哀牢山造山带构造演化及其两侧盆地耦合   总被引：1，自引：0，他引：1  

邓茂林  张志斌  李长青 《云南地质》2010,29(2):177-181

哀牢山造山带的崛起和盆地耦合,对东西两侧沉降盆地的构造-沉积性质起关键性作用。转换构造性质不仅形成了逆冲推覆与走滑剪切联合作用的构造共生组合,形成两类不同性质的沉积盆地。  相似文献   

Silurian Sedimentation in the South Qilian Belt: Arc-Continent Collision-related Deposition in the NE Tibet Plateau?     

YAN Zhen  FU Changlei  Jonathan C. AITCHISON  ZHOU Renjie  Solomon BUCKMAN  CHEN Lei 《《地质学报》英文版》2020,94(4):901-913

The South Qilian belt mainly comprises an early Paleozoic arc-ophiolite complex, accretionary prism, microcontinental block, and foreland basin. These elements represent accretion-collision during Cambrian to Silurian time in response to closure of the Proto-Tethyan Ocean in the NE of the present-day Tibet Plateau. Closure of the Proto-Tethyan Ocean between the Central Qilian block and the Oulongbuluke block and the associated collision took place from NE to SW in a zipper-like style. Sediment would have been dispersed longitudinally SW-ward with a progressive facies migration from marginal alluvial sediments toward slope deep-water and deep-sea turbidites. This migration path indicates an ocean basin that shrank toward the SW. The Balonggongga'er Formation in the western South Qilian belt represents the fill of a latest Ordovician-Silurian remnant ocean basin that separated the Oulongbuluke block from the Central Qilian block, and records Silurian closure of the Proto-Tethyan Ocean and subduction beneath the Central Qilian block. However, alluvial deposits in the Lajishan area were accumulated in a retro-foreland basin, indicating that continent-continent collision in the eastern South Qilian belt occurred at c. 450–440 Ma. These results demonstrate that the Proto-Tethyan Ocean closed diachronously during early Paleozoic time.  相似文献   

Coeval basin formation,plutonism and metamorphism in the Northern Tasmanides: extensional Cambro-Ordovician tectonism of the Charters Towers Province     

R. A. Henderson  C. L. Fergusson  I. W. Withnall 《Australian Journal of Earth Sciences》2020,67(5):663-680

Abstract

The Charters Towers Province, of the northern Thomson Orogen, records conversion from a Neoproterozoic passive margin to a Cambrian active margin, as characteristic of the Tasmanides. The passive margin succession includes a thick metasedimentary unit derived from Mesoproterozoic rocks. The Cambrian active margin is represented by upper Cambrian–Lower Ordovician (500–460?Ma) basinal development (Seventy Mile Range Group), plutonism and metamorphism resulting from an enduring episode of arc–backarc crustal extension. Detrital zircon age spectra indicate that parts of the metamorphic basement of the Charters Towers Province (elements of the Argentine Metamorphics and Charters Towers Metamorphics) overlap in protolith age with the basal part of the Seventy Mile Range Group and thus were associated with extensional basin development. Detrital zircon age data from the extensional basin succession indicate it was derived from a far-field (Pacific-Gondwana) primary source. However, a young cluster (<510?Ma) is interpreted as reflecting a local igneous source related to active margin tectonism. Relict zircon in a tonalite phase of the Fat Hen Creek Complex suggests that active margin plutonism may have extended back to ca 530?Ma. Syntectonic plutonism in the western Charters Towers Province is dated at ca 485–480?Ma, close to timing of metamorphism (477–467?Ma) and plutonism more generally (508–455?Ma). The dominant structures in the metamorphic basement formed with gentle to subhorizontal dips and are inferred to have formed by extensional ductile deformation, while normal faulting developed at shallower depths, associated with heat advection by plutonism. Lower Silurian (Benambran) shortening, which affected metamorphic basement and extensional basin units, resulted in the dominant east–west-structural trends of the province. We consider that these trends reflect localised north–south shortening rather than rotation of the province as is consistent with the north–south paleogeographic alignment of extensional basin successions.

1. KEY POINTS

2. Northern Tasmanide transition from passive to active margin tectonic mode had occurred by ca 510?Ma, perhaps as early as ca 530?Ma.

3. Cambro-Ordovician active margin tectonism of the Charters Towers Province (northern Thomson Orogen) was characterised by crustal extension.

4. Crustal extension resulted in the development of coeval (500–460?Ma) basin fill, granitic plutonism and metamorphism with rock assemblages as exposed across the Charters Towers Province developed at a wide range of crustal levels and expressing heterogeneous exhumation.

5. Protoliths of metasedimentary assemblages of the Charters Towers Province include both Proterozoic passive margin successions and those emplaced as Cambrian extensional basin fill.

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中国中央造山系原- 古特提斯多阶段复合造山过程     

董云鹏  惠博  孙圣思  杨钊  张菲菲  何登峰  孙娇鹏  史小辉 《地质学报》2022,96(10):3426-3448

中国中央造山系是由亲劳亚的北方陆块群、亲冈瓦纳的南方陆块群及其间大量过渡性微陆块历经复杂拼合而成的复合型造山带，是中国大陆完成主体拼合的构造结合带。中央造山系自西而东包括昆仑造山带、祁连造山带和秦岭- 大别造山带，保存了古生代—早中生代时期华北、华南、柴达木、塔里木、羌塘等众多大小陆块造山过程的丰富信息，是研究东特提斯构造域原、古特提斯洋构造演化的重要窗口。本文综述了中央造山系地质、地球化学和高精度年代学等多学科研究成果，得到以下主要认识：① 550 Ma之前，众多大小陆块孤立散布于原特提斯洋；② 541~485 Ma，原特提斯洋各分支开始俯冲；③ 485~444 Ma，原特提斯洋持续俯冲，导致秦岭二郎坪弧后盆地、昆仑祁漫塔格弧后盆地打开；④ 444~420 Ma，原特提斯北祁连洋、南祁连洋和商丹洋闭合，昆仑祁漫塔格弧后盆地关闭；⑤ 420~300 Ma，昆仑地区古特提斯洋继承原特提斯洋，古特提斯勉略洋逐步扩张；⑥ 300~250 Ma，昆仑洋自阿其克库勒湖- 昆中缝合带向木孜塔格- 布青山- 阿尼玛卿缝合带发生俯冲后撤；⑦ 250~200 Ma，原- 古特提斯昆仑洋、古特提斯勉略洋关闭；⑧ 200 Ma以来，中央造山系转入陆内造山阶段。  相似文献   

Isotope geochemistry of the Tieluping silver-lead deposit, Henan, China: A case study of orogenic silver-dominated deposits and related tectonic setting   总被引：22，自引：0，他引：22  

Yan-jing Chen  Franco Pirajno  Ying-hui Sui 《Mineralium Deposita》2004,39(5-6):560-575

The Tieluping silver deposit, which is sited along NE-trending faults within the high-grade metamorphic basement of the Xionger Terrane in the Qinling orogenic belt, is part of an important, recently discovered Mesozoic orogenic-type Ag-Pb belt. Ore formation includes three stages: an early barren quartz-pyrite stage (E), an intermediate polymetallic sulfide ore stage (M), and a late barren carbonate stage (L). Carbon, sulfur and lead isotope systematics indicate that the E-stage fluids are deeply sourced; the L-stage fluids are shallow-sourced meteoric water; whereas the M-stage fluids are a mix of deep-sourced and shallow-sourced fluids. Sulfur and lead isotope data show that the ore-forming fluids must have originated from a source with elevated radiogenic lead and low ³⁴S values, that differs significantly from exposed geologic units in the Xionger Terrane, the lower crust and the mantle. This supports the view that the carbonate-shale-chert sequences of the Guandaokou and Luanchuan Groups south of the Machaoying fault might be the favorable sources, although little is known about their isotopic compositions. A tectonic model that combines collisional orogeny, metallogeny and hydrothermal fluid flow is proposed to explain the formation of the Tieluping silver deposit. During the Mesozoic collision between the North China Craton and South China Block (Early-Mid Triassic Indosinian Orogeny), crustal slabs containing the carbonate-shale-chert sequences of the Guandaokou and Luanchuan Groups, locally rich in organic matter (carbonaceous shale), were thrust northwards beneath the Xionger Terrane along the Machaoying fault. Metamorphic devolatilisation of this underthrust slab probably provided the ore-forming fluids to develop the Ag-Pb ore belt, which includes the Tieluping silver deposit. Fluids and magmas were emplaced during extensional stages related to the Jurassic-Cretaceous Yanshanian Orogeny.Editorial Handling: B. Lehmann  相似文献   

P-T Conditions of Metamorphism in the Neoproterozoic Rocks of the Negele Area, Southern Ethiopia     

Tadesse Yihunie  Mamoru Adachi  Makoto Takeuchi 《Gondwana Research》2004,7(2):489-500

Neoproterozoic rocks constitute the Kenticha, Alghe and Bulbul litho-tectonic domains in the Negele area of southern Ethiopia. Structural features and fabrics in these rocks were developed during north-south folding (D1), thrusting (D2) and shearing (D3) deformation. From micro-structural inferences and fabric relationships in semi-pelitic schists/gneisses of the Kenticha and Alghe domains, three episodes of metamorphic mineral growths (M1, M2 and M3) are inferred to have accompanied the deformational events. Pressure-Temperature estimates on equilibrium garnet-plagioclase-biotite and garnet-biotite assemblages from semi-pelitic schists/gneisses of the two domains indicate metamorphic recrystallization at temperatures of 520–580°C and 590–640°C, and pressures of 4–5 kb and 6–7 kb in the Kenticha and Alghe domains, respectively. These results correspond to regional metamorphism at a depth of 16–20 km for the Kenticha and 22–25 km for the Alghe domains. The P-T results suggest that the protoliths to the rocks of the Kenticha and Alghe domains were subjected to metamorphism at different crustal depths. This implies exhumation of the Alghe gneissic rocks from intermediate crustal level (ca. 25 km) before juxtaposition with the Kenticha sequence along a north-south trending thrust at the present crustal level during the Neoproterozoic. The combined deformation, fabric and mineral growth data suggest that rocks in the Kenticha and Alghe domains evolved under similar tectono-metamorphic conditions, which resulted from crustal thickening and uplift followed by extension and orogenic collapse, exhumation and cooling before litho-tectonic domains coalesced and cratonized in the Neoproterozoic southern Ethiopian segment of the East African Orogen.  相似文献   

The Rössing Uranium Deposit: a product of late-kinematic localization of uraniferous granites in the Central Zone of the Damara Orogen, Namibia     

I.J Basson  G Greenway   《Journal of African Earth Sciences》2004,38(5):259

The Rössing granite-hosted uranium deposit in the Central Zone of the Pan-African Damara Orogen, Namibia, is situated in the “SJ area” to the south of the Rössing Dome. The coincidence of a number of features in this area suggests that mineralization is closely linked to late-kinematic evolution of the Rössing Dome. These features include: (1) the rotation of the dome's long axis (trend of 017°), relative to the regional F₃ trend of 042°; (2) southward dome impingement, concomitant with dome rotation, producing a wedge-shaped zone of alkali-leucogranites, within which uranium mineralization is transgressive with respect to granites and their host lithologies; uranium mineralization and a high fluid flux are also confined to this arcuate zone to the south and south-east of the dome core and (3) fault modeling that indicates that the SJ area underwent late-D₃ to D₄ brittle–ductile deformation, producing a dense fault network that was exploited by leucogranites. Dome rotation and southward impingement occurred after a protracted period of transtensional tectonism in the Central Zone, from ca. 542 to 526 Ma, during which I- and S-type granites were initiated in a metamorphic core complex. Late-kinematic deformation involved a rejuvenation of the stresses that acted from ca. 600 to 550 Ma. This deformation overlapped with uranium-enriched granite intrusion in the Central Zone at 510 ± 3 Ma. Such late-kinematic, north–south transpression, which persisted into the post-kinematic cooling phase until at least 478 ± 4 Ma, was synchronous with left-lateral displacement along NNE-trending (“Welwitschia Trend”) shears in the vicinity of Rössing. Late-kinematic deformation, causing block rotation, overlying dome rotation and interaction of the more competent units of the Khan Formation with the Rössing Formation in the dome rim was pivotal in the localization of uranium-enriched granites within a highly fractured, high-strain zone that was also the site of prolonged/high fluid flux.  相似文献   

北秦岭新元古代前属于扬子板块的地球化学证据   总被引：18，自引：1，他引：17  

张本仁  许继锋 《高校地质学报》1998,4(4):369-382

秦岭是扬子板块和华北陆块间的复合造山带,其中存在两个古缝合带,北面的新元古代到早古生代商－丹缝合带介于北秦岭和南秦岭之间,南面的晚古生代勉－略缝合带形成于南秦岭与扬子陆块北缘之间,属于确知的扬子陆块内部打开形成的类型。北秦岭在地壳增生历史,元古宙上地慢性质,以及元古宙以来地幔相对富Nb、Ta、Cu,高Rb／Sr、Ba／Sr、Ba／La、Th／La、Nb／Ta比值和相对贫Fe、Mo方面均与南秦岭和扬子陆块北段一致。而与华北板块南段明显不同。变玄武岩类的Pb同位素三维空间拓扑图和铀εNd（t）－206Pb／204Pb图显示,区域一级地球化学界面位于北秦岭与华北陆块的分界处,二级界面才是商丹－缝合带。构造侵位于该带中的松树沟蛇绿岩<1000 Ma士)中已发现并存着N—MORB和E—MORB型变拉斑玄武岩。表明它们的岩浆分别来自亏损地幔和深部地幔热柱源区。松树沟蛇绿岩与勉,略蛇绿岩中的N—MORB型岩石具有与此相似的同位素组成和特征元素对比值,暗示松树沟蛇绿岩所代表的古洋壳也应属于扬子板块内部型。加之,新元古代之前秦岭只存在裂谷系而无板块结合带,故可确定北秦岭原来应属于扬子板块的组成部分。对秦岭群和宽坪群变拉斑玄武岩及松树沟E—MORB和N—MIORB进行地球化学对比的结果,既能够支持北秦岭是在扬子板块的洋壳洋岛基础上发展形成的微陆块的推断,又可解释北秦岭幔源岩石具有特高Th／La、Yb／Hf、Sc／Th比值和壳幔更富于放射成因钳的原因。此外。对本研究结果在秦岭造山带发展动力学方面的意义也进行了初步讨论。  相似文献   

祁连山东段的元古宙陇山群   总被引：6，自引：0，他引：6  

宋志高 《地球学报》1995,16(2):204-210

陇山群是从祁连山东段原“牛头河群”哑岩系下部分解出来的变质岩系，它包括从下到上的大理岩和片麻岩两个岩组。依其片麻岩组先后同位素年代学的研究，主要最早一组年龄值为８１３－８１１Ｍａ，相当中－上元古代。作者从该岩群的出露和展布，认为在构造体系上，它属祁连山带的基底隆起部分，并讨论了赋存在片麻岩组内陈家调铁铜矿床的特征及其地质意义。  相似文献   

金平白马寨铜镍矿床综合信息成矿预测模型   总被引：4，自引：0，他引：4  

宋立军  朱杰勇 《云南地质》2003,22(2):161-169

系统研究哀牢山造山带金平白马寨铜镍矿床的地质、地球物理及地球化学特征。提出本矿床为含矿基性—超基性岩浆熔离—结晶分异和矿浆依次脉冲式贯入的铜镍硫化物矿床成矿模式，最终建立本区铜镍矿床的综合信息成矿预测模型。  相似文献