Chemie Der Erde-Geochemistry最新文献_第3页

Petrogenesis of post-collisional granites in the Arabian-Nubian Shield: The peraluminous A-type granites of the mounts Um-Sudaydat and Um-Erjaj plutons, South Eastern Desert, Egypt 阿拉伯-努比亚地盾碰撞后花岗岩的岩石成因：埃及东南部沙漠Um-Sudaydat和Um-Erjaj岩体的过铝质a型花岗岩

IF 2.9 3区地球科学 Q2 GEOCHEMISTRY & GEOPHYSICS

Chemie Der Erde-Geochemistry

Pub Date : 2025-11-03 DOI: 10.1016/j.chemer.2025.126346

Mohammed Z. El-Bialy , Abdel-Aal Abdel-Karim , Mokhles Azer

The Younger Granite plutons of Gabal Um Erjaj (GUE) and Gabal Um Sudaydat (GUS) in the Eastern Desert of Egypt provide key insights into the geological history and crustal evolution of the Arabian-Nubian Shield (ANS). These granitic intrusions represent the final phase of magmatic activity in the region, cutting through older Neoproterozoic basement rocks. Both plutons exhibit sharp, non-reactive contacts with the surrounding rocks, with no evidence of thermal alteration. Based on modal analysis, these granites are primarily alkali feldspar granites and syenogranites. The GUS granites display more deformation features and inequigranular textures, suggesting a shallower level of intrusion compared to GUE. Electron microprobe analyses reveal significant compositional variations between the two plutons, particularly in feldspar and biotite chemistry. Geochemically, both granitoid suites exhibit peraluminous, ferroan A-type characteristics, with distinct geochemical signatures that differentiate them from other A-type granites. Geothermometric analyses indicate moderate to high crystallization temperatures for accessory minerals, suggesting a highly fractionated magmatic origin. Trace element distributions, including pronounced negative Nb, Ti, and Eu anomalies, coupled with high Y/Nb ratios (>1.2), indicate a predominantly crustal-derived melt. The post-collisional geodynamic setting of these granitoids within the ANS aligns with lithospheric delamination and slab breakoff processes, contributing to the extensive crustal melting. The geotectonic discrimination diagrams support their classification as A₂-type granites, reinforcing their post-collisional evolution. These findings emphasize the significance of crustal processes in the formation of post-collisional A-type granites, contributing to a broader understanding of the crustal evolution within the ANS.

埃及东部沙漠Gabal Um Erjaj （GUE）和Gabal Um Sudaydat （GUS）的年轻花岗岩岩体为研究阿拉伯-努比亚地盾（ANS）的地质历史和地壳演化提供了重要的线索。这些花岗岩侵入物代表了该地区岩浆活动的最后阶段，穿过了更古老的新元古代基底岩。这两个岩体都表现出与周围岩石尖锐的非反应性接触，没有热蚀变的证据。模态分析表明，这些花岗岩主要为碱长石花岗岩和正长花岗岩。GUS花岗岩表现出更多的变形特征和非等粒状结构，表明其侵入程度较GUE浅。电子探针分析揭示了两种岩体在长石和黑云母化学成分上的显著差异。地球化学特征表明，这两组花岗岩均表现出过铝、铁a型特征，具有明显的地球化学特征，区别于其他a型花岗岩。地热分析表明，副矿物的结晶温度适中至较高，表明其岩浆成因高度分异。微量元素分布，包括明显的负Nb， Ti和Eu异常，加上高Y/Nb比率（>1.2），表明主要是地壳衍生的熔融。这些花岗岩类在ANS内的碰撞后地球动力学背景与岩石圈分层和板块断裂过程一致，导致了广泛的地壳融化。大地构造判别图支持其a2型花岗岩的分类，加强了其后碰撞演化。这些发现强调了地壳过程在碰撞后a型花岗岩形成中的重要性，有助于更广泛地了解ANS内部的地壳演化。

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引用次数: 0

Garnet mineral chemistry as proxy for skarn-forming processes in the Schwarzenberg District, Erzgebirge, Germany 德国Erzgebirge施瓦岑贝格地区柘榴石矿物化学作为矽卡岩形成过程的代表

IF 2.9 3区地球科学 Q2 GEOCHEMISTRY & GEOPHYSICS

Chemie Der Erde-Geochemistry

Pub Date : 2025-10-25 DOI: 10.1016/j.chemer.2025.126344

Nils Reinhardt , Jens Gutzmer , Marcus Oelze , Joachim Krause , Mathias Burisch

Polymetallic W-(Sn), Sn-Zn±(In), and Zn-Pb±(Sn) skarns in the Schwarzenberg District of the western Erzgebirge are expressions of a polyphase mineral system that formed between >330 Ma and ~295 Ma. Due to the polyphase nature of the skarns, the physicochemical conditions of skarn formation and the actual timing of ore formation have remained poorly constrained. To better understand skarn-forming processes in the Erzgebirge, we obtained new mineral chemical data of prograde garnet from all major skarns across the Schwarzenberg District by electron microprobe and laser ablation-inductively coupled plasma-mass spectrometry. Results illustrate that the oldest generation of skarns formed under relatively fluid-buffered conditions and high fluid/rock ratios. Associated garnet has a pronounced andradite component, contains low concentrations of HFSE, Mn, and Ga and is variably enriched in Sn, W, As, and Li. Elevated concentrations of HFSE, Mn, and Ga in garnet from skarns with skarnoid textures indicate that these formed under mainly rock-buffered conditions (low fluid/rock ratios). Associated garnet is dominantly grossular and invariably low in Sn and W concentrations. The mineral chemistry of garnet from the youngest skarn bodies indicates renewed ingress of magmatic-hydrothermal fluids marked by an intermediate grandite composition, low HFSE, Al, and Ga concentrations as well as a variable enrichment of Sn and W. Although these general patterns are well defined, our data also clearly reveal considerable variability of garnet compositions on the local scale. The same is true for Sn and W concentrations in garnet of all stages. These are found to be too variable as to constitute meaningful exploration vectors. However, they are well suited to place general constraints on the physicochemical conditions of polyphase skarn formation in the Schwarzenberg District.

二日格西施瓦施贝格地区多金属W-(Sn)、Sn- zn±（In）和Zn-Pb±（Sn）夕卡岩是形成于>；330 Ma ~ ~295 Ma之间的多相矿物体系的表现。由于矽卡岩的多相性质，矽卡岩形成的物理化学条件和成矿的实际时间仍然缺乏限制。为了更好地了解Erzgebirge矽卡岩的形成过程，我们利用电子探针和激光烧蚀-电感耦合等离子体质谱技术，从Schwarzenberg地区所有主要矽卡岩中获得了新的顺行石榴石矿物化学数据。结果表明，最老一代夕卡岩形成于相对流体缓冲条件和高液岩比条件下。伴生石榴石具有明显的赤铁矿成分，含有低浓度的HFSE、Mn和Ga，并以不同的方式富集Sn、W、As和Li。在具有类矽卡岩结构的矽卡岩中，石榴石中HFSE、Mn和Ga的浓度升高表明它们主要是在岩石缓冲条件下形成的（低流体/岩石比）。伴生石榴石以粗晶为主，且总是低锡、低钨浓度。来自最年轻矽卡岩体的石榴石的矿物化学表明岩浆热液流体的重新进入，其特征是中等花岗岩组成，低HFSE， Al和Ga浓度，以及Sn和w的可变富集。尽管这些一般模式被很好地定义，但我们的数据也清楚地揭示了石榴石组成在局部尺度上的相当大的变化。各阶段石榴石中锡、钨的浓度也是如此。人们发现这些变量太大，无法构成有意义的勘探向量。然而，它们很适合于对施瓦岑贝格地区多相矽卡岩形成的物理化学条件进行一般约束。

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引用次数: 0

The diversity, classification, and formation of the CM chondrite group: A review CM球粒陨石群的多样性、分类和形成：综述

IF 2.9 3区地球科学 Q2 GEOCHEMISTRY & GEOPHYSICS

Chemie Der Erde-Geochemistry

Pub Date : 2025-10-22 DOI: 10.1016/j.chemer.2025.126343

Makoto Kimura , Michael K. Weisberg , Richard C. Greenwood , Akira Yamaguchi

In this paper, we examine the diverse features of CM (Mighei-type) and related carbonaceous chondrites, including their petrologic classification, secondary heating, brecciation, and we explore anomalous CM-like chondrites. CM chondrites experienced varying degrees of aqueous alteration, resulting in a range of petrologic subtypes from 3.0 to 2.0. The most abundant subtypes are 2.3–2.0, which may reflect melting of significant amounts of ice, resulting in the formation of the heavily altered CM chondrites in the inner regions of the parent body. Additionally, some CM and related chondrites have undergone secondary heating after aqueous alteration. The source of heat for these chondrites is still uncertain, but impacts are the most likely the cause due to the evidence for a short duration of heating. CM chondrites are mainly genomict breccias and contain clasts of various petrologic grade and degree of heating, though some CMs contain xenolithic clasts. Highly recrystallized clasts are particularly important, as they might have formed in the interior, hotter regions of the CM parent body. Subsequently, these clasts may have been mixed with other typical CM lithologies due to impact events. CM chondrite fragments are commonly found in other meteorites, such as HED meteorites and ordinary chondrites. This indicates a widespread distribution of CM chondrite fragments in the main asteroid belt, with incorporation into other meteorites taking place significantly later than chondrule formation. There have been numerous descriptions of anomalous CM or related chondrites. We tentatively classify these anomalous CMs into four categories: highly ¹⁶O-rich, medium ¹⁶O-rich, an unusual mineral group, and others. However, the processes involved in the formation of these anomalous chondrites and their relationships to the more typical CMs remain unclear, as detailed documentation of most of the anomalous CMs is currently lacking. CM chondrites primarily consist of chondrules, refractory inclusions, opaque minerals, and a matrix material, similar to other C chondrites. The petrographic and bulk chemical features of CMs are most similar to CO chondrites. However, CM and CO chondrites did not originate from a single parent body. CM chondrites provide valuable information about the conditions and processes that operated in the outer region of the early solar system.

本文研究了CM （mighei -型）及其相关碳质球粒陨石的岩石学分类、二次加热、角化等特征，并对异常类CM球粒陨石进行了探索。CM球粒陨石经历了不同程度的水蚀变，形成了3.0 ~ 2.0的岩石学亚型。最丰富的亚型是2.3-2.0，这可能反映了大量冰的融化，导致在母体内部区域形成了严重蚀变的CM球粒陨石。此外，一些CM和相关球粒陨石在水蚀后经历了二次加热。这些球粒陨石的热量来源仍然不确定，但撞击是最有可能的原因，因为有证据表明加热的持续时间很短。CM球粒陨石以基因组角砾岩为主，含不同岩石品位和加热程度的碎屑，部分CM球粒陨石含xenolithic碎屑。高度再结晶的碎屑尤其重要，因为它们可能形成于CM母岩内部较热的区域。随后，由于撞击事件，这些碎屑可能与其他典型的CM岩性混合。CM球粒陨石碎片通常存在于其他陨石中，如HED陨石和普通球粒陨石。这表明CM球粒陨石碎片在主小行星带广泛分布，与其他陨石的结合发生在球粒形成的明显晚于球粒形成。有许多关于异常CM或相关球粒陨石的描述。我们暂时将这些异常cm分为四类：高16o富、中等16o富、不寻常矿物群和其他。然而，这些异常球粒陨石的形成过程及其与更典型的CMs的关系仍然不清楚，因为目前缺乏大多数异常CMs的详细文件。CM球粒陨石主要由球粒、难熔包裹体、不透明矿物和基质物质组成，类似于其他C球粒陨石。CMs的岩石学和整体化学特征与CO球粒陨石最为相似。然而，CM和CO球粒陨石并非起源于单一的母体。CM球粒陨石提供了关于早期太阳系外部区域运行的条件和过程的宝贵信息。

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引用次数: 0

Magmatic evolution and molybdenum mineralization potential analysis in the Mangling granite, northern Qinling orogenic belt, China 北秦岭造山带芒岭花岗岩岩浆演化与钼矿化潜力分析

IF 2.9 3区地球科学 Q2 GEOCHEMISTRY & GEOPHYSICS

Chemie Der Erde-Geochemistry

Pub Date : 2025-10-01 DOI: 10.1016/j.chemer.2025.126338

Rui-Yang Liu

The Qinling orogenic belt experienced magmatic remelting and intrusion, forming Mo mineralization belt associated with Late Yanshanian magmatism, highlighting the role of Yanshan period in Mo enrichment. Ore-bearing granitic rocks (monzogranite and granite porphyry) from northern Qinling were analyzed using petrography, SEM, TIMA, whole-rock geochemistry, Sr-Nd-Pb isotopes, zircon and titanite UPb dating, zircon LuHf isotopes, and EMPA of key minerals (zircon, titanite, pyrite, plagioclase, quartz, biotite). These data constrain the petrogenesis and metallogenic mechanisms of Mo mineralization in the region. The Mangling granites (SiO₂ = 64.78–73.36 wt%, Mg# = 34.02–40.65, A/CNK = 1.24–1.67) originated from the lower crust, as indicated by isotopic data (Isr = 0.7064–0.7087, εNd(t) = −7.05 to ∼ −13.97). Magmatic-hydrothermal processes, including ascent (155.7 Ma), emplacement (152.1 Ma), and mixing, formed highly differentiated Mo-bearing granite porphyry (TE_1,3 = 1.03–1.45). Partial melting and cooling produced monzogranite as the parental rock at 135.6 Ma. Under favorable conditions, crystallization and differentiation enriched Mo in the residual melt, leading to the formation of ore-bearing granite porphyry during the Early Cretaceous (133.8 Ma). These processes highlight the magmatic controls on Mo enrichment in Mangling area.

秦岭造山带经历岩浆重熔侵入，形成与燕山晚期岩浆活动相关的钼矿化带，突出了燕山期对钼矿的富集作用。采用岩石学、SEM、TIMA、全岩地球化学、Sr-Nd-Pb同位素、锆石和钛矿UPb测年、锆石LuHf同位素以及主要矿物（锆石、钛矿、黄铁矿、斜长石、石英、黑云母）的EMPA对北秦岭含矿花岗岩（二长花岗岩和花岗岩斑岩）进行了分析。这些资料约束了该区钼成矿的成因和成矿机制。同位素数据（Isr = 0.7064 ~ 0.7087, εNd(t) = - 7.05 ~ ~ - 13.97）表明，芒岭花岗岩（SiO2 = 64.78 ~ 73.36 wt%, Mg# = 34.02 ~ 40.65, A/CNK = 1.24 ~ 1.67）来源于下地壳。岩浆-热液作用包括上升（155.7 Ma）、侵位（152.1 Ma）和混合作用，形成了高分异的含钼花岗斑岩（TE1,3 = 1.03-1.45）。135.6 Ma部分熔融冷却形成二长花岗岩为母岩。早白垩世（133.8 Ma），在有利条件下，结晶分异富集了残余熔体中的钼，形成了含矿花岗斑岩。这些过程突出了岩浆对芒岭地区钼富集的控制作用。

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引用次数: 0

Chemistry and He isotope systematics of olivine as tracers of source in mantle xenoliths from Harrat Hutaymah and Harrat Kishb Cenozoic lava fields, Western Saudi Arabia 沙特西部Harrat Hutaymah和Harrat Kishb新生代熔岩田地幔捕虏体中橄榄石示源化学及He同位素系统

IF 2.9 3区地球科学 Q2 GEOCHEMISTRY & GEOPHYSICS

Chemie Der Erde-Geochemistry

Pub Date : 2025-09-30 DOI: 10.1016/j.chemer.2025.126342

Ahmed Hasan Ahmed , Abdel-Kader M. Moghazi , Finlay M. Stuart , Shehta Abdallah , Moustafa Hashad , Kamal A. Ali

Mantle xenoliths from the Cenozoic volcanic fields of Harrat Hutaymah and Harrat Kishb, located in the western part of the Arabian Shield, consist of proto-granular lherzolite, harzburgite, and to a lesser extent dunite and wehrlite. The olivine displays variations in Mn, Ni, and Ca contents relative to the forsterite (Fo) content that is similar to that of residual mantle olivine, which crystallized after being exposed to low to intermediate degrees of melt derived from mantle peridotite. The elemental ratios of Ca-Fe-Ni-Mg-Mn in the olivine further indicate a contribution from peridotite. Pressure-temperature calculations and previous geochemical studies indicate that the peridotite xenoliths were entrained from below the crust-mantle boundary (~35 km in the mantle lithosphere) under the Arabian Shield. Olivine ³He/⁴He ratios range from 6.1 to 8.5 R_a, which overlap the range of <7 to 9 R_a recently reported for off-craton-derived subcontinental lithospheric mantle (SCLM) xenoliths and is consistent with mantle beneath the region. This tends to rule out the overprinting of the SCLM by fluids/melts derived from the deep upwelling mantle sampled by the Afar plume. However, the influence of deep mantle fluid may be cryptic and warrants further exploration because the He content of the Afar mantle plume is unknown.

位于阿拉伯地盾西部的Harrat Hutaymah和Harrat Kishb新生代火山田的地幔捕虏体主要由原粒状橄榄岩、黑锌矿组成，少量含泥质和硅质岩。橄榄石的Mn、Ni和Ca含量相对于橄榄石（Fo）含量的变化与地幔残余橄榄石的变化相似，这些橄榄石是在暴露于源自地幔橄榄岩的低至中等程度熔融后结晶的。橄榄石中的Ca-Fe-Ni-Mg-Mn元素比值进一步表明橄榄岩的贡献。压力-温度计算和先前的地球化学研究表明，橄榄岩包体来自于阿拉伯地盾下地壳-地幔边界以下（地幔岩石圈~ 35km）。橄榄石3He/4He比值范围为6.1 ~ 8.5 Ra，与最近报道的离克拉通衍生的次大陆岩石圈地幔（SCLM）包体的<；7 ~ 9 Ra范围重叠，与该地区地幔一致。这就排除了来自阿法尔地幔样本的深部上升流地幔的流体/熔体对SCLM的叠加作用。然而，深层地幔流体的影响可能是隐蔽的，由于阿法尔地幔柱的He含量尚不清楚，因此值得进一步探索。

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引用次数: 0

Geochemistry and U-Pb geochronology of the Neoproterozoic aluminous A-type granite in the south-western Tanzania: Implications to the Tonian geodynamic evolution of Southern Africa 坦桑尼亚西南部新元古代铝质a型花岗岩的地球化学和U-Pb年代学：对南部非洲Tonian地球动力学演化的启示

IF 2.9 3区地球科学 Q2 GEOCHEMISTRY & GEOPHYSICS

Chemie Der Erde-Geochemistry

Pub Date : 2025-09-30 DOI: 10.1016/j.chemer.2025.126339

Emmanuel O. Kazimoto , Charles H. Kasanzu , Ernest Mulaya , Remigius Gama , Rachid Benaouda

This study presents new insights on the Litembo granite, a 30 km wide pluton located south of the Ubendian Belt in the southern Tanzania, East Africa. Whole-rock geochemistry, U-Pb zircon geochronology, and the Rb-Sr isotope system were used to determine its geochemical composition, age, and origin, contributing to regional geological and geodynamic context. The granite is metaluminous to peraluminous, ferroan, and calc-alkalic with high concentrations of Sr, Rb, Ba, High Field Strength Elements (HFSE; e.g., Zr, Y, Nb, and Ta), and high Ga/Al ratios. The total Rare Earth Element (REE) concentrations of the granite range from 335 to 693 ppm, showing fractionated REE patterns in the chondrite-normalized spider diagram ((La/Yb)_CN = 9.40–15.41) and a negative Eu anomaly (Eu/Eu*; mean = 0.87). Primitive mantle-normalized spidegrams reveal negative patterns for Ti, Sr, P, Y, and Cs, along with enrichment in Large Ion Lithophile Elements (LILE; e.g. Rb and Ba). Geochemical features of the rock are akin to anorogenic (A-type) granites, implying formation of Litembo granite from a deep source melt, involving plagioclase, garnet, and amphibole and/or complex differentiation processes, under extensional tectonics. An initial ⁸⁷Sr/⁸⁶Sr ratio (∼0.7113) suggests evolved crustal origins, with a Rb–Sr imprecise age of about 658 ± 20 Ma. Laser ablation ICP-MS U-Pb zircon dating yields crystallisation ages of 737.1 ± 2.9 Ma and 730.1 ± 3.0 Ma, indicating emplacement between 730 and 740 Ma, followed thermal diffusion of Rb and Sr in the rock at about 660 Ma. These ages and compositional features align with the Tonian intraplate (alkaline and carbonatite magmatism) in southern Africa and support for a thermal event linked to Rodinia's breakup, preceding development of the Mozambique Belt.

这项研究提供了关于Litembo花岗岩的新见解，Litembo花岗岩是位于东非坦桑尼亚南部乌本甸带以南的一个30公里宽的岩体。利用全岩地球化学、U-Pb锆石年代学和Rb-Sr同位素系统确定了其地球化学组成、年龄和成因，为区域地质和地球动力学背景提供了依据。花岗岩为铝质、过铝质、铁质和钙碱性花岗岩，具有高浓度的Sr、Rb、Ba、高场强元素（HFSE，如Zr、Y、Nb和Ta）和高Ga/Al比值。花岗岩总稀土元素（REE）含量在335 ~ 693 ppm之间，呈分异分布（La/Yb）CN = 9.40 ~ 15.41)，呈负Eu异常（Eu/Eu*，平均值= 0.87）。原始地幔归一化柱面图显示Ti、Sr、P、Y和Cs为负模式，同时大离子亲石元素（LILE，如Rb和Ba）富集。岩石的地球化学特征与造山（a型）花岗岩相似，暗示在伸展构造作用下，立腾堡花岗岩由深源熔体形成，涉及斜长石、石榴石、角闪孔和/或复杂的分异过程。最初的87Sr/86Sr比值（~ 0.7113）表明演化的地壳起源，Rb-Sr的不精确年龄约为658±20 Ma。激光烧蚀ICP-MS U-Pb锆石年龄分别为737.1±2.9 Ma和730.1±3.0 Ma，结晶年龄介于730 ~ 740 Ma之间，Rb和Sr在660 Ma左右发生热扩散。这些年龄和成分特征与非洲南部的托尼亚板块内（碱性和碳酸盐岩岩浆作用）一致，并支持与罗迪尼亚分裂有关的热事件，在莫桑比克带发育之前。

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引用次数: 0

Coupling hydrolyzed rice husk and ferric oxidation to enhance bio-oxidation of gold concentrate with high arsenic and sulfur 稻壳水解与铁氧化耦合促进高砷高硫金精矿生物氧化

IF 2.9 3区地球科学 Q2 GEOCHEMISTRY & GEOPHYSICS

Chemie Der Erde-Geochemistry

Pub Date : 2025-09-23 DOI: 10.1016/j.chemer.2025.126341

Shiqi Zhang , Hongying Yang , Linlin Tong , Zhenan Jin , Pengcheng Ma

The bio-oxidation efficiency of refractory gold concentrate with high arsenic and sulfur is generally limited. In present study, the two-step ferric-biological process was employed to treat this gold concentrate, with an emphasis on investigating the impact of different organic nutrients on bio-oxidation performance. The results indicated that the addition of appropriate dosage of hydrolyzed rice husk (HRH, 1.2 g/L) combined with ferric oxidation significantly improved the bio-oxidation efficiency. The microbial growth rate and adsorption capacity were increase by 1.75 and 1 times, respectively. Specifically, it effectively facilitated the growth and adsorption of Sulfobacillus spp., while exhibiting no significant inhibitory effect on Leptospirillum spp. growth. Consequently, the homogeneity of the planktonic microbial community was improved. These effects resulted in a 0.06, 0.84, and 1.03 times increase in the oxidation efficiency of As, Fe, and S compared with one-step bio-oxidation, achieving extraction levels of 98.4 ± 0.2 %, 74.5 ± 0.1 %, and 60.4 ± 1.0 %, respectively. In consequence, the extraction levels of Au and Ag increased by 63.0 % and 51.3 %, respectively, reaching 93.7 ± 0.6 % and 91.6 ± 0.5 %. This study elucidated the enhancement mechanism of HRH on bio-oxidation and provided a theoretical basis for the efficient utilization of refractory gold ores and the application of lignocellulose in biohydrometallurgy.

高砷高硫难处理金精矿的生物氧化效率普遍有限。采用铁-生物两步法处理该金精矿，重点研究了不同有机营养物对其生物氧化性能的影响。结果表明，添加适量的水解稻壳（HRH, 1.2 g/L），配合铁氧化，显著提高了生物氧化效率。微生物生长速率和吸附量分别提高1.75倍和1倍。具体来说，它能有效促进亚硫酸盐杆菌的生长和吸附，而对钩端螺旋体的生长没有明显的抑制作用。从而提高了浮游微生物群落的均匀性。结果表明，与一步法氧化相比，砷、铁和硫的氧化效率分别提高了0.06倍、0.84倍和1.03倍，萃取率分别为98.4%±0.2%、74.5±0.1%和60.4±1.0%。Au和Ag的提取率分别提高了63.0%和51.3%，分别达到93.7±0.6%和91.6±0.5%。本研究阐明了HRH对生物氧化的增强机理，为难处理金矿的高效利用和木质纤维素在生物湿法冶金中的应用提供了理论依据。

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引用次数: 0

A new framework for exploration targeting: Integrating multifractal geochemical analysis, structural controls and fuzzy C-means unsupervised clustering 多重分形地球化学分析、构造控制与模糊c均值无监督聚类相结合的找矿新框架

IF 2.9 3区地球科学 Q2 GEOCHEMISTRY & GEOPHYSICS

Chemie Der Erde-Geochemistry

Pub Date : 2025-09-20 DOI: 10.1016/j.chemer.2025.126340

Reza Ghezelbash , Abbas Maghsoudi , Mehrdad Daviran

In mineral exploration, detecting weak geochemical anomalies in covered areas remains a significant challenge due to overlapping backgrounds and anisotropic mineralization controls, particularly in tectonically complex regions like the Takhte-Soleyman district, northwest Iran, part of the Urumieh-Dokhtar magmatic arc (UDMA). This study addresses these issues by introducing a novel framework that enhances exploration targeting for gold (Au) and lead‑zinc (PbZn) deposits. The methodology integrates multifractal geochemical anomaly separation, including multifractal inverse distance weighting (MIDW), spectrum-area (S-A) and local singularity mapping (LSM) models, alongside distance-distribution analysis (DDA) and fuzzy c-means (FCM) clustering, to account for structural and geochemical complexities. Factor analysis identifies key elemental associations—Au with As and Sb, and PbZn with Ag and Cd—while DDA delineates northwest (NW) and northeast (NE) trending faults as critical controls, with approximately 85 % of Au and 77 % of PbZn deposits located within 1 km of these faults. The framework refines prospectivity models by optimizing FCM clustering with the V_XB index, targeting high-potential zones. Results demonstrate FCM-based LSM's superior anomaly detection, achieving area under curve (AUC) values of 94.8 % for Au and 88.08 % for PbZn, with strong spatial correlations to known deposits, offering a practical tool for exploration in challenging environments. This approach advances mineral prospectivity mapping (MPM) by overcoming limitations of traditional methods, with potential applications to other metallogenic provinces.

在矿产勘探中，由于背景重叠和矿化控制各向异性，特别是在构造复杂的地区，如伊朗西北部的Takhte-Soleyman地区，乌鲁木齐-多克塔尔岩浆弧（UDMA）的一部分，探测覆盖区域的弱地球化学异常仍然是一个重大挑战。本研究通过引入一种新的框架来解决这些问题，该框架可以增强金（Au）和铅锌（PbZn）矿床的勘探目标。该方法集成了多重分形地球化学异常分离，包括多重分形逆距离加权（MIDW）、光谱面积（S-A）和局部奇点映射（LSM）模型，以及距离分布分析（DDA）和模糊c均值（FCM）聚类，以解释结构和地球化学的复杂性。因子分析确定了关键元素组合- Au与As和Sb， PbZn与Ag和cd -而DDA圈定了西北（NW）和东北（NE）走向断裂为关键控制，约85%的Au和77%的PbZn矿床位于这些断裂的1公里范围内。该框架通过使用VXB指数优化FCM聚类来细化前景模型，以高潜力区域为目标。结果表明，基于fcm的LSM异常检测效果较好，Au和PbZn的曲线下面积（AUC）分别为94.8%和88.08%，与已知矿床具有较强的空间相关性，为复杂环境下的勘探提供了实用工具。该方法克服了传统方法的局限性，促进了矿产远景填图的发展，在其他成矿省份也有应用前景。

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引用次数: 0

Analysis of clustering methods for geochemical anomaly identification through weighted sample catchment basins 集水区加权样本地球化学异常识别聚类方法分析

IF 2.9 3区地球科学 Q2 GEOCHEMISTRY & GEOPHYSICS

Chemie Der Erde-Geochemistry

Pub Date : 2025-09-13 DOI: 10.1016/j.chemer.2025.126337

Maryam Shirjang , Abbas Maghsoudi , Reza Ghezelbash

The cruciality of geochemical exploration in discovering new mineral deposits demands the use of high-performance computational techniques to recognize geochemical anomaly patterns associated with mineralization. High dimensionality and complexity of geochemical datasets lead to use of brand-new methods including machine learning tools to get more efficient and accurate outcome. In this regard, advanced clustering methods have gained significant popularity over the years in the field of mineral exploration. This study presents an integrated mineral exploration approach using multiple clustering algorithms to identify Cu mineralization potential in the Kariz-Now district, Razavi Khorasan, northeastern Iran. The methodology uses faults within the study area to weight the catchment basins and brings grade characteristics of role-playing elements along with fault weights to highlight the potential areas. Three clustering techniques including K-Means (KM), Fuzzy C-Means (FCM), and DBSCAN were applied to the variables attached to their corresponding sample catchment basins to predict potential areas. The results were validated by success rate curves of the selected methods and the area under curve was calculated. The results reveal that DBSCAN has higher area under curve (AUC) than KM and FCM. Furthermore, there is a strong correlation between predicted anomalies and Paleogene volcanic and sedimentary rocks, particularly in areas with high fault density.

地球化学勘探在发现新矿床中的重要性要求使用高性能计算技术来识别与成矿有关的地球化学异常模式。地球化学数据集的高维性和复杂性导致使用包括机器学习工具在内的全新方法来获得更高效和准确的结果。在这方面，先进的聚类方法多年来在矿产勘查领域得到了很大的普及。本研究提出了一种综合矿产勘探方法，使用多聚类算法来识别伊朗东北部Razavi Khorasan Kariz-Now地区的铜成矿潜力。该方法利用研究区内的断层对流域进行加权，并结合角色扮演元素的品位特征和断层权重来突出潜在区域。将K-Means （KM）、模糊C-Means （FCM）和DBSCAN三种聚类技术应用于相应样本流域的变量，以预测潜在面积。通过所选方法的成功率曲线对结果进行验证，并计算曲线下面积。结果表明，DBSCAN的曲线下面积（AUC）高于KM和FCM。此外，预测异常与古近系火山岩和沉积岩具有很强的相关性，特别是在断层密度高的地区。

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引用次数: 0

Mineral chemistry of porphyry indicator minerals in Kuh-e-Kapout Cu porphyry deposit, Kerman Cenozoic Magmatic Arc: Petrogenetic and exploration implications 柯曼新生代岩浆弧Kuh-e-Kapout铜斑岩矿床斑岩指示矿物矿物化学特征：成因及找矿意义

IF 2.9 3区地球科学 Q2 GEOCHEMISTRY & GEOPHYSICS

Chemie Der Erde-Geochemistry

Pub Date : 2025-09-04 DOI: 10.1016/j.chemer.2025.126327

Alireza Zarasvandi , Nasim Haghighat Jou , Nader Taghipour , Mohsen Rezaei , Johann Raith , Mohammad Amiri Hoseini , Ghazal Zarasvandi

<div><div>The Kuh-e-Kapout porphyry copper deposit is located at the south end of the Kerman Cenozoic Magmatic Arc in the Jebal-Barez area. This article presents a first-time study on the evolution and origin of the magmatic-hydrothermal system associated with porphyry mineralization in this deposit. This deposit is affected by Jebal-Barez-type granitoids, which exhibit weak mineralization properties in PCDs. Using tools such as porphyry indicator minerals can help recognize the process that led to mineralization in this deposit. Based on electron probe micro-analyzer data from Biotite, plagioclase, and amphibole as indicator minerals, the physicochemical conditions of the hydrothermal-magmatic system associated with mineralization have been determined. This deposit is hosted in an arc-related, shallow calc-alkaline intrusive complex with a quartz diorite composition. In the study of drill cores, the central parts exhibit potassic alteration linked to copper sulfide mineralization veins, which includes potassium-rich phases of hydrothermal biotite and potassium feldspar that replace primary ferromagnesian minerals. This alteration transitions into a superimposed phyllic zone, characterized by increased sericitization of feldspars and mostly the presence of quartz±pyrite±Chalcopyrite veins. In the upper parts of the drill cores, advanced argillic alteration is indicated by fine-grained sulfides, sericite, and fluorite. Quartz diorite in the phyllic alteration zone intruded by an unmineralized microdiorite dike. Research on indicator minerals in quartz diorite and microdiorite, particularly in the potassic mineralizing zone in quartz diorite intrusion, provided insights into the physicochemical conditions of ore formation condition: biotites on the Fe/(Fe + Mg)-Al<sup>IV</sup> diagram are plotted in the phlogopite field, indicating the Mg-biotite type, which is associated with I-type granitoid. These data show the mantle-crust mixture source for quartz diorite with mineralized properties. Biotite and calcic amphibole geochemistry exhibiting calc-alkaline affinity with subduction-related orogeny for the quartz diorite and microdiorite porphyries. Based on biotite and amphibole geochemistry, the oxygen fugacity of the magmatism is estimated to have a range of high (HM) to moderate (NNO) characteristics, respectively. The ratio of log <em>f</em>(H<sub>2</sub>O)<em>/f</em>(HF) > 1 and log <em>f(</em>H<sub>2</sub>O)<em>/ f</em>(HCl) > 1 based on biotite geochemistry indicates the mineralized fluid was relatively water-rich. Data points of Plagioclase from quartz diorite and microdiorite plotted on the Na<sub>2</sub>O + K<sub>2</sub>O + CaO (wt%)-SiO<sub>2</sub> diagram, are between anorthite and albite. The excess Al in these data does not result from alteration and resulted from a magma with high PH<sub>2</sub>O. Biotite chemistry indicates that mineralization in the quartz diorite magmatism occurred within a relatively closed system in the potas

Kuh-e-Kapout斑岩铜矿位于Jebal-Barez地区Kerman新生代岩浆弧南端。本文首次对该矿床与斑岩成矿有关的岩浆-热液系统的演化及成因进行了研究。该矿床受jebal - barez型花岗岩类的影响，在PCDs中表现出弱矿化特征。使用诸如斑岩指示矿物之类的工具可以帮助识别导致该矿床成矿的过程。以黑云母、斜长石和角闪孔为指示矿物的电子探针显微分析数据，确定了与成矿有关的热液-岩浆系统的物理化学条件。矿床赋存于一个与弧相关的浅钙碱性侵入杂岩中，其成分为石英闪长岩。在岩心研究中，中心部位表现出与铜硫化物矿化脉相关的钾蚀变，其中包括热液黑云母和钾长石的富钾相，取代了原生镁铁矿物。这一蚀变转变为层状叠加带，其特征是长石绢云母化增加，石英±黄铁矿±黄铜矿脉多存在。在岩心上部，以细粒硫化物、绢云母和萤石为标志，显示出超前的泥质蚀变。未矿化微闪长岩脉侵入的叶状蚀变带内的石英闪长岩。石英闪长岩和微闪长岩中指示矿物的研究，特别是石英闪长岩侵入中钾成矿带的指示矿物的研究，揭示了成矿条件的物理化学条件：在辉云母田中绘制了Fe/(Fe + Mg)-AlIV图上的黑云母，显示为Mg-黑云母类型，与i型花岗岩类相关联。这些资料显示了具有矿化性质的石英闪长岩的幔壳混合源。石英闪长岩和微闪长斑岩的地球化学特征显示出钙碱性亲和作用，与俯冲相关造山作用有关。根据黑云母和角闪孔地球化学特征，估计岩浆活动的氧逸度分别具有高（HM）至中等（NNO）特征。基于黑云母地球化学的log f(H2O)/f(HF) >； 1和log f(H2O)/f(HCl) >； 1表明矿化流体相对富水。石英闪长岩和微闪长岩的斜长石在Na2O + K2O + CaO (wt%)-SiO2图上的数据点位于钙长岩和钠长岩之间。这些资料中的过量铝不是蚀变的结果，而是由高PH2O岩浆引起的。黑云母化学表明，石英闪长岩岩浆成矿作用发生在钾蚀变带一个相对封闭的体系内。矿化呈藤蔓状，以黄铜矿和黄铁矿为主。在成矿条件和物理化学推断结果方面，分析样品的黑云母化学与UDMA其他肥沃矿床的黑云母化学结果一致。总的来说，本研究的硅酸盐地球化学特征表明Kuh-e-Kapout岩浆-热液系统的物理化学性质与其他UDMA铜斑岩矿床相似。

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引用次数: 0