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Tian Z.,Changan University | Tian Z.,Key Laboratory for the Study of Focused Magmatism and Giant Ore Deposits | Tian Z.,CAS Guangzhou Institute of Geochemistry | Li Y.,Changan University | And 8 more authors.
Jilin Daxue Xuebao (Diqiu Kexue Ban)/Journal of Jilin University (Earth Science Edition) | Year: 2016

The Early Permian volcanic rocks in Haerjiawu Formation are distributed in eastern Tangbale ophiolite belt on the southwest margin of Junggar basin. The volcanic rocks are mainly composed of greyish-green or purplish-red (vesicular) (amygdaloidal) basalt, basaltic andesite, and andesite. The high-precision LA-ICP-MS zircon U-Pb dating reveals that they were formed in Early Permian at the age of (296.6±8.1) Ma, MSWD=7.7 (93% conf.). Geochemically the volcanic rocks belong to sub-alkaline series. They have relatively high content of alkali (w(Na2O+K2O)=3.95%-6.39%), and enriched in sodium. The LREE are relatively enriched ((La/Yb)N=3.49-14.66) and well fractionated ((La/Sm)N=1.68-3.51); while the HREE fractionation is weak ((Gd/Yb)N=1.38-2.56). Only some of the samples have weak negative Eu anomalies (δEu=0.88-1.15). All samples are enriched in LILE; while HFSE are relatively depleted in Nb and Ta but slightly enriched in Zr, Hf. These characteristics, along with element correlation diagram, indicate that the volcanic rocks in Qiada area mainly generated in intra-plate continent with partial island arc environments. These volcanic rocks were from extensional setting of post-collisional period. These island-arc characteristics are inherited from pre-collisional arc component. © 2016, Jilin University Press. All right reserved. Source


Yang G.X.,Ajsy Laboratory of Western Chinas Mineral Resources and Geological Engineering | Yang G.X.,Changan University | Li Y.J.,Ajsy Laboratory of Western Chinas Mineral Resources and Geological Engineering | Li Y.J.,Changan University | And 7 more authors.
Acta Petrologica Sinica | Year: 2010

Kalamaili potassic basaltic rocks occur within the Lower Carboniferous Batamayineishan Formation, NE margin of the Junggar Basin. The potassic basaltic rocks mainly composed of trachybasalt and basalic trachyandesite, have moderate SiO2(46. 29% -51. 56% ) values, relatively high alkali ( K 2O + Na2O = 5. 39% ∼ 6. 96% ) , TiO2 (0. 94% ∼ 1. 21% ) contents and K20/Na20 ratios ( K 2 O/Na2 0=0. 5-1.4), displaying characteristics of shoshonitic basalts series. Through researching petrogeochemistry, showing the rocks enriched in LILE (such as K, Rb and Sr) and LREE ( (La/Yb)n =4. 39 -6. 25) , possess positive Eu anomalies (δ Eu = 1.3 -1.7) , relatively depleted in HFSE ( such as Zr, Hf) , with strong negative Ta, Nb and Ti "TNT" anomalies, high Ba/ Nb and Ba/Ta ratios (38 -93, 574 - 1470 respectively) , indicating typical island-arc characteristics, and Nd-Sr isotopes show a depleted mantle source. The ratios of incompatible element ( Nb/La) N and Ba/La (0. 33 -0. 41, 11. 07 - 18. 82 respectively) , and high Nb (4. 45 × 10-6 - 7. 76 × 10 ) contents, suggesting that these potassic basaltic rocks were derived from a metasomatized, phlogopite- and/or amphibole-bearing mantle source. Through hierachical set of discrimination diagrams of tectonic settings for Kalamaili potassic basalt, indicating Batamayineishan Formation shoshonitic basalts formed in the post-collisional arc-type surroundings. Due to intracontinental adjustment in the post-collisional period, lithosphere extended and thinned, with this process, the mantle wedge ( phlogopite and/or potassic amphibole-spinel facies lherzolite) metasomatized by fluid in earlier stage melted partially under decompression and high temperature, forming shoshonitic basaltic magma, leading to post-collisional type magma movement ( characteristics by arc volcanic rocks in geochemistry) , the erupted lavas became the Batamayineishan Formation shoshonitic basalts. Source


Yang G.,Changgan University | Li Y.,Changgan University | Wu H.,Xinjiang Institute of Geological Exploration for Nonferrous Resources | Zhong X.,Changgan University | And 4 more authors.
Journal of Asian Earth Sciences | Year: 2011

The Huangyangshan pluton occurs in the Kalamaili region which is situated in the central part of the Central Asian Orogenic Belt, East Junggar, Xinjiang (NW China). The granitoid rocks are composed of medium-grained biotite (richterite, arfvedsonite) alkali-feldspar granite, fine grained arfvedsonite alkali-feldspar granite and microgranular enclaves. The granites have a pronounced A-type affinity: they are metaluminous to weakly peraluminous and calc-alkaline to alkaline in composition with high concentrations of Na2O+K2O varying from 8.4 to 9.2wt.%, high FeOt/MgO and 10,000Ga/Al ratios, low abundances of CaO, MgO and TiO2, enrichment in some LILEs (such as Rb and Th) and HFSEs (such as Zr, Y and REEs except Eu), depletion in Sr and Ba. Moreover, they display characteristic tetrad REE patterns and non-CHARAC trace element behavior, which is well demonstrated in highly differentiated rocks with strong hydrothermal interaction. The U-Pb zircon LA-ICP-MS ages of the host rocks and enclaves are 311±5Ma and 300±6Ma, respectively. The similar of these two ages suggests that host rocks and enclaves formed at a same time. Furthermore, the time span closely corresponds to known ages of post-collisional A-type granitoids of the Junggar terrane. Geochemical, geochronological and isotopic data (ΣNd(T) in the range +5.2 to +6.6 and ISr mostly in the range 0.7031-0.7041) suggest that the Huangyangshan intrusions, and the enclaves are of mixed origin and are most probably formed by the interaction between the lower crust- and mantle-derived magmas in the Late Carboniferous post-collisional tectonic setting (A2 type granite). The magma for the Huangyangshan granites was derived by partial melting of an enriched subcontinental lithospheric mantle (SCLM) that was modified by slab-derived components from an earlier subduction event, this melting resulted from heat supplied from the asthenosphere through an opening created during the break-off of an oceanic slab. This further proves the important contribution of the Late Paleozoic granitic magmatism in terms of vertical crustal growth in northern Xinjiang. © 2010 Elsevier Ltd. Source


Cheng Y.,Xinjiang Institute of Geological Exploration for Nonferrous Resources | Yan C.-X.,Xinjiang Institute of Geological Exploration for Nonferrous Resources | Zhu S.-S.,Xinjiang Institute of Geological Exploration for Nonferrous Resources | Yu Y.-L.,Xinjiang Institute of Geological Exploration for Nonferrous Resources | Zhang H.,Xinjiang Institute of Geological Exploration for Nonferrous Resources
Northwestern Geology | Year: 2012

The Haerdaban lead-zinc deposit is located in the Biezhentaoshan area of west part of the Western Tianshan, which belongs to Sailimu Cu, Pb, Zn, Nb, Ta, W and P metallogenic belt. Ore body, which is stable extension, occur in the low-grade metamorphic marine clastic rocks and carbonate rocks of the Middle Proterozoic Changcheng System. The main ore body is beds-, lens-like bedding output with banded, brecciated, and disseminated structure. Metal minerals in the ore are mainly galena and sphalerite. Moreover, mineral assemblages in gangue are simple, including calcite and dolomite. Compared with the Jiekeli strata-bound lead-zinc deposit in Kazakhstan, the Haerdaban lead-zinc deposit is similar to formed settings, times, locations, ore characteristics and quality. Preliminary analysis shows that its genetic types are stratabound type, which is discovered for the first time in Precambrian strata of western Tianshan. It is confirmed that the Jiekeli strata-bound lead-zinc deposit extended east to Sailimu area, Xinjiang, China. Furthermore, it is of great significance for lead and zinc exploration of the region in the future. Source

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