Causes and consequences of protracted melting of the mid-crust exposed in the North Himalayan antiform

Geochemical variations in Miocene adakitic rocks from the western and eastern Lhasa terrane: Implications for lower crustal flow beneath the Southern Tibetan Plateau

“…However, as shown in Fig. 8, the Kuday and Mayum adakitic rocks display different Sr-Nd isotopic characteristics to gneiss and granites of the North Himalayan (Zhang et al, 2004) and High Himalayan Crystalline Series (Harris et al, 1988), which have anomalously enriched Sr-Nd isotopic compositions relative to the adakitic rocks, suggesting that the crust beneath the Himalayan area was not the source for the Kuday and Mayum adakitic rocks (King et al, 2007). King et al (2007) suggested that the Kuday dykes were produced by partial melting of Asian crustal material that had been moved southward by ductile flow, from below the eastern part of the Lhasa terrane to a new position beneath the Tethyan Himalayas.…”

“…Chung et al (2009) suggested that the Kuday dykes were derived from the lower crust. As discussed above, the Kuday and Mayum rocks have geochemical characteristics similar to the adakitic (2008) and Yue and Ding (2006); Yarlung MORB is from Miller et al (2003), Mahoney et al (1998), Xu and Castillo (2004), and Zhang et al (2005); lower crust in the western Lhasa terrane is from Miller et al (1999); Shoshonitic dykes are from Zhao et al (2009); adakites related to slab melting are from Kay (1978), Kay et al (1993), and Stern and Kilian (1996); Early Cretaceous granite and rhyolites in the western Lhasa terrane are from Zhu et al (2009); Northern Himalayan gneiss and granites are from Zhang et al (2004); High Himalayan Crystalline Series is from Harris et al (1988); mafic granulite in the east Himalayan syntaxis is from Xu et al (2010) (other data sources and symbols are as in Figs. 1 and 3).…”

“…In addition, based on the Sr-Nd isotope composition of adakitic rocks in the Lhasa terrane, Gao et al (2010) considered that the mafic granulite in the Himalaya terrane is unlikely to be a non-radiogenic end-member for the mixing array in the Sr-Nd plot. Finally, the adakitic rocks in the Lhasa terrane have different Sr-Nd isotopic characteristics to the gneiss and granites of the North Himalayan (Zhang et al, 2004) and High Himalayan Crystalline Series (Harris et al, 1988), which have anomalously enriched Sr-Nd isotopic compositions relative to the adakitic rocks (Fig. 8).…”

Paleoproterozoic S-type granites in the Helanshan Complex, Khondalite Belt, North China Craton: Implications for rapid sediment recycling during slab break-off

“…S-type magmas are commonly produced by partial melting of metapelites and metagreywackes under water-undersaturated conditions (e.g., Vielzeuf and Holloway, 1988;Patiño Douce and Harris, 1998;Zhang et al, 2004;Guo and Wilson, 2012;Wang et al, 2012). A series of experiments show that metasediments tend to yield melts with low FeO abundances (generally <3 wt.% FeO) despite variations in Al 2 O 3 content (Patiño Douce and Johnston, 1991; Montel and Vielzeuf, 1997;Patiño Douce and Harris, 1998;Fig.…”

Channel flow, ductile extrusion and exhumation in continental collision zones: an introduction

“…Most U-Th-Pb ages for the melts in the central Himalaya range from 23-22 Ma (Harrison et al 1995;Hodges et al 1996;Coleman 1998;Searle et al 1999;Godin et al 2001;Daniel et al 2003;Harris et al 2004) to 13-12 Ma (Edwards & Harrison 1997;Wu et al 1998;Zhang et al 2004). However, evidence for leucosome melt production during the Oligocene also exists (Coleman 1998;Thimm et al 1999;Godin et al 2001).…”