西藏沙让斑岩Mo矿床S-Pb同位素组成及地质意义

<正>西藏冈底斯斑岩铜钼矿床主要形成于中新世后碰撞环境,位于雅鲁藏布江缝合带以南,东西成带展布,如驱龙、达布等(Wu et al.,2014;Zheng et al.,2015),而始新世碰撞环境斑岩矿床目前报道的只有沙让钼和吉如铜矿(Zhao et al.,2014;Zheng et al.,2014)。沙让钼矿床位于中部拉萨地块,西藏工布江达县境内,是冈底斯带上发现的首例独立斑岩型钼矿床,目前该矿床的研究主要集中在矿床地质、     

豫西卢氏八宝山铁铜多金属矿床黄铁矿成分研究

<正>东秦岭地区不仅是我国世界级钼矿的聚集区也是一个重要的金矿和多金属矿聚集区(Mao et al.,2011)。这些矿床主要形成在235¹10Ma,且在过去的十年间得到了众多学者的大量研究(Stein et al.,1997;Mao et al.,2002,2011;李永峰等,2005;叶会寿等,2006;Zhang et al.,2007,2011;Chen et al.,2008,2009;Zhu et al.,2009;Xu et al.,2010;     

Zircon SHRIMP Dating for the Weiya Pluton, Eastern Tianshan: Its Geological Implications

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…     

峨眉山地幔柱岩浆矿床成矿流体介质组成及意义

<正>地幔柱岩浆作用是地球深部挥发分脱出的重要通道,形成了Fe-Ti-V氧化物与Cu-Ni-PGE硫化物岩浆矿床。二叠纪时期的峨眉山地幔柱(~259 Ma,Zhong et al.,2014)与西伯利亚地幔柱(~250 Ma,Kamo et al.,1996)形成世界级超大型的Noril’sk Cu-Ni-PGE硫化物矿床和攀枝花、红格、太和、白马、新街等Fe-Ti-V氧化物矿床,而峨眉山地幔柱硫化物矿床的规模较小。两类矿床的氧化还原环境有明     

扬子地块中元古代基性岩体群成因及其成矿作用——以四川会理竹箐基性岩体群为例

<正>在中国,钒钛磁铁矿主要产在约260 Ma的峨眉山大火成岩省内(Zhou et al.,2005),竹箐岩体群虽然位于扬子地台西缘的ELIP的内带范围内,但与晚古生代形成ELIP的岩浆活动无关。有人提出扬子地台很可能参与了Columbia超大陆的聚合过程(Zhang et al.,2006;Sun et al.,2008;Wu et al.,2008;Zhao et al.,2010),然而,关于扬子地块与Columbia超大陆之间关系的研     

Multiple Stratigraphy Study of the Ordovicianin SW Ordos,China

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     

江苏东海片麻状碱性花岗岩的年代学与地球化学:对扬子板块东北缘新元古构造演化的启示

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).     

喜马拉雅造山带晚奥陶纪-早志留纪地质事件记录

<正>青藏高原是由"多陆块、多岛弧"组成,自新元古代以来,经历了长期的构造岩浆作用,记录了"多洋盆、多俯冲、多期碰撞和多期造山"的动力学作用过程(Hsu et al.,1995;Yin and Harrison,2000),又称为"造山的高原"(Dewey,et al.,2005;许志琴等,2006)。现有数据表明,自~750 Ma以来,     

Distribution and Geochemical Implication of Aromatic Hydrocarbons across the Meishan Permian-Triassic Boundary

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 ;…     

峨眉山地幔柱岩浆的起源及演化:苦橄岩和玄武岩流体组成和C-He-Ar同位素的制约

<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     

Impact,Mechanism,Monitoring of Land Subsidence in Coastal Cities(Annual Work of IGCP 663)

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     

桂林茅茅头大岩现代碳酸盐沉积物210Pb分布特征

<正>~(210)Pb技术已经广泛应用到冰芯(Kehrwald et al.,2008)、海洋(Sternberg et al.,1979)和湖泊沉积物(Wu Yanhong et al.,2010)、以及洞穴沉积物(Baskaran et al.,1993)定年研究中。不同于其他地质载体,洞穴沉积物接受的外界~(210)Pb输入,却隔着洞穴顶板、岩溶含水层、土壤和植被等,在这个特殊的背景下,洞穴沉积物中~(210)Pb将表现出什么     

山东莱芜小官庄铁矿床表生氧化过程中的铜同位素分馏及其找矿意义

<正>近年来,铜同位素的研究及其地质应用取得了重要进展(Maréchal et al.,1999;Zhu et al.,2000;Mathur et al.,2005;Markl et al.,2006;Pokrovsky et al.,2008;Maher et al.,2011;Dekov et al.,2013;Mathur and Fantle,2015),     

峨眉山大火成岩省基性岩和酸性岩年龄差异原因

峨眉山大火成岩省酸性岩浆作用主要有三期(Xu et al.,2008 and reference therein):第一期酸性岩浆事件年龄为260. 38±0,95 Ma,与蛾眉山玄武岩等时(He et al.,2007);第二和第三期的年龄分别为252.6±4.2 Ma和238.4±3,4 Ma.     

江西德兴地区中侏罗世斑岩铜成矿系统、冷却、剥蚀历史:来自同位素年代学和低温热年代学的制约

<正>目前,对于斑岩铜矿的研究主要集中于探讨温度区间为200⁸00℃范围内矿床的成因问题,例如岩体形成时代及顺序、矿化和热液蚀变时代以及热液活动时限等(Barra et al.,2002;Masterman et al.,2004;Deckart et al.,2005;Pollard et al.,2005;Campbell et al.,2006;Mao et al.,2006;Baumgartner et al.,2009;Redmond and Einaudi,2010;Sillitoe and Mortensen,2010;Vry et al.,2010;Shen et al.,2012;Zhu et al.,2012)。虽然这些问题很重要,但是仍然不足以全面的认识和     

Fault System, Diapirism and Oil (Gas) Migrationin the Yinggehai Basin, South China Sea

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 …     

滇西北休瓦促晚白垩世高分异Ⅰ型花岗岩成因及其对藏东地区晚中生代构造演化的限定

在印度—欧亚板块碰撞之前,拉萨—羌塘板块之间的碰撞也是导致青藏高原隆升的重要原因,而且也是地球科学中一个热点课题(Sengor,1979,1987;Murphy et al.,1997;Wang et al.,2008;Zhang et al.,2012;Zhu et al.,2013)。然而,中特提斯洋何时关闭,以及拉萨—羌塘板块之间碰撞的延续时间仍然在持续的讨论中(Murphy et al.,1997;Zhu et al.,2013;Zhang et al.,2012,2014)。先前的研究主要集中在拉萨和羌塘板块内部,少有关注藏东地区的岩浆活动对青藏高原晚中生代演化的限定。Wang等(2014a)研究已发现藏东义敦岛弧晚白垩世(110~80 Ma)花岗岩的形成可能与拉萨—羌塘板块之间的碰撞有关,深入研究这些岩体的成因及区域热演化历史将有利于对藏东地区晚中生代构造演化作出进一步的限定。休瓦促晚白垩世的岩体位于义敦岛弧南段的中甸地区,主要由3个岩相组成:岩相1黑云母花岗斑岩、岩相2二长花岗岩和岩相3浅色碱性长石花岗岩,它们的成岩年龄为85.5~84.4 Ma。这3个岩相为准铝质到弱过铝质(A/CNK=0.96~1.07),具有较高的Si O2(70.0%~76.0%)、K2O+Na2O(7.5%~10.7%)、Ga/Al(2.5~4.7),及较低的CaO(0.39%~1.67%)、Mg O(0.01%~0.57%)和P2O5(0.01%~0.17%);相对富集LREEs、Rb、Th、U和Ta,相对亏损HREEs、Ba、Sr、P和Ti,并具有负的Eu异常(Eu/Eu*=0.24~0.59)。相比于经典的A型花岗岩,休瓦促晚白垩世花岗岩具有较高的Sr((10.1~256.0)×10-6,多数大于100×10-6)及较低的Fe O*/Mg O(1.2~9.9)和Zr+Nb+Ce+Y((248~483)×10-6,多数小于350×10-6),呈现出高分异I型花岗岩的特征。这3个岩相均具有相对较高的(87Sr/86Sr)i(0.707 5~0.709 8)值,负的εNd(t)(-8.0~-6.9)和εHf(t)(-7.6~-3.2)值,及古老的Nd和Hf模式年龄(1.7~1.3 Ga),指示它们具有相似的来源即来自于古老的中基性下地壳的部分熔融;此外,锆石的δ18O值具有较大的变化范围(5.9‰~8.4‰,部分小于6.5‰),且在岩体中广泛发育的镁铁质包体指示源区还有部分幔源物质的加入(Valley et al.,2005)。尽管休瓦促晚白垩世岩体相比于同地区同时代的具有埃达克质的热林、红山和铜厂沟岩体(Wang et al.,2014a),具有相对较高的Si O2和较低的Sr/Y比值,但这4个岩体具有相似的(87Sr/86Sr)i、εNd(t)、εHf(t)和δ18O值,指示着它们具有相同的来源。故休瓦促晚白垩世花岗岩成因模式可概括为,在拉萨—羌塘地块晚碰撞—碰撞后伸展背景下,伸展减压作用导致幔源熔体上涌,促使加厚下地壳物质发生部分熔融,形成的熔体与少量幔源物质混合,之后经历较强的结晶分异作用而形成。前人已在松潘—甘孜地块西缘、羌塘地块及义敦岛弧等藏东地区开展了大量的低温热年代学研究(Jolivet et al.,2001;Lai et al.,2007;Reid et al.,2005a;Wang and Wei,2013;Wilson and Fowler,2011;Xu and Kamp,2000;Zheng et al.,2006)。本文通过统计这些研究中三叠世花岗岩的磷灰石裂变径迹年龄发现,在藏东地区存在着一期约90Ma的地壳整体抬升事件。结合中甸地区在86~80 Ma发育有形成于晚碰撞—碰撞后伸展环境的花岗岩,指示着拉萨—羌塘板块的碰撞作用及藏东地区的地壳抬升时间可能要早于晚白垩世,并且拉萨—羌塘地块的碰撞作用直到80 Ma仍然没有停止(Wang et al.,2014b)。     

Carbon Isotope Reversals of Changning-Weiyuan Region Shale Gas, Sichuan Basin

<正>1 Introduction Many high yield shale gas areas in the World are discovered carbon isotope reversals:Barnett,Fayetteville(Zumberge et al.,2012),Marcellus(Tilley et al.,2013),Haynesville(Ferworn et al.,2008),Albany shale gas(Gao et al.,2014),Utica shale gas(Xia et al.,1999;Xia et al.,2012;Xia et al.,2013),the Foothills(Tilley et al.,2011),     

Timing of Magma Mixing in the Gangdisê Magmatic Belt during the India-Asia Collision: Zircon SHRIMP U-Pb Dating

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…     

Modification of the High-Pressure-Type Chromites into the Low- Pressure-Type: Petrological Investigation of the Podiform Chromitites in the Luobusa Ophiolite, Tibet

<正>The podiform chromitites in the Luobusa ophiolite,Southern Tibet,have received much attention because of the presence of ultrahigh-pressure minerals,such as microdiamonds(Bai et al.,1993;Yang et al.,2007;Xu et al.,2009),coesite(Yang et al.,2007)and highly reduced metal phases(Bai et al.,2000;Robinson et al.,2004).The