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海沟金矿成矿期正长闪长斑岩脉岩中包含捕获碎屑锆石和岩浆结晶锆石。其中:岩浆结晶锆石U-Pb年龄的加权平均值为(132.4±1.5)Ma(n=18,MSWD=0.48,概率为0.96),可代表脉岩结晶年龄;在锆石U-Pb谐和年龄图上样品的上交点年龄为(2 460±29)Ma,下交点年龄为(137±18)Ma,前者可代表捕获碎屑锆石的成岩年龄,后者与脉岩中岩浆结晶锆石测年结果相近。综合分析认为,海沟金矿的成矿年龄应为132.4～128Ma,是陆内碰撞造山向伸展造山的构造转换时期。软流圈地幔隆起及其有关的地质和成矿作用是海沟金矿形成的主因。大海沟辉长闪长岩体为成矿同期同源岩体,其成岩年龄应代表海沟金矿成矿年龄的上限。
During the ore-forming period of the Haigou gold deposit, the capitals and the magmatic zircons are trapped in the Chang-diorite porphyry vein. Among them, the zircon U-Pb ages of magmatic zircons are (132.4 ± 1.5) Ma (n = 18, MSWD = 0.48, probability 0.96) The age of the sample on the age map is (2 460 ± 29) Ma and the dating point is (137 ± 18) Ma. The former can represent the diagenetic ages of the captured detrital zircons and the latter is related to the magmatic zircons The dating results are similar. The comprehensive analysis shows that the age of the ore-forming of Haigou gold deposit should be 132.4 ~ 128Ma, which is the period of tectonic transition from intracontinental collision orogenic to extensional orogeny. The asthenospheric mantle uplift and its related geology and mineralization are the main reasons for the formation of the Haigou gold deposit. The Daxigou gabnic diorite body is a contemporaneous source rock in the metallogenic stage and its diagenetic age should represent the upper limit of the metallogenic age of the Haigou gold deposit.