破山独立银矿卤族元素地球化学

通过对破山独立银矿卤族元素和Mn等成矿元素的研究，认为破山银矿中卤族元素和Mn与Ag的成矿作用密切相关，由于矿区北部桃园花岗岩体侵入时带来了大量F等矿化剂元素，使含矿层中Ag、Pb、Zn等再次被活化浸出，成矿物质主要以卤族元素的络合物形式迁移和搬运，在构造有利部位同时在富Mn岩层富集成矿。由于卤族元素地球化学性质的差异，在不同深度矿体附近形成不同的扩散晕，可以利用这些规律指导找矿。     

建筑石灰中CaO,MgO的测定

用镍坩埚代替银坩埚,氢氧化钠熔融分解试样。分取两份试验,一份在ｐＨ〉１３的条件下,预先加入适量氟化钾抑制硅的干扰,以三乙醇胺掩蔽铁铝。用ＣＭＰ混合指示,ＥＤＴＡ标准溶液滴定钙;另一份在ｐＨ＝１０的条件下,用酸性铬蓝Ｋ－萘酚绿Ｂ混合指示剂,ＥＤＴＡ标准溶液滴定钙镁含量,差减法求得镁的含量。     

湘中地区中奥陶统“桃江式”锰矿的成矿作用研究

湘中地区“桃江式”锰矿产于中奥陶统磨刀溪组斜坡相-盆地边缘相沉积之中。发育锰矿层１～２层,锰矿层具有粒序层理、平行层理、斜纹层、水平纹层及角砾状等构造,夹于深水低能的暗色泥岩之中,是一种碳酸盐重力流沉积。其形成受区域构造、岩相古地理、沉积事件及水介质物理化学条件等的影响。其沉积学和地球化学特征显示锰质主要由海底热水补给,是一种热水成矿作用的产物。     

“桃江式”锰矿床地质特征及其地球化学特征

“桃江式”锰矿赋存于奥陶系中统磨刀期组，作者通过对区域深大断裂，成锰沉积盆地，矿床地质特征和含锰岩系地球化学特征的综合分析，揭示出其成矿成矿物质来源于热水溶液。     

Geochemical features and genesis of continental cobalt-rich ferromanganese crusts

Mass cobalt-rich ferromanganese microcrusts and nodules similar in morphology and chemical composition to cobalt-rich ferromanganese deep-ocean crusts were found in Cenozoic volcanic rocks in southern Primorye. Research has shown that ore genesis of this type is genetically related to argillization and destruction of siliceous rocks by CO₂-rich fluids, which is confirmed by experimental data on carbon erosion of iron-containing materials. Two types of this fluid ore genesis are recognized: (1) relatively high-temperature (vapor-condensate), related to late volcanic processes and fracture gas infiltration, and (2) low-temperature (vapor-liquid-condensate), controlled by degassing followed by carbon mobilization (gasification). Primarily colloidal ferromanganese segregations have high contents of Co, Ni, Pb, Cu, and Ce, typical of oceanic ore genesis. Regardless of the concentrations of these metals in the protoliths, their contents in microcrusts are similar (n-10n wt.%). This indicates the same ore genesis mechanism and similar sorption properties of the colloidal ferromanganese material formed. Barium- and cerium-rich ferromanganese microcrusts and nodules are abundant. Condensed drops of iron-containing platinum were found in apobasaltic nickel-rich ferromanganese segregations. There is a cerium paradox expressed as a minimum or a total lack of cerium among rare-earth phosphates associated with ferromanganese microcrusts. Fluid destruction and oxide metallization of ocean-floor basalts are assumed to be the main source of metals for oceanic ferromanganese crusts and nodules.     

Mineral paragenesis of the Kalahari managanese field, South Africa

The mineralogy of the managanese ores of the giant Paleoproterozoic Kalahari manganese deposit of the Transvaal Supergroup has been subject of many studies and up to now 135 different ore and gangue minerals have been described, of which eight represent new mineral species. Through correlation of different mineral assemblages with specific geological events and by determining relative ages of minerals in outcrop, hand specimen and under the microscope an attempt is made in this publication to construct a paragenetic sequence for this complex mineral assemblage. Sedimentation and early diagenesis of the Hotazel Formation, composed of interbedded iron formation and braunite lutite, was followed by low-grade metamorphism and associated stratabound metasomatism. Braunite lutite of sedimentary origin, comprising 97% of the total ore reserve, is composed of braunite, hematite and kutnahorite, and abundant early diagenetic kutnahorite and manganoan calcite forming laminae and ovoids. Fluid flow during late diagenesis or lower greenschist facies metamorphism led to stratabound metasomatic oxidation of Mn-bearing carbonates to hausmannite and Mn-poor calcite. Three structurally controlled hydrothermal alteration events succeed metamorphism. These events are referred to as Wessels, Mamatwan and Smartt events. The Wessels alteration event is the oldest of the three events and it is of great economic importance because virtually all of the high-grade ore (> 42% Mn), 3% of the total ore reserve, formed during this event through alteration of carbonate-rich low-grade Mamatwan-type ore (braunite lutite) to high-grade, carbonate-poor Wessels-type manganese ore. This Wessels hydrothermal alteration event took place in the northwestern part of the Kalahari deposit, associated with a system of major north-south- and minor east-west-striking normal faults. The Mamatwan alteration event is observed throughout the Kalahari manganese deposit but alteration is very localized. Reduction halos and discolouration of braunite lutite around fracture or joint-hosted sulphide-carbonate mineralization are typical of the Mamatwan alteration event. In contrast, the Smartt alteration event is characterized by oxidation of braunite lutite and the formation of todorokite and manganomelane. Syn- and Post-Kalahari supergene alteration has taken place below the suboutcrop of the Hotazel Formation against the calcretized sediments of the Cenozoic Kalahari Formation. Cryptomelane and pyrolusite are the predominant products of surficial weathering.     

深海锰结核以煤代焦还原熔炼新工艺研究

针对锰结核焦炭还原熔炼成本高、焦炭生产过程环境污染严重等问题,作者提出了锰结核以煤代焦还原熔炼新工艺,对减少锰结核冶炼环境污染、降低冶炼成本,具有积极意义.以东北太平洋中部深海锰结核为原料,对还原温度、还原时间、硅石加入量、无烟煤加入量对锰结核中Co、Ni、Cu、Fe、Mn回收率的影响进行了研究.结果表明:500 g锰...     

海洋中锰的生物地球化学循环研究

痕量元素在海洋生物地球化学循环中起的作用已受到越来越广泛的关注,近年来形成了新的国际科学计划———痕量元素及其同位素的海洋生物地球化学研究(GEOTRACES)。锰是GEOTRACES关键参数之一,国际GEOTRACES组织推荐各国组织的GEOTRACES航次对其在全球大洋中的分布进行重点研究。本研究就痕量元素锰的海洋生物地球化学研究进行了较为详细的综述,介绍了锰在海洋中的来源及输送通量、分布、水体中的赋存形式及其迁移转化、生态学功能以及主要的分析方法等。总结了在这一研究领域所取得的成果及存在的不足,并对今后的发展方向进行展望。