Geochronology and geochemical characteristics of Late Triassic porphyritic rocks from the Zhongdian arc, eastern Tibet, and their tectonic and metallogenic implications

Double-layer structure of the crust beneath the Zhongdian arc, SW China: U–Pb geochronology and Hf isotope evidence

“…The Zhongdian arc, which is the southern part of the Yidun arc, contains many Late Triassic intermediate-felsic porphyritic intrusions and associated andesites. The porphyries host porphyry Cu deposits, including the Pulang, Xuejiping, Chundu, and Lannitang deposits (Hou et al, 2004b(Hou et al, , 2007Li et al, 2011;Ren, 2011;Wang et al, 2011;Leng et al, 2012;Chen et al, 2014). In addition, several Late Cretaceous Mo-Cu polymetallic deposits related to the granitic plutons are found in this region, such as in the Xiuwacu, Relin, Hongshan, and Tongchanggou areas Li et al, 2007Li et al, , 2013Meng et al, 2013;H.…”

“…In addition, numerous Late Triassic to Cenozoic dioritic-granitic plutons were intruded into the Triassic volcanic and sedimentary rocks ( Fig. 1; Reid et al, 2007;Weislogel, 2008;Wang et al, 2011;Chen et al, 2014).…”

“…The Zhongdian arc is the southern part of the Yidun arc, and it contains Late Triassic porphyry Cu deposits (e.g., Pulang, Xuejiping, and Chundu) (Hou et al, 2004b(Hou et al, , 2007Li et al, 2011;Wang et al, 2011;Chen et al, 2014) and Cretaceous Mo-Cu polymetallic deposits (e.g., Xiuwacu, Relin, and Hongshan) H. J. Peng et al, 2014;X.…”

“…However, the ages and formation mechanisms of Late Triassic ore-bearing porphyries (e.g., S. X. Wang et al, 2008a;Ren, 2011;Wang et al, 2011;Leng et al, 2012;Chen et al, 2014) and Late Cretaceous granitic intrusions related to Mo-Cu polymetallic deposits (e.g., Xu et al, 2006;Li et al, 2007Li et al, , 2013Huang, 2013;Meng et al, 2013;H. J. Peng et al, 2014;X.…”

Oxygen isotope and trace element geochemistry of zircons from porphyry copper system: Implications for Late Triassic metallogenesis within the Yidun Terrane, southeastern Tibetan Plateau

“…However, the origin of the Late Triassic magmatism remains a subject of debate. Whole-rock adakitic geochemical signatures (low Y and Yb Chemical Geology 441 (2016) [148][149][150][151][152][153][154][155][156][157][158][159][160][161] concentrations, high Sr/Y and La/Yb ratios; Leng et al, 2007;Ren et al, 2011), high MgO contents (N1.6 wt.%, Chen et al, 2013), high initial 87 Sr/ 86 Sr ratios (e.g., 0.7058-0.7077, Wang et al, 2011;0.7044-0.7070, Chen et al, 2013), negative εNd (t) (e.g., εNd (t) = − 1.88 to − 4.93, Wang et al, 2011;εNd (t) = −1.4 to −5.4, Chen et al, 2013) and relative high zircon εHf (t) values (εHf (t) = − 2.1 to + 6.1; Cao, 2014) suggest that these Late Triassic porphyritic intrusions and volcanic rocks were generated as a result of either the interaction between melts derived from different magmatic reservoirs (e.g., subducting slab and mantle wedge, Wang et al, 2011; crust and oceanic plate/asthenosphere mantle, Leng et al, 2007;Ren et al, 2011;Liu and Li, 2013; enriched midocean ridge basalt (MORB)-source and underplated mafic materials, Chen et al, 2013) or are derived mainly from a single magmatic reservoir (e.g., the juvenile mafic lower crust, Cao, 2014). Apart from these different hypotheses proposed for the origin of Late Triassic magmatism, little is currently known about the controls on the copper mineralization in this region.…”