Prototethyan Accretionary Orogenesis Along the East Gondwana Periphery: New Insights From the Early Paleozoic Igneous and Sedimentary Rocks in the Sibumasu

New geochronological and geochemical data document a new widely distributed succession of igneous sedimentary rocks within the Sibumasu that extend from SW Yunnan through SE Asia as far Sumatra. Our revealed presence an Ordovician-Silurian (mainly ?490–430 Ma) zone. The early Paleozoic granites in zone display similar elemental Sr–Nd–Pb–Hf isotopic compositions. They were derived common mixed source ancient crustal materials with juvenile component formed subduction-related setting. Detrital-zircon U-Pb apparent ages previously defined Precambrian Lancang Ximeng units portion are range 3,306–428 Ma 3,316–512 Ma, youngest age-peaks 505 447 respectively, indicating lower (Cambrian-Silurian) sequences. Tarutao Unit its equivalents yield 3,177–510 suggesting maximum deposited time being Cambrian-Ordovician. All these detrital zircon define two main peaks ?554–528 964–905 ?Hf(t) values to those Qiangtang, Tethyan Himalaya, eastern Indochina. detritus likely India-Antarctica region East Gondwana. We propose late Cambrian-Silurian outward-propagating accretionary orogen response consumption Prototethyan Ocean Asia. might represent part easterly migrating along northern margin Gondwana Cambrian-late Silurian.