安徽铜陵冬瓜山铜矿矽卡岩形成过程中元素质量迁移——与凌其聪等同行探讨

质量平衡法是研究岩石蚀变过程中元素迁移的有效方法之一，其关键环节是确定蚀变过程中的不活动元素。凌其聪和刘丛强（2003）《层控矽卡岩型矿床成矿系统的元素活动性及质量迁移——以铜陵冬瓜山铜矿为例》一文中认为在安徽铜陵冬瓜山铜矿矽卡岩形成过程中Zr、Hf、Y、Nb为不活动元素的结论欠妥，证据不足，从而导致提出采用不同不活动元素为标准计算的结果有所差异的错误认识。本文采用龚庆杰等（2006）提出的新改进方法对其岩石分析数据重新进行研究，结果表明安徽铜陵冬瓜山铜矿矽卡岩形成过程中Zr、Th、P2O5在系统中可视为不活动元素，由此确定的岩石质量迁移率为-0.7326，这与凌其聪和刘丛强（2003）一文中采用Zr的计算结果相一致。     

蚀变作用的多原岩系统及质量平衡

介绍了造成岩石地球化学不均匀性的原因，主要有测量误差、闭合问题及岩石学方面的控制等。各有其不同的研究和解决方法。对于蚀变岩的多原岩系统，常用不相容高场强元素（HFSE）来描述岩石性质，用其作为监视器，可作出各相容元素（或成分）的分异线；用不活动元素蚀变线与分异线的产点来确定原始成分，并在此基础上进行蚀变岩质量变化的计算。     

云南镇沅金矿煌斑岩蚀变过程中元素活动规律

广泛分布于云南镇沅金矿、与金矿化在时间上、空间上密切共生的煌斑岩普遍遭受不同程度的蚀变。根据岩石的蚀变相对强弱，本区煌斑岩可分成新鲜（弱蚀变）、蚀变两种。质量平衡方程对蚀变过程中元素活动规律的计算结果表明，引起本区煌斑岩蚀变的流体为一种含过渡元素、亲石元素、挥发性元素和亲硫元素（或成矿元素）的富硅、铝碱性流体，这种流体可能是本区煌斑岩岩浆演化到晚期分异出来的产物。关键词     

6122铀矿床蚀变岩中的物质迁移变化

应用水热蚀变过程中不活动元素确定蚀变岩质量变化的方法，对6122铀矿床不同标高蚀变岩的物质组分迁移变化进行了定量计算，探讨了围岩蚀变垂直分带性和成矿流体性质。研究表明，6122铀矿床矿化围岩蚀变过程中TiO2为不活动组分；围岩蚀变垂直分带上存在“土酸下碱”的特征；成矿流体为富含Na^ 、P的碱性流体。     

云南镇沅金矿煌斑岩矿化过程中元素活动规律

广泛分布于云南镇流金矿、与金矿化在时间上、空间上密切共生的煌斑岩普遍遭受不同程度的蚀变,部分经历了矿化作用,根据岩石的蚀变相对强弱及是否矿化,本区煌斑岩可分成新鲜（弱蚀变）、蚀变、矿化三种。在用质量平衡方程计算了区内煌斑岩蚀变过程中元素活动规律的基础上,本文采用该方法计算了煌斑岩矿化过程中元素的活动规律。结果表明,引起本区煌斑岩矿化的流体为一种富含K2O、CaO、CO2、F、Cl、S、As、Sb、An、Ag等组分的流体;成矿元素（Au）的来源及稳定同位素显示这种流体具有多源性。     

云南老王寨金矿煌斑岩蚀变、矿化过程中元素活动规律

广泛分布于云南老王寨金矿、与金矿化在时间上、空间上密切共生的煌斑岩普遍遭受不同程度的蚀变，部分经历了矿化作用，根据岩石的蚀变程度及是否矿化可将本区煌斑岩发成新鲜（弱蚀变）、蚀变、矿化三种。质量平衡方程对煌斑岩蚀变、矿化过程中元素活动规律的计算结果表明，引起本区煌斑岩蚀变的流体为一种含过渡元素、新石元素、挥发性元素和亲硫元素（或成矿元素）的富硅、铝碱性流体，这种流体可能是本区煌斑岩石浆演化到晚期分异出来的产物；引起本区煌斑岩矿化的为富含Ｋ２Ｏ、ＣａＯ、ＣＯ２、Ｆ、Ｃｌ、Ｓ、Ａｓ、Ｓｂ、Ａｕ、Ａｇ等元素的流体，这种流体具有多源性     

莲花山斑岩型钨-金矿床蚀变矿化过程中元素迁移定量研究

广东莲花山斑岩型钨-金矿床蚀变类型可以分作钾化、云英岩化、绿泥石化、绢云母化和青盘岩化。不同原岩不同类型蚀变岩元素质量得失的定量计算结果表明,Th、TiO₂、Al₂O₃、P₂O₅、Ta和Hf等在蚀变矿化过程中基本表现出惰性特征,质量得失较少,主元素在岩石中含量的变化主要受原岩类型的影响,其次受到蚀变作用类型的影响,成矿元素及与其有关的其他微量元素在蚀变岩中则主要表现出较大程度的富集。稀土元素在蚀变矿化过程中迁移作用不明显。本文结合蚀变矿化的地质特征及镜下观察结果对不同蚀变带中元素质量得失作了详细解释。     

扬子地块西南缘拉拉IOCG矿床矿化蚀变元素地球化学研究

拉拉IOCG矿床是我国西南地区著名的大型铁铜矿床,矿床中与铜(钼)矿化密切相关的钠长石化、碳酸盐化、钾长石化、黑云母化、萤石化等蚀变作用广泛发育。本文在对该矿床中黑云母片岩系列和钠长石变粒岩系列大量赋矿岩石样品进行岩相学研究的基础上,选取典型蚀变与矿化样品进行主、微量元素分析测试,通过质量比簇判别法和等浓度公式元素定量迁移计算研究矿床中蚀变元素特征及其与矿化的关系。质量比簇判别法和等浓度图解法确定了两个系列岩石共有的主量元素不活动组分为SiO_2,微量元素不活动组分为Yb。主量元素定量迁移计算表明黑云母片岩系列铜矿化与钠长石化和碳酸盐化成正相关关系,钠长石变粒岩系列铜矿化与钾长石化和碳酸盐化成正相关关系,且变粒岩系列碳酸盐化程度较片岩系列更强。稀土元素和金属元素定量迁移计算发现拉拉IOCG矿床中U、Co、Mo、Ni等成矿金属元素在蚀变过程中随Cu矿化大量带入,说明热液蚀变是拉拉Fe-Cu-Au-U-Mo-REE多金属矿床形成的主要原因。蚀变与矿化关系分析表明二者基本是同步发生,蚀变的过程也是矿化的过程,即蚀变的标志也是找矿的标志。拉拉IOCG矿床中蚀变元素地球化学特征及其与矿化关系的研究,对于矿床成矿理论的丰富及矿区进一步找矿勘探工作都具有重要意义。     

胶东玲珑金矿田煌斑岩蚀变过程元素迁移行为及其意义

胶东矿集区内普遍发育煌斑岩脉,对煌斑岩的热液蚀变现象进行研究可以揭示蚀变流体的地球化学特性。对玲珑金矿田两处新鲜与蚀变煌斑岩进行了56项氧化物和微量元素分析,结果发现玲珑金矿田的煌斑岩为富钾煌斑岩,稀土元素在煌斑岩蚀变过程中未发生明显分异现象。确定煌斑岩蚀变过程中的不活动元素可以采用坪台法,其优点在于克服了等浓度图解法中拟合过原点直线的技术缺陷。质量平衡计算法与元素含量比值法的本质区别在于二者相差一比例系数,即蚀变岩与原岩的质量比率,元素含量比值法可视为质量平衡计算法在岩石轻微蚀变时的一个特例。玲珑金矿田的煌斑岩与金矿成矿流体具有相同的构造通道,引起煌斑岩蚀变的这期金矿成矿流体富K2O、Rb、Be、Ba、W、Pb、Zn、Sb、B、Mn、Ta,贫Na2O、CaO、MgO、Sr等元素,可选取W、Pb、Zn、Sb、B、Be、Rb、Ba为该区金矿的成矿指示元素。     

蚀变岩岩石质量平衡及主要成分变异序列——以河南西峡石板沟金矿热液蚀变岩为例

河南西峡石板沟金矿为一典型的蚀变岩型金矿, 近ＮＷ 向的剪切带为主要控矿因素。近矿蚀变岩类型主要有硅化、黄铁矿化、绢云母化、钾长石化,且具有分带特征。按照蚀变分带进行了系统的岩石学和岩石化学采样, 研究了蚀变岩的岩石质量平衡、体积变化（ｆｖ ＝ ９７ ．２４％ ～７１．６３％ ） 和主成分变异,讨论了活泼元素和惰性元素在岩石蚀变过程中的变化规律,建立了主成分变异序列。     

REE and HFS element behaviour in the alteration facies of the Erenler Dağı Volcanics (Konya,Turkey) and kaolinite occurrence

Mainly high-K, calc-alkaline, Late Miocene to Pliocene volcanic rocks cropped out of the Konya area in Central Anatolia, Turkey. The volcanic rocks are predominantly andesitic to dacitic in composition and rarely basalt, basaltic andesite, basaltic trachyandesite and pyroclastics. Kaolinite, illite, Ca-montmorillonite, alunite, jarosite, minamiite and silica polymorphs were formed by widespread and intense hydrothermal alteration in or around the volcanic products. To investigate the effects of hydrothermal alteration on the chemistry of volcanic rocks, the whole rock chemical composition (major and trace elements, including rare-earth elements (REE) was analysed. The results of the study demonstrate notable differences in the REE behaviour in the different sample groups. REE trends of fresh parent rocks to weakly-, moderately-altered, kaolinitic and alunitic rocks are characterised by strong LREE enrichment ((La/Lu)_cn = 14.57, 11,8 to 15.20, 4.54 to 13.30, 12.5 to 24.2 and 34.6 to 47.26, respectively). Most of the samples have pronounced negative and/or weakly-negative Eu anomalies ranging from 0.75 to 0.98 while three samples have weakly-positive Eu anomalies. LRE element contents are higher than those of HREE in the samples. The LRE elements were strongly enriched in the kaolinitic and alunitic alteration; in weakly- and moderately-altered rocks. LREE are nearly immobile whereas HRE elements show different behaviour in different rock groups. The HFS and TRT elements are slightly mobilised in weakly-altered rocks, but enriched in other alteration types. Elements commonly assumed to be immobile (e.g. Y, Zr, Nb, Hf, TiO₂, Al₂O₃, REE) show variation in mass calculation. LIL elements showed enrichment over LREE and MREE, and similar behaviour, in contrast with HFSE. A clear increment of trans-transition elements (TRTE) was found mainly in alunitic and partly in kaolinitic samples.     

Mass change calculations in altered rock series

A technique is presented whereby precursors of altered rocks in a fractionated rock series can be identified, and changes in chemical components, mass and volume accurately calculated. The procedure utilizes elements with high degrees of immobility in hydrothermal and associated interactive water-rock systems. Igneous rock series, and sedimentary and metamorphic rocks with primary continuity of chemical composition, are amenable to this treatment. In the procedure for igneous rocks, best-fit fractionation lines are established for an immobile igneous compatible-incompatible element pair, the latter element functioning as the fractionation monitor. Alteration paths are linear and pass through the origin. Intersections of the fractionation and alteration lines yield the immobile element concentrations in the precursors to the altered rocks; mobile components are determined from fractionation lines and monitor values. Total mass changes are proportional to the displacement of altered samples from the fractionation line. Masses of other elements in an altered sample (reconstructed values) are recalculated to the concentration of the monitor element in the precursor. Chemical changes are the differences between the calculated precursor compositions and the reconstructed altered rock compositions. Errors are mainly a function of the positioning of the fractionation lines.     

The behaviour of so-called immobile elements in hydrothermally altered rocks associated with volcanogenic submarine-exhalative ore deposits

Evidence is available that some elements, notably Zr, TiO₂, Y, Sc, Ce and Nb are largely immobile during the alteration of volcanic rocks owing to metamorphism, hydrothermal events and weathering (e.g. Floyd and Winchester, 1978). However, it is shown, by reference to analyses of rocks from the environment of five volcanogenic massive sulphide bodies, that while Zr, TiO₂ (and Ce?) are mostly immobile even during intense hydrothermal alteration, Y and particularly Sc and Nb may be extremely mobile. When elements are removed by solution in a hydrothermal fluid it seems that reaction rates are such that these elements are almost totally removed from the rock. Therefore, of the so-called immobile trace elements, only Zr and TiO₂ may be used with any reliability to identify the degree of magmatic differentiation in an hydrothermally altered rock. However, if an element has been mobile it is usually readily identified as having moved.     

Subseafloor hydrothermal alteration during the Early Proterozoic at Garpenberg,Central Sweden

The Early Proterozoic sulfide deposit at Garpenberg is located in the metallogenetic province of central Sweden. It is a strata-bound massive sulfide deposit contained in a supracrustal sequence of mainly acid metavolcanic rocks. Stratiform Zn-Pb-Cu mineralization is underlain by Cu-bearing stockwork ore and an extensive alteration zone. The sulfide ores and their altered wall rocks were formed by subseafloor hydrothermal activity. The alteration pattern observed in the wall rocks of this deposit is consistent with a hydrothermal system where the fluid consists mainly of seawater and a high water/rock mass ratio predominates. The hydrothermal activity caused the destruction of the primary mineralogy, mainly feldspars, and a general redistribution of the chemical elements in the altered wall rocks which were principally depleted in Ca, Na and Eu and enriched in Mg. Eu was redeposited with the ore metals near or at the seafloor and Ca was deposited as limestone. Most of the major and trace elements show large mobility during the alteration; only Ti, Zr, Y and REE (excluding Eu) behaved as relatively immobile elements.     

滇中大红山岩群变质火山岩类的原岩性质和构造属性

大红山岩群中的变质火山岩类经在了区域性的海水蚀变和区域变质的改造,其岩石学特征和化学成分都发生了较大的变化,不活动组分的研究显示,其原岩主查拉斑玄武岩类,且具有形成于洋中脊环境的地球化学特征,可能属于Ｔ型地幔源区的洋中脊玄武岩（ＭＯＲＢ）大红山式Ｃｕ－Ｆｅ矿床具有富洋壳成矿元素特性,与所识别的变质火山岩类的原岩和形成的大地构造背景是一致的。     

围岩蚀变过程中地球化学组份质量迁移计算

在以往围岩蚀变的质量迁移研究基础上,本文提出了一种判定惰性元素的方法,同时结合等浓度线和加权最小二乘法,给出研究热液围岩蚀变中组分质量迁移的计算方法。在判定惰性元素时,更多地应用了线性回归分析中的方差分析与回归诊断参数与计算方法。这一系列的参数与方法被用于评述沃溪金锑钨矿床褪色化围岩蚀变质量迁移,取得了较好的效果。研究表明,在沃溪矿床围岩蚀变过程中,Ｔｉ表出现了一定的活动性。     

围岩蚀变过程中地球化学组份质量迁移计算——以湖南沃溪Au-Sb-W矿床为例

在以往围岩蚀变的质量迁移研究基础上,本文提出了一种判定惰性元素的方法,同时结合等浓度线和加权最小二乘法,给出研究热液围岩蚀变中组分质量迁移的计算方法。在判定惰性元素时,更多地应用了线性回归分析中的方差分析与回归诊断参数与计算方法。这一系列的参数与方法被用于评述沃溪金锑钨矿床褪色化围岩蚀变质量迁移,取得了较好的效果。研究表明,在沃溪矿床围岩蚀变过程中,Ｔｉ表出现了一定的活动性。     

蚀变岩中物质迁移的定量计算：以锡矿山锑矿床为例

本文提出了确定沉积岩蚀变作用过程中的不活动组分的方法，并以锡矿山锑矿床为例，定量计算了蚀变岩中各组分的带入带出量，研究表明：锡矿山锑矿硅化过程中ＴｉＯ２和Ａｌ２Ｏ３为不活动组；ＳｉＯ２，Ｋ２Ｏ，Ｎａ２Ｏ及锑，硫，坤，汞，铅和钡为带入组分；而ＣａＯ，ＭｇＯ，Ｆｅ２Ｏ３，ＭｎＯ及铜，锌为带出组分，锑，钡，硫，ＳｉＯ２和ＣａＯ有较大的带进或带出量，锡矿山锑矿床矿石矿物为单一辉锑矿可能是由于矿液中缺少其它