Adakite-like signature of porphyry granitoid stocks in the Meiduk and Parkam porphyry copper deposits,NE of Shahr-e-Babak,Kerman, Iran: Constrains on geochemistry

The Middle Miocene porphyry granitoid stocks of Meiduk and Parkam porphyry copper deposits are intruded in the north-western part of the Dehaj-Sarduiyeh volcano-sedimentary belt in the south-eastern extension of the Urumieh-Dukhtar Magmatic Arc (UDMA) in Iran. The porphyritic to microgranular granitoids are mainly consist of quartz diorite, granodiorite and diorite. The whole rock geochemical analyses of these rocks reveals sub-alkaline, calc-alkaline, meta-peraluminous and I-type characteristics. Their geochemical characteristics such as Al₂O₃ content of 13.51–17.05 wt%, high Sr concentration (mostly >400 ppm), low Yb (an average of 0.74 ppm) and Y (an average of 9.02 ppm) contents, strongly differentiated REE patterns (La/Yb ≥ 20), lack of Eu anomaly (Eu/Eu¹ ≥ 1) are indicative of adakitic signature. Their enrichment in low field strength elements (LFSE) and conspicuous negative anomalies for Nb, Ta and Ti are typical of subduction related magmas. Detailed petrological studies and geochemical data indicated that Meiduk and Parkam porphyry granitoids were derived from amphibole fractionation of hydrous melts at a depth of >40 km in a post-collisional tectonic setting.     

Tellurides,selenides and associated minerals in the Tunaberg copper deposits,SE Bergslagen,Central Sweden

Summary The Tunaberg copper deposits, SE Bergslagen, Central Sweden, locally contain tellurium and selenium minerals not previously reported from this locality. Hessite, tellurobismutite, tellurium, tetradymite, kawazulite, clausthalite and selenian galena are found as inclusions in bornite and chalcopyrite in a skarn sulphide ore with Cd-rich sphalerite, cobaltite and cobalt pentlandite (assemblage A), and in a skarn iron ore with magnetite (assemblage B). Accessory minerals included in bornite and chalcopyrite are auriferous silver, electrum, carrollite, stannoidite, mawsonite, parkerite, aikinite, emplectite, wittichenite and two unidentified Cu-Ag-Bi sulphosalts.The tellurides, selenides and associated minerals in assemblage A occur, in part, as early crystallites and, in part, as segregations from a high-temperature bornite solid solution, which presumably crystallized from metamorphogenic skarn-forming ore solutions, about contemporaneous with the formation of diopside above 475°C and of retrogressive tremolite above 420°C. Minerals of Bi-Te-Se-Pb-Ag in assemblage B presumably crystallized at lower aS₂ and higher aCu⁺ from residual hydrothermal solutions of similar metamorphogenic origin.

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Telluride, Selenide und assoziierte Minerale in der Tunaberg Kupfer-Lagerstätte, SE Bergslagen, Zentralschweden

Zusammenfassung Die Kupferlagerstätten von Tunaberg, SE Bergslagen, Zentral-Schweden enthalten stellenweise Tellur-und Selen-Minerale, die hier bisher nicht bekannt waren. Hessit, Tellurobismutit, gediegen Tellur, Tetradymit, Kawazulit, Clausthalit und selen führender Bleiglanz kommen als Einschlüsse in Bornit und Kupferkies in einem Skarn-Sulphiderz mit cadmiumreichem Sphalerit, Cobaltit und Cobalt-Pentlantit (Paragenese A), und in einem Eisenskarnerz mit Magnetit (Paragenese B) vor. Akzessorische Minerale in Bornit und Calcopyrit sind goldführendes Silber, Electrum, Carrollit, Stannoidit, Mawsonit, Parkerit, Aikinit, Emplektit, Wittichenit und zwei noch nicht identifizierte Cu-Ag-Bi Sulphosalze.Die Telluride, Selenide, und assoziierte Minerale in der Paragenee A kommen teils als frühe Kristalliten und teils als Segregationen aus einer Hoch-Temperatur Bornit-solid solution vor, die auf metamorphogene skarnbildende Erzlösungen zurückgehen. dürfe. Diese Vorgänge fallen zeitlich mit der Bildung von Diopsid oberhalb von 475°C und von retrogradem Tremolit oberhalb von 420°C zusammen. Bi-Te-Se-Pb-Ag-Minerale der Paragenese B kristallisierten bei niedrigerem aS₂ und höherem aCu⁺ aus residualen hydrothermalen Lösungen metamorphen Ursprunges.

     

The Sarcheshmeh porphyry copper deposit,Kerman, Iran: A mineralogical analysis of the igneous rocks and alteration zones including halogen element systematics related to Cu mineralization processes

The giant Sarcheshmeh porphyry Copper deposit is located 65 km southwest of Kerman City, southeastern Iran. Numerous Miocene porphyry stocks and dykes intruded thick sequences of Upper Cretaceous sedimentary and Eocene volcanic rocks. Hypogene and supergene porphyry Cu mineralization occurs within the granodioritic porphyry and host rock sequence, which was extensively altered to a dominantly potassic, phyllic, and argillic assemblage with interstitial to distal propylitic types.Biotite-bearing assemblages occur as both primary phenocrysts and secondary replacements showing variable size, colour, and shape. Fluorine contents (0.22 to 1.33 wt.%) and X_Mg (0.54 to 0.71) in biotites from the potassic and phyllic zones are higher than those of non-mineralized granitoids (F = 0.09 to 0.56 wt.%, X_Mg = 0.43 to 0.54), whereas their Cl contents (Cl = 0.05 to 0.24 wt.%) are lower than those of the non-mineralized granitoids (Cl = .0.11 to 0.45). The biotites from the phyllic zone have higher log (fH₂O/fHF) and log (fH₂O/fHCl) values than those of the potassic zone, as well as the granitoid and andesitic dykes. The log (fHF/fHCl) values determined for the granitoid, potassic and phyllic zones are similar, though more negative than those of the andesitic dykes. The log (fHF/fHCl) values have a similar range for biotite from the granitoid, and potassic and phyllic zones. The halogen fugacity ratios established for fluids associated with the Sarcheshmeh deposit from their F and Cl contents in biotite show that the granitoid, potassic zone and phyllic zone are increasingly affected by meteoric waters. The fluids that circulated in the phyllic zone are predominantly of meteoric origin, possibly overprinting original phyllic zone halogen contents.The Cl intercept values of biotite in the granitoid, and phyllic and potassic are similar to other ore-forming systems and tend to be more Cl-rich than Cl-intercept values of biotites in common igneous rocks. Calculated F/Cl intercept values for biotite in the granitoid and potassic zone are also consistent with many other porphyry copper forming systems.     

Recognition of an enhanced multi-element geochemical signature of porphyry copper deposits for vectoring into mineralized zones and delimiting exploration targets in Jiroft area,SE Iran

Delimiting exploration targets using geochemical exploration data can be a challenging issue when different geochemical signatures represent the same deposit-type sought. In this regard, fuzzy operators have been used to integrate different geochemical evidence layers into a single model for generating target areas. In this paper, a GIS-based expected value function was adapted to integrate different geochemical evidence layers into a stronger geochemical signature for delimiting exploration targets. Then, the expected value function and fuzzy operators were compared. The comparison demonstrated that the former is more efficient than the later for generating a stronger geochemical evidence layer. The higher efficiency of the expected value function is because it simultaneously uses the value of all input variables and their relative importance in the process of integration. The proposed approach was evaluated by using a lithogeochemical data set for prospecting porphyry-Cu deposits in Jiroft area, Kerman province, southeast of Iran, as a case study.     

The geochemistry of gossans associated with Sarcheshmeh porphyry copper deposit,Rafsanjan, Kerman,Iran: Implications for exploration and the environment

The Sarcheshmeh copper deposit is one of the world's largest Oligo-Miocene porphyry copper deposits in a continental arc setting with a well developed supergene sulfide zone, covered mainly by a hematitic gossan. Supergene oxidation and leaching, have developed a chalcocite enrichment blanket averaging 1.99% Cu, more than twice that of hypogene zone (0.89% Cu). The mature gossans overlying the Sarcheshmeh porphyry copper ores contain abundant hematite with variable amounts of goethite and jarosite, whereas immature gossans consist of iron-oxides, malachite, azurite and chrysocolla. In mature gossans, Au, Mo and Ag give significant anomalies much higher than the background concentrations. However, Cu has been leached in mature gossans and gives values close or even less than the normal or crustal content (< 36.7 ppm). Immature gossans are enriched in Cu (160.3 ppm), Zn (826.7 ppm), and Pb (88.6 ppm). Jarosite- and goethite-bearing gossans may have developed over the pyritic shell of most Iranian porphyry copper deposits with pyrite–chalcopyrite ratios greater than 10 and therefore, do not necessarily indicate a promising sulfide-enriched ore (Kader and Ijo). Hematite-bearing gossans overlying nonreactive alteration halos with pyrite–chalcopyrite ratios about 1.5 and quartz stringers have significant supergene sulfide ores (Sarcheshmeh and Miduk). The copper grade in supergene sulfide zone of Sarcheshmeh copper deposit ranges from 0.78% in propylitized rocks to 3.4% in sericitized volcanic rocks, corresponding to the increasing chalcopyrite–pyrite or chalcocite–pyrite ratios from 0.3 to 3, respectively. Immature gossans with dominant malachite and chrysocolla associated with jarosite and goethite give the most weakly developed enrichment zone, as at God-e-Kolvari. The average anomalous values of Au (59.6 ppb), Mo (42.5 ppm) and Ag (2.6 ppm) in mature gossans associated with the Sarcheshmeh copper mine may be a criterion that provides a significant exploration target for regional metallogenic blind porphyry ore districts in central Iranian volcano–plutonic continental arc settings. Drilling for new porphyry ores should be targeted where hematitic gossans are well developed. The ongoing gossan formation may result in natural acidic rock drainage (ARD).     

西藏冈底斯成矿带与俯冲-碰撞作用相关的斑岩铜矿的找矿方向

本文从构造-岩浆演化、典型矿床特征、构造-岩浆产物空间分布特征等方面,对冈底斯成矿带形成于195~80Ma的与俯冲-碰撞作用相关的斑岩(-矽卡岩)型铜矿的找矿方向进行了探讨。认为研究区与俯冲-碰撞作用相关的斑岩型铜矿大致可分为早-中侏罗世、晚侏罗-早白垩世、晚白垩世3个成矿时期,分别对应于雅鲁藏布江洋向北、班公湖怒江洋向南相向俯冲、班公湖怒江洋碰撞关闭、雅鲁藏布江洋向北持续俯冲、雅鲁藏布江洋向北晚期俯冲等构造-岩浆事件。与早期相向俯冲相关的雄村式矿床,在拉萨东部达孜-工布江达一带具有良好找矿前景;与中期俯冲-碰撞相关的多龙式矿床,在昂龙岗日、东恰错、桑日等火山岩浆弧区成矿条件较佳;与晚期俯冲相关的尕尔穷式矿床,在冈底斯东段和西段具有较大的找矿潜力。     

Enhancement of hydrothermal alteration zones using the spectral feature fitting method in Rabor area, Kerman, Iran

Rabor exploration area is in southeast of Kerman province, south of Urumieh-Dokhtar volcanic belt. Since there are many evidences of porphyry copper mineralization in this belt, prospecting and exploration of the intact and undiscovered places, especially the southern part of this belt, seems necessary. In this paper, use has been made of the “spectral feature fitting” (SFF) method to process ASTER satellite data (in Rabor exploratory area as a case study) for the identification and enhancement of hydrothermal alteration zones related to probable porphyry copper mineralization. The method is based on the comparison of absorption features in the image and the reference spectra. The distribution map of the indicator clay minerals, such as kaolinite, muscovite, illite, montmorillonite, alunite, pyrophyllite, dickite, chlorite, and epidote in Rabor exploratory area has been prepared with the help of this method. Identification and enhancement of alteration zones and overlaying Pay-Negin ore index on every individual zone reveal the capability and high efficiency of the SFF method in processing ASTER satellite data and preparing the distribution map of alteration minerals. Field and laboratory studies have shown that main alterations in this area are phyllic and argillic. These studies confirm the results obtained from remote sensing in the area.     

Copper isotope fractionation in the Meiduk porphyry copper deposit,Northwest of Kerman Cenozoic magmatic arc,Iran

The Meiduk deposit possesses three different Cu reservoirs each with a unique Cu isotope signature. δ⁶⁵Cu for the leached cap minerals ranges from ?2.5 to +0.49‰ to ?0.45 to +0.3‰ for hypogene minerals and from +1.3 to +4.4‰ for supergene enrichment minerals. Oxidation of hypogene sulphides and effective trapping of copper (from solutions derived from the leached cap) in the supergene enrichment zone caused this relationship. A systematic pattern of low Cu isotope values close to the surface and higher isotope values with depth reveals a palaeo‐fluid pathway in the northwest–southeast direction over the deposit. Thus, the copper isotope data from leached cap and enrichment minerals can be used to monitor copper migration during supergene weathering at the Meiduk deposit.     

纳米比亚西南部斑岩型铜矿地质特征

纳米比亚西南部奥兰治河海伯地区是纳米比亚重要的铜矿产地之一,区内的海伯铜矿和罗雷铜矿具有明显的斑岩型成矿特征。控制铜矿的斑岩体为古元古代威尔斯锥夫岩基的岩枝、岩株状分支,矿体的围岩为古元古界奥兰治河群海伯亚群。威尔斯锥夫岩基与奥兰治河群均为钙碱性火成岩和火山-沉积岩组合,形成于大陆边缘俯冲带的构造背景环境,结合海伯铜矿和罗雷铜矿地质及同位素特征,文章认为该区斑岩型铜矿可能为板块构造成矿。     

与花岗质岩浆系统有关的石英脉型钨矿和斑岩型铜矿成矿流体特征比较

文中对比了与S型花岗岩有关的石英脉型钨矿和与I型（及少数A型）花岗岩类有关的斑岩型铜矿床的成矿流体特征。它们的共同点在于成矿流体都由岩浆流体演化而来,在后期逐渐有大气降水的加入。差异性在于：（1）石英脉型钨矿成矿流体主要属于中—中高温、中—中低盐度的NaCl-H2O±CO2体系,而斑岩型铜矿属于中高-高温、高盐度的Na...     

新疆准噶尔斑岩铜矿地质特征及成矿作用

在前人工作基础上,文章综述了新疆准噶尔斑岩铜矿地质特征和成矿背景。划分出4个成矿带,即晚志留世—早泥盆世初琼河坝地区斑岩铜钼矿带、中泥盆世卡拉先格斑岩铜矿带、早石炭世希勒库都克-索尔库都克斑岩-矽卡岩铜钼矿带和晚石炭世包古图斑岩铜矿带。准噶尔成岩成矿时代分为4期,即晚志留世—早泥盆世初（427～411 Ma）、中泥盆世（378～374 Ma）、石炭纪（332～296 Ma）、二叠纪—三叠纪叠加成矿期（269～266 Ma;230～200 Ma）。斑岩铜矿成矿温度从高温延续到低温（530～120℃）,但主要成矿区间在中温阶段（300～180℃）;流体盐度w(NaCleq)变化于0.5%～21.75%之间和28.9%～66.76%之间。包古图和云英山矿床成矿流体主要为岩浆水,哈腊苏和玉勒肯哈腊苏矿床成矿流体为岩浆水混合大气降水。硫同位素组成集中于零值附近,指示成矿物质来源于地幔或与地幔有关的岩浆。斑岩铜矿的形成主要与中性、中酸性和酸性斑岩侵入活动有关,其形成的构造环境有大陆岛弧、大洋岛弧和后碰撞环境。     

西藏冈底斯三处斑岩铜矿床流体包裹体及成矿作用研究

对西藏冈底斯斑岩铜矿带中的驱龙、冲江斑岩铜矿床和与斑岩有关的帮浦铜多金属矿床进行了流体包裹体岩相学、显微测温和激光拉曼探针分析。对斑岩中斑晶石英、硅化脉石英和热液矿物硬石膏内流体包裹体的观测表明,与成矿有关的流体包裹体可以分为气相包裹体、液相包裹体、含子晶的多相包裹体等3类。它们的均一温度变化较大（191～550℃）,气相包裹体与含子晶多相包裹体的均一温度相近,主要集中于300～550℃之间。流体的盐度ω（NaCleq）为1．91％～66．75％,含石盐子晶包裹体的盐度ω（NaCleq）范围为32．70％～66．75％。激光拉曼光谱分析表明,子晶以石盐为主,并有较多的黄铜矿;气相包裹体和液相包裹体的气相中含有CO2。低密度的气相包裹体与高密度的液相包裹体、高盐度的含子晶包裹体共生,其均一温度范围一致,但盐度相差较大,指示成矿流体有不混溶作用或沸腾作用。成矿流体来自于岩浆的出溶;金属硫化物直接来源于岩浆。斑晶石英内流体包裹体中的不混溶作用与岩浆的初始沸腾有关;硅化脉石英捕获的流体包裹体与岩浆的二次沸腾有关;而硬石膏内流体包裹体的不混溶与两种不同性质流体的混合作用有关。斑晶石英中包裹体内的黄铜矿子晶是岩浆流体高金属含量的表征而不是矿化开始的标志。冈底斯成矿带内斑岩铜矿的成矿始于岩浆期后高温阶段,随后的高-中温热液阶段是流体大量沉淀矿质的重要时期。     

黑龙江铜山断裂的变形特征及铜山铜矿床蚀变带-矿体重建

黑龙江铜山铜矿床系多宝山铜矿田的重要组成部分,它和多宝山矿床同是中亚造山带东段最古老的斑岩铜矿床(奥陶纪)。铜山断裂为铜山斑岩铜矿床内最为重要的一条成矿后断裂,它截切矿体和蚀变带,因而导致矿化中心、深部找矿方向不明。现阶段的研究对其运动学特征还存有较大争议,缺乏对该带变形特征与性质的细致观察与鉴别。据此,本文开展详细地野外及室内研究工作,取得如下新认识:1)铜山断裂为近东西走向的压扭性断裂,最典型的构造几何学特征为发育北东-北东东走向劈理、构造透镜体、以及岩脉及热液脉扭曲现象。2)断裂带内石英、黄铜矿、黄铁矿、闪锌矿的镜下变形特征和石英C轴组构特征显示低温变形条件,依据矿物和岩石变形特点判断铜山断裂主体为脆性断裂。3)构造解析表明铜山断裂运动学特征为:上盘由南东向北西方向斜向逆冲。综合断裂上、下盘地质体界线、蚀变和脉系分布特征等,判断上盘相对下盘大致沿NW320°方向水平移动距离700~800m,垂向抬升550~700m,错开蚀变外带(青磐岩化带、石英-绢云母-伊利石-绿泥石化带)和矿化带。4)铜山断裂的次级断裂截切了中晚三叠世白云母花岗岩,推测铜山断裂活动时限晚于中晚三叠世。5)复原铜山断裂上盘和下盘的空间位置至铜山断层活动前,重建铜山铜矿床蚀变带-矿化体,初步判断铜山断裂活动前铜山矿床为纺锤形态。根据重建后矿化和蚀变的分布规律推断下盘Ⅲ号矿体的南侧位置应有尚未发现的成矿斑岩和矿体,为深部找矿提供了依据。     

Environmental geochemistry of toxic heavy metals in soils around Sarcheshmeh porphyry copper mine smelter plant,Rafsanjan, Kerman,Iran

The Sarcheshmeh copper mine smelter plant is one of the biggest copper producers in Iran. Long-time operation of about 25 years of the smelter plant causes release of potentially toxic heavy metals into the environment. In this paper, geochemical distribution of toxic heavy metals in 28 soil samples was evaluated around the Sarcheshmeh smelter plant. Soils developed over the nonmineralized and uncontaminated areas have an average background concentration of 41.25 mg kg⁻¹ Cu, 26.6 mg kg⁻¹ As, 12.7 mg kg⁻¹ Pb, 0.9 mg kg⁻¹ Sb, 1.9 mg kg⁻¹ Mo, 1.7 mg kg⁻¹ Sn, 0.2 mg kg⁻¹ Cd, 0.15 mg kg⁻¹ Bi, 235 mg kg⁻¹ S and 73.4 mg kg⁻¹ Zn, respectively. As a result of smelting process, the upper soil layers (0–5 cm) were polluted by Cu (>1,397 mg kg⁻¹), Cd (>3.42 mg kg⁻¹), S (>821 mg kg⁻¹), Mo (>10.3 mg kg⁻¹), Sb (>11.7 mg kg⁻¹), As (>120.6 mg kg⁻¹), Pb (>83.8 mg kg⁻¹), Zn (>214.9 mg kg⁻¹), and Sn (>3.7 mg kg⁻¹), respectively. These values are much higher than the normal concentration of the elements in the uncontaminated soil layers. The elemental values decrease with distance travelled away of the smelter plant, especially at minimum wind direction. Furthermore, high contaminated values of Cu (8,430 mg kg⁻¹), As (500 mg kg⁻¹), Pb (331 mg kg⁻¹), Mo (61 mg kg⁻¹), Sb (56.2 mg kg⁻¹), Zn (664 mg kg⁻¹), Cd (17.2 mg kg⁻¹), Bi (13.4 mg kg⁻¹), and S (3,780 mg kg⁻¹) were observed in the upper soil layers close to the smelting waste dumps. Sequential extraction analysis shows that about 270 mg kg⁻¹ Cu, 28 mg kg⁻¹ Pb, 50.33 mg kg⁻¹ Zn, and 47.84 mg kg⁻¹ As were adsorbed by Fe and Mn oxides. The carbonate phases include 151 mg kg⁻¹ Cu, 28 mg kg⁻¹ Pb, 25 mg kg⁻¹ Zn, and 32.99 mg kg⁻¹ As. Organic matter adsorbed 314.6 mg kg⁻¹ Cu and 29.18 mg kg⁻¹ Zn.     

新疆哈密土屋铜矿床地质和地球化学特征

土屋铜矿床是我国近年来发现的特大型斑岩铜矿床,其独特矿床地质背景和矿床规模已经引起国内外地质学界和矿业界的广泛关注;本文详细叙述该矿床的地质背景,对矿床的地质、地球化学特征进行系统研究和总结,对矿床的成矿作用动力学过程进行探讨。研究表明,该矿床成矿物质具有深部来源特征,而岩浆在侵位过程中受到上地壳物质一定程度的混染;成矿流体以岩浆水为主,天水和岩浆水的混合仅为少量;石英流体包裹体均一温度较低,但盐度较高;含矿斑岩体是多次脉动式侵位的,成岩时代主要集中于早石炭世(367～358 Ma);成矿时代为晚于成岩时代(347.3±2.1 Ma～322.7±3 Ma)。     

Some secondary ore formation features of the Sar-Cheshmeh porphyry copper-molybdenum deposit,Kerman, Iran

New secondary mineral features and the control of secondary molybdenum enrichment have now been recognized at the Sar-Cheshmeh copper deposit. In part of the deposit, copper is locally concentrated within a subvolcanic unit — the so-called Late Fine Porphyry in amounts that seem too great to have come from the primary phase of the same unit. Clay minerals are believed to have influenced the deposition of copper by through-flowing oxidized zone solutions within this otherwise subeconomic unit. These solutions have caused argillic alteration and copper concentration within the plagioclase phenocrysts. Fractures are filled with chrysocolla, but little chrysocolla was observed within the altered plagioclase phenocrysts. The scattered layers of sedimentary unroofing breccia — horizontal layers of Quaternary age accumulated within the depressions at the top of the deposit — contain minor amounts of native copper. The breccia consists of angular to subangular clasts of local derivation cemented by a matrix of hematite, limonite, geothite, and small rock fragments. Native copper, the only copper mineral associated with the breccia, mainly adhers to the cavity walls in the cementing materials. The amount of molybdenum within the leached capping of the Sar-Cheshmeh deposit is generally controlled by the amount of pyrite. Abundant pyrite has caused the retention of molybdenum within the leached capping of the pyritic halo as a result of the more acidic solution during weathering, in contrast to the leached zone of the pyrite-poor stock, where molybdenum is partially mobile.     

东准噶尔卡拉先格尔斑岩铜矿带改造与叠加成矿作用研究

卡拉先格尔斑岩铜矿带位于我国新疆北部,大地构造位于中亚成矿域的中段、西伯利亚克拉通南缘与华北-塔里木克拉通北缘增生造山带的接合部位,夹于北西向额尔齐斯-玛因鄂博断裂带和北北西向可可托海-二台断裂带的交汇处。研究发现卡拉先格尔斑岩铜矿带在成矿构造地质、矿石组构、元素组合和成矿期次等方面表现出多期改造与叠加成矿的特征。在前期区域成矿背景、典型矿床研究的基础上,本文总结了卡拉先格尔斑岩铜矿带的构造演化与成矿过程:在中-晚泥盆世,卡拉先格尔斑岩铜矿带处于与俯冲有关的岛弧构造背景,有两期中酸性斑岩侵入与Cu-Au-Mo矿化作用;早石炭世时,区域处于碰撞造山阶段,NW向韧性剪切变形造成原斑岩中的矿化发生迁移与再定位,片理构造发育处局部得到富集;晚石炭世到二叠纪是后碰撞伸展阶段,形成了卡拉先格尔斑岩铜矿带一系列张性构造和叠加的脉状矿化;进入中生代后,常见热液脉状铜矿化充填叠加到早期矿化之上,但同时本矿带遭受强烈的抬升与剥蚀作用。     

An SVM-based machine learning method for the separation of alteration zones in Sungun porphyry copper deposit

Sungun porphyry copper deposit is in East Azarbaijan province, NW of Iran. There exist four hypogene alteration types in Sungun: potassic, propylitic, potassic–phyllic, and phyllic. Copper mineralization is essentially associated more with the potassic and less with the phyllic alterations and their separation is, therefore, quite important. This research has tried to separate these two alteration zones in Sungun porphyry copper deposit using the Support Vector Machine (SVM) method based on the fluid inclusion data, and seven variables including homogenization temperatures, salinity, pressure, depth, density and the Cu grade have been measured and calculated for each separate sample. To apply this method, use is made of the radial basis function (RBF) as the kernel function. The best values for λ and C (the most important SVM parameters) that perform well in the training and test data are 0.0001 and 1, respectively. If these values for λ and C are applied, the phyllic and potassic alteration zones in the training and test data will be separated with an accuracy of about 95% and 100%, respectively. This method can help geochemists in separating the alteration zones because classifying and separating samples microscopically is not only very hard, but also quite time and money consuming.     

Distribution of sulphur, and sulphide-iron and copper in bedrock associated with porphyry copper deposits, highland valley, British Columbia

A selective leach based on extraction with potassium chlorate-hydrochloric acid was used to investigate distribution of sulphide-iron and copper associated with the JA and Valley Copper deposits. Results emphasize patterns related to sulphide, versus total metal, and are shown to be consistent with mineralogical zoning in the deposits.