Contribution of syncollisional felsic magmatism to continental crust growth: A case study of the Paleogene Linzizong volcanic Succession in southern Tibet

Petrogenesis of the Early Eocene adakitic rocks in the Napuri area, southern Lhasa: Partial melting of thickened lower crust during slab break-off and implications for crustal thickening in southern Tibet

“…180-70 Ma) igneous rocks and coeval (ca. 50) gabbros and basalts are characterized by depleted Sr-Nd-Hf isotopic compositions (e.g., Chu et al, 2006;Dong et al, 2008;Ji et al, 2009;Mo et al, 2007Mo et al, , 2008Wen et al, 2008aWen et al, , 2008b, indicating that southern Lhasa has a juvenile middle-lower crust that was not a suitable source for the Napuri adakitic rocks. Conversely, there is abundant geophysical data that indicates that the Indian continental lithosphere has subducted beneath the Qiangtang block (e.g., Nábělek et al, 2009;Owens and Zandt, 1997;Schulte-Pelkum et al, 2005) and the Indian crust can be traced to 31°N (Nábělek et al, 2009).…”

The formation of Qulong adakites and their relationship with porphyry copper deposit: Geochemical constraints

“…The Gangdese orogenic belt is composed mainly of Late Paleocene-Early Eocene (60-40 Ma) Linzizong Formation volcanic rocks and CretaceousTertiary (120-24 Ma) granite batholiths (Allegre et al, 1984;Mo et al, 2008). According to previous studies, multiple metallogenic events occurred in the different tectonic settings of the Indo-Asian collision, identified as the main-collisional convergent setting (~65-41 Ma), the late-collisional transform setting (~40-26 Ma), and the postcollisional crustal extension setting (~25-0 Ma) (Chung et al, 2005;Hou et al, 2006).…”

“…12. Also plotted are literature data for Jurassic porphyries from Qulong , Cretaceous adakites from Mamen ), Lizizong volcanics (Mo et al, 2008) and Miocene adakites Hou et al, 2004bHou et al, , 2013Qin et al, 2014;Xu et al, 2010) and fields of Indus-Yalung ophiolites (Miller et (Zhu et al, 2012a) and ultrapotassic rocks from south Tibet (Gao et al, 2007a;Liu et al, 2014;Miller et al, 1999;Zhao et al, 2009). The Nd-isotope model ages (T DM ) of the Qulong adakites range from 0.62 to 0.71 Ga (Table 4).…”

Crustal–lithospheric structure and continental extrusion of Tibet

“…After this time only continental red-bed deposition occurred, indicating that the entire region was subaerial. During the Late Cretaceous to Early Eocene (c. 120-50 Ma), the Lhasa Block formed the southern margin of Asia and was an Andean-type margin with a 2500 km long, up to c. 100 km wide, subduction-related I-type granite batholith (Gangdese granites) comprising abundant hornblende-and biotite-bearing granodiorites and granites with an extensive calc-alkaline volcanic suprastructure (Linzizong volcanic rocks; Mo et al 2007Mo et al , 2008Wen et al 2008a,b;Chiu et al 2009). The oldest U-Pb zircon age from the Gangdese granites is 188.1 AE 1.4 Ma (Chu et al 2006) suggesting a longlasting I-type batholith from Early Jurassic to Early Eocene time.…”