湘南燕山期区域三叉断裂构造型式及成矿作用

全铁军^{1, 2}，奚小双¹，孔 华¹，吴堑虹¹，陈泽锋¹

(1. 中南大学 地球科学与信息物理学院，有色金属成矿预测教育部重点实验室，长沙 410083；
2. 湖南有色金属地质勘探局，长沙 410007)

摘 要：在对湘南中生代区域成矿构造进行研究的过程中发现了热柱三叉断裂构造，认为这种构造是燕山早期地幔对流活动在岩石圈形成的一种构造型式。其主要证据包括：湘南有色金属矿床呈3个不同方向的线状分布；其交汇中心与湘南穹窿构造中心吻合；构造系统中矿床和成矿岩体具有同时性。已有花岗岩和火山岩的地质、地球化学研究表明，燕山期华南深部存在地幔活动，这为湘南发育热柱三叉断裂构造提供了深部构造背景支持。三叉断裂构造型式的发现和认识为湘南成矿作用和成矿规律研究提供了新的构造模型。

关键词：三叉断裂；地幔柱；华南地区；花岗岩；成矿作用

Yanshanian triple junction tectonic pattern and metallogenesis in southern Hunan, China

QUAN Tie-jun^{1, 2}, XI Xiao-shuang¹, KONG Hua¹, WU Qian-hong¹, CHEN Ze-feng¹

(1. Key Laboratory of Metallogenic Prediction of Nonferrous Metals, Ministry of Education,
School of Geosciences and Info-Physics, Central South University, Changsha 410083, China;
2. Hunan Nonferrous Metal Geo-exploration Bureau, Changsha 410007, China)

Abstract:The mesozoic metallogenesis and tectonics in southern Hunan, China, were studied, and a triple junction was found. It is a tectonic pattern in lithosphere and its forming mechanism may be attributed to mantle convection in early Yanshanian. The main evidences for triple junction are shown as follows: the nonferrous metal deposits in southern Hunan distribute in line style in three directions; convergence center of distribution lines of nonferrous metal deposits coincide with the centre of southern Hunan dome; these deposits and their hosting granites in the triple junction system are isochronic. Geological and geochemical studies on the granite and volcanics indicate that there exist mantle activities in deep crust of southern China, which is a deep tectonic background support to the triple junction developed in southern Hunan. The finding and viewpoint of triple junction tectonic pattern in southern Hunan bring out a new tectonic model to discuss metallogenesis and its rules in this area.

Key words:triple junction; mantle plume; southern China; granite; metallogenesis