Abstract: The gabbroic pebble-bearing greywacke and bownish-black serpentine conglomerate of the Nanmingshui Formation overlie unconformably serpentinized harzburgite and metagabbro in the Karameri paleoplate suture zone in East Junggar,Xinjiang.On the basis of ammonoid fossils newly discovered and previous data of brachiopod fossils,the age of the Nanmingshui Formation is placed between C~2₁—C₂~1.The unconformity between the Nanmingshui Formation and ophiolites indicate that the tectonic emplacement of ophiolites in the Karameri suture zone took place before the deposition of the Manmingshui Formation.This emplacement resulted from collision of the Kazakhstan pale- oplate and the Siberia paleoplate.The author considers that there might occur hidden deposits of Cr,Ni and Cu below the outcrops of the Nanmingshui Formation.