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1.
西藏羌塘地区火山岩主要见于第三系石坪顶组，主要岩石类型是呈熔岩被产出的火山熔岩，包括辉石粗安岩、角闪粗面岩、角闪英安岩、黑云母英安岩等，其次可见次火山岩相的黑云母英安质碎斑熔岩和黑云母粗面质碎斑熔岩，以及辉石黑云母花斑岩．它们均为陆相中心式喷发的产物．岩石化学上属钾玄岩组合，可进一步分为钾玄岩系列和高硅钾玄岩系列，具非常典型的二元岩浆混合成因火山岩的岩石化学特征．其ＲＥＥ及微量元素特点表明二元岩浆混合前两个端元岩浆分别来自幔源和壳源．这些火山岩岩浆热事件对盆地有机烃类转化为石油和天然气是有利的，而破坏作用仅仅发生在火山机构附近 相似文献
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THE EARLY UPLIFT IN NORTHERN TIBETAN PLATEAU: EVIDENCE FROM THE STUDY ON CENOZOIC VOLCANIC ROCKS IN QIANGTANG REGION 相似文献
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THE LITHOSPHERIC EVOLUTION IN THE QIANGTANG BLOCK OF NORTHERN TIBET PLATEAU: EVIDENCE FROM CENOZOIC VOLCANISM 相似文献
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DISCUSSION ABOUT THE PETROGENESIS OF THE CENOZOIC VOLCANIC ROCKS FROM YUMEN AND HOH XIL AREA, QINGHAI-TIBET PLATEAU 相似文献
5.
藏北改则新生代早期逆冲推覆构造系统 总被引：2，自引：0，他引：2
藏北改则及邻区新生代早期发育大型逆冲推覆构造系统,由不同方向的逆冲断层、不同时代的构造岩片、不同规模的飞来峰和构造窗、不同类型的褶皱构造组成。羌塘中部发育羌中薄皮推覆构造,石炭系板岩和二叠系白云质灰岩自北向南逆冲推覆于上白垩统与古近系红层之上,形成大型逆冲岩席和弧形逆冲断层,原地系统古近纪红层下伏三叠系—侏罗系海相烃源岩。羌塘南部发育南羌塘薄皮推覆构造,导致班公—怒江蛇绿岩、三叠系—侏罗系海相地层及侏罗纪混杂岩自北向南逆冲推覆于古近纪红层与下白垩统海相沉积岩层之上,形成三条蛇绿岩片带、大量飞来峰和厚度较大的构造片岩。中新世早期火山岩层和湖相沉积呈角度不整合覆盖逆冲断层、褶皱构造和逆冲岩席,不整合面上覆火山岩年龄为23.7～19.1Ma,指示中新世早期改则及邻区基本结束了强烈逆冲推覆构造运动。估算羌中逆冲推覆构造的推覆距离约100～115km,南羌塘逆冲推覆构造的推覆距离约82～110km;新生代早期改则逆冲推覆构造系统近南北方向逆冲推覆总距离为182～225km,对应地壳缩短率为(50.3±2.7)%。 相似文献
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THE METAMORPHIC FEATURE,AGE AND MECHANISM OF AMUGANG GROUP IN NORTHERN TIBET 相似文献
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A.
nal 《Geological Journal》2008,43(1):95-116
The Middle Miocene Orduzu volcanic suite, which is a part of the widespread Neogene Yamadağ volcanism of Eastern Anatolia, consists of a rhyolitic lava flow, rhyolitic dykes, a trachyandesitic lava flow and basaltic trachyandesitic dykes. Existence of mafic enclaves and globules in some of the volcanic rocks, and microtextures in phenocrysts indicate that magma mingling and mixing between andesitic and basaltic melts played an important role in the evolution of the volcanic suite. Major and trace element characteristics of the volcanic rocks are similar to those formed in convergent margin settings. In particular, incompatible trace element patterns exhibit large depletions in high field strength elements (Nb and Ta) and strong enrichments in both large ion lithofile elements (Ba, Th and U) and light rare earth elements, indicating a strong subduction signature in the source of the volcanic rocks. Furthermore, petrochemical data obtained suggest that parental magmas of rhyolite lava and dykes, and trachyandesite lava and basaltic trachyandesite dykes were derived from subduction‐related enriched lithospheric mantle and metasomatized mantle (± asthenosphere), respectively. A detailed mineralogical study of the volcanic suite shows that plagioclase is the principal phenocryst phase in all of the rock units from the Orduzu volcano. The plagioclase phenocrysts are accompanied by quartz in the rhyolitic lava flows and by two pyroxenes in the trachyandesitic lava flows and basaltic trachyandesitic dykes. Oxide phases in all rocks are magnetite and ilmenite. Calculated crystallization temperatures range from 650°C to 800°C for plagioclase, 745°C–1054°C for biotite, 888°C–915°C for pyroxene and 736°C–841°C for magnetite–ilmenite pairs. Calculated crystallization pressures of pyroxenes vary between 1.24–5.81 kb, and oxygen fugacity range from −14.47 to −12.39. The estimates of magmatic intensive parameters indicate that the initial magma forming the Orduzu volcanic unit began to crystallize in a high‐level magma chamber and then was stored in a shallow reservoir where it underwent intermediate‐mafic mixing. The rhyolitic lava flow and dykes evolved in relatively shallower crustal magma chambers. Copyright © 2007 John Wiley & Sons, Ltd. 相似文献
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CONTRAST STUDY OF OIL AND GAS EXPLORATION POTENTIAL FOR QIANGTANG, CHANGDOU AND WEST YUNNAN BASIN DURING JURASSIC 相似文献
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BASIN-RANGE TRANSITION AND GENETIC TYPES OF SEQUENCE BOUNDARY OF THE QIANGTANG BASIN IN NORTHERN TIBET 相似文献
11.
青藏高原新生代三阶段造山隆升模式:火成岩岩石学约束 总被引：18，自引：1，他引：17
从岩石从地构造学的角度,分析讨论了青藏高原新生代岩浆作用的特点、差异、成对性及其对高魇隆升深部动力学过程的岩石约束,在此基础上是提出青藏高原是以冈底斯－羌塘造山带为核心,通过三次造山幕事件而形成的高原隆升新模式。 相似文献
12.
Shi Zhiqiang Yi Haisheng Lin Jinhui Zhu Lidong Liu Dengzhong Huang Jijun Tao ZhuanWT ”BX 《地学前缘》2000,(Z1)
PROVENANCE OF LOWER TERTIARY REDBEDS IN HOH XIL BASIN AND UPLIFT OF NORTHERN TIBET PLATEAU 相似文献
13.
拉萨地块火山岩系内早—中侏罗世双壳类动物群及其古生物地理 总被引：4，自引：0，他引：4
在拉萨以东约１００ ｋｍ 处的下波郎和得中等地, 广泛出露着以火山岩系沉积为主体的叶巴组, 新近从中发现了大量的双壳类化石, 以Ｋｏｂａｙａｓｈｉｔｅｓ ｈｅｍｉｃｙｌｉｎｄｒｉｃｕｓ Ｈａｙａｍｉ, Ｐｒｏｐｅａ ｍｕｓｓｉｕｍ （ Ｐｒｏｐｅａｍｕｓｓｉｕｍ） ｌａｅｖｉｒａｄｉａｔｕｍ （ Ｗａａｇｅｎ） , Ｐｒｏｎｏｅｌｌａ ｐｉｎｄｉｒｏｅｎｓｉｓ Ｃｏｘ 和Ｃｏｒｂｉｃｅｌｌｏｐ ｓｉｓｌａｅｖｉｓ （Ｓｏｗｅｒｂｙ） 为代表, 共计１９ 属２０ 种。双壳类动物群古生物地理面貌同北侧羌塘—印支地块早—中侏罗世双壳类动物群以及欧洲和日本同期双壳类动物群有极大的相似性, 在某种程度上又具有东亚区、欧洲区以及埃塞俄比亚区的某些特征属, 在一定程度上显示出不同生物地理区动物群的混生面貌。从生物地理区系的角度来看, 班公湖—怒江缝合带虽然有可能是侏罗纪一度出现的洋盆, 但其张开的幅度和持续的时间不足以导致其南、北两侧产生独立的生物地理区系 相似文献
14.
The Qiangtang Basin located in northern Tibet is a Jurassic foreland basin, whereas the sedimentation for the arc\|basin system during the Late Triassic. Paleomagnetic sampling sites and sections include the Lower Jurassic section in Juhuashan, Shuanhu district, the Middle and Upper Jurassic section in Nadigangri Mountain and the Lower Cretaceous section in Abushan, Shuanhu district. The Lower Jurassic Nadigangri Fm. is composed of tuffaceous volcanic rocks and turbidite (lower) and purple clastic rocks. The Middle Jurassic consists of Quemocuo Fm. purple clastics , Buqu Fm. carbonates and Xiali Fm. gypsum\|bearing varicolored clastics.The Upper Jurassic includes Suowa Fm. carbonates and Xueshan Fm. purple clastics. The Lower Cretaceous Abushan Fm. is lacustrine clastics.1723 oriented paleomagnetic samples of Jurassic and Cretaceous strata were collected in 1997.The sampling sections is located in Shuanhu district of northern Tibet. Although it is unlikely that the sections studied formed by constant and continuous deposition, field evidence indicates no major breaks in the Jurassic sedimentation, except early Bajocian stage. Based on sections of actual survey, all sampling was done using a portable gas\|powered core drill, and cores were oriented with magnetic compass and inclinometer. Samples were obtained at common stratigraphic spacing of 0 5～5m, partly 5cm at some important geological boundary\|surfaces and beds/members. 25mm diameter and 20～50mm length paleomagnetic core samples were drilled in cropping field. The measuring of most samples was completed at the China Academy of Geosciences Paleomagnetic Laboratory using a type DSM\|2 digital rotational magnetometer (its sensitivity of reaching 10 -5 A/m) made by SCHONSTEDT Company of U.S.A., and SCHONSTEDT TSD\|1 for thermal demagnetization. The apparatus used for AF demagnetization was a commercial (SCHONSTEDT GSD\|5)instrument, capable of reaching 100mT peak field. 10% of total measuring samples were completed at the Beijing Geological Institute Paleomagnetic Laboratory of China Academy of Sciences using a type 2G\|755R magnetometer made by Superconducting Technology for weak magnetized samples (sensitivity of reaching 10 -8 A/m). Most samples were stepwise thermally demagnetized, at 50℃ intervals from 100 to 700℃. 相似文献
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GEOCHEMISTRY OF THE PLIOCENE SHOSHONITIC ROCKS FROM OIYUG BASIN, CENTRAL TIBET 相似文献
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GEOCHEMISTRY OF VOLCANIC ROCKS IN WESTERN PART OF JINSHAJIANG STRUCTURAL BELT AND ITS TECTONIC SETTING 相似文献
18.
松辽盆地早白垩世营城组火山岩系含有丰富的珍珠岩,为松辽盆地重要的油气勘探目的层位。在松辽盆地边缘东南隆起九台地区出露有比较新鲜的珍珠岩,内部斑晶保存完好,裂隙发育;斑晶矿物主要有斜长石、黑云母、角闪石,还有镁铁质的单斜辉石和斜方辉石。对含斑晶珍珠岩和剔除斑晶后的珍珠岩玻璃质分别进行地球化学分析,斑晶矿物进行单矿物电子探针成分研究。其结果表明：该珍珠岩属于酸性高钾钙-碱性系列,微量和稀土元素特征显示与上部地壳相似;斑晶矿物单斜辉石为斜紫苏辉石和次透辉石,斜方辉石为紫苏辉石,均显示变质成因,属于捕虏晶;与珍珠岩相邻层位玄武岩的斑晶斜长石为拉长石,单斜辉石为铁次透辉石,属于岩浆成因。这些特征表明,珍珠岩原岩可能来自于上部地壳,其辉石等捕虏晶为岩浆上侵运移过程与围岩发生混染作用的结果。 相似文献
19.
托云火山群的火山地质特征及其构造意义 总被引：9，自引：1，他引：9
结合托云盆地新生代火山岩的卫星影像解译与野外验证成果，发现托云盆地内的7个火山口和棋盘式走滑断裂系统，首次提出了托云火山群的概念．这些火山口可以划分成中心式火山和溢流玄武岩2种类型，形成的火山机构包括塌陷破火山口、火山颈和锥状岩席．火山岩主要为碱性玄武岩，部分玄武岩中可见橄榄岩类等深源岩石包体和普通辉石等矿物巨晶．因此，托云盆地新生代火山岩具有幔源岩浆的性质，断裂构造活动为其上升就位提供通道，火山岩应是由多个火山口近于同时喷发形成的，不具有由上、下两套火山岩系构成的双层结构． 相似文献
20.
PALEOMAGNETIC ESTIMATE OF THE MESOZOIC—CENOZOIC LATITUDINAL DISPLACEMENT OF TERRENES IN THE QINGHAI—TIBET PLATEAU AND ITS SIGNIFICANCE1 QianFang ,PreliminarystudyonthehorizontalmovementofNgariarea ,Tibet,sincePliocene[A].AbstractfromInterna tionalSymposiumonHimalayaGeologySciences[C].1984,2 49～ 2 5 0 .
2 JiangChunfa .OpeningandclosingstructuresofKunlun[M ].Beijing :GeologicalPublishingHouse ,1992 ,15 4～ 2 17.
3 XuZhiqin ,… 相似文献