华北太行—燕山—辽西地区燕山期(J—K)造山过程与成矿作用

太行—燕山—辽西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,亦是燕山期煤田分布的重要地带。讨论了该区18个燕山期金属矿床及其相关的侵入体的同位素年龄,两者在时间上的总体一致性,以及重要煤田的形成与特征时代的沉积建造相伴生,均从年代学的约束方面提供了成矿作用与燕山期岩浆—构造事件的成因联系。在已有的燕山造山带岩浆构造事件序列的基础上,把成矿作用纳入其中,提出了该造山带燕山期岩浆—沉积—构造—成矿事件序列的初步框架。进而,从物质组成的角度,讨论了该造山带金属成矿作用与火成岩组合的成因联系;同时也讨论了成矿作用可能的源区以及成矿作用的阶段性与造山带之间的成生联系。提出了造山带与成矿作用的初步框架模型。前造山幕—初始造山幕(J1)和后造山幕(K21)比较宁静的构造环境和湿热环境为煤田形成提供良好的动力学环境。同造山幕的大规模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及伴生主要的Au和Pb、Zn矿床;峰期造山幕(J3),陆壳升温达峰值,导致上地壳岩石的大规模熔融作用,形成大规模花岗质岩浆的侵入,伴生大量Mo矿;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Fe矿床的形成,同时,新形成的侏罗纪下地壳熔融,伴生Cu矿。

Yanshanian(Jura-Cretaceous)Orogenic Processes and Metallogenesis of the Taihangshan-Yanshan-West Liaoning Orogenic Belt, North China

The Taihangshan-Yanshan-West Liaoning orogenic belt is a Yanshanian(J—K)Au-Mo-Pb-Zn-Ag-Cu-Fe metallogenic belt,and also an important area of Yanshanian coal field in Eastern China.This paper discusses the isotopic ages of both the eighteen ore deposits and ore related intrusive bodies of Yanshanian(J-K)time,the simultaneity,in general,of both the ore-deposits and the intrusions,as well as the association of the large coal field with the characteristic sedimentary formation,give a charonological constraint for the genetic relationship between the metallogenesis & coal-formation and the Yanshanian magmatic-tectonic events.Based on the Yanshanian magmatic-sedimentary-tectonic event sequence of this belt,in this paper,with adding the ages of both the ore-deposits and the coal field,a preliminary scheme of the Yanshanian magmatic-tectonic-metallogenesis event sequences is suggested.And then from the view of the composition,the genetic relationships between the ore-deposits and the intrusions and then the possible source of the ore deposits as well as the genetic relationships between the metallogenesis and coal-field and the orogenic episodes are discussed in this paper.During both the pre-and initial orogenic episode(J1)and post-orogenic episode(K21),both the neutral tectonics and the warm environment are considered as a good geodynamic setting for the formation of large coal fields.During the syn-orogenic episodes,the large-scale magmatism is regarded to be a good geodynamic setting for metallogeneses.During the early orogenic episode(J2),both the andesitic magmas and the Au & Pb-Zn ore-deposits mainly are formed by the partial melting of the Archean lower crust.During the peak orogenic episode(J3),both the large-scale granitic magmas and the Mo ore-deposits are generated from the intensive melting of the Archean upper crust.During the late orogenic episode(K11),the gabbro-monzodiorite & Fe ore-deposits and the monzonite-quartze monzonite & Cu ore-deposits are formed at the beginning of the temperature decreasing of the upper crust.