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1.
林周盆地位于冈底斯板块中部,对其进行盆地分析将为理解冈底斯板块构造演化过程提供重要的沉积学证据。本文以林周盆地中侏罗统却桑温泉组为研究对象,开展岩石学和碎屑锆石U-Pb年代学研究,结果显示却桑温泉组岩屑石英砂岩最年轻碎屑锆石年龄为169 Ma,存在620~540 Ma,1 220~1 055 Ma等年龄峰值,其中最年轻碎屑锆石年龄是对特提斯洋壳俯冲引发的岩浆事件的响应。碎屑锆石区域对比研究表明却桑温泉组物源主要来自冈底斯中部唐加-松多造山带,为特提斯洋向北俯冲、向南增生过程的沉积记录。  相似文献   

2.
雅鲁藏布江蛇绿岩的形成与日喀则弧前盆地沉积演化   总被引:10,自引:0,他引:10       下载免费PDF全文
雅鲁藏布江蛇绿岩被时代连续的日喀则群沉积覆盖及其形成时代(120-110Ma)与冈底斯弧开始发育的时代(115-100Ma)十分相近的事实使人们有理由提出:雅鲁藏布江蛇绿岩是否代表着印度板块与拉萨地块间的特提斯-喜玛拉雅洋残迹的疑问。根据近期的研究,笔者认为雅鲁藏布江蛇绿岩不是形成于三叠纪的特提斯-喜玛拉雅洋的残迹,而是特提斯-喜玛拉雅洋向拉萨地块俯冲的初期(阿普第-阿尔必期),由俯冲作用在冈底斯弧前地区引发的海底扩张作用形成的一种俯冲带上叠型蛇绿岩(supra-subduction zone ophiolites).至森诺曼期,弧前海底扩张作用停止,雅鲁藏布江蛇绿岩开始向南仰冲,在其南侧形成增生杂岩楔。仰起的蛇绿岩开始向日喀则弧前盆地提供蛇绿质碎屑,如冲堆组。森诺曼期-土仑期,盆地接受了一套深水复理石沉积,沉积物源部分来自南部边缘脊的蛇绿质碎屑,而大部分则来自北侧的弧火山岩和岩浆岩碎屑。森诺期-路坦丁期,盆地逐渐变浅,接受了浅海-滨海沉积,物源均来自北部的岩浆弧。至始新世末期,发育在盆地南侧的增生杂岩楔与印度板块发生碰撞,日喀则弧前盆地闭合。  相似文献   

3.
青藏高原冈底斯地处印度河-雅鲁藏布江结合带和班公湖-双湖-怒江对接带之间, 其经历了复杂的沉积-岩浆演化史.将青藏高原冈底斯地层区划分为8个构造-地层分区, 并分时段对各个分区的沉积特征进行归纳, 总结了冈底斯从新元古代到中生代沉积盆地的发展与演化历史: 冈底斯震旦纪由陆缘裂谷开始演化; 晚古生代, 前期以稳定宽阔的碳酸盐岩沉积为主, 发育碳酸盐岩台地与台盆, 从石炭纪起, 开始转化为伸展性质的裂陷大陆边缘, 盆地类型主要为陆缘裂谷; 中生代, 班公湖-怒江特提斯洋向南与雅鲁藏布新特提斯洋向北双向俯冲, 大部分区域早期处于隆升状态, 中生代末期发育大型的岩浆弧带, 盆地类型以弧间盆地和弧前盆地为主.   相似文献   

4.
中亚造山带南缘二叠纪的构造背景一直存在争议。以内蒙古西乌旗罕乌拉地区发育的寿山沟组为研究对象,开展了野外地质、岩石学、碎屑锆石LA-ICP-MS U-Pb年龄研究。2个样品锆石阴极发光图像和Th/U值指示,锆石为岩浆成因锆石。103颗碎屑锆石年龄测试结果显示,年龄信息可划分为5组:285~328Ma,峰期年龄302Ma;338~361Ma;455~490Ma;757Ma;1278Ma、2380Ma。最年轻的年龄为285Ma,结合侵入其中的花岗岩同位素年龄,指示西乌旗罕乌拉地区寿山沟组沉积时限介于285~280Ma之间,主体沉积时代应为早二叠世Sakmarian期—Artinskian期。寿山沟组碎屑锆石反映出近源、快速沉积的特点,沉积物源中含有较多的火山碎屑物,可能代表弧后盆地沉积,为早二叠世古亚洲洋闭合前洋壳俯冲消减作用的沉积响应。结合区域资料,寿山沟组碎屑锆石的年龄对应于东北地区的变质基底及其后的构造岩浆事件,物源区物质主要来自于苏尼特左旗—锡林浩特—西乌旗一带早石炭世末—晚石炭世岩浆弧及贺根山—东乌旗一带,并进一步限制了华北与西伯利亚两大板块的缝合线应位于寿山沟组发育地区的南部,即索伦缝合带,拼合时代最可能为晚二叠世—早三叠世。  相似文献   

5.
桑日群广泛分布于冈底斯火山岩浆弧的中东段,是新特提斯洋俯冲作用的代表性记录。本文对冈底斯中段厅宫地区桑日群比马组开展了碎屑锆石U-Pb同位素测年和地球化学特征研究,结果表明:比马组所含的碎屑锆石具有85.7~143.5Ma、160.2~191.2Ma、334.4~364.1Ma和904Ma四个年龄段,其中最年轻的碎屑锆石年龄为85.7±1.9Ma,结合古生物资料,认为比马组形成于早—晚白垩世,其物源主要来自于拉萨地块,尤其是冈底斯岩基剥蚀源区;岩石地球化学特征显示,比马组沉积主要来源于长英质岩石,是上地壳源区物质经风化剥蚀后搬运沉积形成。  相似文献   

6.
印度与亚洲大陆的碰撞是青藏高原演化的重要构造事件,碰撞过程被记录在拉萨地块南部的晚白垩世到古新世的沉积-岩浆作用中。林周盆地的晚白垩世设兴组及其之后不整合覆盖的林子宗火山岩,是解析碰撞过程的重要记录。本文对设兴组最高层位的砂岩和玄武岩夹层进行了岩石学、地球化学和年代学研究,探讨了岩石成因和构造意义。设兴组砂岩属于杂砂岩,碎屑物质主要来自中酸性岩浆岩源区;锆石Hf同位素指示设兴组大部分碎屑物质来源于盆地北面的中部拉萨地块,少部分来自盆地南部的冈底斯岩基;砂岩中最年轻的碎屑锆石年龄指示林周盆地设兴组是在98Ma之后接受沉积的。以夹层产出在设兴组顶部的玄武岩和玄武安山岩,富集轻稀土元素、亏损重稀土元素、弱负Eu异常,强烈富集Ba、Th、U、Pb等大离子亲石元素,显著亏损Nb、Ta等高场强元素,属于高钾钙碱性玄武岩系列,与典型安第斯型玄武岩特征吻合。玄武岩和玄武安山岩的锆石均为捕获锆石,其最年轻碎屑锆石年龄限定了设兴组玄武岩的喷发晚于110Ma。综合分析表明,林周盆地晚白垩世时期为夹持在冈底斯岩浆弧与中部拉萨地块之间的弧后盆地,新特提斯洋壳晚白垩世俯冲到冈底斯弧和弧后盆地之下,大约在98~110Ma之后喷发到林周盆地的很少量中基性岩浆构成了设兴组顶部的玄武岩和玄武安山岩夹层,是新特提斯洋俯冲相关的幔源岩浆作用。林周盆地设兴组(晚于98Ma)与上覆的林子宗火山岩(底部约为65Ma)之间呈大约33Myr的构造间断,可能代表了冈底斯弧的碰撞之前的隆升剥蚀过程。  相似文献   

7.
洞中拉地区的辉绿玢岩出露于冈底斯弧背断隆带东段,地质研究程度很低,过去一直认为形成于古生代二叠纪。为精确地限制洞中拉辉绿玢岩的形成时代,对冈底斯东段墨竹工卡县洞中拉地区的辉绿玢岩进行锆石SHRIMP U-Pb定年,结果显示洞中拉辉绿玢岩的年龄为117.1Ma±1.0Ma,为早白垩世中期。与冈底斯带中北部地区带状岩浆大爆发的年龄(大约110Ma)时限和冈底斯弧后裂谷拉张作用的时限(120~95Ma)相一致。洞中拉辉绿玢岩可能是冈底斯弧背断隆东段早白垩世弧间裂谷阶段岩浆侵位的产物,与班公湖-怒江特提斯洋壳向南、新特提斯洋壳向北的双向俯冲有关。  相似文献   

8.
黑龙江西部龙江地区位于中亚造山带东段,黑河-贺根山缝合带与西拉木伦缝合带之间,地层记录了两大古板块之间古亚洲洋闭合过程的信息。本文对龙江地区乐平统林西组和下-中三叠统老龙头组的砂岩样品进行碎屑重矿物和碎屑锆石U-Pb同位素年代学研究。碎屑重矿物组合以锆石+磷灰石+金红石+角闪石+绿帘石+重晶石的组合为特征,表明物源主要来自于中酸性岩浆岩,并有少量变质岩及沉积岩组分。林西组样品最年轻的锆石年龄为278±3Ma,老龙头组样品最年轻的锆石年龄为247±3Ma、243±4Ma及237±3Ma,结合前人的研究,限定了林西组沉积于乐平世,老龙头组沉积于早三叠世-中三叠世。碎屑锆石年龄谱明显分为五组:237~258Ma、270~329Ma、357~558Ma、680~1633Ma及1893~1966Ma。其中237~258Ma的碎屑锆石主要来自与古亚洲洋洋壳消亡前的俯冲增生过程相关的火山活动,270~329Ma的碎屑锆石主要来自大石寨组火山岩及其同期侵入岩,357~558Ma的碎屑锆石来自早古生代-晚古生代早期岩浆弧,680~1633Ma的碎屑锆石可能来自兴安及额尔古纳地块的变质基底,而较古老的~1800Ma的锆石年龄暗示了华北克拉通基底的物源信息。通过研究发现林西组及老龙头组样品前30%年轻的碎屑锆石年龄与地层沉积年龄之差都小于100Ma,结合对砂岩碎屑组成、重矿物组合及盆地与火山弧位置关系的研究,认为研究区乐平世-中三叠世沉积盆地具有汇聚背景,为弧前盆地。  相似文献   

9.
西藏达金砾岩的沉积时代、物源及构造背景   总被引:1,自引:1,他引:0  
李顺  丁林  付佳俊  岳雅慧 《岩石学报》2016,32(11):3537-3546
达金砾岩出露于西藏阿里地区冈仁波齐峰南麓,因其地层中发现深海有孔虫化石而受到广泛关注,然而由于达金砾岩的沉积时代不确定,对其沉积的大地构造背景也没有统一的认识。本文中,根据最年轻的碎屑锆石U-Pb年龄限定达金砾岩的最大沉积时代为渐新世末-中新世初(24~27Ma)。综合野外观察,砂岩碎屑统计和碎屑锆石U-Pb年龄分析,本文认为达金砾岩的底部和顶部地层中碎屑物质直接来源于北侧的冈底斯弧,而其中部地层中碎屑物质(包括有孔虫化石)应再旋回自西侧的弧前盆地错江顶群地层。达金砾岩与上覆的冈底斯砾岩连续沉积,且其沉积时代,源区分析结果都与冈底斯砾岩一致,因此本文认为达金砾岩应隶属于冈底斯砾岩。达金砾岩地层变形较弱,产状近乎水平,应沉积于拉张应力背景下,可能与渐新世末-中新世初俯冲的印度板片的"折返"和"断离"有关。  相似文献   

10.
冈底斯带晚中生代构造演化模式一直存在争议。此次研究了中冈底斯带扎布耶茶卡北部区域则弄群火山岩的野外特 征和锆石U-Pb年龄。锆石U-Pb定年结果表明,扎布耶茶卡北部则弄群火山岩主要喷发于154.2~142.1 Ma。研究首次获得 晚侏罗世的则弄群火山岩年龄为154 Ma,比前人提出的则弄群火山岩浆活动起始时间(130 Ma) 提前了24 Ma,据此将则 弄群的时代定为晚侏罗世至早白垩世。根据研究获得的最新年代学数据,结合冈底斯带火山岩的前人研究资料,显示冈底 斯带中生代弧火山岩具有从南向北逐渐年轻的趋势。因此,最早期南冈底斯弧中生代火山岩可能与新特提斯洋板片北向俯 冲有关,晚侏罗世至早白垩世的中冈底斯带弧火山岩受到了新特提斯洋板片北向俯冲和班公湖-怒江洋板片南向俯冲的双 重影响,早白垩世中期的北冈底斯带弧火山岩则与班公湖-怒江洋板片的南向俯冲密切相关。研究成果为冈底斯带晚中生 代构造演化模式提供了火山岩方面的新证据。  相似文献   

11.
大陆弧岩浆幕式作用与地壳加厚:以藏南冈底斯弧为例   总被引:1,自引:0,他引:1  
大陆弧岩浆带位于汇聚板块的前缘,记录了洋陆俯冲过程和大陆地壳生长过程,是研究壳幔相互作用的天然实验室.越来越多的研究发现,大陆弧岩浆的生长与侵位并不是均一的、连续的过程,而是呈现阶段性、峰期性特征,即幕式岩浆作用.弧岩浆峰期与岩浆平静期相比,岩浆增生速率显著增强,易于发生岩浆聚集,继而形成大的岩基,如北美西部科迪勒拉造...  相似文献   

12.
Located on the south of the Gangdese,the Qiuwu Formation has traditionally been considered as Eocene coal-bearing clastic sediments consisting of sandstone,mudstone and conglomerate,unconformably on top of Gangdese batholith.However,its precise age and depositional environment remain ambiguous.Here,we present a newly measured stratigraphic section near the Ngamring County,western Xigaze.Detrital zircon U-Pb ages were also applied to trace the provenance of sediments and to constrain the maximum depositional age of the Qiuwu Formation.Sedimentary facies analyses indicate subaqueous fan and alluvial fan depositional environments.Clast composition of the conglomerate is dominated by magmatic rocks at the lower part,while chert and mafic detritus occur in the upper part,suggesting a southern source.Sandstone modal analyses indicate that the compositions of quartz,feldspar and lithic grains changed from transitional arc to dissected arc,implying the unroofing of the Gangdese arc.Detrital zircon U-Pb ages of the Qiuwu Formation are compared with those from Gangdese magmatic rocks and Yarlung-Zangbo ophiolites,suggesting that the Gangdese arc is a main source of the Qiuwu detritus and that the southern source played a role during the later stage.The major peak of detrital zircon ages is at 45-55 Ma,which corresponds to Linzizong volcanic rocks in southern Gangdese arc.The weighted mean age of the five youngest zircons from the lower part of the section is 21.0 ± 2.2 Ma,suggesting that the Qiuwu Formation was deposited in early Miocene,coeval with other conglomerates exposed along the southern margin of Gangdese.Combining new observations with previously published data,we propose that the provenance of the Qiuwu Formation had shifted from a single northern source to double sources from both the north and the south.Activities of Great Counter Thrust were primarily responsible for the shift by making the south area a high elevation to provide sediments for the Qiuwu Formation.  相似文献   

13.
刘文  吴建亮  雷传扬  王波  郎兴海 《岩石学报》2019,35(6):1738-1756
班公湖-怒江特提斯洋盆的闭合时限对理解班公湖-怒江结合带的构造演化意义重大。本文采用碎屑锆石年代学的方法,分析了班公湖-怒江结合带西段革吉地区沙木罗组下段与沙木罗组上段的物源特征及差异,为班公湖-怒江特提斯洋盆西段的闭合时间提供了新的证据。研究结果表明沙木罗组下段碎屑锆石年龄分布于2586±26Ma~130±1. 5Ma之间,显示出1个主峰年龄约165Ma,1个次峰年龄约240Ma。碎屑锆石年龄分6个组别,集中在2600~2400Ma、2000~1900Ma、1000~840Ma、500~400Ma、340~200Ma和200~130Ma,分别与新太古代克拉通汇聚事件、哥伦比亚超大陆相关的构造热事件、新元古代构造热事件、冈瓦纳大陆边缘安第斯型造山作用的岩浆活动事件、龙木错-双湖结合带岩浆活动事件和班公湖-怒江特提斯洋盆俯冲消减的岩浆活动事件一一对应。沙木罗组上段碎屑锆石年龄分布于2558±22Ma~101±1. 0Ma之间,显示出1个主峰年龄约107Ma,2个次峰年龄分别约226Ma、150Ma。碎屑锆石年龄集中分布于1个年龄组为122~101Ma,记录了班公湖-怒江特提斯洋盆俯冲消减的岩浆活动。通过与潜在源区的年龄谱峰进行对比,沙木罗组下段物源区与南羌塘地块有良好的亲缘性,表明其沉积物物源主要为南羌塘地块,其中南羌塘岩浆弧可能为其主要贡献者。沙木罗组上段物源区与南羌塘地块和北拉萨地块均具有良好的亲缘性,其沉积物物源具有双源性,分别来源于南羌塘岩浆弧和北拉萨岩浆弧。沙木罗组下段和上段沉积物物源的差异性暗示它们形成的沉积环境和物源区不同。对比分析沙木罗组下段和上段岩石学、碎屑锆石形态学等特征,也揭示了类似的差异性。结合其他相关地质资料,认为班公湖-怒江特提斯洋盆在革吉地区的主体闭合时间约115~110Ma,其代表性岩浆事件为南羌塘地块和北拉萨地块的早白垩世岩浆弧,沙木罗组为班公湖-怒江特提斯洋盆由俯冲消减到闭合过程中的沉积产物。  相似文献   

14.
西秦岭大草滩群的形成时代和构造意义探讨   总被引:2,自引:0,他引:2  
大草滩群a岩组中最年轻的一组锆石206Pb/238U年龄加权平均值为404.9±4.8 Ma(MSWD=0.11),b岩组中最年轻的锆石206Pb/238U年龄值为385±5 Ma,c岩组样品中最年轻的锆石206Pb/238U年龄值为375±6 Ma,这一结果将大草滩群的最大沉积时代有效地限定在405~375 Ma之间。结合生物化石组合资料,大草滩群的时代归属于晚泥盆世。根据岩石组合、沉积相、构造变形、形成时代和物源分析等资料综合研究表明,晚泥盆世大草滩群河湖相粗粒碎屑岩形成时的大地构造背景是位于安第斯型活动大陆边缘的弧前拉张—裂陷盆地,作为北秦岭微陆(+岩浆弧)与华北大陆西南缘碰撞的沉积响应,是碰撞造山作用以后南部洋壳持续俯冲阶段同火山—岩浆活动的弧前沉积体系。  相似文献   

15.
In order to reconstruct tectonic evolution history of the southern margin of Asia (i.e., Lhasa terrane) before the India-Asia collision, here we present a comprehensive study on the clastic rocks in the southern Lhasa terrane with new perspectives from sedimentary geochemistry, detrital zircon geochronology and Hf isotope. Clasts from the Jurassic-Early Cretaceous sedimentary sequences (i.e., Yeba and Chumulong Formations) display high compositional maturity and experienced moderate to high degree of chemical weathering, whereas those from the late Early-Late Cretaceous sequences (Ngamring and Shexing Formations) are characterized by low compositional maturity with insignificant chemical weathering. Our results lead to a coherent scenario for the evolution history of the Lhasa terrane. During the Early-Middle Jurassic (∼192-168Ma), the Lhasa terrane was speculated to be an isolated geological block. The Yeba Formation is best understood as being deposited in a back-arc basin induced by northward subduction of the Neo-Tethys ocean with sediments coming from the interiors of the Lhasa terrane. The Middle Jurassic-Early Cretaceous Lhasa-Qiangtang collision resulted in the formation of a composite foreland basin with southward-flowing rivers carrying clastic materials from the uplifted northern Lhasa and/or Qiangtang terranes. During the late Early-Late Cretaceous (∼104-72Ma), the Gangdese magmatic arc was uplifted rapidly above the sea level, forming turbidites (Ngamring Formation) in the Xigaze forearc basin and fluvial red beds (Shexing Formation) on the retro-arc side. At the end of Late Cretaceous, the Lhasa terrane was likely to have been uplifted to high elevation forming an Andean-type margin resembling the modern South America before the India-Asia collision.  相似文献   

16.
Cenozoic conglomerates are exposed discontinuously along the length of the Yarlung Tsangpo suture zone on the southern margin of the Gangdese arc. These conglomerates (the “Gangdese Conglomerates” herein) record a crucial stage in the uplift and erosion histories of the southern Tibet after the initial India–Asia collision. In the Mt. Kailas area, the Gangdese Conglomerates strata consist of multiple sedimentary cycles and each cycle is a fining-upward sequence that was deposited by alluvial fan, braided-river and delta systems. Whereas in the Xigaze area, the Gangdese Conglomerates strata comprise a coarsening-upward sequence that was deposited by delta, braided-river and alluvial fan systems. Based on the detrital and igneous zircon U–Pb ages, the depositional ages of the Gangdese Conglomerates are late Oligocene to early Pliocene (ca. 26–5 Ma) in the Mt. Kailas area, late Oligocene to middle Miocene (ca. 26–15 Ma) in the Xigaze area, and late Oligocene to early Miocene (ca. 26–19 Ma) in the Zedong area. Paleocurrent measurements and provenance data (i.e., conglomerate clast composition, sandstone petrology and detrital zircon age) indicate that the initial detritus of the Gangdese Conglomerates were entirely derived from the north (mainly from the Gangdese arc). Sediment resulting from denudation to the south (the Xigaze forearc basin, the Yarlung Tsangpo suture zone and the northern margin of the Indian plate) first appeared by the early Miocene (ca. 19 Ma) and subsequently increased in abundance gradually. Our new results, together with previous data from the Xigaze area, reveal 3 major stages in the evolution of the Yarlung Tsangpo River system: (1) the southward-flowing stage (ca. 26–19 Ma) featured southward-draining transverse rivers that transported materials from the Gangdese arc southward. Southward paleocurrents in the Gangdese Conglomerates indicate a northern source. (2) The westward-flowing stage (ca. 19–15 Ma) developed due to the uplift of the suture zone and Tethys Himalaya to the south. Northward-draining rivers began to develop, and lakes resembling a string of beads formed and finally connected together, initiating the westward-flowing paleo-Yarlung Tsangpo River. Westward paleoflows were recorded in the Gangdese Conglomerates. (3) The eastward-flowing stage (ca. 15 Ma–present) resulted from differential uplift and denudation of the southern Tibet, which reversed the direction of the young Yarlung Tsangpo River by ca. 15 Ma. The deposition of the Gangdese Conglomerates was controlled by eastward paleoflows. At this point, the modern eastward-flowing Yarlung Tsangpo River system was established.  相似文献   

17.
取自圆包山组砂岩样品中的碎屑锆石作LA-ICP-MS U-Pb定年,获得两个数据年龄区间:409~431Ma(峰值420Ma)和458~488Ma(峰值488Ma)。圆包山组底部发育的笔石化石和420Ma的锆石峰值年龄将圆包山组的时代限定为早志留世后,通过与兴蒙造山带的构造演化对比,认为圆包山组时代为早志留世至早泥盆世。对圆包山组中发育的沉积构造进行古流向分析,认为圆包山组物源区位于杭乌拉北西方向。结合区域岩浆演化资料分析,圆包山组物源区为呼和套尔盖地区。在圆包山组中还检测到继承锆石,新元古代分布于559~952Ma,中元古代分布于1011~1460Ma,古元古代分布于1629~2490Ma。从前人对西伯利亚板块南部、塔里木板块以及南蒙古微板块的相关锆石年龄结果总结发现,华北板块与周围板块最主要的区别在于没有或者很少有中元古代晚期至新元古代早期的锆石年龄记录,阿拉善地块也缺少1.0~1.2Ga锆石年龄记录。综上,认为研究区在古生代构造位置属于南蒙古微板块南部的一部分,元古代物源来自塔里木板块。另外由碎屑锆石年龄在地层中分布特征来看,研究区在早泥盆世后隆升作用明显,构造活动性增强,受到塔里木板块影响逐渐加强。  相似文献   

18.
西藏冈底斯南部陆陆碰撞早期成矿作用分析   总被引:4,自引:0,他引:4  
冈底斯带南部发育有大量的斑岩铜钼矿床和矽卡岩型铜铅锌多金属矿床,形成了斑岩铜矿带和多金属矿带.前人的研究表明,成矿带内的矿床形成年代大都小于30Ma,处于碰撞后期伸展构造环境.本文对冈底斯带中南部的甲龙矽卡岩型铁矿、撒当金银矿床(点)和多底沟矽卡岩型钼矿床(点)开展了年代学研究,结果显示:甲龙铁矿黑云母二长花岗斑岩的锆石LA-ICP-MS U-Pb年龄为61.1 ±0.4Ma,MSWD=0.94;撒当赋矿安山岩锆石LA-ICP-MS U-Pb年龄为62.6±0.5Ma,MSWD=1.51;多底沟钼矿床(点)3件辉钼矿Re-Os模式年龄为64.3±0.8Ma ~ 69.2±3.3Ma,加权平均模式年龄为66.7±6.4Ma(MSWD=8.1).三个矿床(点)的同位素年龄表明成岩成矿事件和印度-欧亚板块陆陆碰撞早期构造岩浆事件有关.结合前人工作,我们提出冈底斯中南部发生了大规模与陆陆碰撞早期岩浆事件有关的成矿作用,形成了大面积分布的矿床,具有良好的找矿前景,应引起更多关注.  相似文献   

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