Palaeo‐Mesoproterozoic magmatic and metamorphic events from the Kuluketage block, northeast Tarim Craton: geochronology, geochemistry and implications for evolution of Columbia

Abstract

Banded iron formations (BIFs), granites and diabases are extensively distributed in the Kuluketage block of the northeast Tarim Craton. Here we report laser ablation–inductively coupled plasma–mass spectrometry (LA‐ICP‐MS) zircon U–Pb ages and whole‐rock elemental data for these rocks. The detrital zircons from the BIFs show a peak age of 2.0–1.8 Ga with a weighted mean age of 1945 ± 10 Ma (MSWD = 0.77), and the zircons from the granite give an upper intercept age of 1974 ± 27 Ma (MSWD = 1.05). The trace element features suggest that the Asitingbulake granite, which belongs to the I‐type granite, may originate from the re‐melting of continental crust in a ~1.95 Ga collisional orogenic setting. Recently, the 2.0–1.8 Ga continuous magmatic and metamorphic events which are contemporaneous with the global orogenic event have been reported in the Kuluketage block and other massifs around the Tarim Craton (e.g. Central Tianshan, Dunhuang, Quanji, Altyn Tagh, West Kunlun). Based on the previous geochronological data, two 2.0–1.8 Ga orogens associated with the assembly of the Columbia supercontinent can be identified along the north and south margins of Tarim Craton: (1) the north Tarim Orogen, Central Tianshan–Kuluketage–Dunhuang orogenic belt and (2) the south Tarim Orogen, West Kunlun–Altyn Tagh–Aketashtage–Quanji orogenic belt. Additionally, this paper reports a new zircon U–Pb age of 1497 ± 21 Ma (MSWD = 0.96) from the Baowenbulake diabase dykes where the trace element features suggest that the parental magma of Baowenbulake diabases is derived from the mantle in an intra‐plate rifting or extensional setting. The ~1.5 Ga diabases from northwest Tarim corresponded to a major episode of mafic magmatism during the early Mesoproterozoic period identified in other crustal fragments of Laurentia, Siberia, Greater Congo, South China and North China Craton and probably belong to one of the three major large igneous provinces associated with the breakup of the Mesoproterozoic Columbia supercontinent. The data from this paper provide important constraints on the configuration of the Tarim Craton during the assembly and breakup of the Columbia supercontinent. Copyright © 2017 John Wiley & Sons, Ltd.