Where was the Ailaoshan Ocean and when did it open: A perspective based on detrital zircon U–Pb age and Hf isotope evidence

First Identification of Late Permian Nb‐Enriched Basalts in Ailaoshan Region (SW Yunnan, China): Contribution From Emeishan Plume to Subduction of Eastern Paleotethys

“…Sone and Metcalfe () suggested that the Ailaoshan suture is located along the shear zone, because the northern part of the shear zone merges with the Ailaoshan ophiolite belt. Supported by the different detrital zircon U‐Pb age populations and Hf isotope signatures on the Cambrian‐Devonian sedimentary units on different sides of the Ailaoshan fault, Xia et al () suggest that the fault may represent the actual location of the suture. The Ailaoshan region is a fan‐shaped terrane (~500 km long and 20–100 km wide; Figure b).…”

“…(b) Simplified tectonic map of the Ailaoshan region (modified after J. Xu et al, ). Location of the Ailaoshan suture (blue dashed line) is from Xia et al (). (c) Geological sketch map of the Ailaoshan metamorphic complex showing the location of samples (modified after Yunnan Bureau of Geology and Mineral Resources, ).…”

Zircon U–Pb ages, Hf isotope data, and tectonic implications of Early–Middle Triassic granitoids in the Ailaoshan high-grade metamorphic belt of Southeast Tibet

“…Their similar emplacement ages and geochemical signatures indicate that sea-floor spreading already existed in the Middle Devonian (Jian et al 2009a, b). The sedimentary fragments of different ages from Silurian-early Permian and were deposited in a range of environments, including a deep-marine setting in a rifted continental margin, a shallow-marine setting, and on the ocean floor (Jian et al 2009a;Xia et al 2015).…”

“…Integrated geological, geochronological, and geochemical studies of the Jinshajiang-Ailaoshan-Song Ma suture zone suggest that the ocean, as a subsidiary ocean in the Paleo-Tethyan system, opened in the Silurian and closed in the early Permian (Zhong 1998;Wang et al 2000;Jian et al 2008Jian et al , 2009aFan et al 2010;Zi et al 2012a;Vuong et al 2013;Lai et al 2014a, b;Xia et al 2015). Extensive Permo-Triassic magmatism developed to the west of the Jinshajiang-Ailaoshan-Song Ma suture zone during the westward subduction of the oceanic plate and the subsequent collision between the eastern QiangtangSimao-Indochina and Yangtze blocks (Hoa et al 2008;Jian et al 2008Jian et al , 2009bFan et al 2010;Liu et al 2011Liu et al , 2012bLiu et al , 2015aZi et al 2012a, b, c;Lai et al 2014a;Roger et al 2014;Shi et al 2015).…”

“…The suture zones represent a subsidiary branch (Zhong 1998;Metcalfe 2006Metcalfe , 2013Jian et al 2009a, b;Hu et al 2015) or a back-arc ocean basin (Metcalfe 2006(Metcalfe , 2013Fan et al 2010) of the main eastern Tethyan Ocean. Several studies have proposed that the initial opening of the Jinshajiang-Ailaoshan-Song Ma Ocean began in the Silurian (Jian et al 2009b;Xia et al 2015) and that oceanic spreading continued from the Late Devonian to the early Permian (Wang et al 2000;Jian et al 2008Jian et al , 2009aZi et al 2012a;Vuong et al 2013;Lai et al 2014b). Based on the existence of a volcano-plutonic arc along the eastern margin of the eastern QiangtangSimao-Indochina block, it is commonly interpreted that the oceanic lithosphere underwent westward subduction from the middle Permian to the Early Triassic (Jian et al 2009a, b;Fan et al 2010;Liu et al 2011;Zi et al 2012b;Lai et al 2014a).…”