LA-ICP-MS U-Pb zircon age of intermediate-acidic intrusive rocks in Jiama of Tibet and its metallogenic significance

This paper deals with the emplacement timing of the intermediate-acidic intrusive rocks in Jiama of Tibet and its metallogenic significance.Based on the measured geological data and LA-ICP-MS U-Pb zircon ages of the four intermediate-acidic intrusive rocks,the authors preliminarily regularized the timing sequence,which is from early to late in order of porphyry granite(15.31 Ma～16.27 Ma)-quartz diorite porphyrite-adamellite porphyry(14.81 Ma)-granodiorite-porphyry;Exemplified by molybdenum,the Jiama ore deposit assumes three periods of metallogenesis,i.e.,the ore-forming processes corresponding respectively to different degrees of magmatic activities of porphyry granite or quartz diorite porphyrite,adamellite porphyry and granodiorite-porphyry.The Jiama ore deposit resulted from the superposition of the three periods of magma-mineralization.