【作者】 周家云；

【导师】 郑荣才； 刘亚川；

【作者基本信息】 成都理工大学 ， 沉积学， 2008， 博士

【摘要】 论文对四川会理拉拉铜矿矿床地球化学特征及其成矿大陆动力学背景进行了深入研究。全文共分七章内容进行阐述。论文首先概述了大陆动力学及成矿作用的诞生和意义,指出了大陆动力学是确定成矿系统的形成、演化与区域构造演化的关键,其研究是对传统成矿理论的突破,也是最终确定矿床成矿作用过程和矿床成因模式的关键,对于矿区的找矿勘探工作部署具有重要的指导意义。本文根据拉拉铜矿构造成矿动力学机制,河口群、辉长岩群年龄和岩石地球化学特征分析岩石成因和构造背景,建立起拉拉铜矿区域大陆动力学演化序列;根据矿床年龄和矿床地球化学特征,矿床成矿物质和成矿流体来源研究矿床成因和成矿期次,确定不同时期不同地质体与矿床之间的成矿关系(物质、流体、热动力),并最终以各地质体为媒介反演该区大陆动力学演化的不同构造背景下的成矿作用,从而确定矿床成矿过程和矿床成因模式。首先,矿体严格产于古元古代晚期河口群中部的变钠质火山岩层位,矿石地球化学特征和河口群相似,河口群火山岩属于海底喷发的碱性系列,形成于陆间裂谷或坳拉槽环境,说明拉拉铜矿具有伴随河口群火山喷流—沉积的早期同生沉积成岩成矿作用;其次,矿区东西向构造对矿床展布具有明显的控制作用,这些区域和矿床地质特征显示了新元古代早期(1000Ma左右)华南地块西南缘格林威尔构造运动(早晋宁运动)南北向的挤压导致了拉拉地区含矿岩系东西向叠瓦式冲断-褶皱构造体系的形成和变质成矿作用的发生;第三,矿区辉长岩与矿床时空分布密切相关,辉长岩可能是新元古代中期(850Ma)Rodinia超大陆裂解时超级地幔柱源成因,由此推断,拉拉铜矿成矿作用晚期地幔柱辉长岩浆热事件对矿床巨量金属元素堆积起到极其重要的成矿“引擎”的作用,辉长岩侵位时携带的巨大热量与早期含矿地层发生“引潮共振”,为成矿元素的重新活化、迁移、富集提供了强大的热动力,最终形成拉拉地区巨量金属元素的富集。更多还原

【Abstract】 This paper has done the thorough researches on the geochemical characteristics and continental geodynamics of LaLa copper deposit. The whole paper contains 7 chapters to expatiate.The paper summarizes the naissance and significance of continental geodynamics and it’s mineralization, and points out that continental geodynamics is the key of confirming metallogenic system formation, evolvement, and regional structure evolvement. This research is a breakthrough of traditional mineralization theory, and also is the key of confirming the mineralization process and genetic mode of deposit, which is very important significance for ore-searching and exploration work in mining district. Based on analysis of regional tectonics, deposit signature, age and geochemical characers of Hekou group and gabbro, this paper points out rock origin and structure background and sets up the continental geodynamics evolvement sequence of Lala area. Based on the research of source of mineralizing materials and mineralizing fluid, confirm the attribute of a relation (content, water, heat) between different geologic body and deposit, inverse the mineralization in different continental geodynamics evolvement background by geologic body, and confirm the deposit mineralizing process and genetic mode in the end.Firstly, the ore body strictly lies in volcanic rocks of middle layer of hekou group of late Paleoproteozoic. Ores and hekou group have similar geochemical characters. The volcanic rocks, Hekou group, which belongs to alkalescence system erupted under the sea, formed in intercontinental cracks and aulacogen. According to what mentioned above, it is explained that Lala copper is associated with early syngenetic sediment diagenetic mineralization accompanying with hekou group eruption.Secondly, east-west axis’ structure in this area constrain the association of deposits which show that north-south direction compression of Greenwiller movement caused the east-west axis’ imbricate thrust-fold structure system and metamorphic mineralization in upper Proterozoic era(about 1000Ma).Thirdly, The spatiotemporal distribution of this gabbros closely relate to the deposits. Gabbro waspossibly the super mantle plume source whih the Rodinia supercontinent dividing in middle Proterozoic era(850Ma). It is deduced that mantle plume gabbro magma happening is the "engine" of large metal accumulation in late mineralization process of LaLa copper. The great heat and ore containing stratum caused " tide-producing resonance", that is the power of ore-forming element reactived, transfered and enriched, and finally lead to huge metal element enrichment in LaLa area.更多还原