黄铁矿叠层石丘堆式沉积与块状硫化物的富集作用

通过对黄铁矿叠层石组构、成分、微量元素、硫同位素、分子生物标志物与产出的构造环境背景的研究可知 ,黄铁矿叠层石的形成是通过沿同生断裂上升喷溢入海的热流体长期脉动作用 ,构成栖息在热水喷口与热液丘堤周围的嗜热微生物群落生存的食物链基础 ,使嗜热微生物围绕热水喷口繁殖的结果。沿同生断裂上升喷溢入海的热流体长期脉动过程中不断吸附、富集成矿元素 ,并将海水中的硫酸盐还原为H2 S。微生物吸附的Fe2 + 与S2 -作用 ,形成黄铁矿叠层石。微生物群落在热水喷口与丘堤附近不均衡发展 ,产生了成矿带内块状硫化物矿床中的黄铁矿叠层石丘堆。这种黄铁矿叠层石丘堆体是寻找富矿的显著标志 ,具有重要的成因与找矿意义     

Geo–tectonic Position of Tin Polymetallic Mineralization Zone in the Southern Da Hinggan Mountains Area, Inner Mongolia, China: An Introduction to This Special Issue

Abstract: As a part of the main activities of Japan‐China technical cooperation project, a test survey area, approximately 5,000 km², was established for the implement of its geological and geochemical research program. A major mineralization zone called Huanggang–Ganzhuermiao–Wulanhaote Sn‐Cu polymetallic mineralization zone is recognized in the southern Da Hinggan Mountains area. The southern half of this zone is known as the sole Sn‐mineralization zone in North China. The survey area lies in this prominent zone. As the most of the papers presented in this issue have concerns to the geology and mineralization in this survey area, this report was prepared to introduce geo‐tectonic situation of the Sn‐Cu polymetallic mineralization zone in the Inner Mongolia orogenic belt. The belt is divided into four tectonic facies (from NW to SE); I: Wuliyasitai volcano‐plutonic zone, II: Hegenshan ophiolite mélange zone, III: Sunitezuoqi volcano‐plutonic zone, IV: Wenduermiao ophiolite mélange zone. The subject Sn‐Cu polymetallic mineralization zone is situated in the southeastern part of the Sunitezuoqi magmatic zone. About this Sunitezuoqi magmatic zone, three geo‐tectonic characteristics are pointed out. In late Carboniferous to early Permian period, subduction of Hegenshan oceanic crust occurred, which accelerated volcano‐plutonic activities and brought about basic to intermediate volcanic rocks of tholeiitic to calc‐alkaline series represented by Dashizhai Group in the Sunitezuoqi magmatic zone. Late Jurassic to early Cretaceous acidic rocks representing the most culminated volcanism and plutonism in Mesozoic era in the Da Hinggan Moutains area are distributed very extensively in and around the Sn‐Cu polymetallic mineralization zone. The Proterozoic metamorphic basement rocks called Xilinhaote complex are distributed close to the mineralized area in the Sunitezuoqi magmatic zone. Although the real mineralization was known associated with Mesozoic acidic to intermediate volcano‐plutonic activities, it is thought that the lower Permian Dashizhai volcanic rocks and pre‐Cambrian basement rocks might have played certain significant role in the process respectively of extraction of elements and formation of the magma favorable for such mineralization in the Sunitezuoqi magmatic zone. It would be necessary to give further considerations to these three geological units in relation to the Sn‐Cu polymetallic mineralization.     

Geology and Mineralization at the Dajing Tin-polymetallic Ore Deposit, Inner Mongolia, China

Abstract: Dajing is a large-scale tin–polymetallic ore deposit in north China with Sn, Cu, Pb, Zn, Ag, and minor elements such as Co and In. The deposit is controlled by a passage-host structure system. Two groups of NE direction faults such as F₂ and F₁ are characterized by sinistral and multiphase activities, and the syn-ore NE faults with their derivative faults nearly in N-S direction constitute an important structure system as channelway for ore fluid. Around F₂ fault (mineralization center), metallic elements display horizontal zoning outwards from Sn, Cu to Cu, Sn, Pb, Zn, Ag and to Pb, Zn, Ag. Controlled by sinistral pull-apart vein system, the WNW direction host structure yielded the ore vein to "W" shape on horizontal plan while to staircase shape on vertical profile. Multiperiodic activities of the host structures system lead to multistage of ore mineralization. Four mineralization stages are recognized in the main mineralization, i.e. 1) cassiterite–arsenopyrite–quartz stage, 2) cassiterite-sulfide (or Cu–poly–metallic mineralization) stage, 3) massive pyrite stage, and 4) galena-sphalerite stage. Besides, fluid activities are identified here at the pre-mineral stage of the formation of quartz veins and sheared deformation, and at the post-mineral stage of quartz–calcite–fluorite deposition.
The earlier tin-rich ore solution raised from NE faults and its nearly N-S derivatives filled the NW-WNW direction fractures, and formed tin ore veins. Subsequent mineralization of Cu-polymetallic stage, pyrite stage and galena-sphalerite stage, overlapping on the same fracture system, sequentially expanded outwards from the fractures, and produced different kinds of ore types and mineralization zoning.     

川西北马脑壳金矿床构造-流体-金成矿作用系统演化模式

基于对马脑壳金矿床构造变形分析及流体包裹体研究,探讨了马脑壳金矿床形成过程和热液成矿机制,认为自印支运动以来,该区先后经历了韧性、韧-脆性及脆性等多期构造变形演化过程,并伴有多次热液活动。热液的来源及性质与构造变形作用密切相关,早期韧性构造变形期,热液来源以地层建造水和变质水为主,而韧-脆性变形期以来大气降水不断加入并逐渐占据优势。由韧性→韧-脆性和韧-脆性→脆性构造变形机制的转变,引起热液发生混合及相分离作用,并导致热液体系T、pH、fo₂、fs₂等物化条件降低变化,造成热液中含金络合物溶解度大幅度下降而发生沉淀成矿作用。概括总结了马脑壳金矿床构造-流体-金成矿作用系统演化模式。     

铅同位素特征对成矿物质来源的制约--以华北地块北缘中段铅锌银矿床为例

华北地块北缘中段是我国铅锌银矿床的重要富集区之一.对这些矿床的成因研究长期以来存在诸多争论.笔者依据成矿地质、地球化学和成矿年代学等特征,将本区铅锌银矿床划分为四种类型.通过对铅同位素地质特征的研究,探讨了成矿物质来源,指出区域古元古代变质基底和中新元古代地层是成矿物质的重要来源之一.     

秦岭—巴山地区成矿背景和成矿作用的新进展

“八五”－“九五”期间秦岭的多项研究中，主要取得以下新进展：1．创立了抽拉－塑夺片构造新理论，丰富和发展了岩石圈板块或壳块运动方式的多样性。2．发现了东西向的秦岭造山带从显生宙以来有南北向的隆升带和沉积盆地，特别是太白、宝鸡－佛坪－汉南隆升带的发现，将从根本上改变秦岭乃至中国中东部构造格架的认识。3．南北向沉积盆地转谈东西向造山带的Ⅱ型造山带，深部构造岩片抽拉－逆冲推覆在中（新）生代陆相沉积盆地之上所形成的Ⅲ型造山带，为地壳表层增添了两种新型的造山带。4．首次提出秦岭造山带中存在三类沉积盆地，三种盆－山转换，三个发展阶段及三种型式（Ⅰ，Ⅱ，Ⅲ）的造山带，这在国内外均属首创。5．重新厚定商丹带、勉略带和二郎坪带的构造属性，形成时代，首次提出秦岭受三种体制，四个发展阶段的新观点，受抽拉构造形成的陆内造山带是秦岭最重要的划时代发展阶段。6．最先提出立交桥式结构观点。7．发现了一批前震旦系变质地层结晶岩系，重新厚定了一些地层的时代，特别是西秦岭，西成铅锌矿田中元古界地层的发现和超大型厂坝矿床产于其中，有重大的理论和实际意义。8．提出准浊流态流体的新概念。9．创立了在统一地质－成矿场制约下的多重岩片控矿论和构造一成矿体系，首次在秦岭提出三种统一地质－成矿场，三大构造一成矿体系，三种矿床模式及三种区域找矿模式。10．首次在秦岭提出超大型矿床的富集部位，大型矿床受鞘褶皱控制的观点。11．对若干矿床的成因提出新认识，特别是西成铅锌矿床，漳腊金矿床的新认识有重大的指导作用。12．划分出三级成矿远景区三个，四级远景区十三个，五级远景区：A级11个，B级9个，C级7个，还提出10个寻找大型矿床和穆龙套式金矿的地区。     

柴达木盆地深层地下水成矿模式及其成矿规律

论述了柴达木盆地深层地下水成矿模式及其成矿规律。不仅剖析了深层地下水成矿的研究概况和化学成分的现今性状与时空分布规律 ;而且首次探讨了深层地下水的水文地质发育史 ,进行了古水文地质再造 ,提出了古水文地质旋回的新概念。同时 ,还揭示出“围压深埋型烃类运聚形成的石油 (气 )藏”及其“高压围限的低压区、毗邻高压区的低压区、卸压区和早熟型等 4大聚油 (气 )区”和“高山深盆浅水蒸发型盐湖富钾卤水矿床”及其“水平分带、垂向叠加效应和水型相关”等 3大成矿规律。据此 ,对于石油 (气 )藏和盐湖富钾卤水等资源开展了成矿予测 ,并且指出了勘查开发方向     

云南个旧塘子凹锡多金属矿床地质表征

本文在前人对区域地质调查的基础上，通过对塘子凹矿床成矿特征及规律的研究，认为搪子凹锡多金属矿床的成因与中三叠统的大理岩、燕山晚期的淡色花岗岩共同作用有关，燕山晚期花岗岩体的空间形态直接控制矿体的产出部位。花岗岩以构造侵位方式侵位于中三叠统大理岩中，其空间细部特征受五子山复背斜和南北向隐断裂的作用。指出八处成矿有利部位。     

个旧锡矿33号矿群地质特征与其外围找矿方向

个旧锡矿区是老矿区，开采历史悠久，目前资源紧张，急需开展找矿增储研究。33号矿群是近年新勘查的矿体，以接触交代矿床为主，经工程揭露，现已探明一定锡储量，目前矿山生产急需向外围找矿，以期扩大储量，但苦于找矿工程方向不清。我们通过对隐伏花岗岩体形态，锡、铜的矿化强度模型，地表地球化学结合地质研究，指出33号矿群的北东，芦塘坝断裂与炸药库断裂交截部位附近为最有利的找矿空间。