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81.
塔里木--卡拉库姆地区的油气地质特征与区域地质演化 总被引:3,自引:0,他引:3
本文系统归纳总结与对比分析了塔里木盆地、北阿富汗-南塔吉克斯坦盆地和卡拉库姆盆地的油气地质特征,并在此基础上探讨了该地区古生代以来地质演化对盆地演化和油气地质特征的控制作用。塔里木盆地奠基在前南华系结晶基底之上,中亚两个盆地奠基在南天山洋闭合之后形成的前二叠系褶皱基底之上。塔里木盆地的盖层沉积明显受到了南侧“原特提斯(北昆仑)”、古特提斯和新特提斯的影响,由于北昆仑带向西尖灭于北帕米尔,中亚两个含油气盆地的中-新生界则主要受到南侧古特提斯和新特提斯的影响。中亚两个盆地的海陆交互相和礁灰岩相侏罗系向东到塔西南相变为陆相,这从烃源岩的角度决定了塔西南与中亚两个盆地中-新生界不同的含油气性。塔里木盆地中-新生界有利的油气生储盖组合主要存在于前陆盆地的陆相地层中,它与下伏古生界含油气层系的叠加作用提高了其油气潜力。 相似文献
82.
斑岩铜矿床在东特提斯成矿域中的时空分布特征 总被引:7,自引:1,他引:6
已有的斑岩铜矿床成矿模型多是建立在环太平洋地区矿床资料的基础上,相对而言,特提斯成矿域中的斑岩铜矿床还有待梳理和总结.本文以特提斯构造演化与成矿为主线,将东特提斯成矿域中的斑岩铜矿床空间上划分为土耳其Pontides、伊朗中部Sahand-Bazman、巴基斯坦Chagai、中国玉龙、中甸、班公湖、冈底斯7条成矿带和中南半岛、土耳其Anatolides地块2个成矿区;时间上分别对应于早三叠世、晚三叠世、白垩纪中期、白垩纪末-古新世初、中始新世、中中新世等6个时段;构造背景分别为古、新特提斯洋盆俯冲或俯冲后的碰撞;讨论认为Sahand-Bazman铜矿带的形成背景与玉龙成矿带可对比. 相似文献
83.
Chien-Yuan Tseng Huai-Jen Yang Houng-Yi Yang Dunyi Liu Cailai Wu Chiu-Kuang Cheng Cheng-Hong Chen Choon-Muar Ker 《Gondwana Research》2009,16(2):285
Adakitic intrusive rocks of 430–450 Ma were discovered in the North Qilian orogenic belt, the western section of the Central Orogenic System (COS) in China. These adakitic rocks were lower crust melts rather than slab melts as indicated by their crustal Ce/Pb, Nb/U, Ti/Eu, and Nd/Sm ratios and radiogenically enriched (87Sr/86Sr)i of 0.7053–0.7066 and εNd(t) of − 0.9 to − 1.7. While they are all characterized by low Yb (< 1.1 ppm) and Y (< 11.5 ppm) abundances with high Sr/Y (> 65) and (La/Yb)N (> 13.7) ratios, these adakitic rocks are classified into the low-MgO–Ni–Cr and high-MgO–Ni–Cr groups. The low-MgO samples were derived from partial melting of thickened lower crust, whereas the high-MgO samples were melts from delaminated lower crust, which subsequently interacted with mantle peridotite upon ascent. Adakitic rocks from the adjacent North Qinling orogenic belt also originated from thickened lower crust at 430 Ma. In addition, the North Qilian and North Qinling orogenic belts both consist of lithological assemblages varying from subduction-accretionary complexes at south to central arc assemblages, which include adakitic rocks, then to backarc phases at north. Such a sequence reflects northward subduction of the Qilian and Qinling oceans. In these two orogenic belts, the occurrence of adakitic rocks of common origin and ages together with the similarities in tectonic configurations and lithological assemblages are considered to be the evidence for the continuity between eastern Qilian and western Qinling, forming a > 1000 km Early Paleozoic orogenic belt. In such a tectonic configuration, the Qilian and Qinling oceans that subducted from south possibly represent parts of the large “Proto-Tethyan Ocean”. This inference is supported by the coexistence of Early Paleozoic coral and trilobite specimens from Asia, America and Australia in the North Qilian orogenic belt. Post-400 Ma volcanic rocks occur in the North Qinling orogenic belt but are absent in the North Qilian orogenic belt, indicating that these two orogenic belts underwent distinct evolution history after the closure of the Proto-Tethyan Ocean ( 420 Ma). 相似文献
84.
M. Reuter W. E. Piller M. Harzhauser O. Mandic B. Berning F. Rögl A. Kroh M.-P. Aubry U. Wielandt-Schuster A. Hamedani 《International Journal of Earth Sciences》2009,98(3):627-650
In the central Iranian Esfahan-Sirjan and Qom basins sedimentation of the Oligo-/Miocene Qom Formation took place on extensive
mixed carbonate–siliciclastic ramps. During this time, both basins were positioned at the Eurasian margin of the Tethyan Seaway,
which connected the western and eastern regions of the Tethys Ocean at least until the late Burdigalian. During the so-called
Terminal Tethyan Event the Tethyan Seaway was then closed due to the collision of the African/Arabian and Iranian/Eurasian
plates. Facies analysis of the sedimentary record of both basins indicates paleoenvironments ranging from terrestrial to open
marine settings, including mangrove, restricted inner shelf lagoon, seagrass meadow, reefal, and deeper offshore environments.
Recognition of eight depositional sequences and elaboration of an integrated biostratigraphic framework (calcareous nannoplankton,
planktic and larger benthic foraminifers, gastropods, and pectinids) allow us to construct a basin-spanning stratigraphy.
The assignment of the recognized sea-level lowstands to the Ru 3 to Bur 3 lowstands of the global sea-level curve enables
a comparison with time-equivalent sections from the Zagros Basin, which was part of the African/Arabian Plate on the opposing
southern margin of the Tethyan Seaway. The so calibrated sections display restrictions of the Tethyan Seaway and interruption
of the south Iranian gateways between the Qom Basin and the Proto-Indopacific in relation to ongoing plate collision during
the early Burdigalian. 相似文献
85.
86.
通过对额尔古纳八卡地区酸性侵入岩进行LA-ICP-MS锆石U-Pb定年研究表明,八卡区内5个代表性的酸性侵入岩体中的锆石大部分为自形-半自形晶,显示其为岩浆成因锆石;岩浆作用集中于3个阶段。其包括:1)新元古代早期岩浆活动,正长花岗岩加权平均年龄为798 Ma±6 Ma,其形成可能与Rodinia超大陆裂解的构造背景有关;2)晚二叠世-早三叠世的岩浆活动,岩石年龄介于238~267 Ma,结合花岗岩特征,反映其形成于古亚洲洋闭合后的造山后环境;3)花岗岩的138 Ma±1 Ma、137 Ma±2 Ma岩体年龄显示了早白垩世岩浆作用的存在,该岩浆事件与蒙古-鄂霍茨克缝合带的演化有关。 相似文献
87.
TECTONIC SETTING AND METALLOGENESIS OF THE PRINCIPAL SECTORS OF THE TETHYAN EURASIAN METALLOGENIC BELT 总被引:1,自引:0,他引:1
Slobodan Jankovic 《大地构造与成矿学(英文版)》2001,25(1)
Three global metallogenic belts were formed in the world during Mesozoic and post-Mesozoic times. Two of them are situated along the western and eastern Pacific margins, and the third one - the Tethyan Eurasian metallogenic belt (TEMB) is related to the domain of Eurasian plate and flanked on the south by the Afro-Arabian and Indian plates. The general tectonic evolution of the realm where the TEMB was formed is closely connected with the history of Tethys. The emplacement of ore deposits and the development of regional metallogenic units are related to a definitive time interval and to specific tectonic settings such as: (1) Intracontinental rifting along the northern margin of Gondwana and/or fragments already separated; (2) Oceanic environments (i.e. ophiolite complexes and ocean floor sediments) host podiform chromite deposits, volcano-sedimentary cupriferous pyrite deposits (Cyprus type), stratiform manganese deposits, and sporadically PGE deposits; (3) Subduction related settings involve mainly porphyry copper deposits, hydrothermal massive sulphide polymetallic deposits, and epithermal deposits. So far identified mineralization of porphyry copper exceeds in the TEMB over 100 million tons of copper metal; and(4) Collision and post-collision continent-continent setting includes deposits of lead-zinc, antimony, gold, in some sectors tin deposits, as well. The giant deposits of Li-pegmatite occur sporadically.The TEMB is almost a continuously mineralized belt, but within it, some sectors display specific features of tectonic settings, association of elements, minerals and morphogenetic types of mineralization. 相似文献
88.
藏南帕里至达吉地带的上地壳结构特征──REFTEK顺带广角地震观测结果分析 总被引:3,自引:1,他引:3
本文主要介绍1992年中美喜马拉雅和青藏高原深剖面与综合研究项目第一阶段(INDEPTHI-1)广角地震观测资料利用Seis81程序(Cerveny,1981)进行二维解释所获得的帕里一达吉地带的上地壳结构特征。主要成果为:(1)前寒武结晶基底之顶界表现为R1界面。据本项目地质调查,藏南拆离系(STDS)在帕里以北约10km处出露,向北缓倾并向地下延伸。认为R1界面不仅是结晶基底之顶界的反映,而且STD可能沿着R1界面展布,也即R1界面同时是一条沉积盖层和基底之间的拆离层。R1界面埋深3±0.6—11±0.6km。(2)上述拆离层在萨马达一达吉之间,以R1界面之上的负速度梯度楔状体(LVL)为特征。LVL可能是STDS活动时拖带下沉的中生代特提斯沉积,或可能是含水破碎带。(3)在结晶基底内部存在第二条拆离带(LVZ),表现为T2反射波组。LVZ在帕里埋深8.5±0.6km,向北陡倾,至萨马达为22.5±0.6km深;再向北,倾角变缓,至达吉之下,达27±0.6km深。LVZ在帕里─萨马达之间,厚仅0.5km;至达吉,增厚至5km;也具楔形负速度梯度带性质;它可能是花岗岩局部融熔体之反映...更多。(4)在萨马达─达吉。 相似文献
89.
90.
KINEMATIC FEATURES OF TECTONIC DEFORMATION OF TERRANES IN THE XIZANG (TIBETAN) TETHYAN BELT 下载免费PDF全文
Shen Xianjie 《地震地质》1992,14(3):204
From the point of view of plate kinematics a unified convergence velocity model is employed to derive a series of kinematic equations for deformation of Himalaya and Lhasa-Gangdise terranes during the Himalayan orogeny.These equations describe terrane shortening,crust-upper mantle thickening,lateral strike-slip movement,plateau surface uplift,erosion planation and isostatic height of the crust,etc.These kinematic equations for terrane deformation derived on the basis of mass conservat 相似文献