The characteristics of ultra-high pressure metamorphic (U-HPM) rocks in the Sulu zone are similar to thosein the Dabieshan zone, however the corresponding petrological-tectonic units in Dabieshan (the northernAndean-type magmatic arc complex, central UHPM rock-bearing melange zone, southern mobilizedmetamorphic complex of Yangtze margin) are difficult to establish in the Sulu zone. On the basis of thedetailed study on regional geology, petrology, geochemistry and isotopic geochronology, the westernboundary of the Sulu UHPM zone is roughly defined in the area between the Muping fault and Mishanfault. It is impoftant that three individual granulite units have been distinguished in the area east to theMuping fault, which are eclogitized granulite unit, retrogressive granulite unit from UHPM eclogites, andhigh-pressure granulite unit. These three granulite units as well as UHPM unit in Rongcheng area, whichwas suffered metamorphism of amphibolite factes and never granulite factes, have different metamorphicand deformed history and are bounded by deep-large scale ductile shear zones each other. Therefore thenorthern Sulu UHPM zone can be divided into four petrological-tectonic units from southeast to northwestHaiyangsuo metamorphic complex (eclogitized crystalline basement of the YangtZe craton), RongchengUHPM complex, Weihai metamorphic complex (granulites retrograded from UHPM eclogites), andKunyushan boundary metamofphic-magmatlc complex. These high-grade metamorphic crystalline unitscome from deep crust, and are products relative to UHPM process including its formation, evolution andexhumation. At present, they are imbricated and superimposed each other by late tectonics as crystallinenappes, similar to thin skin thrusting.
