论文部分内容阅读
采用先进的SHRIMP定年技术对辽宁阜新排山楼金矿区成矿前变形的闪长玢岩脉、变形花岗斑岩脉、成矿后的闪长玢岩脉和大石头沟黑云母花岗岩的锆石进行了U-Pb年龄测定,获成矿前变形闪长玢岩脉的206Pb/238Pb年龄为(126±2)Ma;变形花岗斑岩脉为(124±1)Ma;成矿后的闪长玢岩脉为(125±1)Ma;大石头沟黑云母花岗岩为(124±1)Ma。这4类岩浆岩的年龄在误差允许范围内可基本视为同时代的。这一结果揭示,排山楼韧性剪切带型金矿床是中生代燕山晚期形成的,这与前人采用Ar-Ar法测得矿石蚀变黑云母的年龄犤(124.4±0.391)Ma犦是一致的。这表明,在中国东部,许多产在前寒武系岩层中、受韧性剪切带控制的金矿床形成时代是中生代燕山晚期。广泛产在胶东、辽西北票—蒙东赤峰、河北张家口和内蒙古乌拉山等地区的金矿床都主要是中生代燕山晚期形成的,表明燕山晚期是中国东部最重要的金矿化期。
Using the advanced SHRIMP dating technique, we studied the deformation of the diorite veins, the deformed granite porphyry veins, the dioritic dikes after mineralization and the biotite granites of the Dashitougou granite Zircon U-Pb dating. The 206Pb / 238Pb ages of pre-mineralized diorite veins were (126 ± 2) Ma and the deformed granite porphyry veins were (124 ± 1) Ma. After the ore-forming (125 ± 1) Ma for the diorite porphyrite and (124 ± 1) Ma for the Dashitougou biotite granite. The age of these four types of magmatic rocks within the error allowable range can be basically regarded as contemporaneous. This result reveals that the Paishanlou ductile shear zone type gold deposit was formed in the late Yanshanian Mesozoic, which is consistent with the age of (124.4 ± 0.391) Ma 犦 measured by the Ar-Ar method before the alteration of ore-hosted biotite of. This indicates that in the eastern part of China, many gold deposits controlled by ductile shear zones in the Precambrian strata formed during the late Mesozoic Yanshanian era. The gold deposits widely distributed in Jiaodong, Northwest Liaoning-Chidong, East Zhangjiakou, Hebei and Wulashan in Inner Mongolia are mainly formed in the late Yanshanian Mesozoic, indicating that the late Yanshanian period is the most important gold mineralization period in eastern China.