Time Constraints and SHRIMP of Zircon from Plagioclase Granite of Ophiolitic in Aletunkunduo

On the basis of analysis and research of previous datum, it is put forward that ophiolitic melange of Aletunkunduo is the extended eastward part of ophiolitic belt from Kalameili, which starts from the belt of Kalameili-Tazale-Daheishan-Aletunkunduo in the west. Plagioclase granite in the ophiolitic melange occurs in the top of gabbro, they have gradually or abruptly changing contact relationship. With SHRIMP method Zircon U-Pb Dating is carried out with Plagioclase granite, the result is(351±6 Ma)that reflects that ophiolitic melange of Aletunkunduo have formed in 351Ma. Meanwhile the study on ophiolitic melange overlying rocks in the Late Carboniferous can also state that ophiolitic melange from Aletunkunduo emplacement ages is not later than Late Carboniferous.