Constructing the Early Mesozoic Gangdese Crust in Southern Tibet by Hornblende-dominated Magmatic Differentiation

Mesozoic crustal evolution of southern Tibet: Constraints from the early Jurassic igneous rocks in the Central Lhasa terrane

“…Namling: 212−207 Ma: Ma et al, 2017;Dazhuka: 205−170 Ma, Chu et al, 2006;Guo et al, 2013;Ji et al, 2009;Meng et al, 2016b;Nyemo: 180−178 Ma, Guo et al, 2013;Meng et al, 2016b;Zhang et al, 2007b;Quxu: 220−210 Ma, Ma et al, 2018;Meng et al, 2016a;Qulong: 182 Ma, Yang et al, 2008;Sangri: 190−179 Ma, Dong and Zhang, 2013;Shui et al, 2018;Gyaca: 201−197 Ma, Dong and Zhang, 2013;Shui et al, 2018;Xu et al, 2019;Zhongsa: 203−192 Ma, Zhu et al, 2011). Classification of amphiboles according to Leake et al (1997).…”

“…In the SLT, the Early Mesozoic L i t h o s a c c e p t e d m a n u s c r i p t 2 0 2 0 0 4 2 8 magmatic rocks include plutonic and volcanic rocks. The plutonic rocks mainly consist of diorite, tonalite, granodiorite and granite with minor hornblende gabbro, and their bulk-rock geochemical data are characterized by medium-K calc-alkaline and metaluminous, typical of I-type granitoids with zircon εHf(t) > 0 (e.g., Guo et al, 2013;Meng et al, 2016a, b;Shui et al, 2018;Xu et al, 2019;Zhu et al, 2011). In the CLT, the Early Mesozoic magmatic rocks occur as batholiths in the eastern CLT and plutons in the central CLT (Fig.…”

Identification of a new source for the Triassic Langjiexue Group: Evidence from a gabbro-diorite complex in the Gangdese magmatic belt and zircon microstructures from sandstones in the Tethyan Himalaya, southern Tibet

“…During the last decade, ages of 237-170 Ma for calc-alkaline magmatism in the Gangdese magmatic belt have indicated that an active continental margin existed along the southern margin of the Lhasa terrane. Examples include Middle Triassic-Jurassic volcanic rocks of the Yeba, Bima, and Xiongcun Formations (Kang et al, 2014;Ma et al, 2017bMa et al, , 2018aWei et al, 2017;Zhang et al, 2012;Zhu et al, 2008) and their coeval plutonic equivalents (Chu et al, 2006;Ji et al, 2009;Lang et al, 2017;Tafti et al, 2014;Wang et al, 2016aWang et al, , 2017Xu et al, 2017Xu et al, , 2019. These findings indicate that the southern margin of the Lhasa terrane was subjected to intense Middle Triassic to Jurassic magmatism due to subduction of the Neotethyan oceanic lithosphere (Wu et al, 2010).…”

“…2)-for example, the 237-211 Ma Changguo and Beise volcanic rocks in southern Lhasa (Wang et al, 2016a, the ca. 220-215 Ma cumulate appinite in the Quxu region (Meng et al, 2016b;Ma et al, 2018b), the 230-225 Ma Daga granite (Meng et al, 2018), the 212-206 Kazi granite (Ma et al, 2017a), and the 203-201 Ma Cuijiu igneous complex (Xu et al, 2019). The Changguo and Beise volcanic rocks, Daga granite, and Cuijiu igneous complex are considered to have been formed in an active continental margin (Wang et al, 2016aMeng et al, 2018;Xu et al, 2019), while the Quxu ca.…”

Fingerprinting metal transfer from mantle

“…Alternatively, the subduction-modified lower crust has been proved to be metal (such as Cu and Au)-rich, and its melt has the capability to form large porphyry and epithermal deposits 14,15 . The middle–lower crust in post-subduction settings has recently been studied for sulfide compositions, and most of them (such as Kohistan arc lower crust outcrops, Gangdese arc cumulates, Yunnan lower-crust garnet amphibolite xenoliths) are Cu-rich (up to 1000 ppm 16 ) and Au-rich (up to 16 ppb 15 ). These ore-forming components (Au, Cu), though locally remobilized during later metamorphism, could be preserved in arc cumulates in the lower continental crust (Fig.…”