摘要
八里坡钼矿是在金堆城钼矿床外围找矿中新发现的斑岩型钼矿床,对其含矿斑岩和矿石进行了成岩成矿年龄精测。采用LA-ICP-MS方法对八里坡斑岩体进行单颗粒锆石U-Pb测年,获得成岩年龄为155.9±2.3Ma;采用ICP-MS法测定八里坡钼矿中辉钼矿Re-Os同位素年龄,获得等时线年龄为156.3±2.2Ma;两种方法获得的年龄一致,表明成岩与成矿同时形成。八里坡斑岩体与东秦岭南泥湖、上房沟等斑岩体成岩年龄一致,早于金堆城钼矿床成矿年龄,表明八里坡斑岩体可能是新一期成岩成矿作用,形成于燕山运动的A幕,产出于东亚构造体制转变初期的地球动力学背景,具有重要成岩成矿意义。
Located in the eastern Qinling molybdenum belt, the Balipo deposit is a porphyry Mo deposit discovered in recent years. This study provides the first highly precise dating for the mineralization and rock-forming of the Balipo molybdenum deposit. The LA-ICP-MS dating of zircon from the Balipo granitic porphyry yields an age of 155.9±2.3 Ma. The Re-Os model ages of the deposit are between 152.8±1.1- 157.8±2. 2 Ma, and Re-Os isochrone age is 156. 3 ± 2. 2 Ma. The fact that the zircon U-Pb and molybdenite Re-Os isotopic ages are quite similar suggests that the Balipo molybdenum deposit formed at least 10 Ma earlier than that the Jinduicheng, Nannibu, Shangfanggou and Leimengou porphyry molybdenum deposits distributed along the molybdenum belt. The Balipo porphyry rock formed at the same time as the Nannihu and Shangfanggou porphyry, implying that the Bailipo may result from a new round diagenesis and mineralization during Episode A of the Yanshan Movement. The results also suggest that the rock formed at the geodynamical setting of early-stage eastern Asian tectonic regime transformation and is of important significance to diagenesis and mineralization.
出处
《地质学报》
EI
CAS
CSCD
北大核心
2009年第8期1159-1166,共8页
Acta Geologica Sinica
基金
国家自然科学基金项目(编号40534020
40702015)资助成果
