In this paper we present a review of mineral systems in northern Xinjiang, NW China, focussing on the Tianshan, West and East Junggar and Altay orogenic belts, all of which are part of the greater Central Asian Orogen...In this paper we present a review of mineral systems in northern Xinjiang, NW China, focussing on the Tianshan, West and East Junggar and Altay orogenic belts, all of which are part of the greater Central Asian Orogenic Belt (CAOB). The CAOB is a complex collage of ancient microcontinents, island arcs, oceanic plateaux and oceanic plates, which were amalgamated and accreted in Early Palaeozoic to Early Permian times. The establishment of the CAOB collage was followed by strike-slip movements and affected by intraplate magmatism, linked to mantle plume activity, best exemplified by the 250 Ma Siberian Traps and the 280 Ma Tarim event. In northern Xinjiang, there ale numerous and economically important mineral systems. In this contribution we describe a selection of representative mineral deposits, including subduction-related porphyry and epithermal deposits, volcanogenic massive sulphides and skarn systems. Shear zone-hosted Au lodes may have first formed as intrusion-related and subsequently re-worked during strike-slip deformation. Intraplate magmatism led to the emplacement of concentrically zoned (Alaskan-style) mafic-ultramafic intrusions, many of which host orthomagmatic sulphide deposits. A huge belt of pegmatites in the Altay orogen, locally hosts world-class rare metal deposits. Roll-front,展开更多
The Muruntau gold deposit in the Central Kyzylkum,Uzbekistan is one of the largest single gold deposits worldwide.Data available from the literature are reviewed with the aim to(1) integrate the present knowledge on...The Muruntau gold deposit in the Central Kyzylkum,Uzbekistan is one of the largest single gold deposits worldwide.Data available from the literature are reviewed with the aim to(1) integrate the present knowledge on this unique deposit from Russian and English literature;(2) show the considerable progress made in the understanding of the genesis of the Muruntau deposit during the last decades;and(3) point to problems still open for future research.Deposit formation occurred through a multi-stage process involving sedimentation,regional metamorphism including thrusting,magmatism with formation of hornfels aureoles and several stages of hydrothermal activity.According to recent knowledge,synsedimentary or pure metamorphic formation of gold mineralization seems unlikely.The role of granite magmatism occurring roughly within the same time interval as the main hydrothermal gold precipitation remains uncertain.There are no signs of interaction of matter between the magma(s) and the hydrothermal system(s).On the other hand,there was an intense,high-temperature(above 400 ℃)fluid- wall rock interaction resulting in the formation of gold-bearing,cone-like stockworks with veins,veinlets and gold-bearing metasomatites.Several chemical and isotope indicators hint at an involvement of lower-crustal or mantle-related sources as well as of surface waters in ore formation.Deposit formation through brecciation involving explosion,hydrothermal or tectonic breccias might explain these data.Further investigations on breccia formation as well as on the exact timing of relevant sedimentary,metamorphic,magmatic and hydrothermal events are recommended.展开更多
Zircon is widely used to simulate melt generation,migration and evolution within the crust and mantle.The achievable performance of melt modelling generally depends on the availability of reliable trace element partit...Zircon is widely used to simulate melt generation,migration and evolution within the crust and mantle.The achievable performance of melt modelling generally depends on the availability of reliable trace element partition coefficients(D).However,a large range of D_(REE) values for zircon from natural samples and experimental studies has been reported,with values spanning up to 3 orders of magnitude.Unfortunately,a gap of knowledge on this variability is evident.In this study we model the crystallization processes of common REE-bearing minerals from granitic melts and show that the measured zircon D_(REE) would be elevated if there is crystallization of REE-enriched minerals subsequent to zircon.Nevertheless,compared to zircon D_(REE) values measured from experimental studies,this mechanism appears to have a less significant influence on those from natural granite samples since the quantity of crystallized REE-enriched minerals is very low in natural magmatic systems and/or most of them crystallize prior to zircon.Combined with recently published studies,this work supports that analysis of natural zircon/host groundmass pairs provides more robust D_(REE) values applicable to natural systems than those measured from experimental studies,which can be used to constrain the provenance of detrital zircons.展开更多
基金funded by"State Key Laboratory of Geological Processes and Mineral Resources(GPMR200624),China University of Geosciences"
文摘In this paper we present a review of mineral systems in northern Xinjiang, NW China, focussing on the Tianshan, West and East Junggar and Altay orogenic belts, all of which are part of the greater Central Asian Orogenic Belt (CAOB). The CAOB is a complex collage of ancient microcontinents, island arcs, oceanic plateaux and oceanic plates, which were amalgamated and accreted in Early Palaeozoic to Early Permian times. The establishment of the CAOB collage was followed by strike-slip movements and affected by intraplate magmatism, linked to mantle plume activity, best exemplified by the 250 Ma Siberian Traps and the 280 Ma Tarim event. In northern Xinjiang, there ale numerous and economically important mineral systems. In this contribution we describe a selection of representative mineral deposits, including subduction-related porphyry and epithermal deposits, volcanogenic massive sulphides and skarn systems. Shear zone-hosted Au lodes may have first formed as intrusion-related and subsequently re-worked during strike-slip deformation. Intraplate magmatism led to the emplacement of concentrically zoned (Alaskan-style) mafic-ultramafic intrusions, many of which host orthomagmatic sulphide deposits. A huge belt of pegmatites in the Altay orogen, locally hosts world-class rare metal deposits. Roll-front,
基金supported by several grantsfrom DAAD,DFG(Wo 489/15-1,15-2KL 692/11-1,11-2)+1 种基金NSERC,NHM CERCAMS,IGCP(IGCP-473)the IGCP project 592 sponsored by IUGS and UNESCO
文摘The Muruntau gold deposit in the Central Kyzylkum,Uzbekistan is one of the largest single gold deposits worldwide.Data available from the literature are reviewed with the aim to(1) integrate the present knowledge on this unique deposit from Russian and English literature;(2) show the considerable progress made in the understanding of the genesis of the Muruntau deposit during the last decades;and(3) point to problems still open for future research.Deposit formation occurred through a multi-stage process involving sedimentation,regional metamorphism including thrusting,magmatism with formation of hornfels aureoles and several stages of hydrothermal activity.According to recent knowledge,synsedimentary or pure metamorphic formation of gold mineralization seems unlikely.The role of granite magmatism occurring roughly within the same time interval as the main hydrothermal gold precipitation remains uncertain.There are no signs of interaction of matter between the magma(s) and the hydrothermal system(s).On the other hand,there was an intense,high-temperature(above 400 ℃)fluid- wall rock interaction resulting in the formation of gold-bearing,cone-like stockworks with veins,veinlets and gold-bearing metasomatites.Several chemical and isotope indicators hint at an involvement of lower-crustal or mantle-related sources as well as of surface waters in ore formation.Deposit formation through brecciation involving explosion,hydrothermal or tectonic breccias might explain these data.Further investigations on breccia formation as well as on the exact timing of relevant sedimentary,metamorphic,magmatic and hydrothermal events are recommended.
基金financially supported by China Postdoctoral Science Foundation(Grant Nos.2020T130621,20180838)Opening Foundation of Key Lab of Submarine Geosciences and Prospecting Techniques+3 种基金MOE,Ocean University of China(Grant No.SGPT-20190F-05)the Fundamental Research Funds for the Central Universities of China(Grant No.201813026)the Science and Technology Project of Qinghai Province(Grant No.2019-ZJ-7009)funding under Natural Environment Research Council Grant NE/P017452/1“From arc magmas to ores(FAMOS):A mineral systems approach”。
文摘Zircon is widely used to simulate melt generation,migration and evolution within the crust and mantle.The achievable performance of melt modelling generally depends on the availability of reliable trace element partition coefficients(D).However,a large range of D_(REE) values for zircon from natural samples and experimental studies has been reported,with values spanning up to 3 orders of magnitude.Unfortunately,a gap of knowledge on this variability is evident.In this study we model the crystallization processes of common REE-bearing minerals from granitic melts and show that the measured zircon D_(REE) would be elevated if there is crystallization of REE-enriched minerals subsequent to zircon.Nevertheless,compared to zircon D_(REE) values measured from experimental studies,this mechanism appears to have a less significant influence on those from natural granite samples since the quantity of crystallized REE-enriched minerals is very low in natural magmatic systems and/or most of them crystallize prior to zircon.Combined with recently published studies,this work supports that analysis of natural zircon/host groundmass pairs provides more robust D_(REE) values applicable to natural systems than those measured from experimental studies,which can be used to constrain the provenance of detrital zircons.