Abstract:

We report here our new perspectives on magmatismrelated mineralization temporally concentrated in the CarboniferousPermian periods in the vast region of the northern Xinjiang Autonomous Region. Our broad aim is to provide a conceptual basis for discussion towards an improved understanding of the mineralization and further exploration. We confirm the idea that the DevonianCarboniferous magmatism and related mineralization in the region is a consequence of plate tectonics， and such mineralization may have well continued until the Triassic. The onset of the mantle plume activities in the region is poorly constrained， which may date back to the Late Carboniferous and prevailed in the Permian. The coexistence and coevality of the two tectonomagmatic processes resulted in the abundant mineralization and its variability in time and space. The major types of mineralization include (1) magnetite deposits hosted in the strata of Late Devonian/Early Carboniferous age (perhaps formed from volcanic flows as interpreted， but more like skarn/hydrothermal deposits in character)， (2) porphyry/skarn Cu (and Mo) deposits of Late Devonian through Early Triassic age， and (3) CuNi sulfide and TiVmagnetite deposits of Permian age associated with maficultramafic intrusive complexes. The latter deposits that are widespread along orogenic belts are coeval (280±5 Ma) with the hidden flood basalt in the Tarim Basin in southern Xinjiang (interpreted as a large igneous province or LIP). This observation suggests the possibility that the LIP may in fact be much greater in its spatial distribution. If proved， this will have profound implications for the Permian TiV magnetite and CuNi sulfide mineralization in the region， i.e.， the association of such known deposits with the orogenic belts may reflect the tectonic exposure and more and larger deposits may in fact yet be discovered in more sites and over a much greater area away from the orogenic belts.

Key words: Northern Xinjiang, CarboniferousPermian period, plate tectonics, large igneous province, coexistence of tectonic regime