【摘要】 本文全面收集了胶东矿集区矿床和相关岩石的同位素年龄,讨论了该区金矿床大规模成矿的时间和构造背景。数据显示成矿作用发生于中生代,以110~130Ma为高峰;成矿事件同步或略滞后于中生代花岗岩浆活动。铷锶和锆石SHRIMP年龄表明中生代花岗岩类形成于多次热事件,大量继承锆石的存在和较高的ISr值(>0.709)指示花岗岩浆主要源于地壳物质的部分熔融或重熔。矿石和成矿流体的ISr值普遍高于0.709,并略高于中生代花岗岩类,指示成矿流体和物质主要来自地壳内鄙。讨论显示,中生代华北与华南古板块的碰撞造山作用是导致胶东矿集区形成的主导因素;花岗岩类侵入和大规模成矿作用耦合于碰撞造山带的3阶段地球动力学演化,即早阶段挤压-地壳缩短-隆升,中阶段岩石圈拆沉并转向伸展构造体制,晚阶段伸展;最强烈的成矿作用发生在碰撞造山过程的挤压向伸展转变期;已建立的碰撞造山成岩成矿和流体作用模式可以较好解释胶东矿集区的矿床、花岗岩类的特征。更多还原

【Abstract】 In this paper we use published isotopic ages for gold deposits and related rocks in the Jiaodong peninsula ( East Shandong Province) to investigate the time and tectonic setting of the large scale gold metallogeny in the region, which contains world-class lode gold deposits. According to this database, metallogenic processes in this area occurred in the Mesozoic, with peak activities between 110 Ma and 130 Ma. In the Jiaodong gold province the mineralising events are coeval with or postdates Mesozoic granitoid intrusions. Both the Rb-Sr isochron ages and zircon SHRIMP dating results suggest that Mesozoic granitoids were emplaced during several thermal events. The identification of inherited zircons coupled with ISr ratios ( > 0. 709) indicate that these granitoids were mainly sourced from the continental crust by remelting or partial melting. The ISr values obtained from ores and fluid inclusions are generally higher than 0. 709, and slightly higher than those for Mesozoic granitoids. This also indicates that both ore fluids and metals were mainly sourced from the crust. A synthesis of the available data suggests that collision between the South and North China continents was probably the dominant factor responsible for the gold metallogeny in the Jiaodong gold province. Granitoid emplacement and large-scale gold metallogenesis can be related to three important stages in the geodynamic evolution of a collisional orogen ( compression-crustal thickening-uplift, lithospheric delamination and transition to extension and a final extension phase). The most important metallogenic phase occurred at the transition from collisional compression to extension tectonics. A previously developed model for collisional orogeny, metallogeny and fluid flow (CMF) can be used to interpret the key characteristics of ore deposits and igneous rocks in the Jiaodong gold province.更多还原