1. Faculty of Earth Sciences，China University of Geosciences，Wuhan 430074，China; 2. Hubei Institute of Geological Survey，Wuhan 430034，China

Zaohuogou Early Silurian granite (436. 8 ～433. 7 Ma) dominated by granodiorite and monzogran- ite is located in the central ophiolitic tectonic melange belt of eastern Kunlun． The surrounding rocks are Mesoprot- erozoic Wanbaogou group and Ordovician- Silurian Nachitai group，respectively． The contents of SiO 2 in the grano- diorite and monzogranite are 56. 12% ～63. 49% and 70. 62% ～76. 54%，respectively，belonging to calkaline se- ries． The monzogranite shows the characteristics of the alkaline rocks，and the rocks are metaluminous- peralumi- nous series with A/CNK as 0. 79 ～1. 02，belonging to I- type granites． The ∑ＲEE in granodiorites is lower than in the monzogranites，and both the rocks displayed the characteristics of enrichment in LＲEE and relative loss in HＲEE． The granodiorite has slight negative abnormality in Eu， and both the two rocks are charaterized by depletion in HFS and enrichment in LILE． The geological characteristics reveal that the Zaohuogou granites were island arc granites． They were derived from the partial melting of the lower island arc crust of eastern Kunlun which caused by the underplating of the mantle wedge in the period of the Prototethys oceanic crust subduction． The discovery of Zaohuogou granites indicates that the eastern Kunlun was still in the stage of the Prototethys oceanic crust subduc- tion during the Early Silurian．