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Distribution and Geochemical Implication of Aromatic Hydrocarbons across the Meishan Permian-Triassic Boundary 总被引:5,自引:0,他引:5
INTRODUCTIONThe Permian-Triassic ( Tr/P) boundary , datedto be (251 .4±0 .3) Ma ago ,is marked by the mostdrastic mass extinction of organisms in the Phanero-zoic .In order to explore the pattern and the cause ofthe mass extinction,extensive research has been fo-cused on biostratigraphy , isotopic chronostratigra-phy , event stratigraphy , ecostratigraphy and se-quence stratigraphy (Payne et al .,2004 ; Reichowetal .,2002 ; Yin et al .,2001 ;Jin et al .,2000 ;Zhanget al .,1996 ,1995 ;… 相似文献
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Zircon SHRIMP Dating for the Weiya Pluton, Eastern Tianshan: Its Geological Implications 总被引:18,自引:4,他引:18
ZHANG Zunzhong GU Lianxing WU Changzhi LI Weiqiang XI Aihua WANG Shuo State Key Laboratory of Mineral Deposit Research 《《地质学报》英文版》2005,79(4):481-490
1 Introduction Voluminous literature has resulted from study of the geology and tectonic evironments of post-orogenic granitoids in eastern Tianshan (He et al., 1995; Han et al., 1997; Gu et al., 1999, 2001; Li et al., 2003; Chen et al., 2004). Previous contributions (Hu et al., 1997; Li et al., 2003) indicate that major events of continental collision in northern Xinjiang occurred around 300 Ma. Then, the tectonics converted from compression to extension, resulting in the uplifting of th… 相似文献
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处于扬子板块东北缘的苏鲁造山带出露的基底岩石主要是各类片麻岩,其中花岗质片麻岩约占80%以上,它们普遍遭受了强烈的角闪岩相退变质作用改造(刘福来等,2004).资料表明,这些岩石原岩的年龄主要集中在700~800 Ma(Li S G et al.,1993;刘福来等,2003,2004;Zheng Y F et al.,2003,2004),峰期年龄约750 Ma(Zheng Y F et al.,2003). 相似文献
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《吉林大学学报(地球科学版)》2015,(Z1)
<正>峨眉山大火成岩省由大量的溢流玄武岩、基性-超基性岩体、少量的苦橄岩、凝灰岩、流纹岩和正长岩等组成,峨眉山地幔柱二叠纪活动时(256~263 Ma,Fan et al.,2008;Zi,et al.,2010;Tang,et al.,2015)位于赤道附近,活动中心位于大理-丽江-攀枝花一带。苦橄岩作为地幔柱岩浆作用早期形成的岩石,可以揭示地幔柱岩浆源区、原始条件及演化等过程。大理-宾川-丽江地区苦橄岩的Sr-Nd同位素显示地壳混染程度小 相似文献
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《吉林大学学报(地球科学版)》2015,(Z1)
额尔古纳地块上的佳疙瘩组一直以来被认为是一套前寒武纪变质岩系。该套地层最初由宁奇生等人在额尔古纳右旗佳疙瘩村附近建立,由于缺乏标准生物化石资料,只依据区域变质程度和变形特点将其时代归为了元古代(宁奇生等,1959)。之后,黑龙江省区域地层表编写组在丰富该套岩层基础上,将其改称为群(黑龙江省地质局,1979)。后来,内蒙古自治区岩石地层采用了上述划分方案,但保留了原始创建名称——佳疙瘩组,并沿用至今(内蒙古自治区地质矿产局,1996)。最新的地质填图资料表明佳疙瘩组为一套海相陆源细碎屑岩-碳酸盐岩-中基性火山岩沉积建造,属活动陆缘型沉积,时代为新元古代(郭灵俊等,2005)。但是,由于缺乏系统的精确同位素年代学资料,佳疙瘩组的时代归属问题一直未得到解决。尤其是近年来随着同位素地质年代学的发展,在东北地区,原来被认为是古老基底的岩层大多并非形成于前寒武纪,而是古生代或中生代(Wilde,2000,2003;Wu et al.,2007;苗来成等,2007;Wang et al.,2012;Wu et al.,2012;Xu et al.,2012)。那么,佳疙疸组形成时代到底如何?物源如何?鉴于此,本文采集了佳疙瘩组的6个火山岩、1个石英片岩和1个黑云母片岩样品,并分别进行了LA-ICP-MS/SIMS锆石U-Pb定年工作,以确定其形成的时代及构造演化历史,这对揭示区域构造演化具有重要意义。样品中的锆石大部分呈自形—半自形晶,显示出典型的岩浆生长环带或条痕状吸收的特点,暗示其岩浆成因。测年结果表明:采自佳疙瘩村附近建组剖面上的黑云母片岩和晶屑凝灰岩分别给出了(762±6)Ma和(797±7)Ma的最小沉积年龄,而粗玄岩却给出了(160±2)Ma的结晶年龄;采自佳疙瘩村以北的3个玄武安山岩和1个流纹岩分别给出了(158±6)Ma、(132±2)Ma、(126±2)Ma和(128±1)Ma的结晶年龄;另外,采自八大关牧场附近的石英片岩(正变质岩)给出了(182±1)Ma的最小结晶年龄,表明其原岩形成于早侏罗世。同时,两个碎屑岩中的年龄分布(763、793~798、821~834、852、894~895和927~934 Ma)与邻区新元古代岩浆期次具有很好的吻合性,也出现了少量的古老的锆石年龄(1.5~1.6 Ga,1.7~1.8 Ga和2.0~2.5 Ga)。根据以上定年结果,同时结合在区域上与佳疙瘩组整合接触的上覆额尔古纳河群是在~738 Ma之后沉积的前人研究成果(Zhang et al.,2014),以及区域地质资料和新元古代岩浆作用的时空分布特征,我们得出:1)额尔古纳地块上的佳疙瘩组并非前人认为的单一的前寒武纪变质岩系,而是由不同时代(新元古代—早白垩世)的岩浆岩和沉积岩组成;2)额尔古纳地块上的佳疙瘩组中沉积物物源是直接由研究区及其邻区所暴露的地质体风化剥蚀的产物所提供;3)额尔古纳地块上的佳疙瘩组可能为一套构造混杂岩,但相关证据需下一步深入研究来确定。 相似文献
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DAI Shuang QIANG Lei TIAN Chao XI Haiyu LUO Junhu LI Rongxi LIANG Jiwei WANG Weiguo LI Guoshan 《《地质学报》英文版》2019,93(Z1):98-101
正The Ordovician (485.4 Ma-443.8Ma) is the longest period of the Paleozoic,which was characterized by a peak of greenhouse climate in Earth history,as well as extreme high sea level (Haq and Schutter,2008;Munnecke et al.,2010),with warm and humid conditions in early-middle period and seawater temperature up to 45℃(Trotter et al.,2008).The carbon cycle fluctuated greatly (Melchin et al.,2013;Cramer et al.,2015) and 相似文献
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胶东青山群基性火山岩的Ar-Ar年代学和地球化学特征: 对华北克拉通破坏过程的启示 总被引:5,自引:3,他引:2
青山群火山岩是华北克拉通破坏期间最具代表性的地幔或地壳熔融产物,记录了华北深部地质演化的重要信息。本文对胶东青山群基性火山岩进行了40Ar/39Ar定年和岩石地球化学分析,结合前人报道的胶东青山群酸性火山岩资料,发现:(1)基性火山岩喷发年龄为122~113Ma,早于青山群酸性火山岩(110~98Ma);(2)基性和酸性火山岩显示了不同的元素和同位素地球化学特征。岩石成因分析表明,基性火山岩为交代富集地幔部分熔融作用的产物,而酸性火山岩为古老下地壳和中生代底侵岩浆的熔融产物(Ling et al.,2009)。因此,胶东地区青山群火山岩记录了岩浆熔融源区从地幔向下地壳的转变。这与长时间尺度的岩石圈减薄过程中热能由地幔向地壳传递过程相吻合,而不同于地壳拆沉作用所预测的岩浆演化趋势。 相似文献
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YAN Xuexin YANG Tianliang XU Yan TOSI Luigi STOUTHAMER Esther ANDREAS Heri LIN Jinxin HUANG Xinlei 《《地质学报》英文版》2019,93(Z1):158-159
正Land subsidence is a worldwide geohazard consisting in the lowering of the ground surface due to natural and human-induced processes occurring in the shallow and deep subsoil.Over the last two decades,land subsidence has caused damages and widespread impacts to a variety of infrastructures in coastal cities (Ma et al.,2011;Liu et al.,2016;Minderhoud et al.,2018).Meanwhile,it is particularly alarming as it reduces the ground 相似文献
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Timing of Magma Mixing in the Gangdisê Magmatic Belt during the India-Asia Collision: Zircon SHRIMP U-Pb Dating 总被引:19,自引:0,他引:19
MO Xuanxue DONG Guochen ZHAO Zhidan GUO Tieying WANG Liangliang CHEN Tao State Key Laboratory of Geo-Processes Mineral Resources China University of Geosciences Beijing School of Earth Science Resources China University of Geosciences Beijing Heibei Bureau of Geology Mineral Exploration Development Shijiazhuang Hebei 《《地质学报》英文版》2005,79(1)
1 IntroductionIt is widely accepted that the collision of India withEurasia proceeded from "soft" to "hard" phases between c.65-70 Ma and c. 45 Ma (Yin and Harrison, 2000; Flower etal., 2001; Dong, 2002; Mo et al., 2003; Zhou et al., 2004,and references therein). Obviously, it is important tounderstand what kind of process took place at the depth ofthe Tibetan Plateau and its timing and geodynamicenvironment responding to the India-Eurasia continentalcollision. The giant Gangdise granito… 相似文献
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<正>碳酸盐熔体具有极低的粘度和独特的元素配分型式,是引起地幔交代作用和化学组成不均一性的重要介质之一(Yaxley et al.,1991;Rudnick et al.,1993;Coltorti et al.,1999)。火成碳酸岩是碳酸盐熔体结晶的产物,其镁(Mg)同位素组成可以为碳酸岩浆作用过程中镁同位素的分馏行为和地幔的镁同位素组成特征提供重要制约。为此,我们系统研 相似文献
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YIN Xiulan Institute of Geomechanics Chinese Academy of Geological Sciences Beijing China LI Sitian China University of Geosciences Wuhan China YANG Jihai ZHANG Qiming China Offshore Oil Nahai Weast Corp. Zhangjiang China 《Continental Dynamics》2000,(1)
1. Introduction In recent years, growing attention has been focused on diapirs because of their significance to hydrocarbon accumulation in basins (Barber & Brown, 1988; Martin Hovland et al., 1989; Law et al., 1989; Collier et al., 1990; Lewis et al., 1994; Carmelo Monaco et al., 1996; Hieke et al., 1996; Hieke et al., 1996; Lewis et al., 1996; Limonov et al., 1996; Gallardo & Blackwell, 1999). With more and more effort devoted to the studies of the northern continental marginal basins … 相似文献
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Environmental Assessments of Trace Metals in Sediments from Dongting Lake, Central China 总被引:1,自引:0,他引:1
INTRODUCTIONFresh water lakes are one of the planet’s mosti mportant freshwater resources.They support life invarious forms,develop tourism and provide uniquerecreational opportunities.It is also a good source ofthe provision of drinking-water for local communi-ties.Studies on trace elements in rivers,lakes,andsedi ments(Zhou et al.,2004;Gray et al.,2000;Grosheva et al.,2000;Klavins et al.,2000;Aucoinet al.,1999;Bortoli et al.,1998;Elbaz-Poulichet etal.,1996;Johansson et al.,1995;F r… 相似文献