内蒙古狼山造山带构造演化与成矿响应

Mineralization response to the structural evolution in the Langshan orogenic belt,Inner Mongolia.

狼山造山带位于华北地台北缘西段,它经历了新太古代和古元古代结晶基底形成与变形、中元古代被动陆缘裂陷槽裂解→沉积→闭合、新元古代晚期开始的活动陆缘、海西期→中生代以来的挤压造山并伴有大量中酸性岩浆侵入的漫长构造演化与发展过程。该造山带有丰富的锌、铅、铜、铁、金等矿产资源,矿床(化)类型、矿床规模与时空分布规律都与其成矿地质背景、构造演化有密切的耦合关系,在不同构造演化阶段有不同的矿床形成:在新太古代主要形成了海底火山环境热水沉积条带状铁矿、在中元古代主要形成了与被动陆缘裂解过程相关的海底啧流.沉积铅锌铜铁硫化物矿床、而在海西期—中生代以来挤压造山过程中的岩浆热液活动,既形成了中小型的斑岩型铜金矿床、又对中元古代等先成的喷流-沉积矿床产生了明显的改造和叠加成矿作用。东升庙、炭窑口和霍各乞矿床的部分铜矿是造山过程中叠加成矿的结果。

The Langshan orogenic belt, located in the western part of northern margin of North China Platform, has experienced a long tectonic evolution and development process, which includes： ①the formation of its crystalline basement in Neoarchean and deformation in Early Proterozoic;② the break-up, deposition and closure of its passive continental margin aulacogen in Mesoproterozoic; ③the begining of its continental margin activities in late Neo-Proterozoic; ④ the development of compression and orogeny from Hercynian to Mesozoic with considerable intrusion of acid-intermediate magma. Abundant Zn, Pb, Cu, Fe, Au minerals occurred in the Langshan orogenic belt. The types, scales and the regulations of temporal and spatial distribution of these ore deposits show a close coupling relationship with ore-forming geological setting and tectonic evolution, and different deposits were formed in each stage of tectonic evolution in Langshan orogenic belt （as follows）： ⑤ the hydrothermal sedimentary banded-iron formation （BIF） deposits were formed in submarine volcanic environment in Neoarchean; ⑥the submarine exhalative-sedimentary lead-zinc-copper-iron sulfide deposits, related to the break-up process of the Langshan passive continental margin aulacogen, were formed in the Mesoproterozoic ; ⑦ the middle-small sized porphyry copper-gold deposits were formed by the magmatic-hydrothermal activities, related to the process of compression and orogeny of Hercynian to Mesozoic. They were superimposed on the exhalative-sedimentary deposits of Mesoproterozoic and gave apparent modification to the latters. But parts of the Dongshengmiao, Tanyaokou and Hougoqi copper deposits were formed by the magmatic-hydrothermal process in the later orogeny.