.

关键词： Longxi Formation Hanjiang Formation Sandbian Ordovician graptolite Kwangsian Orogeny

内蒙古贺兰山地区古元古代晚期的花岗岩浆事件及其地质意义:同位素年代学的证据

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岩石学报 2009年第8期25卷 1830-1842页

作者：耿元生周喜文王新社任留东 Chinese Acad geol sci Inst Geol Beijing 100037 Peoples R China

位于华北克拉通西缘的贺兰山杂岩主要由孔兹岩系和变形花岗岩(正片麻岩)所组成,前者主要由夕线石榴片麻岩、石榴二长片麻岩、变粒岩和少量的大理岩及麻粒岩所组成,后者主要包括黑云斜长片麻岩、石榴子石花岗岩、斑状花岗岩和片麻状变质... 详细信息

位于华北克拉通西缘的贺兰山杂岩主要由孔兹岩系和变形花岗岩(正片麻岩)所组成,前者主要由夕线石榴片麻岩、石榴二长片麻岩、变粒岩和少量的大理岩及麻粒岩所组成,后者主要包括黑云斜长片麻岩、石榴子石花岗岩、斑状花岗岩和片麻状变质闪长岩。本文报道了该区变形花岗岩的锆石SHRIMP U-Pb定年结果。黑云二长片麻岩和石榴子石花岗岩分别形成于2053±58Ma和2047±42Ma,斑状花岗岩和片麻状闪长岩分别在1955Ma和1920Ma侵位。大量的年代学资料表明,在华北克拉通北缘存在一条古元古代晚期的花岗杂岩带,该带中的花岗杂岩主要形成于三个阶段,第一阶段大于2.0Ga,第二阶段主要出现在2.0～1.87Ga期间,第三阶段的花岗杂岩在1.85～1.80Ga期间侵位。年代学研究还表明,古元古代晚期的花岗岩浆作用常常与变质事件紧密相关。

关键词：内蒙古贺兰山地区古代晚期岩浆事件地质意义同位素年代学证据 area North China Craton 变形花岗岩黑云斜长片麻岩花岗杂岩 regional metamorphism 华北克拉通北缘 stage 石榴子石黑云二长片麻岩 zircon SHRIMP 闪长岩片麻状

贺兰山孔兹岩系的变质时代及其对华北克拉通西部陆块演化的制约

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岩石学报 2009年第8期25卷 1843-1852页

作者：周喜文耿元生 Chinese Acad geol sci Inst Geol Beijing 100037 Peoples R China

贺兰山孔兹岩系作为华北克拉通西部孔兹岩带的重要组成部分,其变质时代问题一直悬而未决。利用SHRIMP锆石U-Pb定年技术,对贺兰山孔兹岩系中3个代表性富铝片麻岩(石榴堇青钾长片麻岩、石榴堇青二长片麻岩与石榴黑云斜长片麻岩)样品进行... 详细信息

贺兰山孔兹岩系作为华北克拉通西部孔兹岩带的重要组成部分,其变质时代问题一直悬而未决。利用SHRIMP锆石U-Pb定年技术,对贺兰山孔兹岩系中3个代表性富铝片麻岩(石榴堇青钾长片麻岩、石榴堇青二长片麻岩与石榴黑云斜长片麻岩)样品进行了精确定年。发现这3种岩石虽处不同层位,但其碎屑锆石年龄却非常集中,各测点^(207)Pb/^(206)Pb年龄总体变化在2.0～2.1Ga之间,加权平均年龄则在2017～2040Ma之间。这些碎屑锆石都具有岩浆结构特征,反映当时曾存在大规模花岗质岩浆活动,所成岩体为孔兹岩系沉积提供了充足物源。另有少量大于2.5Ga的碎屑锆石(2520～2949Ma),表明本区存在太古代岩浆活动记录。本区石榴堇青二长片麻岩中发育典型的变质增生锆石,其成因很可能与黑云母的脱水熔融反应有关。利用该锆石确定贺兰山孔兹岩系的变质时代为1950±8Ma。该时代与东部大青山、乌拉山孔兹岩系变质时代相同,表明华北克拉通西部的阴山地块与鄂尔多斯地块大体是以平行的方式正面拼贴到一起的。

关键词：贺兰山孔兹岩系变质时代华北克拉通演化 region khondalite series metamorphic age North China Craton 黑云斜长片麻岩碎屑锆石年龄岩浆活动石榴 magmatic origin 鄂尔多斯地块 time SHRIMP ages Ordos block 富铝片麻岩

A comparison of the biological,geological events and environmental backgrounds between the Neoproterozoic-Cambrian and Permian-Triassic transitions

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science China Earth sciences 2010年第12期53卷 1873-1884页

作者： ShuZhong Shen MaoYan Zhu XiangDong Wang GuoXiang Li ChangQun Cao Hua Zhang Chinese Acad sci State Key Lab Palaeobiol & Stratig Nanjing Inst Geol & Palaeontol Nanjing 210008 Peoples R China

The Neoproterozoic-Cambrian(N-C) and Permian-Triassic(P-T) transitions have been regarded the two most critical transitions in earth history because of the explosive biological radiation in the early Cambrian(the Cambrian Explosion) and the largest mass extinction at the *** studies suggest that these two critical transitions showed certain comparability in major evolutionary *** other words,a series of biological,geological,and geochemical events that had happened in the N-C transition occurred repeatedly during the P-T *** events included continental re-configuration related to the deep mantle dynamics,global-scale glaciations,large C-,Sr-,and S-isotope perturbations indicating atmospheric and oceanic changes,abnormal precipitation of carbonates,and associated multiple biological radiations and mass *** coupling of those events in both N-C and P-T transitions suggests that deep mantle dynamics could be a primary mechanism driving dramatic changes of environment on the earth's surface,which in turn caused major biological re-organizations.A detailed comparison of those events during the two critical transitions indicates that despite their general comparability,significant differences do exist in magnitude,duration,and *** supercontinent Rodinia began to rift before the Snowball Earth *** contrast,the supercontinent Pangea entered the dispersal stage after the greatest glaciation from the Late Carboniferous to *** data and qualitative analyses of different fossil groups show a more profound mass extinction during the N-C transition than at the end-Permian in terms of ecosystem *** is indicated by the disappearance of the whole Ediacaran biota at the N-C *** subsequent appearances of many new complex animals at phylum level in the early Cambrian mark the establishment of a brand new ***,the end-Permian mass extinction is manifested mainly by the extin

关键词： Neoproterozoic-Cambrian Permian-Triassic transition biological events geological events environmental background

A model for carbon isotope distribution of methane duringdiagenesis

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Chinese science Bulletin 1998年第7期43卷 576-578页

作者： Ping Guan Yongchang Xu Wenhui Liu Darui Wang Peking Univ Dept Geol Beijing 100871 Peoples R China Chinese Acad sci Lanzhou Inst Geol Lanzhou 730000 Peoples R China Res inst Petr Explorat & Dev Beijing 100083 Peoples R China

The evolution of methane carbon isotope with depth has been discussed based on diagenetic reaction kinetics and isotopic Rayleigh fractionational theory. A mathematical model to describe data of methane carbon isotope... 详细信息

关键词： methane carbon isotope maturity Rayleigh fractionation.

The Rb-Sr isochron of ore and pyrite sub-samples from Linglong gold deposit, Jiaodong Peninsula, eastern China and their geological significance

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Chinese science Bulletin 2000年第24期45卷 2272-2277页

作者： Jinhui Yang Xinhua Zhou Chinese Acad sci Inst Geol & Geophys Lab Lithosphere Tecton Evolut Beijing 100029 Peoples R China

Here we report the first direct Rb-Sr dating of pyrites and ores using sub-sampling from lode gold deposits in Linglong, Jiaodong Peninsula, which is a supra-large lode gold deposit and propose this as a useful geochronological technique for gold mineralization with poor age constraint. The Rb-Sr data of pyrites yield an isochron age of (121.6±8.1) Ma, whereas those of ore and ore-pyrite spread in two ranges from 120.0 to 121.8 Ma and from 110.0 to 111.7 Ma. Studies of characteristic of gold deposit and microscopy of pyrite and quartz indicate that the apparent ages of ore and ore-pyrite are not isochron ages, only mixed by two end members, i.e. the primitive hydrothermal fluids and wall rocks, whereas the isochron age of pyrite sub-samples constrains the age of gold mineralization (121.6±8.1) Ma, i.e. early Cretaceous, which is in good agreement with the published SHRIMP zircon U-Pb ages.

关键词： Linglong gold deposit main stage of gold mineralization Rb-Sr isochron age pyrite sub-sample.

geologic relationships and geochronology of the Cenozoic volcanoes and interbedded weathered mantles of Yulinshan in Qiangtang, North Tibet

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Chinese science Bulletin 2000年第24期45卷 2214-2220页

作者： Lin Ding Yong Zhou Jingjiang Zhang Wanming Deng Chinese Acad sci Inst Geol & Geophys Lab Lithosphere Tecton Evolut Beijing 100029 Peoples R China

The Yulinshan accumulations of volcanic rocks and interbedded weathered mantles provide a unique chance for studying the processes and environment of the formation of the planation surface in central Tibetan Plateau. Geochemical, 40Ar/39Ar and K/Ar geochronologic investigations of the weathered mantles and high-potassium volcanic rocks reveal that the volcano-weathered mantle accumulations formed under arid or semi-arid subtropic environment in 30-24 Ma. The sole planation surface of the Qiangtang region finally formed in about 20 Ma.

关键词： weathered mantle volcanic rock geochronology planation surface Tibetan Plateau.

Platinum-group elements for the Kudi ophiolite, western Kunlun

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Chinese science Bulletin 2000年第6期45卷 551-556页

作者： Zhihong Wang Quanlin Hou Jiliang Li Haihong Chen Chinese Acad sci Inst Geol & Geophys Lab Lithosphere Tecton Evolut Beijing 100029 Peoples R China

The analyses of PGE characteristics for the Kudi ophiolite, western Kunlun, are reported in this note. The Ir-depleted anomalous ancient upper mantle represented by the Kudi mantle peridotites had been percolated and mixed by remelted oceanic crust material from a supra-subduction zone, leaving the rocks relatively enriched in Pd. The PGE contents in the Kudi cumulate pyroxenites and gabbros vary from 2.4 to 23.94 ng/g, and the highest values are in pyroxenites. The Pd/lr ratios increase from the pyroxenites to the gabbros. The PGE patterns for the Kudi cumulate rocks are steeply positively sloped. The Pd enrichment in these rocks is similar to that in pyroxenites from the Thetford ophiolite and the Troodos ophiolite. The Kudi diabase and basalts have low PGE contents and positively sloped PGE patterns, and are comparable with the upper pillow lava?from the Troodos ophiolite, indicative of the environment of back-arc spreading center in a supra-subduction zone.

关键词： platinum-group elements supra-subduction zone Kudi ophiolite western Kunlun.

A Study of the Kunlun-Qilian-Qinling Suture System

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Acta geologica Sinica(English Edition) 2001年第4期75卷 364-374页

作者： BIAN Qiantao, GAO Shanlin, LI Dihui, YE Zhengren, CHANG Chengfa, LUO Xiaoquan institute of geology and Geophysics, Chinese Academy of sciences, Beijing 100029 science Press, Chinese Academy of sciences, Beijing 100717 Chinese Acad sci Inst Geol & Geophys Beijing 100029 Peoples R China Chinese Acad sci Beijing 100717 Peoples R China

The Late Neoproterozoic-Early Palaeozoic suture zones within the Central Orogenic Belt of China can be considered a system—the Kunlun-Qilian-Qinling suture system (KQQ suture system). It is basically divided into the western, central and eastern sectors. The western sector consists of the Küda-Subashi suture zone, the Mazar-Kangxiwar suture and the central West Kunlun microblock. The central sector covers the following five suture zones: the Altun, North Qilian, Qaidam northern marginal, Qimantag-Wutuo and East Kunlun southern marginal sutures, in addition to some microblocks such as the mid-south Qilian, Qaidam, Ayakkum and Maqen microblocks. The eastern sector is composed of the Shangdan suture zone, Mianlüe suture zone and central Qinling-Dabie microblock. The KQQ suture system experienced (1) extending-rifting of the Rodinia super-continent in the early-middle Sinian (～780–600 Ma); (2) the formation and evolution of the KQQ archipelagic ocean during the Late Sinian-Ordovician (～600–440 Ma), and (3) closing of the KQQ ocean and forming of the KQQ suture system during the Late Ordovician—early Silurian (～440–400 Ma). As a system comprising many suture zones and microblocks, the KQQ suture system constitutes the foundation of the Central Orogenic Belt of China.

关键词： A Study of the Kunlun-Qilian-Qinling Suture System