摘要
胶东半岛的原生金金属储量约占全国的 1/7。郯—庐断裂两侧的地质差异由新太古代延续到早白垩世晚期 ,指示胶东半岛为一独立大地构造块体。结合大别—苏鲁超高压—高压变质带的被错开及该变质带的三叠纪同位素年龄峰值 ,郯—庐断裂的主活动期可限定在后三叠纪—早白垩世晚期。金矿的同位素年龄和半岛南部广泛的金矿化指示区域成矿主要发生在侏罗纪—早白垩世 ,乳山矿区的矿化蚀变特征则暗示成矿作用与变质热液无关 ;由于区内主变质期早于新元古代 ,故认为半岛的成矿起因于晚中生代大范围基底部分融熔及与此相关的岩浆热液活动 ,与欧亚陆缘演化有关。因此 ,胶东半岛的金矿与典型“绿岩型”金矿不可比 。
The lode Au metal tonnage in the Shandong Peninsula forms 1/7 of the national total. The geological contrasts on the two sides of the Tan-Lu Fault can be recognized from Neo-Archaean to Early Cretaceous, suggesting that the Shandong Peninsula is a separate tectonic block. The age of this nearly N-S orientated sinistral strike-slip fault is confined to the post-Triassic-late Late Cretaceous interval on the basis of the offset of the Dabie-Sulu ('Su' denoting Northern Jiangsu and 'lu' Southern Shandong Peninsula) eclogites and blueschists and their Triassic radiometric age peak. The radiometric dating of ores and the metallogenesis in Southern Shandong Peninsula show that the regional gold veining is of Jurassic-Late Cretaceous age, corresponding to the wallrock alteration evidence that the veining is unrelated to the pre-Neo-Proterozoic regional metamorphism. As a result, the regional gold metallgenesis is attributed to the partial melting of the pre-Cambrian basement of the Shandong Peninsula and relevant hydrothermal activity, which resulted from the Eurasian marginal evolution of Jurassic-Late Cretaceous age. The gold deposits mostly hosted by Late Mesozoic granitoids in the peninsula are not comparable with the known greenstone ones of Neo-Archaean age in the world , and some Mesozoic igneous rocks should be paid more attention to in the gold prospecting.
出处
《西安工程学院学报》
2001年第3期1-10,共10页
Journal of Xi'an Engineering University
