胶东郭城金矿稀土元素地球化学特征及其对成矿的指示意义

郭城金矿位于胶莱盆地东北缘,矿体产出与荆山群地层,矿化类型以黄铁矿化和磁黄铁矿化为主,相比胶东其它金矿床成矿地质条件较为特殊。采用ICP-MS方法分别对郭城金矿矿石、牧牛山岩体和中基性脉岩中的稀土元素的组成进行了测定,探讨了成矿物质和成矿流体来源的问题。结果显示,矿石稀土元素配分曲线具有右倾型和平坦型两种型式。具平坦型配分曲线特征的矿石与花岗岩稀土元素配分曲线型式接近,二者具有较强的相关性;具右倾型配分曲线特征的矿石与脉岩的曲线型式类似,二者的相关性较好。晚期碳酸盐化的矿石具有极高的稀土含量。脉岩Eu异常不明显,矿石和花岗岩均具明显的Eu负异常。表明了成矿物质来源于牧牛山岩体和地壳深部,成矿流体来源于深部岩浆演化,矿床的形成具有多期次性。     

云南老王寨金矿床微量元素和同位素组成及成矿物质来源的限定

云南老王寨金矿床的玄武岩、矿化玄武岩、煌斑岩、矿化煌斑岩的Ａｕ、Ｎｉ、Ｃｕ等微量元素不同步富集，表明金不是在玄武岩和煌斑岩岩浆和热液作用过程中富集的。矿化围岩的金相对富集程度高，铜、铅、锌、银的相对富集程度低。矿化玄武岩的δ＾１８Ｏ值为１０．５‰，玄武岩的δ＾１８Ｏ值为８．７‰；含少量黄铁矿的矿化煌斑岩的δ＾１８Ｏ值为１４．７‰，弱蚀变煌斑岩的δ＾１８Ｏ值为１１．２％，最强烈矿化煌斑岩δ＾１８Ｏ值     

粤西阳春盆地合水金矿区煌斑岩地球化学特征及其成矿意义

粤西阳春盆地合水金矿在空间上与煌斑岩具有密切的联系,金矿化主要产于蚀变的煌斑岩及砂岩的构造破碎带中。岩矿鉴定表明,本区煌斑岩的矿物成分主要由黑云母斑晶及长石组成,属于云煌岩类。云煌岩具有高硅、高钾特征,SiO_2含量平均为56.86%,K_2O含量平均为6.33%,属高钾质粗安岩系列煌斑岩。蚀变煌斑岩与新鲜云煌岩的化学成分对比表明,随着蚀变作用的进行,表现为全碱含量的显著降低和全铁含量的显著增加。蚀变煌斑岩与新鲜云煌岩的微量元素对比表明,在本区的热液蚀变过程中伴随有热液成矿元素的明显富集,其中CuBi-Sb-W-Cd的异常微量元素组合特征可以作为本区金矿化蚀变与找矿的标志性伴生元素组合。区内煌斑岩稀土元素具有总量高,LREE显著富集,HREE强烈亏损的特征,配分曲线为明显的右倾型。本区新鲜云煌岩的Au含量较低,其提供Au来源的可能性较小,但煌斑岩破碎带为成矿提供了十分有利的空间环境。本区的金矿化主要是由后期热液蚀变作用所致,其成因很可能与外围的花岗岩浆活动有关。     

甘肃枣子沟金矿床形成环境及矿床成因

甘肃枣子沟金矿是一座位于西秦岭西段夏河—合作金多金属成矿带的大型金矿床。稀土元素配分曲线右倾,为轻稀土富集,负Eu异常明显,表现为壳源岩浆的特征。矿石中的微量元素分布与闪长岩相似,说明成矿热液来源于闪长岩。金矿石中黄铁矿δ34S在-7.47‰～-9.26‰之间,表明硫主要来源于岩浆期后热液。次生包裹体均一温度为120～270℃,属中低温热液型。     

新疆阿克陶县达灵一带金矿地质特征与矿床成因探讨

详细描述阿克陶县达灵一带金矿地质特征,矿床围岩热液蚀变明显,主要有硅化、褐铁矿、黄铁矿、毒砂矿化。故工区内成矿类型推断为破碎带蚀变岩型。从矿床地质特征、矿石物质成分、矿体的赋存地层、侵入岩岩体性质等方面探讨矿床成因,矿石类型属原生矿。     

江苏甘家巷铅锌矿区稀土元素地球化学特征及指示意义

对江苏南京甘家巷矿区铅锌矿床不同类型岩石和矿石的稀土元素地球化学特征进行研究,探讨了岩石和矿石中稀土元素地球化学行为。结果显示:矿床中稀土元素的分布较为一致;甘家巷矿区稀土元素总量变化大,总体来看,稀土总量在铅锌矿石、底砾岩和粉砂岩中相对富集;在稀土元素配分模式图上,轻稀土相对富集,稀土配分曲线向右缓倾,轻稀土元素随原子序数的增加富集程度降低,重稀土元素分布比较平坦。相对较稳定;稀土元素地球化学特征指示甘家巷矿区为受F2断裂和不整合面控制的中低温热液矿床。     

Q型聚类分析在确定成矿脉岩中的应用——以桦甸大庙子-菜抢子金矿区为例

吉林桦甸大庙子-菜抢子金矿区脉岩十分发育，且与成矿关系密切。通过近两年对该矿区实际地质调查研究，并重新采集各矿床脉岩、矿石样品30件，以Au、Ag、Cu等8种成矿元素作为变量，用Q型聚类分析的相关系数法进行了统计计算，计算得出金-黄铁矿型矿体与辉绿岩、煌斑岩、花岗斑岩有关；金-多金属型矿体主要与二长花岗斑岩、闪长玢岩有关，并与实际地质调查认识一致。由此明确了本矿区随着岩浆由中性向酸性演化，成矿由贵金属向多金属矿化转变。并在空间上形成叠加．     

云龙县旧州南山铁金矿床地质特征与控矿因素分析

通过对云龙旧州南山铁金矿床的赋矿地层岩性、控矿构造、围岩蚀变、矿化特征的研究,同时与典型矿床(胶东金矿田)对比,可知云龙县旧州南山铁金矿床的主要控矿要素是多期次断裂构造、高孔隙的石英砂岩、煌斑岩脉及强烈的蚀变作用(硅化、黄铁矿化等),矿床是明显受构造控制的、与岩浆热液活动密切相关的石英脉型、蚀变岩型金矿床。     

数学地质方法在南秦岭汉阴黄龙金矿中的应用

汉阴黄龙金矿大地构造位置处于南秦岭构造带内，矿区内岩石受多期构造变形变质作用，并叠加有稍晚期岩浆活动。金矿化类型以蚀变岩型为主，其次为石英脉型，矿化受脆—韧性剪切带和围岩蚀变的控制，主要蚀变类型有黑云母变斑晶化、黄铁矿化、碳化和石榴石化。为查明构造—蚀变与成矿之间的关系，通过主量元素聚类分析法和因子分析法进一步确认韧性剪切带中的脆性断层破碎带是矿区内主要的控矿构造，黑云母变斑晶化蚀变与金矿化关系最密切，并通常与黄铁矿化叠加出现，对成矿有利；蚀变岩型金矿石与硅化相关性不大。金相关成矿元素Q型聚类分析、R型聚类分析和因子分析结果表明，金成矿作用可能贯穿于脆—韧性剪切作用和岩浆活动的整个过程，受多期热液叠加和后期岩浆热液活动的影响。因此，黄龙金矿属于脆—韧性剪切带型金矿，并可能受后期岩浆热液叠加再富集。     

河南汝阳东沟钼矿岩石矿物特征

东沟钼矿属斑岩型钼矿床。矿体形态受岩体形态、大小、围岩的物理性质和次级裂隙的发育程度控制。赋矿岩石主要为熊耳群中-中酸性火山喷出岩,少部分的次火山岩和燕山期钾长花岗斑岩;矿化对围岩没有选择性,与多期次构造活动所形成的次级裂隙的密集程度有关。钼矿化与围岩的蚀变有关。赋矿岩石及矿体围岩曾受多次热液蚀变作用,可分为2个成矿期：岩浆晚期及岩浆期后热液期。岩浆期后热液期为主要成矿期,由3个矿化阶段组成。由岩浆期后钾化蚀变与辉钼矿化关系密切,且仅分布于近矿围岩中,可作为寻找钼矿的指示矿物。     

Rare Earth Element Geochemistry on Magmatic Rocks and Gold Deposits in Shizishan Ore-Field of Tongling, China

REE geochemical characteristics of the magmatic rocks and gold deposits in Shizishan ore-field of Tongling were studied. Three types of the magmatic rocks have almost the same chondrite-normalized REE patterns, Eu and Ce anomalous values, and ∑REE, ∑LREE/∑HREE regular changes, which indicates that their magmas come from the same source and their digenetic mechanism is fractional crystallization. In three gold deposits, the mineral ores and related altered rocks have similar chondrite-normalized REE patterns and sharp Eu positive anomalous values. The REE contents reduced from the magmatic rocks to skamization or alteration magmatic rocks, skam type ores, sulphide type ores, wall-rocks limestone or marble. The REE geochemical characteristics of the ores and related rocks show that primary fluids originated from magmatic differentiation in lower pressure of shallow crust, ore-forming hydrothermal solutions gained REE and mineralization elements further from leaching the magmatic rocks, then superimposed and reformed the limestones or marbles and deposited ore-forming material.     

胶东玲珑金矿区煌斑岩及其蚀变岩地球化学特征

煌斑岩与金矿化在时间、空间和成因方面关系密切。选择胶东玲珑矿区煌斑岩及其蚀变岩开展56项元素地球化学研究,结果发现胶东玲珑金矿区煌斑岩在成分上相当于高钾玄武质粗面安山岩,相对中国基性岩富K2O、Fe2O3、P2O5、轻稀土、Th、U、Pb、Be、Sr、Ba、Li、Rb、F、Cr,贫Na2O、Ti2O、CaO、MnO、重稀土、Nb、Ta、Sc、W、Bi、Zn、Cd、As、Co、V、B。玲珑金矿区蚀变煌斑岩相对新鲜煌斑岩贫Na2O,富MnO、Pb、Zn、As、W、Sb、Cd、Au、Ag,这表明引起煌斑岩蚀变的这期热液流体富含W、Pb、Zn、Cd、Au、Ag、As、Sb等热液成矿元素。花岗岩风化指数WIG可较好地适用于煌斑岩蚀变过程的研究,且较蚀变指数CIA在反映蚀变程度上更灵敏。     

吉林省金城洞地区金矿成矿物质来源

金城洞地区金矿按产出地质背景划分为产于晚太古宙变质岩系中的金矿和产于花岗岩侵入体中的金矿。变质岩系金丰度分析表明,本区变质岩石金丰度背景值为2.04×10^-9,花岗岩金丰度分析表明,中生代二长岩中金丰度为66.07×10^-9,其它花岗岩中则较低,为0.7～2.83×10^-9;各类岩石金易溶性实验表明,区内斜长角闪岩、二长岩、煌斑岩中金呈易释放金形式存在,可为金矿成矿提供部分成矿物质,其它岩石中金呈不易释放金的形式存在。区内岩(矿)石硫同位素组成δ³⁴S在+0.04～+4.8‰之间,与陨石硫δ³⁴S 值(-1～+5.1‰)相近;各类岩(矿)石稀土元素模式曲线平行分布,以LREE富集、弱—无铕异常为特征,反映了它们具有相似的来源;各类铅同位素分析表明,变质岩、花岗岩、金矿石的铅同素组成投点均落于μ=8.5和μ=9.58之间,进一步反映了成矿物质来源于深源(下地壳和上地幔之间) 。     

甘肃枣子沟金矿床稀土元素地球化学特征

对比研究了枣子沟金矿区内不同类型矿石与成矿有关的岩浆岩及地层的稀土元素地球化学特征,借以示踪成矿物质来源。研究表明,矿床不同类型矿石的稀土元素配分曲线既有相似又有差别,反映成矿物质具有多样性;矿石与容矿岩石（地层、岩浆岩）稀土元素配分曲线颇为相似,总体呈右倾型,具Eu负异常。表明成矿与容矿岩石（地层、岩浆岩）具有一定的成因联系。成矿物质来源于壳源及壳幔混合。地幔流体可能参与了矿床成矿作用。成矿环境表现为早期还原,晚期由还原向氧化转化。     

Geochemistry of Ore-bearing Lamprophyre from the Cu-Ni Deposit in Dhi Samir,Yemen

Magmatic Cu-Ni sulfide deposits are generally associated with mafic-ultramafic rocks and it has not been reported that lamprophyre is one of the surrounding rocks of Cu-Ni sulfide deposits．The Dhi Samir deposit in Yemen,however,is a rare example of Cu-Ni deposits which are hosted in lamprophyre dikes．In this paper,comprehensive research is made on petrology,petrochemistry and isotope geochemistry for Cu-Ni-bearing rocks in the Dhi Samir area and the results show that dark rocks related to Cu-Ni orebodies are sodium-weak potassium and belong to calc-alkaline series lamprophyre,especially camptonite,characterized by enriched alkali,iron and titanium．In these rocks large-ion-lithophile elements are obviously concentrated,while high field strength elements slightly depleted,showing clear negative anomalies of Ta and Nb,and weak deficiency of Ti．The ∑REE is very high(225．67-290．05 ppm)and the REE partition curves are flat and right-inclined,featuring a LREEenriched pattern with low negative Eu anomalies．Study of magmatic source areas indicates that the rocks have low(87Sr/86Sr)and high εNd(t),and the magmas were probably derived from the enriched mantle Ⅰ(EM-Ⅰ)end-member．Based on the LA-ICPMS on zircon U-Pb isotope dating,the lamprophyre in the Dhi Samir mining area has an age of 602±2．6 Ma,indicating that the rock was formed in the late Proterozoic and in an intraplate setting due to magmatism of an extensional environment in the post-Pan-Africa orogeny．     

河南卢氏官坡—五里川锑矿带稀土元素特征及与成矿的关系

为了研究河南省卢氏县官坡—五里川锑成矿带成矿机制,对其稀土元素地球化学特征进行分析。锑矿带内锑矿石及其他类型岩石轻、重稀土元素比值较高,且都呈现为Eu负异常,稀土元素配分模式总体上表现为轻稀土富集型。锑矿带内各种类型岩(矿)石中稀土总量分布表现出一定规律性,大理岩、锑矿石中稀土元素总量较高,构造带岩石及附近围岩的稀土元素总量偏低,说明锑矿带的锑及成矿热液主要来自于下地壳和上地幔,热液上升过程中锑矿床经历了多阶段的分馏、交代作用,导致稀土元素从围岩中大量迁出,并富集于锑矿床内。     

Rare Earth Elements Geochemistry of Laowan Gold Deposit in Henan Province： Trace to Source of Ore-Forming Materials

The compositions of REE in quartz and pyrite from the main stage of the Laowan gold deposit in Henan Province and that in quartz from Laowan granite were determined by inductively coupled plasma-mass-spectrometry (ICP-MS) to trace the source of ore-forming materials. Meanwhile, the REE compositions of the deposit ore, granite and metamorphic wall rock were also considered for comparative studies in detail. The range of ∑REE of quartz and pyrite from the deposit ores is 4.18×10-6～30.91×10-6, the average of ∑REE is 13.39×10-6, and the average of ∑REE of quartz in the Laowan granite is 6.68×10-6. There is no distinct difference of REE parameters between the deposit ore quartz and granite quartz. The quartz in gold deposit has the same REE particular parameters as quartzes from Laowan granite, such as δEu, δCe, (La/Yb)N and (La/Sm)N, partition degree of LREE to HREE, especially, the chondrite-normalized REE patterns, but no similarity to those from metamorphic wall rock, which shows that ore-forming hydrothermal fluid is mainly the fluid coming from the Laowan granite magma, rather than metamorphic fluid. Meanwhile, comparison studies on REE features between minerals from the deposit ores and related geological bodies in the deposit show that REE characteristics of minerals can serve as an indicator of ore-forming fluid properties and sources, while the REE characteristics of the bulk samples (such as deposit ores, granites and wall rocks) can not trace the source of the ore-forming materials exactly.     

Geochemical Characteristics of Rare Earth Elements in Gejiu Tin Polymetallic Deposits, Yunnan Province, China

In order to get a better understanding of metallogeny, the geochemical characteristics of REE and trace element for Gejiu tin polymetallic deposits were studied by comparing concentrations of REE and trace elements in different type ores and rocks, including skarn-type ore, bedded-type ore, vein-type ore, altered granite, country rocks. Results of this study indicated that the metallogenic matters for different type ores in the study area might be derived from the same origin source, which may be mainly related to granitic activities. Furthermore, there are some differences in concentrations of REE in different ores due to their different depositiona! mechanism during that time. LREE concentrations were enriched relatively in the vein-type ores and the bedded-type ores with relatively low total REE concentrations, whereas total REE concentrations were higher in the skarn-type ores with LREE and HREE concentrations in wide variation ranges.