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The East Kunlun Orogenic Belt of the northern Tibetan Plateau can be divided by the Qimantagh-Xiangride, Aqikekulehu-Kunzhong and Muztagh-Buqingshan sutures into, from north to south, the Northern Qimantagh, Central Kunlun and Southern Kunlun belts. The Yazidaban ophiolitic mélange, located in thewesternmost region of the Qimantagh-Xiangride suture between the Northern Qimantagh and Central Kunlun belts, consists predominantly of serpentinite, basalt, diabase and andesite. The serpentinites are characterized by low total rare earth element (SREE) concentrations and depletion of mid-REEs, showing an ophiolitic ultramafic affinity. The basalts have low SREE concentrations, a slight enrichment in light REEs, depletion of large ion lithophile elements and insignificant fractionation of high field strength elements, which are attributed to an incompatible element-enriched mid-ocean ridge basalt. Both diabases and andesites are characterized by high SREE, strong enrichment in light REEs, depletion of Nb, Ta, P and Ti, and significant fractionation of high field strength elements. These geochemical characteristics indicate that the diabase and andesite were mostly generated in a subduction-related setting. Igneous zircons from the diabase yielded a 206Pb/238U age of 421.5 ± 2.2 Ma (MSWD = 0.44), representing the formation time of the subduction-related rocks. Together with the regional geology, these constraints on the ultramafic rock, basalt, andesite and diabase suggest that the Yazidaban ophiolitic mélange represents the remnants of oceanic crust from a back-arc basin and the associated subduction-related magmatic rocks. [ABSTRACT FROM AUTHOR]