太行—燕辽地区燕山期造山过程、岩浆源区与成矿作用

Yanshanian (Jurassic-Cretaceous) orogenic processes, magma sources and metallogenesis as well as coal formation in the Taihangshan-Yanshan-West Liaoning region

太行—燕辽造山带是中国东部一个重要的燕山期(J-K)Au-Mo-Pb-Zn-Ag-Cu-Fe金属成矿带和重要煤田分布区。本文首先讨论了该区18个金属矿床以及相关侵入岩的同位素年龄数据,选取了其中10个比较可信的数据作为成矿作用的近似年龄,以及运用4个煤田的已有的相关地层的时代,在已有的岩浆-构造事件序列的框架基础上,扩展提出该区岩浆-沉积-构造-变质-成矿事件序列的初步框架。进而,讨论造山过程,岩浆源区与成矿作用的可能成生联系。前造山幕—初始造山幕(J1)和后造山幕(K12)比较宁静的构造和湿热环境为煤田形成提供了良好的动力学环境。同造山幕的大量岩浆活动为金属矿床形成提供重要背景。早期造山幕(J2)伴随古老下地壳的熔融,生成以安山质为主的岩浆活动和伴生以Au为主成矿作用。峰期造山幕(J3),陆壳升温达峰值,导致上地壳岩石大规模熔融作用,形成大规模花岗质岩浆侵入,伴生以Mo为主的成矿作用。晚期造山幕(K11),"过热的"上部地壳开始降温,壳幔深部的镁铁质岩浆更多地喷出和侵入,伴生以Fe矿床的形成,同时,新形成的侏罗纪下地壳熔融,伴生Cu矿。

The Taihangshan-Yanshan-West Liaoning region constitutes the Yanshanian Au-Mo-Pb-Zn-Ag- Cu-Fe metallogenic belt and also serves as an important coalfield area in East China. This paper first dealt with isotopic ages of both ore deposits and related intrusive rocks and then selected some relatively reasonable ages for ore deposits as well as ages for coal-formation. Based on the magmatic-tectonic event sequence available, the authors put forward a preliminary scheme for the magmatic-sedimentary-tectonic-metamorphic-metallogenic event sequence. During the pre-orogenic and initial orogenic episode （J1） and the post-orogenic episode （K2 ）, both the calm tectonics and the warm environment probably served as good geodynamic settings for the formation of large coalfields. During the syn-orogenic episode, the large-scale magmatism might have been a good geodynamic setting for the formation of ore deposits. Magmatism and related mineralization during the early, peak and late orogenic episodes （J2J3,K11） are also discussed.