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宾川宝丰寺碱性斑岩体位于扬子陆块西缘金沙江—红河断裂与宾川—程海断裂夹持部位,属于金沙江—红河富碱斑岩带组成部分,由细晶含黑云母花岗斑岩和粗晶花岗斑岩组成。LA-ICP-MS锆石U-Pb测年结果显示,2件样品的206Pb/238U加权平均年龄分别为34.99±0.37 Ma(MSWD=2.1,n=20)和33.53±0.27 Ma(MSWD=1.4,n=19),均属古近纪始新世岩浆活动的产物。宝丰寺花岗斑岩的成岩年龄与印—亚晚碰撞转换时限(41~26 Ma)和滇西三江富碱斑岩带碱性岩浆活动高峰期(45~30 Ma)一致,表明宝丰寺斑岩成岩作用是印—亚大陆碰撞的响应,形成于晚碰撞期伸展构造背景下。此外,本次获得的宝丰碱性斑岩成岩年龄与滇西斑岩型矿床成矿高峰期年龄(34±2 Ma)吻合,暗示宝丰寺碱性斑岩具有一定的成矿潜力。
Binchuan Baofeng Temple alkaline porphyry body is located in the western margin of the Yangtze block Jinsha River - Honghe fault and Binchuan - Chenghai fault nip, belonging to the Jinshajiang - Honghe alkali-rich porphyry belt, composed of fine crystal black Mica granite porphyry and coarse-grained granite porphyry. LA-ICP-MS zircon U-Pb dating results showed that the weighted average 206Pb / 238U ages of the two samples were 34.99 ± 0.37 Ma (MSWD = 2.1, n = 20) and 33.53 ± 0.27 Ma (MSWD = n = 19), all belong to the product of Paleozoic Eocene magmatic activities. The diagenetic age of Baofengsi granite porphyry coincides with the time limit of Indian sub-Late collision transformation (41 ~ 26 Ma) and the peak of alkaline magmatic activity in Sanjiang alkali-rich porphyry belt (45 ~ 30 Ma), indicating that Baofeng The diagenesis of the porphyry porphyry is the response of the Indian-continental collision and formed under the extensional tectonic setting of the late collision period. In addition, the age of the Baofeng alkaline porphyry obtained here is in agreement with the age of 34 ± 2 Ma in the porphyry deposit of the western Yunnan, indicating that the Baofengsi alkaline porphyry has certain metallogenic potential.