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广西博白_岑溪断裂带位于钦杭成矿带南段,既是一条长期活动的地体边界断裂带,也是一条岩浆活动频繁的W_Mo_Sn_Pb_Zn_Sb_Au_Ag多金属成矿带。文章以该带中的广西博白县油麻坡矽卡岩型钨钼矿床为研究对象,在详细的岩性鉴别和划分的基础上,对矿区内花岗岩类进行了单颗粒锆石LA_ICP_MS锆石U_Pb测年,获得深灰色花岗斑岩的等时线年龄为(479.7±3.9)Ma,灰色黑云母花岗闪长岩为(109.7±1.1)Ma,浅灰色细粒白云母花岗岩为(103.3±1.2)Ma。辉钼矿Re_Os测年获得加权平均年龄为(97.4±1.9)Ma。由此可见,油麻坡岩体为一个复式岩体,由早奥陶世(加里东期)的花岗斑岩和早白垩世(燕山晚期)的黑云母花岗闪长岩和细粒白云母花岗岩组成,其中,黑云母花岗闪长岩构成油麻坡岩体的主体。钨钼矿形成于早白垩世晚期(即燕山晚期),与黑云母花岗闪长岩和白云母花岗岩密切相关。这些高精度测年数据的获得,进一步表明博白断裂带是一条长期活动的断裂,其在加里东期已经活动,并伴有岩浆岩的侵位。燕山晚期,该断裂重新复活,并导致大量的岩浆活动和一定强度的W_Mo_Sn_Pb_Zn_Sb_Au_Ag成矿作用,形成由多个大_中型矿床组成的多金属成矿带。博白_岑溪成矿带属于华南100~80 Ma大规模成矿的一部分,成矿背景与华南地区白垩纪的地壳伸展、钦杭成矿带的再次裂陷有关。
Guangxi Bobai_ Cenxi fault zone is located in the southern part of Qinhang metallogenic belt. It is both a long-term active boundary boundary fault zone and a W_Mo_Sn_Pb_Zn_Sb_Au_Ag polymetallic metallogenic belt with frequent magmatic activities. Taking the Yaumapo skarn-type tungsten-molybdenum deposit in Bobai County of Guangxi as the research object, based on the detailed identification and division of lithology, single granite zircon LA_ICP_MS zircon (479.7 ± 3.9) Ma for the gray-grained granite porphyry, (109.7 ± 1.1) Ma for the gray biotite granite, and (103.3 ± 1.1) Ma for the light gray fine grained muscovite ± 1.2) Ma. The molybdenite Re_Os dating obtained a weighted average age of (97.4 ± 1.9) Ma. Thus, the Yaupo slope rock mass is a compound rock body composed of granitic porphyry of the Early Ordovician (Caledonian) and biotite granodiorite and fine-grained dolomite of the Early Cretaceous (Late Yanshanian) Parent granite, in which biotite granodiorite constitutes the main body of Yupupo rock mass. Tungsten molybdenum was formed in the early Early Cretaceous (ie late Yanshan), closely related to biotite granodiorite and muscovite. The availability of these high-precision dating data further demonstrates that the Bobai Fault is a long-term active fault that has been active in the Caledonian period with emplacement of magmatic rocks. In the late Yanshanian period, the fault reactivated and resulted in a large amount of magmatic activity and a certain intensity of W_Mo_Sn_Pb_Zn_Sb_Au_Ag mineralization, forming a polymetallic metallogenic belt composed of several large-medium-sized deposits. The Bobai Cenxi metallogenic belt belongs to a large-scale metallogeny from 100 to 80 Ma in South China. The metallogenetic background is related to the Cretaceous crustal extension in South China and the re-rifting in the Qinhang metallogenic belt.