黑龙江多宝山成矿区找矿新进展及其地质意义

近年来,多宝山成矿区先后发现了小泥鳅河金矿、三道湾子金矿、争光金锌矿、铜山金矿、上马厂金矿、小新屯金矿点等一大批金银钼锑资源潜力很大的化探异常.依据这些新的矿产勘查和区域地质调查新成果,总结了多宝山成矿区近年来取得的新近展及其地质意义.目的是为多宝山地区的整装勘查与资源潜力预测提供参考依据.     

内蒙古大井矿床碳氧同位素组成及其成因意义

利用碳氧同位素组成可以很好地判别其形成的沉积环境.以内蒙古大井矿床为例,对该矿床16个菱铁矿样品进行碳、氧同位素分析,δ13CPDB变化范围为-1.8‰～-6.6‰,δ18OVPDB变化范围为-23.1‰～-17.3‰.根据矿物δ13C与δ18O值投影到δ13C-δ18O图解中,样品数据在图中的投点落入热水沉积区,说明其形成过程中具有热水沉积作用的发生.古温度可以通过T=16.998-4.52(δ18cO-δ18wO)+0.03(δ18cO-δ18wO)2计算,其形成时的温度平均值为117℃,比海底和湖底的温度要高得多,主要原因在于热水流体参与成矿.碳酸盐的成矿环境可以通过公式Z=2.048(δ13C+50)+0.498(δ18O+50)计算:Z值大于120,表示成矿环境为海水;如果Z值小于120,表示成矿环境为淡水或湖水.内蒙古大井矿床菱铁矿的Z值为100～114,结合区域地质背景,大井矿床形成的古环境为深水湖泊环境.通过对碳氧同位素的分析,结合成矿地质背景、矿床地质特征以及微量元素组成,认为在大井矿床成矿的早期阶段曾经发生过热液沉积作用,本次研究不仅有利于全面理解和认识大井矿床成矿过程的全貌,而且有益于对古湖相环境热液事件的探索.     

http://www.sciencedirect.com/science/article/pii/S1674987110000125

<正>Carbonatites are commonly related to the accumulation of economically valuable substances such as REE.Cu,and P.The debate over the origin of carbonatites and their relationship to associated silicate rocks has been ongoing for about 45 years.Worldwide,the rocks characteristically display more geochemical enrichments in Ba,Sr and REE than sedimentary carbonate rocks.However,carbonatite's geochemical features are disputed because of secondary mineral effects.Rock-forming carbonates from carbonatites at Qinling.Panxi region,and Bayan Obo in China show REE distribution patterns ranging from LREE enrichment to flat patterns.They are characterized by a Sr content more than 10 times higher than that of secondary carbonates.The coarse- and fine-grained dolomites from Bayan Obo H8 dolomite marbles also show similar high Sr abundance,indicating that they are of igneous origin.Some carbonates in Chinese carbonatites show REE(especially HREE) contents and distribution patterns similar to those of the whole rocks.These intrusive carbonatites display lower platinum group elements and stronger fractionation between Pt and Ir relative to high-Si extrusive carbonatite.This indicates that most intrusive carbonatites may be carbonate cumulates.Maoniuping and Daluxiang in Panxi region are large REE deposits.Hydrothermal fluorite ore veins occur outside of the carbonatite bodies and are emplaced in wallrock syenite.The fiuorite in Maoniuping has Sr and Nd isotopes similar to carbonatite.The Daluxiang fiuorite shows Sr and REE compositions different from those in Maoniuping.The difference is reflected by both the carbonatites and rock-forming carbonates,indicating that REE mineralization is related to carbonatites.The cumulate processes of carbonate minerals make fractionated fluids rich in volatiles and LREE as a result of low partition coefficients for REE between carbonate and carbonatite melt and an increase from LREE to HREE.The carbonatite-derived fluid has interacted with wallrock to form REE ore veins.The amount of carbonatite dykes occurring near the Bayan Obo orebodies may support the same mineralization model,i.e.that fluids evolved from the carbonatite dykes reacted with H8 dolomite marble,and thus the different REE and isotope compositions of coarse- and fine-grained dolomite may be related to reaction processes.     

关于变质深熔作用与成岩成矿关系的思考

变质作用与地壳形成演化过程密切伴生 ,并与成岩、成矿作用具密切关系。从动力学系统分析 ,区域变质作用混合岩化作用变质深熔作用是温压递进性变质作用。变质深熔作用是变质过程一个重要组成部分 ,它具有独特的温压、热力学、动力学及地球化学特性 ,文中定义为变质深熔系统 ,简称MAS ,它是由物质来源、能量来源、作用形式 ,物质转移与富集 ,形成时间与位置等要素组成。文中列举与变质深熔作用有关的花岗质岩石及矿床实例 ,并据MAS要素分析其成岩、成矿机制 ,剖析了哀牢山变质带、云开变质带花岗质岩石属变质深熔成因 ,变质带中伟晶岩矿床、剪切带金矿床形成与变质深熔作用具密切关系。当前国际上十分重视在矿床形成和物质转移中的变质作用研究 ,因此深入开展变质深熔作用与成岩、成矿关系研究具重要理论和实践指导意义。     

过去20年矿床事业发展的概略回顾

文章概略回顾了过去20年在找矿和成矿理论研究方面获得的若干重要成就。指出这一阶段虽在一些国家存在矿业不景气，但找矿进展，特别是金、铜矿床、仍很出色。矿业中国都强调了超大型矿床的重要性。在成矿理论方面，主要就多样复杂的海底成矿，三大巨型成矿域，成矿模式，中酸性岩浆岩及有关成矿作用，层控矿床，同位素、微量元素及气液包裹体运用于成矿等问题的研究历史作了回顾。     

江西滑石矿成矿条件及成因分析

通过对长丰、禾源两滑石特征的介绍，分析了滑石矿的成矿地质条件，探讨了该区滑石矿的成因类型。     

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.     

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