Petrogenesis of Cretaceous adakite-like intrusions of the Gangdese Plutonic Belt, southern Tibet: Implications for mid-ocean ridge subduction and crustal growth

Tectono-magmatic evolution of the Gaoligong belt, southeastern margin of the Tibetan plateau: Constraints from granitic gneisses and granitoid intrusions

“…7) (Mitchell et al, 2012;Wang et al, 2014b;Wen et al, 2008a), which is suggestive of magma generation in arc setting. In addition, the early Late Cretaceous Gangdese intrusions show adakitic geochemical characteristics Wen et al, 2008a;Zheng et al, 2014), and these may have been derived from the partial melting of the subducted oceanic slab in the Neo-Tethyan arc.…”

The Gangdese magmatic constraints on a latest Cretaceous lithospheric delamination of the Lhasa terrane, southern Tibet

“…Recently, many studies are focused on the Lhasa-Nyingchi segment, and these studies suggest that (1) most of the late Cretaceous granitic rocks exhibit adakitic affinity (Jiang et al, 2012Ma et al, 2013a;Wen et al, 2008a;Zheng et al, 2014), (2) the identification of charnockite implies there may be coeval oceanic ridge subduction (Zhang et al, 2010aZheng et al, 2014), (3) the Langxian-Lilong batholith may reflect a deep crustal section of the eastern Gangdese batholith (Wen et al, 2008a;Zhang et al, 2014) and (4) the late Cretaceous magmatism contributes much to the crustal growth (Ma et al, 2013b;Zhang et al, 2014;Zheng et al, 2014). However, the geodynamic mechanism for the extensive late Cretaceous magmatism remains controversial and proposed tectonic models include flat Booth et al (2004), Chen et al (2010, Dong and Zhang (2013), Chung et al (2003Chung et al ( , 2009, Guan et al (2010Guan et al ( , 2011Guan et al ( , 2012, Guo et al (2011aGuo et al ( ,b, 2012, Harrison et al (2000), Huang et al (2010), Hou et al (2004), Wen et al (2008a,b), Ji et al (2012), Jiang et al (2011Jiang et al ( , 2012Jiang et al ( , 2014, Lin et al (2013), Liu et al (2012a,b), Ma et al (2013a,b,c), Mo et al (2006) subduction (Wen et al, 2008b), ridge subduction (Zhang et al, 2010a;Zheng et al, 2014), and slab rollback …”

“…Many studies have focused on granitoids in the Mainling-Nang region, most of which are Cretaceous in age (108-68 Ma) Ma et al, 2013a,b,c;Quidelleur et al, 1997;Wen et al, 2008a,b;Zhang et al, 2010a;Zheng et al, 2014;Zhu et al, 2011). Four samples were collected near Lilong (09FW25, 09FW26, ML03-1 and ML04-1), from east part of this region, all of which are quartz diorites with similar ages of 90-87 Ma, and are consistent with previous dating results (90-86 Ma) of Zhang et al (2010a).…”

“…Both of them develop some early Mesozoic magmatic activities and peaks of Miocene (around 16 Ma), but the Lhasa-Kailas segment possesses a most important stage of Eocene (with a peak at around 51 Ma) while the LhasaNyingchi segment is represented by several magmatic stages, that The late Cretaceous magmatisms are mainly found in the NangMainling area (Fig. 1) (Guan et al, , 2011Ma et al, 2013a,b,c;Quidelleur et al, 1997;Zhang et al, 2010aZhang et al, , 2014Zheng et al, 2014;Zhu et al, 2011), and Late Oligocene granitic rocks are focused in the Nyingchi region (Booth et al, 2004;Chung et al, 2003;Guo et al, 2011a;Zhang et al, 2010b;Zheng et al, 2012a;unpublished data). The Miocene granitic rocks are distributed in the copper mine between Lhasa and Maizhokunggar, including Lakang'e , Qulong (Hou et al, 2004;Mo et al, 2006;Wang et al, 2006) and Jiama (Chung et al, 2003;Qin et al, 2011;Ying et al, 2011).…”

“…Most of the late Cretaceous granitic rocks from eastern Gangdese batholith show adakitic affinities, but the explanations of their petrogenesis are controversial, that include partial melting of newly underplated mafic lower crust Wen et al, 2008a) or oceanic slab (Jiang et al, 2012) that ascribed to flatten subduction (Wen et al, 2008a,b), mid-ocean ridge subduction Zhang et al, 2010a;Zheng et al, 2014) They are plotted in the overlap region of adakite and arc-related calcalkaline rocks (Fig. 7), thus they would be generated by either partial melting of normal lower crust or by fractional crystallization of more basic magma.…”