Composite nature of the North China Granulite-Facies Belt: Tectonothermal and geochronological constraints   总被引：13，自引：3，他引：13  

Guochun Zhao  Min Sun  Simon A. Wilde  Li Sanzhong  Shuwen Liu  Jian Zhang 《Gondwana Research》2006,9(3):337-348

Granulite-facies rocks are intermittently exposed in a roughly E–W trending belt that extends for approximately 2000 km across the North China Craton, from the Helanshan, Qianlishan, Wulashan–Daqingshan, Guyang and Jining Complexes in the Western Block, through the Huai'an, Hengshan, Xuanhua and Chengde Complexes in the Trans-North China Orogen, to the Jianping (Western Liaoning), Eastern Hebei, Northern Liaoning and Southern Jilin Complexes in the Eastern Block. The belt is generally referred to as the North China Granulite-Facies Belt, previously interpreted as the lowest part of an obliquely exposed crust of the North China Craton. Recent data indicate that the North China Granulite-Facies Belt is not a single terrane. Instead, it represents components of three separate terranes: the Eastern and Western Blocks and Trans-North China Orogen. Each of these units records different metamorphic histories and reflect the complex tectonic evolution of the NCC during the late Archean and Paleoproterozoic. Mafic granulites in the Eastern Block and the Yinshan Terrane (Western Block) underwent medium-pressure granulite-facies metamorphism at about 2.5 Ga, with anticlockwise P–T paths involving near isobaric cooling following peak metamorphism, reflecting an origin related to intrusion and underplating of mantle-derived magmas. Pelitic granulites in the Khondalite Belt (Western Block) underwent medium-pressure granulite-facies metamorphism at about 2.0–1.9 Ga, with clockwise P–T paths, which record the Paleoproterozoic amalgamation of the Yinshan and Ordos Terranes to form the Western Block. Mafic and pelitic granulites in the Trans-North China Orogen experienced high- to medium-pressure granulite-facies metamorphism at 1.85 Ga, with clockwise P–T paths involving nearly isothermal decompression following peak metamorphism, which are in accord with the final collision between the Eastern and Western Blocks to form the North China Craton at 1.8 Ga. The NCGB cannot therefore represent a separate unique terrane; instead it reflects the amalgamation of three separate granulite terranes that evolved independently and at different times.  相似文献   

华北克拉通太古宙地壳演化和最古老的岩石   总被引：16，自引：3，他引：16  

刘敦一万渝生  伍家善S A Wilde董春艳  周红英殷小艳 《地质通报》2007,26(9):1131-1138

简要总结了华北克拉通太古宙地壳演化的规律、认识及存在的问题,特别是近年来在最古老的岩石和锆石年代学研究方面取得的进展。华北克拉通构造热事件主要发生在约2.5Ga,导致大规模陆壳的形成。仅在鲁西、胶东等少数地区有较大规模的约2.7Ga的地质体存在。古元古代晚期的陆陆碰撞使华北克拉通最终形成统一的整体。最近对鞍山地区的研究发现大量3.6～3.8Ga的岩石和锆石。在冀东、信阳、焦作及其他地区也有始太古代—古太古代的岩石和锆石存在。华北克拉通可能存在几个不同的古太古代—始太古代陆核。  相似文献   

The Heilongjiang Group: A Jurassic accretionary complex in the Jiamusi Massif at the western Pacific margin of northeastern China   总被引：45，自引：0，他引：45  

Fu-Yuan  Wu  Jin-Hui  Yang  Ching-Hua  Lo  Simon A.  Wilde  De-You  Sun  Bor-Ming  Jahn 《Island Arc》2007,16(1):156-172

Abstract The tectonic setting of the Eastern Asian continental margin in the Jurassic is highly controversial. In the current study, we have selected the Heilongjiang complex located at the western margin of the Jiamusi Massif in northeastern China for geochronological investigation to address this issue. Field and petrographic investigations indicate that the Heilongjiang complex is composed predominately of granitic gneiss, marble, mafic‐ultramafic rocks, blueschist, greenschist, quartzite, muscovite‐albite schist and two‐mica schist that were tectonically interleaved, indicating they represent a mélange. The marble, two‐mica schist and granitic gneiss were most probably derived from the Mashan complex, a high‐grade gneiss complex in the Jiamusi Massif with which the Heilongjiang Group is intimately associated. The ultramafic rocks, blueschist, greenschist and quartzite (chert) are similar to components in ophiolite. The sensitive high mass‐resolution ion microprobe U‐Pb zircon age of 265 ± 4 Ma for the granitic gneiss indicates that the protolith granite was emplaced coevally with Permian batholiths in the Jiamusi Massif. ⁴⁰Ar/³⁹Ar dating of biotite and phengite from the granitic gneiss and mica schist yields a late Early Jurassic metamorphic age between 184 and 174 Ma. Early components of the Jiamusi Massif, including the Mashan complex, probably formed part of an exotic block from Gondwana, affected by late Pan‐African orogenesis, and collided with the Asian continental margin during the Early Jurassic. Subduction of oceanic crust between the Jiamusi block and the eastern part of the Central Asian Orogenic Belt resulted in the formation of a huge volume of Jurassic granites in the Zhangguangcai Range. Consequently, the collision of the Jiamusi Massif with the Central Asian Orogenic Belt to the west can be considered as the result of circum‐Pacific accretion, unrelated to the Central Asian Orogenic Belt. The widespread development of Jurassic accretionary complexes along the Asian continental margin supports such an interpretation.  相似文献   

IGCP-499 Workshop ＂Depositional Environments of the Gondwanan and Laurasian Devonian＂     

Peter Konigshof Eberhard Schindler Volker Wilde Jurga Lazauskiene M. Namik Yalcin 《《幕》》2006,29(2):135-135

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Recent Experimental Results and Modelling of High-Mach-Number Jets and the Transition to Turbulence     

P. A. Rosen  B. H. Wilde  R. J. R. Williams  J. M. Foster  P. A. Keiter  R. F. Coker  T. S. Perry  M. J. Taylor  A. M. Khokhlov  R. P. Drake  G. R. Bennett  D. B. Sinars  R. B. Campbell 《Astrophysics and Space Science》2005,298(1-2):121-128

In recent years, we have carried out experiments at the University of Rochester’s Omega laser in which supersonic, dense-plasma jets are formed by the interaction of strong shocks in a complex target assembly (Foster et al., Phys. Plasmas 9 (2002) 2251). We describe recent, significant extensions to this work, in which we consider scaling of the experiment, the transition to turbulence, and astrophysical analogues. In new work at the Omega laser, we are developing an experiment in which a jet is formed by laser ablation of a titanium foil mounted over a titanium washer with a central, cylindrical hole. Some of the resulting shocked titanium expands, cools, and accelerates through the vacuum region (the hole in the washer) and then enters a cylinder of low-density foam as a jet. We discuss the design of this new experiment and present preliminary experimental data and results of simulations using AWE hydrocodes. In each case, the high Reynolds number of the jet suggests that turbulence should develop, although this behaviour cannot be reliably modelled by present, resolution-limited simulations (because of their low-numerical Reynolds number).  相似文献   

Newly-discovered Eoarchean TTG gneisses in the Tarim Craton imply plate tectonics at ~3.7 Ga     

Rongfeng Ge  Wenbin Zhu  Simon Wilde  Hailin Wu 《《地质学报》英文版》2018,92(Z1):129-130

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New palynology-based astronomical and revised 40Ar/39Ar ages for the Eocene maar lake of Messel (Germany)     

Olaf K. Lenz  Volker Wilde  Dieter F. Mertz  Walter Riegel 《International Journal of Earth Sciences》2015,104(3):873-889

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Magmatic history of the Eastern Creek Volcanics,Mt Isa,Australia: insights from trace-element and platinum-group-element geochemistry     

M. J. Gregory  R. R. Keays  A. R. Wilde 《Australian Journal of Earth Sciences》2013,60(8):1153-1173

The Paleoproterozoic basalts of the Eastern Creek Volcanics are a series of continental flood basalts that form a significant part of the Western Fold Belt of the Mt Isa Inlier, Queensland. New trace-element geochemical data, including the platinum-group elements (PGE), have allowed the delineation of the magmatic history of these volcanic rocks. The two members of the Eastern Creek Volcanics, the Cromwell and Pickwick Metabasalt Members, are formed from the same parental magma. The initial magma was contaminated by continental crust and erupted to form the lower Cromwell Metabasalt Member. The staging chamber was continuously replenished by parental material resulting in the gradual return of the magma composition to more primitive trends in the upper Cromwell Metabasalt Member, and finally the Pickwick Metabasalt Member formed from magma dominated by the parental melt. The Pickwick Metabasalt Member of the Eastern Creek Volcanics has elevated PGE concentrations (including up to 18 ppb Pd and 12 ppb Pt) with palladium behaving incompatibly during magmatic fractionation. This trend is the result of fractionation under sulfide-undersaturated conditions. Conversely, in the basal Cromwell Metabasalt Member the PGE display compatible behaviour during magmatic fractionation, which is interpreted to be the result of fractionation of a sulfide-saturated magma. However, Cu remains incompatible during fractionation, building up to high concentrations in the magma, which is found to be the result of the very small volume of magmatic sulfide formation (0.025%). Geochemical trends in the upper Cromwell Metabasalt Member represent mixing between the contaminated Cromwell Metabasalt magmas and the PGE-undepleted parental melt. Trace-element geochemical trends in both members of the Eastern Creek Volcanics can be explained by the partial melting of a subduction-modified mantle source. The generation of PGE- and copper-rich magmas is attributed to melting of a source in the subcontinental lithospheric mantle below the Mt Isa Inlier which had undergone previous melt extraction during an older subduction event. The previous melt extraction resulted in a sulfur-poor, metal-rich metasomatised mantle source which was subsequently remelted in the Eastern Creek Volcanic continental rift event. The proposed model accounts for the extreme copper enrichment in the Eastern Creek Volcanics, from which the copper has been mobilised by hydrothermal fluids to form the Mt Isa copper deposit. There is also the potential for a small volume of PGE-enriched magmatic sulfide in the plumbing system to the volcanic sequence.  相似文献   

SHRIMP U-Pb Dating of Detrital Zircons from the Hammamat Group at Gebel Umm Tawat, North-Eastern Desert, Egypt     

S.A. Wilde  K. Youssef 《Gondwana Research》2001,4(2):202

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Local Tsunami Warning in the Pacific Coastal United States   总被引：2，自引：1，他引：1  

Mark?DarienzoEmail author  Al?Aya  George?L.?Crawford  David?Gibbs  Paul?M.?Whitmore  Tyree?Wilde  Brian?S.?Yanagi 《Natural Hazards》2005,35(1):111-119

Coastal areas are warned of a tsunami by natural phenomena and man-made warning systems. Earthquake shaking and/or unusual water conditions, such as rapid changes in water level, are natural phenomena that warn coastal areas of a local tsunami that will arrive in minutes. Unusual water conditions are the natural warning for a distant tsunami. Man-made warning systems include sirens, telephones, weather radios, and the Emergency Alert System. Man-made warning systems are normally used for distant tsunamis, but can be used to reinforce the natural phenomena if the systems can survive earthquake shaking. The tsunami warning bulletins provided by the West Coast/Alaska and Pacific Tsunami Warning Centers and the flow of tsunami warning from warning centers to the locals are critical steps in the warning process. Public knowledge of natural phenomena coupled with robust, redundant, and widespread man-made warning systems will ensure that all residents and tourists in the inundation zone are warned in an effective and timely manner.  相似文献