短波红外光谱技术在矽卡岩型矿床中的应用——以鄂东南铜绿山铜铁金矿床为例

铜绿山铜铁金矿床是长江中下游铜铁多金属成矿带最重要的矽卡岩型矿床之一,矿床的形成与铜绿山石英闪长岩株体密切相关,矿体主要沿北北东向断裂产于石英闪长岩与大理岩/白云质大理岩的接触带,形成钙-镁复合型矽卡岩铜多金属矿化。围岩蚀变由致矿岩体到接触-蚀变矿化中心为:绢云母-绿泥石-钾化带、高岭石-绿泥石-弱矽卡岩化带、皂石-绿泥石-强矽卡岩化带。蚀变矿化期次可分为岩浆-热液期和表生期,其中,岩浆-热液期可分为矽卡岩阶段、退化蚀变阶段、氧化物阶段、硫化物阶段和碳酸盐阶段。绿泥石是钻孔岩芯中出现最多且分布最为广泛的蚀变矿物之一。经短波红外光谱(SWIR)研究发现,从蚀变矿化中心到外围,绿泥石出现由铁绿泥石/铁镁绿泥石逐渐转变为镁绿泥石,且绿泥石Fe-OH特征吸收峰位值(Pos2250)显示出从高值变为低值的趋势。结合其他蚀变矿物的空间分布特征,文章提出绿泥石的高Fe-OH特征吸收峰位值(Pos22502253 nm)与金云母、蛇纹石、绿帘石、皂石和高岭石的大量出现,对指示铜绿山矽卡岩型矿床的矿化中心具有一定的作用。     

鄂东南矿集区典型矽卡岩-斑岩矿床蚀变矿物短波红外(SWIR)光谱研究与勘查应用

鄂东南矿集区是我国著名的矽卡岩-斑岩型铜铁金矿床产区,研究程度较高,近年来矿产勘查进入了深部找矿的新阶段,需要较新的勘查方法与思路。本文介绍了利用短红外光谱(SWIR)技术,对鄂东南典型的铜绿山矽卡岩型Fe-Cu-Au矿床、鸡冠嘴矽卡岩型Cu-Au矿床、铜山口矽卡岩-斑岩型Cu-Mo-W矿床进行的蚀变矿物综合研究最新成果。在确定蚀变矿物组合类型、形成期次、蚀变分带的基础上,揭示了主要蚀变矿物SWIR特征值的指示规律,并进一步提取各个矿床的蚀变矿物SWIR勘查标志,如铜绿山矿床富Fe绿泥石(Pos2250 2253nm)、高结晶度高岭石族(Pos2170 2170nm,Dep2170 0. 18)、白云母族-蒙脱石异常Pos2200值( 2212nm或2202nm)、高岭石、迪开石及皂石的大量出现,可以作为铜绿山铜铁金矿床有效的蚀变矿物勘查标志;鸡冠嘴矿床白云母族-蒙脱石Pos2200特征值的高值( 2209nm)区域对矿体位置具有较好的指示性;铜山口矿床绿泥石的高Fe-OH吸收峰位值(Pos2250 2249nm)和高Mg-OH吸收峰位值(Pos2335 2333nm)的高频出现,可以作为铜山口铜钼钨矿床的有效勘查标志。这些研究成果表明蚀变矿物可以为鄂东南矿集区提供有效的勘查标志体系,同时,这些最新的勘查标志也在铜绿山铜铁金矿床得到了初步的应用和验证。     

新疆东天山地区延东铜矿斑岩-改造叠加成矿作用及其流体演化

<正>土屋-延东铜矿带位于东天山大南湖-头苏泉岛弧带南部[1],是中天山多金属成矿带的重要组成部分[2]。根据脉次间穿插关系、蚀变组合及矿物共生关系,笔者将延东铜矿划分为3个期次,从早到晚依次为:斑岩成矿期、改造叠加期及表生期。斑岩成矿期可以划分为青磐岩化阶段、石英-磁铁矿阶段和石英-硫化物阶段等3个阶段。青磐岩化阶段:蚀变矿物主要为有绿帘石、绿泥石及少量方解石,呈浸染状分布在地层围岩中。石英-磁铁矿阶段:主     

青海纳日贡玛斑岩钼(铜)矿床:蚀变

通过对纳日贡玛斑岩钼（铜）矿床的蚀变类型的详细研究,识别了矿床蚀变的3种主要类型：钾硅酸盐化、青磐岩化和长石分解蚀变.前二者为矿区早期形成的蚀变,长石分解蚀变形成于晚期.钾硅酸盐化蚀变主要以黑云母化、钾长石化为特征,青磐岩化以脉状绿泥石、绿帘石、方解石等蚀变矿物的发育为基本特征,长石分解蚀变则发育绢云母、高岭土、方解石、硬石膏等矿物.研究认为矿化与石英-辉钼矿±硬石膏±黄铜矿±黄铁矿脉、辉钼矿±黄铁矿±黄铜矿脉有较为密切的联系.     

新疆东天山卡拉塔格红海VMS铜锌矿床蚀变与矿化时空分布特征

红海VMS铜锌矿床位于新疆东天山大南湖-头苏泉岛弧带的卡拉塔格地区,矿床上部发育似层状块状硫化物矿体,下部为不整合的脉状-网脉状矿体,块状矿体上盘火山岩盖层中也发育少量铜矿化。本文在前人工作基础上,根据矿物交代次序、脉体穿插关系和矿物共生组合类型,精细划分了矿床的蚀变分带和成矿期次。矿床(含盖层)从浅到深依次发育绿泥石-钠长石-绢云母-碳酸盐化、绿帘石-绿泥石-钠长石-绢云母-碳酸盐化、石英-绢云母-黄铁矿化、块状硫化物矿体、绿泥石-黄铁矿±绢云母化和绿泥石-石英-绢云母化。红海矿床成矿过程可分为VMS成矿期、后期热液叠加期和表生期,其中VMS成矿期可细分为黄铁矿阶段、黄铜矿-闪锌矿阶段和重晶石阶段,后期热液叠加期可细分为钠长石化阶段、绿泥石-绿帘石阶段和石英-碳酸盐阶段。主矿化期及蚀变特征与典型VMS矿床类似,但同时还表现出许多海底交代作用的特征。后期热液在矿体上盘火山岩中所产生的绿帘石化、绿泥石化和绿帘石-石英-黄铜矿-斑铜矿脉、石英-碳酸盐脉等蚀变和矿化,与斑岩矿化系统的青磐岩化类似,表明红海矿床后期可能受到斑岩系统的叠加,矿区具有斑岩铜矿床的找矿潜力。     

蚀变矿物填图技术在斑岩型铜矿找矿勘查中的应用—以滇西北香格里拉松诺矿床为例

松诺铜矿区位于香格里拉格咱斑岩铜矿带红山-普朗铜多金属成矿亚带中段,矿区剥蚀程度较低,具有寻找斑岩型铜矿的潜力。本次蚀变矿物填图工作采用近红外光谱矿物分析技术,识别出绿泥石、绿帘石、高岭石、云母类、蒙脱石类及伊利石等6类主要蚀变矿物,蚀变类型为青磐岩化、绢英岩化;结合物探、化探异常分布,圈定3处找矿靶区,经对KHT2、KHT3钻孔验证,深部均圈定多层铜矿化体。结果表明,近红外光谱矿物分析技术在斑岩型铜多金属矿床勘查评价中可以较好地划分热液矿化蚀变带,进一步明确斑岩型矿化-蚀变中心,为探矿工程部署提供依据。     

黑龙江金厂金矿床18号矿体围岩蚀变及短波红外光谱特征

金厂金矿18号矿体围岩蚀变发育顺序从早到晚为:钾化、硅化、绿泥石化、绢云母化、碳酸盐化、高蛉土化,从内往外依次发育青磐岩化带、绢英岩化带和钾化带.矿化出现在泥化和绢英岩化叠加处,以及泥化和青磐岩化叠加处.通过短波红外光谱测试技术,识别出本矿区有26种蚀交矿物,其中白云母含量与金矿体呈正相关,说明绢云母化与金矿化关系密切;青磐岩化带蚀变矿物组合为绿泥石+绿帘石+伊利石±埃洛石±蒙脱石±石英;钾化带蚀变矿物组合为钾长石+高岭石+埃洛石±蒙脱石±石英;绢英岩化带蚀变矿物组合为绢云母+埃洛石±蒙脱石±高岭石±石英.     

基于红外光谱技术研究云南普朗斑岩铜矿的蚀变和矿化特征

近年来红外光谱技术作为一种绿色、快速、无损、精确探测矿物的技术手段而倍受关注,针对斑岩型矿床蚀变矿物高度叠加、蚀变分带界线不明显、细粒蚀变矿物多、黏土蚀变矿物多等特征,该技术在蚀变矿物识别和勘探信息解读等方面优势突出。本文应用红外光谱技术对云南普朗斑岩铜矿区钻孔ZK1801岩心进行矿物识别和蚀变分带划分的研究,识别出钾硅酸盐化带、绿帘石-绿泥石化带、绿泥石-伊利石化带、石英-伊利石化带和泥化带。研究表明:普朗铜矿整个钻孔的蚀变矿物主要有石英、钾长石、绢云母、绿泥石、绿帘石、高岭石、蒙脱石、伊利石等;根据矿化特征,发现铜矿体广泛赋存在钾硅酸盐化带和绿帘石-绿泥石化带中,与矿化关系密切的蚀变矿物"石英+钾长石+绢云母"和"绿帘石+绿泥石",可以作为普朗矿床勘查的标型蚀变矿物组合;研究区广泛发育的绢云母Al—OH波长随钻孔深度增加而逐渐从2210～2205nm减小到2202～2198nm, Al—OH波长2210～2205nm(长波绢云母)与矿化关系密切,可以作为普朗矿床勘查的指示信息。     

短波红外光谱技术在斑岩-高硫化型浅成低温热液矿床中的应用——以西藏铁格隆南超大型铜(金)矿床为例

铁格隆南铜(金)矿是西藏首例超大型斑岩-高硫化型浅成低温热液矿床.准确划分该矿床的蚀变分带对于后续的找矿勘探具有重要意义.本文主要运用短波红外光谱分析技术对西藏铁格隆南矿床进行蚀变矿物信息提取,同时利用X射线衍射辅助矿物识别;并结合岩相学和电子探针分析,对主要蚀变矿物绢云母的光谱特征进行系统梳理,构建铁格隆南矿区蚀变分带模型,探讨其勘查指示意义.结果表明:短波红外光谱清晰识别出高岭石、明矾石、地开石、叶腊石、绢云母、石膏、水铝石、蒙脱石8种蚀变矿物.根据蚀变矿物组合空间分布特征,从斑岩中心向外,可划分出钾硅酸盐化、绢英岩化、青磐岩化蚀变,在中浅部被高级泥化蚀变广泛叠加.矿区广泛产出绢云母,其主吸收谷波长介于2196～2215 nm(平均值为2206.6 nm)之间,且深部钾硅酸盐化带与绢英岩化带中的绢云母主吸收谷波长差异明显,钾硅酸盐化带中波长可大于2210 nm,可能是绢英岩化蚀变对钾硅酸盐化蚀变叠加改造的结果,绢英岩化带则集中于2206～2208 nm区间.绢云母1400 nm吸收峰波长(Pos1400值)和绢云母Al-OH的吸收深度(Dep2200值)与铜矿化强度呈现良好的耦合关系,可作为后续斑岩-浅成低温热液矿床勘查评价的重要指示标志.绢云母族矿物Al-OH吸收峰(Pos2200值)较小(＜2203 nm)且结晶度指数值越大(＞5.5)的区域揭示铁格隆南矿床的热液成矿中心主要位于ZK2404的深部.     

甘肃岗岔—克莫地区蚀变岩特征与找矿预测

岗岔—克莫金矿区位于西秦岭北缘夏河—合作成矿带,具浅成低温热液型矿床特征,初步显示深部可能具有斑岩成矿系统存在。利用短波红外光谱矿物分析技术对岗岔—克莫金矿区蚀变岩特征的研究表明,矿区内发育的蚀变矿物主要有白云母、伊利石、蒙脱石、高岭石、地开石、绿泥石、绿帘石和次生石英等。近矿蚀变类型主要为绢英岩化。矿区内以下家门沟口为中心向外依次发育了中心带(绢英岩化带)、过渡带(泥化带)和外围带(青磐岩化带)。此外,伊利石结晶度以下家门沟口为中心向外具有明显的降低趋势。研究结果指示下家门沟口可能是矿区的热液活动中心。     

福建紫金山矿田西南铜钼矿段蚀变矿化特征及SWIR勘查应用研究

西南铜钼矿段位于中国著名的福建上杭县紫金山矿田内,是该矿田最新发现的另一个典型的斑岩型矿床。该矿床形成于白垩纪,矿化(浸染状和细脉浸染状)与成矿同期花岗闪长斑岩密切相关。围岩蚀变由深到浅分别为青磐岩化带、绢英岩化带、高级泥化-泥化蚀变带和氧化带。蚀变矿化期次可划分为:(早期)绢英岩化期、斑岩矿化期、浅成低温热液叠加期、成矿后期脉和表生期。其中,斑岩矿化期又可分为钾硅酸盐化阶段、青磐岩化阶段和(晚期)绢英岩化阶段;浅成低温热液叠加期主要为泥化-高级泥化蚀变。对比研究发现,西南矿段具有与典型斑岩矿床相似的矿化蚀变特征,但缺失钾化带且矿化规模小,成矿斑岩以岩枝状(非岩株状)水平侵位,产生非对称蚀变分带,据此推测西南矿段深部可能存在真正的成矿斑岩岩株和大储量及高品位的矿化中心。通过短波红外光谱(SWIR)研究发现,从矿化中心到外围,伊利石结晶度值(IC)和伊利石2200 nm吸收峰位值(Pos2200)均有明显的从高值到低值的变化趋势。此外,研究发现高IC值(2.1)和高Pos2200值(2203 nm)可作为紫金山地区勘查该类矿床的找矿标志。本研究可以为紫金山地区斑岩矿床的成矿规律认识和找矿勘查提供科学依据。     

西藏玉龙斑岩铜矿床绢云母族蚀变矿物短波红外光谱特征及对勘查的指示意义

玉龙斑岩铜矿晚期绢云母化、黏土化蚀变强烈叠加在早期的钾硅酸盐化带内,模糊了蚀变分带特征及其与铜矿化之间的相关性.利用短波红外光谱(SWIR)可快速识别斑岩铜矿床内含羟基蚀变矿物,根据该类矿物的空间分布特征与矿化的对应关系,指导找矿勘查工作.本文对玉龙铜矿床靠近斑岩体中心的三个钻孔进行了详细的蚀变-矿化编录和SWIR分析...     

碰撞造山型斑岩铜矿蚀变分带模式--以西藏冈底斯斑岩铜矿带为例

岛弧环境斑岩铜矿蚀变分带模式已为人们所熟知 ,但碰撞造山环境的斑岩铜矿蚀变分带特征尚不清楚。对此 ,文中以西藏冈底斯斑岩铜矿带为例 ,选择驱龙、冲江、厅宫 3个典型斑岩铜矿 ,对其蚀变系统进行了系统研究。依据蚀变矿物组合可分为 3个蚀变带 ,呈环带状分布。从中心向外依次为钾硅酸盐化带、石英绢云母化带、青磐岩化带。泥化带不太发育 ,通常叠加在其它蚀变带之上。钾硅酸盐化带主要蚀变矿物为钾长石、黑云母、石英、硬石膏 ,伴有大量的黄铜矿与辉钼矿 ,是成矿物质的主要堆积区。石英绢云母化带与钾硅酸盐化带渐变过渡或叠加其上 ,是次于钾硅酸盐化带的储矿部位。蚀变矿物组合为绢云母 +石英 +钾长石 ,金属硫化物有黄铁矿、黄铜矿、辉钼矿、斑铜矿 ,少量的方铅矿、闪锌矿。主要的辉钼矿以石英 +辉钼矿脉的形式出现于本矿带。青磐岩化在斑岩体内不发育 ,矿化极微弱。蚀变岩石组分分析表明 ,岩石蚀变及其分带是岩浆流体 /岩石反应时K ,Na ,Ca ,Mg等组分迁移的结果 ,矿化伴随着蚀变发生。钾硅酸盐化带、石英绢云母化带和青磐岩化带的蚀变岩石与未 (弱 )蚀变斑岩具有一致的稀土配分模式 ,REE含量有规律地变化 ,说明蚀变岩石均经历了源于岩浆的流体的交代 ,不同的蚀变形成于岩浆流体演化的不同阶段。蚀?     

Infrared spectral reflectance characterization of the hydrothermal alteration at the Tuwu Cu–Au deposit, Xinjiang, China

Short-wave infrared (SWIR) reflectance spectroscopy was used to characterize hydrothermal minerals and map alteration zones in the Tuwu Cu–Au deposit, Xinjiang, China. The Palaeozoic hydrothermal system at Tuwu is structurally controlled, developed in andesitic volcanic rocks and minor porphyries. Hydrothermal alteration is characterized by horizontally zoned development of quartz, sericite, chlorite, epidote, montmorillonite and kaolin about individual porphyry dykes and breccia zones, as is shown by changes outward from a core of quartz veining and silicification, through an inner zone of sericite + chlorite to a marginal zone of chlorite + epidote. The alteration system comprises several such zoning patterns. Silicification and sericitization are spatially associated with Cu–Au mineralization. Zoning is also shown by compositional variations such that Fe-rich chlorite and Al-rich sericite occur preferentially toward the core and the most intensely altered parts, whereas Mg-rich chlorite and relatively Al-poor sericite are present on the margin and the relatively weakly altered parts of the hydrothermal alteration system. The compositions of chlorite and sericite, therefore, can be potentially used as vectors to Cu–Au mineralization. Montmorillonite and kaolinite, of probable weathering origin, are located near the surface, forming an argillic blanket overlying Cu–Au mineralization. Sporadic montmorillonite is also present at depth in the hydrothermal alteration system, formed by descending groundwater. Presence of a well-developed kaolinite-bearing zone on the surface is an indication of possible underlying Cu–Au mineralization in this region. Epidote occurs widely in regional volcanic rocks, as well as in variably altered rocks on the margin of the hydrothermal mineralization system at Tuwu. The widespread occurrence of epidote in volcanic country rocks probably reflects a regional hydrothermal alteration event prior to the localized, porphyry intrusion-related hydrothermal process that led to the Cu–Au mineralization at Tuwu.     

Rosia Poieni copper deposit,Apuseni Mountains,Romania: advanced argillic overprint of a porphyry system

The Rosia Poieni deposit is the largest porphyry copper deposit in the Apuseni Mountains, Romania. Hydrothermal alteration and mineralization are related to the Middle Miocene emplacement of a subvolcanic body, the Fundoaia microdiorite. Zonation of the alteration associated with the porphyry copper deposit is recognized from the deep and central part of the porphyritic intrusion towards shallower and outer portions. Four alteration types have been distinguished: potassic, phyllic, advanced argillic, and propylitic. Potassic alteration affects mainly the Fundoaia subvolcanic body. The andesitic host rocks are altered only in the immediate contact zone with the Fundoaia intrusion. Mg-biotite and K-feldspar are the main alteration minerals of the potassic assemblage, accompanied by ubiquitous quartz; chlorite, and anhydrite are also present. Magnetite, pyrite, chalcopyrite and minor bornite, are associated with this alteration. Phyllic alteration has overprinted the margin of the potassic zone, and formed peripheral to it. It is characterized by the replacement of almost all early minerals by abundant quartz, phengite, illite, variable amounts of illite-smectite mixed-layer minerals, minor smectite, and kaolinite. Pyrite is abundant and represents the main sulfide in this alteration zone. Advanced argillic alteration affects the upper part of the volcanic structure. The mineral assemblage comprises alunite, kaolinite, dickite, pyrophyllite, diaspore, aluminium-phosphate-sulphate minerals (woodhouseite-svanbergite series), zunyite, minamyite, pyrite, and enargite (luzonite). Alunite forms well-developed crystals. Veins with enargite (luzonite) and pyrite in a gangue of quartz, pyrophyllite and diaspore, are present within and around the subvolcanic intrusion. This alteration type is partially controlled by fractures. A zonal distribution of alteration minerals is observed from the centre of fractures outwards with: (1) vuggy quartz; (2) quartz + alunite; (3) quartz + kaolinite ± alunite and, in the deeper part of the argillic zone, quartz + pyrophyllite + diaspore; (4) illite + illite-smectite mixed-layer minerals ± kaolinite ± alunite, and e) chlorite + albite + epidote. Propylitic alteration is present distal to all other alteration types and consists of chlorite, epidote, albite, and carbonates. Mineral parageneses, mineral stability fields, and alteration mineral geothermometers indicate that the different alteration assemblages are the result of changes in both fluid composition and temperature of the system. The alteration minerals reflect cooling of the hydrothermal system from >400 °C (biotite), to 300–200 °C (chlorite and illite in veinlets) and to lower temperatures of kaolinite, illite-smectite mixed layers, and smectite crystallization. Hydrothermal alteration started with an extensive potassic zone in the central part of the system that passed laterally to the propylitic zone. It was followed by phyllic overprint of the early-altered rocks. Nearly barren advanced argillic alteration subsequently superimposed the upper levels of the porphyry copper alteration zones. The close spatial association between porphyry mineralization and advanced argillic alteration suggests that they are genetically part of the same magmatic-hydrothermal system that includes a porphyry intrusion at depth and an epithermal environment of the advanced argillic type near the surface.Editorial handling: B. Lehmann     

Spectral characteristics of minerals in alteration zones associated with porphyry copper deposits in the middle part of Kerman copper belt,SE Iran

Visible near infrared and shortwave infrared (VNIR-SWIR, 350 to 2500 nm) reflectance spectra obtained from an analytical spectral device (ASD) have been used to define alteration zones adjacent to porphyry copper deposits (PCDs), in the central part of Kerman magmatic arc, SE Iran. The spectral analysis identified sericite, illite, halloysite, montmorillonite, dickite, kaolinite, pyrophyllite, biotite, chlorite, epidote, calcite, jarosite, and iron oxyhydroxides (e.g. hematite, goethite) of hydrothermal and supergene origin. Identified alteration zones are classified into six principal types namely phyllic, phyllic/propylitic, propylitic, potassic, argillic and advanced argillic. The iron oxide minerals in the oxidized zone were also identified using spectral analysis. Results of spectral analyses of samples are consistent with mineralogical data obtained from X-ray diffraction (XRD) and petrographic studies. Spectroscopic studies by ASD demonstrate that this tool is very useful for semi-quantitative and cost effective identification of different types of alteration mineral assemblages. Furthermore, it can provide a valuable tool for evaluating aerial distribution of alteration minerals while coupled with remote sensing data analysis.     

大兴安岭地区富克山斑岩铜钼矿床地质特征与SWIR勘查应用

富克山铜钼矿是黑龙江省近年来的重大找矿成果之一.详细的野外观察和室内研究发现该矿床具有典型斑岩矿化特征.该矿床致矿斑岩为闪长玢岩，该岩性的侵位导致其自身及围岩中的钾化、黄铁绢英岩化和晚期绿泥石-黄铁矿三期蚀变.矿化主要赋存在与黄铁绢英岩化相关的伟晶岩和花岗闪长岩中.蚀变矿化与致矿闪长玢岩枝的空间分布特征指示矿区南西向深部可能存在大规模致矿岩体.白云母族矿物Pos2200和绿泥石的Pos2250峰位值研究发现，二者受原岩成分影响较大，不宜作为下一步找矿的勘查指标.白云母族IC值(伊利石结晶度)和绿泥石中MnO则主要受到温度的控制，是寻找热液矿化中心的有力工具.该项研究表明，蚀变矿化特征与SWIR分析结合将对矿床勘查起到较为重要的指示作用.