关键词: 胶东金矿集区, 燕山期大型超大型金矿, 火成岩组合, 热的壳幔结构, 洋俯冲环境

Abstract: The deep material composition and crust-mantle structure when large-super large scale metal deposits are forming have always been the focus of research and challenging pursues. The Jiaodong Gold Ore District developed many Yanshanian large-super large scale gold deposits. Based on plate tectonic theory and through examination of regional and ore-forming igneous assemblages and their characterics, the authors discuss in this paper the material composition in earths depth and crust-mantle structure during the gold forming period. The regional igneous assemblages prior to ore forming period are mainly granodiorite-granite(G1G2 suites) and some tonalite-trondhjemite (TT suites) assemblages. The volcanic rock assemblages of the Qingshan Formation are basaltic andesite-andesite-dacite-rhyolite-trachyteandesite-shoshonite-trachyte assemblages, which include high Mg andesite (HMA) and Mg andesite (MA). The ore forming igneous assemblages in the district are wide-spectrum dyke swarm (WSDS) of basic to acid igneous rocks, which include high Mg dirorite (HMgδ) and Mg dirorite (Mgδ). The above-mentioned igneous assemblages and the special igneous rocks of the TTG1, HMA, MA, HMgδ and Mgδ are igneous assemblages of arc setting and have the corresponding characteristics. Therefore they were formed in oceanic subduction environment and have the corresponding crust-mantle structure and material composition. These igneous rocks came from partial melting of different parts of subduction belt, including oceanic crust, mantle wedge and continental crust, revealing a hot crust-mantle structure during the Yanshan era. Both ore-forming igneous and gold metallogenic events resulted from large-scale intrusive magmatic activity of crust (or crust-mantle).

Key words: Jiaodong Gold Ore District, Yanshanian large-super large scale gold deposits, igneous assemblages, hot crust-mantle structure, oceanic subduction setting