SIMS zircon U-Pb geochronology and Sr-Nd isotopes of Ni-Cu-Bearing Mafic-Ultramafic Intrusions in Eastern Tianshan and Beishan in correlation with flood basalts in Tarim Basin (NW China): Constraints on a ca. 280 Ma mantle plume

The Early Permian Tarim Large Igneous Province: Main characteristics and a plume incubation model

“…The Tarim flood basalts have been dated using K-Ar, 40 Ar-39 Ar and U-Pb isotopic techniques, which yielded an age spectrum ranging from 260 Ma to 293 Ma Qin et al, 2011;Wei et al, 2014). Such a wide range largely stems from the use of K-Ar dating which suffers from post-eruption alteration and excess Ar problems.…”

“…1a). For instance, many~280 Ma igneous rocks are found in western Tianshan, eastern Tianshan, Beishan and western Karakurum (Qin et al, 2011;Xu et al, 2013).…”

“…In recent years, a mantle plume model has been variably adopted to explain the generation of the Tarim basalts Pirajno et al, 2008Pirajno et al, , 2009Qin et al, 2011;Tian et al, 2010;Wei et al, 2014;Yu et al, 2011b;Zhang et al, 2008aZhang et al, , 2010bZhou et al, 2009), but is only loosely constrained. In the paragraphs below, the role of mantle plumes in the generation of the Tarim LIP is discussed in detail.…”

An Early Permian (ca. 280Ma) silicic igneous province in the Alxa Block, NW China: A magmatic flare-up triggered by a mantle-plume?

“…Early Permian igneous rocks are widely distributed in NW China (e.g., Qin et al, 2011;Su et al, 2011;Xia et al, 2012;Xu et al, 2013;Zou, 2013a, 2013b;Zhang et al, 2010), including the Tarim, Tianshan and CAOB, and constitute a large igneous province referred to as the Tarim or the Tianshan. A mantle plume has been invoked to explain the characteristics of these rocks (e.g., Qin et al, 2011;Su et al, 2011;Xu et al, 2013;Zhang et al, 2010;Zhou et al, 2004), e.g., widely distributed basaltic rocks (e.g., Zhang et al, 2010), extremely high magma temperatures estimated to be in the range of 1100-1600°C , and widely distributed mafic-ultramafic complexes (e.g., Qin et al, 2011). The Early Permian mantle plume was recently proposed to be situated closer to the Beishan Rift than the Eastern Tianshan and the western Tarim (Su et al, 2012).…”

“…280 Ma) igneous rocks with predominantly ultramafic-mafic rocks are widespread in the Tarim Craton and the Central Asian Orogenic Belt (CAOB) (e.g., Li et al, 2011;Wei et al, 2014;Xia et al, 2012;Xu et al, 2013;Yang et al, 2007Yang et al, , 2013Zhang et al, 2010;Zhou et al, 2004Zhou et al, , 2009, and correspond to the Tarim LIP (e.g., Qin et al, 2011;Su et al, 2011Su et al, , 2012. Recent dating of rocks on the Alxa Block, adjacent to the Tarim Craton and the CAOB, reveals that a large area of Early Permian (ca.…”