A review of mineral systems and associated tectonic settings of northern Xinjiang, NW China

Abstract

KEYWORDSMineral system; Porphyry and epithermal deposits; Volcanogenic massive sulphides and skarn systems; Northern Xinjiang of NW ChinaAbstract 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 are 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) maficeultramafic 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,

Geochronology and geochemistry of igneous rocks in the Bailingshan area: Implications for the tectonic setting of late Paleozoic magmatism and iron skarn mineralization in the eastern Tianshan, NW China

“…Huang et al (2013) Ar age of ca. 277 Ma determined on skarn amphiboles (Pirajno et al, 2011). The Cu-rich Yinbangshan VMS Cu-rich deposit, hosted in rocks of the Yamansu Formation, has not been dated Li et al, 2012), but must be syngenetic with its Early Carboniferous host rocks and thus older than the belt of Late Carboniferous-Permian skarns.…”

“…The Kanggur shear zone contains a series of epithermal Au, orogenic Au, and magmatic Cu-Ni sulfide deposits formed at ca. 290-250 Ma (Mao et al, 2005;Yang et al, 2009;Pirajno et al, 2011).…”

“…1b): (1) Fe skarn deposits, (2) Fe-Cu deposits, (3) Cu-Ag-Pb-Zn skarn deposits, and (4) Cu-rich VMS deposits (Mao et al, 2005;Wang et al, 2006;Pirajno et al, 2011). The Fe skarns include those at Aqishan, Hongyuntan, Bailingshan, Chilongfeng, and Yamansu, whereas Fe-Cu deposits are represented by the Duotoushan, Heifengshan, Shuangfengshan and Shaquanzi.…”

“…This orogenic belt is commonly accepted as a Neoproterozoic to Permian giant accretionary orogen that experienced oceanic plate subduction and terrane accretion episodes, with final ocean closure occurring during the Late Carboniferous to Early Permian (Sengör and Natal'in, 1996;Chen, 2000;Chen and Jahn, 2004;Xiao et al, 2008). As an important component of the CAOB, the Tianshan Orogenic Belt (TOB), is the suture zone direct contact relationship between intrusions and the skarn and iron ores (Mao et al, 2005;Wang et al, 2005;Wang et al, 2006;Pirajno et al, 2011;. The widespread Carboniferous granitoids and marine volcanic-sedimentary rocks have attracted significant attention in the last two decades, in large part, because of the economic iron deposits (C.Z.…”

Geochemistry of primary-carbonate bearing K-rich igneous rocks in the Awulale Mountains, western Tianshan: Implications for carbon-recycling in subduction zone

“…The occurrence of Carboniferous-Permian potassic and ultrapotassic igneous rocks associated with Cu-(Au) mineralization in the Awulale Mountains has been interpreted to be the result of a fundamental shift of geodynamic setting associated with the termination of subduction Pirajno et al, 2011;Yang et al, 2012;Xiao et al, 2013). Generally, the Awulale Mountains can be divided into two sections based on the regional lithology.…”