TWO SUITES OF OPHIOLITE RECOGNIZED IN THE MAQEN AREA, NORTHEASTERN TIBETAN PLATEAU

The A'nyemaqen ophiolite belt lies along the northeastern margin of the Tibetan Plateau and is believed to mark the boundary between the East Kunlun terrain and the ayanhar|Songpan|Garze terrain (Fig.1). The ophiolite in this belt is considered to be Early Permian to Middle Triassic in age (Yang et al., 1996). Our recent study indicates that there is an old ophiolite suite (>421 5Ma), located to the northern margin of this belt (Fig.1). Since the new found ophiolite is near to the Dur'ngoi deposit, so we called it North Dur'ngoi ophiolite. The geological and geochemical characteristics of the two ophiolite suites are different obviously as follows.