Late Triassic granites (ca. 230 Ma) from Cairi area in eastern Qiangtang subterrane, central Tibet: Product of a mid‐oceanic ridge subduction

Abstract

Cai et al., 2010) also have ridge subduction. Due to the special structure and shape of ridges, ridge subduction plays an important role in the angle of the subduction slab, the thermal structure of subduction zones, magmatism, and mineralization (Cole & Stewart, 2009;Z. Zhang et al., 2010). Therefore, the identification of ridge subduction in the subduction zone is very important for understanding the tectonic evolution. The Qiangtang terrane in the central Tibet is sandwiched between the Bangong-Nujiang Suture and Jisha Suture. The Shuanghu Suture Zone divided the Qiangtang terrane into eastern Qiangtang and western Qiangtang subterrane, which is the key area for the evolution of the Shuanghu Palaeo-Tethys Ocean (C. Li, Zhai, Wang, Yin, & Mao, 2009). However, there are different opinions about the closing time of Shuanghu Palaeo-Tethys Ocean, including: (a) studies on the high-pressure metamorphic rocks in the central

Newly Identified A-type Granite in Western Yangtze Block and Its Geochemistry Characteristics

“…Voluminous Neoproterozoic magmatic rocks with arc a nity are distributed along the western Yangtze Block ( In recent years, some researchers have tried to identify pre-Cenozoic ridge subduction in terms of rock suites. The subduction of the oceanic ridge usually produces two magmatic rock combinations: (a) similar to the magmatic rock of normal slab subduction, such as basalt, andesite, dacute, rhyolite, and (b) special arc magmatic rock combination in the extensional environment within the plate, such as adakitic rock, OIB-type basalt, MORB-type basalt, niobium-rich basalt, high-magnesium andesite, boninite (He et al, 2022;Wang et al, 2020; and references therein). Based on the new ndings of this study and the regional geology, several lines of evidence enable us to draw a reliable conclusion that the Neoproterozoic A-type granite in western Yangtze Block where "slab window" magmatic products derived by oceanic ridge subduction:…”