Geochemical characteristics and formation age of Aksukule ophiolite: Evidence from gabbro dyke and pillow basalt in East Kunlun, Xinjiang

As an important mélange zone in the Kunlun orogenic belt, the Kangxiwa-Subas-Whalelake belt is regarded as the remnant zone of the Paleo-Tethys Ocean, and its formation has been closely monitored by the geological community. A new set of ophiolites was identified in the belt by LA-ICP-MS zircon U-Pb dating. The authors found that the age of gabbro from the magnesian units in the ophiolite is 270.3±0.7Ma (MSWD=0.65), and the age of pillow basalt is 263.4±7.4Ma (MSWD=1.5), which belongs to the Late Permian and represents the age of ophiolite formation. Based on the analysis of rock geochemical characteristics and regional background, it is considered that the ophiolite was formed in the mid-ocean ridge environment and belongs to the typical MORB type ophiolite. Based on the characteristics of main, trace elements, tectonic setting and isotopic age, the authors hold that the PaleoTethys oceanic basin continued to exist at least until Late Permian.