Microbeam Analysis Characterization in Petrogenesis and Ore Deposit

A special issue of Minerals (ISSN 2075-163X). This special issue belongs to the section "Mineral Geochemistry and Geochronology".

Deadline for manuscript submissions: closed (25 June 2024) | Viewed by 16217

Special Issue Editors


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Guest Editor
Institute of Mineral Resources, Chinese Academy of Geological Sciences, Beijing 100037, China
Interests: genetic and prospecting mineralogy; microbeam analysis technique and its standardization
Special Issues, Collections and Topics in MDPI journals

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Guest Editor
School of Resources and Environmental Engineering, Hefei University of Technology, Hefei 230009, China
Interests: application of LA-ICP-MS in Earth science; mineral geochemistry; magmatic rocks and metallogenesis

Special Issue Information

Dear Colleagues,

Major breakthroughs in modern geosciences research depend largely on the innovation of observation and analytical technologies. Microbeam analysis is used to accurately analyze the phase, morphology, structure, chemical and isotopic composition of minerals on the micrometer–nanometer scale. According to different primary beam types, microbeam analysis techniques can be divided into the following four categories: (1) electron beam-related microbeam analysis techniques, including electron probes (EPMA), scanning electron microscopes (SEM) and transmission electron microscopes (TEM); (2) laser beam-related microbeam analysis technology, including laser ablation inductively coupled plasma mass spectrometry (LA-Q/HR/MC-ICPMS) and laser-induced atom probes (LI-APT), etc.; (3) ion beam-related microbeam analysis techniques, including secondary ion mass spectrometry (SIMS) and time-of-flight secondary ion mass spectrometry (TOF SIMS), etc.;  (4) X-ray and other beam-related analysis techniques, such as micro-X-ray fluorescence (µXRF), micro-X-ray diffraction (µXRD), micro-infrared spectroscopy (FT-IR), synchrotron radiation (SR), etc. Microbeam analysis has not only resulted in many important technological advances and methodological innovations, but it has also been widely used in various fields of earth science, especially in petrogenesis and ore deposit, which has greatly improved our understanding of the formation of minerals and many geological processes. This Special Issue aims to contribute to the progress of various microbeam analytical technologies and methods, and their applications in mineralogy and ore deposits, including the characterization of Earth and extraterrestrial materials.

Dr. Zhenyu Chen
Dr. Fangyue Wang
Guest Editors

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Keywords

  • electron beam-related microbeam analysis
  • laser beam-related microbeam analysis
  • ion beam-related microbeam analysis
  • x-ray and other beam-related analysis techniques
  • advances in microbeam analysis method
  • new applications of microbeam analysis in petrology and ore deposit research
  • characterization of earth and extraterrestrial materials

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Published Papers (10 papers)

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Research

23 pages, 8354 KiB  
Article
The Discovery of the New UHP Eclogite from the East Kunlun, Northwestern China, and Its Tectonic Significance
by Feng Chang, Guibin Zhang and Lu Xiong
Minerals 2024, 14(6), 582; https://doi.org/10.3390/min14060582 - 31 May 2024
Viewed by 719
Abstract
The East Kunlun Orogenic Belt (EKOB), northwestern China, recording long-term and multiple accretionary and collisional events of the Tethyan Ocean, belongs to a high-pressure to ultra-high-pressure (HP-UHP) metamorphic belt that underwent complex metamorphic overprinting in the early Paleozoic. In this contribution, we carry [...] Read more.
The East Kunlun Orogenic Belt (EKOB), northwestern China, recording long-term and multiple accretionary and collisional events of the Tethyan Ocean, belongs to a high-pressure to ultra-high-pressure (HP-UHP) metamorphic belt that underwent complex metamorphic overprinting in the early Paleozoic. In this contribution, we carry out an integrated study, including field investigations, petrographic observations, whole-rock analyses, zircon U-Pb dating, and P-T condition modeling using THERMOCALC in the NCKFMASHTO system for the eclogites, especially for the newly discovered UHP eclogite in the eastern part of EKOB. The eclogites exhibit geochemistry ranging from normal mid-ocean ridge basalt (N-MORB) to enriched mid-ocean ridge basalt (E-MORB). Zircons from the eclogites yield metamorphic ages of 416–413 Ma, indicating the eclogite facies metamorphism. Coesite inclusions in garnet and omphacite and quartz exsolution in omphacite and pseudosection calculation suggest that some eclogites experienced UHP eclogite facies metamorphism. The eclogites from the eastern part of EKOB record peak conditions of 29–33 kbar/705–760 °C, first retrograde conditions of 10 kbar at 9.5–12.5 kbar/610–680 °C, and second retrograde conditions at ~6 kbar/<600 °C. New evidence of the early Paleozoic UHP metamorphism in East Kunlun is identified in our study. Thus, we suggest that these eclogites were produced by the oceanic crust subducting to the depth of 100 km and exhumation. The presence of East Gouli and Gazhima eclogites in this study and other eclogites (430–414 Ma) in East Kunlun record the final closure of the local branch ocean of the Proto-Tethys and the evolution from subduction to collision. Full article
(This article belongs to the Special Issue Microbeam Analysis Characterization in Petrogenesis and Ore Deposit)
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13 pages, 4396 KiB  
Article
Twinning Impact on the Structure and Hypotheses on the Growth Mechanism of Kermesite: Insights from Yunnan, China
by Hong Yu, Denghong Wang, Zeying Zhu, Wenyuan Li, Dong Wang, Zhenyu Chen, Yike Li and Changhui Ke
Minerals 2024, 14(5), 505; https://doi.org/10.3390/min14050505 - 10 May 2024
Viewed by 876
Abstract
Kermesite (Sb2S2O), a needle-like unstable secondary oxysulfide, has made visible advancements in optimizing its triclinic crystal system through twinning discovery. However, research on twinning behavior at micro and nano scales, including its growth mechanisms and impact on kermesite morphologies, [...] Read more.
Kermesite (Sb2S2O), a needle-like unstable secondary oxysulfide, has made visible advancements in optimizing its triclinic crystal system through twinning discovery. However, research on twinning behavior at micro and nano scales, including its growth mechanisms and impact on kermesite morphologies, remains notably scarce. Our study focuses on kermesite crystal clusters from a private collection in Yunnan, China, confirming the chemical formula as Sb2S1.97O1.03 through EPMA. Single-crystal XRD yielded refined unit cell parameters (a = 8.153(5) Å, b = 10.717(7) Å, c = 5.796(3) Å; α = 102.836(10)°, β = 110.556(8)°, γ = 100.999(12)°), revealing space group P1¯ with Z = 4 and indicating twinning with a ratio of 27.4%. Remarkably, a Transmission Electron Microscope (TEM) provided the first direct observation of twinning in natural kermesite, revealing rotational twins with varying widths and lengths (ranging from 100 nm to several millimeters). Analysis and simulation elucidated that rotational twins, generated by a 180° rotation, align with the mineral’s elongation direction along the [Sb2S2O4]n chains (a-axis), challenging the conventional long-axis direction (b-axis) for crystal growth. This study proposes a symbiotic relationship between kermesite growth and twinning, suggesting that the observed X-shaped growth in crystal clusters results from the collaboration of single crystals (growing along b) and twins (growing along a) in the unit cell. These findings contribute to our understanding of kermesite’s structural complexities and the potential growth and formation mechanism of crystal clusters. Full article
(This article belongs to the Special Issue Microbeam Analysis Characterization in Petrogenesis and Ore Deposit)
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22 pages, 15317 KiB  
Article
A New Insight into the Genesis of Graphite Deposits in Madagascar Using U–Pb Zircon Dating and Electron Microprobe Analysis
by Ming-Jian Yang, Yong-Jun Di, Da Zhang, Da-Tian Wu, Ye Fang and Xin-Ming Zhang
Minerals 2024, 14(5), 484; https://doi.org/10.3390/min14050484 - 2 May 2024
Viewed by 1293
Abstract
Madagascar is globally recognized as an important producer of high-quality flaky graphite. However, current research on graphite deposits in Madagascar remains insufficient. Previous studies have linked the genesis of Madagascan graphite deposits to the metamorphism of sedimentary organic matter. Here, we provide a [...] Read more.
Madagascar is globally recognized as an important producer of high-quality flaky graphite. However, current research on graphite deposits in Madagascar remains insufficient. Previous studies have linked the genesis of Madagascan graphite deposits to the metamorphism of sedimentary organic matter. Here, we provide a case study of graphite deposits in Madagascar, combining new data from the Ambahita graphite deposit (AMG) in southern Madagascar with data from the Antanisoa graphite deposit (ANG) in central Madagascar and the Vohitasara graphite deposit (VOG) on the east coast of Madagascar. We note that the mineral assemblages of graphite-bearing rocks in the AMG, ANG, and VOG are not typical of metamorphic mineral assemblages but rather the results of filling and metasomatism by mantle-derived fluids that occurred after peak metamorphism. Electron microprobe analysis indicates that the graphite of the AMG, VOG, and ANG is usually associated with phlogopite or Mg-biotite; the phlogopite shares a common genesis with other widespread phlogopite deposits across Madagascar. We reveal that the distribution of graphite deposits in Madagascar is primarily controlled by ductile shear zones between blocks. Ductile shear zones that extend deep into the mantle can provide an ideal migration channel and architecture for the emplacement of mantle-derived fluids. The graphite mineralization formed no earlier than the peak metamorphism (490 Ma) and no later than the intrusion of pegmatite veins (389 ± 5 Ma). The distribution of graphite deposits, graphite orebody morphologies, mineral associations, and geochemical data suggest that the genesis of graphite deposits in Madagascar is linked to mantle-derived fluid filling rather than the metamorphism of sediments, as previously suggested. These findings have important implications for similar deposits in Madagascar and potentially globally. Full article
(This article belongs to the Special Issue Microbeam Analysis Characterization in Petrogenesis and Ore Deposit)
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13 pages, 8248 KiB  
Article
Zircon as a Monitoring Tool for the Magmatic–Hydrothermal Process in the Granitic Bedrock of Shitouping Ion-Adsorption Heavy Rare Earth Element Deposit, South China
by Liangxin Gong, Xianguang Wang, Defu Zhang, Wen Zhong and Mingxuan Cao
Minerals 2023, 13(11), 1402; https://doi.org/10.3390/min13111402 - 31 Oct 2023
Cited by 1 | Viewed by 1446
Abstract
The Shitouping pluton in Jiangxi Province, southern China, hosts an ion-adsorption heavy rare earth element (HREE) deposit identified by a recent geological survey. This study reveals the HREE pre-enrichment mechanism during the magmatic–hydrothermal process of granitic bedrock based on the comprehensive study of [...] Read more.
The Shitouping pluton in Jiangxi Province, southern China, hosts an ion-adsorption heavy rare earth element (HREE) deposit identified by a recent geological survey. This study reveals the HREE pre-enrichment mechanism during the magmatic–hydrothermal process of granitic bedrock based on the comprehensive study of zircon structure and composition. Zircon from the Shitouping pluton, composed of syenogranite and monzogranite, can be categorized into three types based on structure and compositions. The Type-1 zircons, the predominate type in monzogranite, are early magmatic zircons with prismatic crystals and bright oscillatory zoning in CL images. In contrast, the late magmatic-hydrothermal zircons (Type-2 and Type-3) mainly occur in the syenogranite. The Type-2 zircons occur as dark CL images and euhedral crystals crystallized during the late magmatic stage. The Type-3 zircons with irregular zoning and abundant mineral inclusions in BSE images are possibly formed via intense hydrothermal alteration during the hydrothermal stage. The increase in Y/Ho ratios from Type-1 to Type-3 zircon indicates that the Shitouping syenogranites underwent magmatic to hydrothermal evolution. Compared with Type-1 and Type-2 zircons, Type-3 zircons exhibit the highest concentrations of F and HREEs. The significant increase in HREE concentrations both in zircons and bulk-rock composition of syenogranite can be attributed to the introduction of HREE-rich fluids during magma evolution. Therefore, we propose that the increase in HREE contents in zircon reflect the exsolution of HREE-rich fluids during a late stage in the magma evolution, which is an important factor controlling HREE enrichment in Shitouping syenogranites and furthermore in the generation of ion-adsorption HREE deposits. Full article
(This article belongs to the Special Issue Microbeam Analysis Characterization in Petrogenesis and Ore Deposit)
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15 pages, 9926 KiB  
Article
Supergene Hydrous Sulfates in the Tuolugou Co-Au Deposit, Northern Qinghai–Tibet Plateau: Implications for Genetic Mechanism and Exploration
by Sida Niu, Huaying Wu, Jianpeng Zhang, Xianglong Niu, Yingchao Wang, Xiaoju Lin, M. Santosh and Jiahao Chen
Minerals 2023, 13(9), 1198; https://doi.org/10.3390/min13091198 - 13 Sep 2023
Cited by 1 | Viewed by 1000
Abstract
Supergene hydrous sulfate minerals form through the oxygenation and weathering of primary sulfides. In the Qinghai–Tibet Plateau region, with an alpine and dry environment, hydrous sulfate minerals oxidized from pyrite-bearing ore bodies provide important clues regarding the mineralization and environment. The Tuolugou sedimentary-exhalative [...] Read more.
Supergene hydrous sulfate minerals form through the oxygenation and weathering of primary sulfides. In the Qinghai–Tibet Plateau region, with an alpine and dry environment, hydrous sulfate minerals oxidized from pyrite-bearing ore bodies provide important clues regarding the mineralization and environment. The Tuolugou sedimentary-exhalative (SEDEX) Co-Au deposit is located in the East Kunlun metallogenic belt of the northern Qinghai–Tibet Plateau in China. In the mining district, pyrite is the prevalent Co-hosting sulfide mineral, and is partially exposed on the surface to weathering and oxidation. Herein, we document the mineral assemblages in the supergene oxidation zone in the Tuolugou deposit, probe the genesis of supergene assemblage, and explore the implications for exploration. Three zones can be recognized in the oxidation zone of the Tuolugou deposit, including the outer zone (natrojarosite), intermediate zone (rozenite and aplowite), and inner zone (roemerite and melanterite). The mechanism of oxidation under aerobic and anaerobic conditions, as well as zoning with different oxidation degrees, are described in detail. Hydrous sulfates such as natrojarosite can be used as possible indicators of the exploration of albitite-related SEDEX deposit in this region. Full article
(This article belongs to the Special Issue Microbeam Analysis Characterization in Petrogenesis and Ore Deposit)
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20 pages, 9814 KiB  
Article
Contraints on Petrogenesis and Fe Fertility of Intrusive Complexes in the Han–Xing Region, North China Craton from Apatite Geochemistry
by Xian Liang, Fangyue Wang, Juquan Zhang, Long Zhang, Junwu Zhang and Jingui Wang
Minerals 2023, 13(4), 469; https://doi.org/10.3390/min13040469 - 26 Mar 2023
Cited by 4 | Viewed by 1820
Abstract
The Han–Xing (Handan–Xingtai) region is famous for its endowment of skarn iron deposits in China. These deposits are mainly spatially and genetically associated with diorite rocks, but these rocks show different Fe ore potential. Major and trace elements composition of apatite from the [...] Read more.
The Han–Xing (Handan–Xingtai) region is famous for its endowment of skarn iron deposits in China. These deposits are mainly spatially and genetically associated with diorite rocks, but these rocks show different Fe ore potential. Major and trace elements composition of apatite from the Kuangshan and Fushan diorite complexes were investigated to explore the potential of apatite as a proxy of petrogenesis and Fe fertility of these rocks. All the investigated apatite grains are identified as fluorapatite, which is typical for magmatic apatite. The Sr, Y, Mn, and Heavy Rare Earth Elements (HREE) contents of apatite in the Kuangshan diorite complex are positively correlated with the increase of melt SiO2 content compared to that in the Fushan diorite complex. Apatite geochemistry indicates that magmas of the Fushan complex mainly experienced the fractional crystallization of hornblende in the deep crustal reservoirs, whereas the Kuangshan complex has experienced the fractional crystallization of hornblende in the deep and the shallow plagioclase fractional crystallization. The F, Cl and S content of the Kuangshan complex estimated by apatite volatile (F = 2632 ppm, Cl = 4100 ppm, SO3 = 140 ppm) is significantly higher than that of the Fushan complex (F = 2488 ppm, Cl = 3400 ppm, SO3 = 90 ppm). The Eu, Ce anomalies, Mn, and SO3 contents of apatite show that both of the two complexes have higher oxygen fugacity (Δ FMQ), but the oxygen fugacity of the Kuangshan complex calculated by Mn and SO3 content (Δ FMQ + 2.41) is higher than that of the Fushan complex (Δ FMQ + 1.77), which may also be one of the reasons for the great difference in ore-forming scale between the two complexes. Our results suggest that the high volatile contents and oxidation states of magma estimated by apatite, as well as the lower Sr/Y in apatite reflect favorable conditions for skarn iron mineralization. Therefore, our study shows that magmatic apatite geochemistry may be a useful tool to distinguish the Fe fertility of plutonic rocks related to skarn deposits. Full article
(This article belongs to the Special Issue Microbeam Analysis Characterization in Petrogenesis and Ore Deposit)
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14 pages, 4868 KiB  
Article
Mineralogical Evidence for Hydrothermal Uranium Mineralization: Discovery and Genesis of the Uranyl Carbonate Minerals in the BLS U Deposit, SW Songliao Basin, Northeast China
by Bo Ding, Hongxu Liu, Deru Xu, Linfei Qiu and Weihong Liu
Minerals 2023, 13(3), 339; https://doi.org/10.3390/min13030339 - 28 Feb 2023
Cited by 4 | Viewed by 1504
Abstract
Diabase intrusions have been widely found in sandstone-type U deposits of the southwestern Songliao Basin, indicating diabase-related hydrothermal fluids might play an important role in this type of U mineralization. The first discovery of U-bearing carbonate minerals in the BLS U deposit provides [...] Read more.
Diabase intrusions have been widely found in sandstone-type U deposits of the southwestern Songliao Basin, indicating diabase-related hydrothermal fluids might play an important role in this type of U mineralization. The first discovery of U-bearing carbonate minerals in the BLS U deposit provides an opportunity for understanding hydrothermal U mineralization and its relationship to diabase intrusions. U-bearing carbonate minerals occurred as thin shells generally ringing ankerite and then surrounded by colloidal pyrite through examination of scanning electron microscopy and energy dispersive spectroscopy. They can be interpreted as uranyl carbonate minerals, with the empirical formula of Ca2.7Fe0.9Mg0.4 (UO2) (CO3)5•9.6H2O, based on infrared absorption spectroscopy and electron microprobe. The formation of uranyl carbonate minerals is most likely related to the CO2-rich hydrothermal fluids from diabase intrusions according to its occurrence state, but the key factors are that the Ca-UO2-CO3 ternary complexes should have been produced in ore-forming hydrothermal fluids and adsorption of ankerite on ternary complexes. Thereby, a potential diabase-related hydrothermal U mineralization model for sandstone-type U deposits can be proposed. The ore-forming fluids that originated from diabase-related hydrothermal are formed through continuously extracting the adsorbed U6+ and dissolving the early U minerals. Then, U in the ore-forming hydrothermal fluids was migrated and transported probably either as uranyl carbonate ions or as Ca-UO2-CO3 ternary complexes. The former is easy to precipitate in the form of pitchblende dispersed in the fossil wood cells, ringing pyrite, and occurring along the edge of adsorbents at the site of reducing capacity change, while the latter will extremely inhibit the reduction of U6+, eventually leading to the precipitation of uranyl carbonate minerals ringing ankerite by adsorption. The above research results can provide mineralogical evidence for hydrothermal U mineralization in sandstone-type U deposits of the Songliao Basin. Full article
(This article belongs to the Special Issue Microbeam Analysis Characterization in Petrogenesis and Ore Deposit)
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16 pages, 5925 KiB  
Article
Application of Spectroscopic Characteristics of White Mica in Porphyry Tungsten Deposits: A Case Study Involving the Shimensi Deposit in Northern Jiangxi
by Zhongxue Zhang, Jingjing Dai, Xianguang Wang, Zhenghua Hu, Xin Wan, Bo Peng and Minghai Fu
Minerals 2023, 13(2), 256; https://doi.org/10.3390/min13020256 - 11 Feb 2023
Cited by 1 | Viewed by 2123
Abstract
Shortwave infrared (SWIR) technology is characterized by high efficiency and convenience and is widely used in the mineral exploration of porphyry, epithermal, and skarn types. However, studies on the SWIR spectral features of porphyry tungsten deposits are still lacking. The Dahutang tungsten deposit [...] Read more.
Shortwave infrared (SWIR) technology is characterized by high efficiency and convenience and is widely used in the mineral exploration of porphyry, epithermal, and skarn types. However, studies on the SWIR spectral features of porphyry tungsten deposits are still lacking. The Dahutang tungsten deposit has reached an ultra large scale, characterized by the porphyry type. Based on the SWIR spectral features of white mica and its petrographic, geochemical, and Raman spectral features, this paper discusses the use of shortwave infrared and Raman spectral features and major and trace element contents in white mica for exploration of the Shimensi mine in Dahutang. The results showed that the SWIR wavelength of the single-frequency Al-O-H absorption peak position (Pos2200) of white micas in ore-bearing intrusions were over 2209 nm; the Raman shift of aluminium atom bridge-bonds (Al, O (br)) were mainly located between 410 and 420 cm−1. The contents of Si, Fe, and Mg were relatively high; the contents of Al, Na, and K were low; and the variation of the Nb/Ta value reflected the magmatic evolution degree. The shift of Pos2200 of white mica showed a correlation with the Raman spectral features and contents of Si, Al, and other elements. This study shows that the SWIR spectral features of white mica were useful for further exploration of the Shimensi area in Dahutang and provided a potential tool for the exploration of porphyry tungsten deposits. Full article
(This article belongs to the Special Issue Microbeam Analysis Characterization in Petrogenesis and Ore Deposit)
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20 pages, 18687 KiB  
Article
Provenance of Ordovician Malieziken Group, Southwest Tarim and Its Implication on the Paleo-Position of Tarim Block in East Gondwana
by Zhe Chang, Zhiqian Gao, Liangliang Zhang, Tailiang Fan, Duan Wei and Jingbin Wang
Minerals 2023, 13(1), 42; https://doi.org/10.3390/min13010042 - 27 Dec 2022
Cited by 2 | Viewed by 1934
Abstract
Tarim is inferred to have a close connection with East Gondwana during the Ordovician, but the position in East Gondwana remains controversial. In this study, we report 316 detrital zircons U-Pb data from three samples of Ordovician Malieziken Group sedimentary rocks, collected in [...] Read more.
Tarim is inferred to have a close connection with East Gondwana during the Ordovician, but the position in East Gondwana remains controversial. In this study, we report 316 detrital zircons U-Pb data from three samples of Ordovician Malieziken Group sedimentary rocks, collected in the Qiate Section, Southwest Tarim, provided new insight into the position of Tarim in East Gondwana. Detrital zircons data indicated the maximum depositional age for the three samples is 489.5 Ma, 478.1 Ma, and 465 Ma, respectively, indicating the Qiate and Kandilike Formation of the Malieziken Group was deposited in Early—Middle Ordovician. The detrital zircons are characterized by two main peaks at ~490 Ma and ~1100 Ma, and three subordinate peaks at ~880 Ma, ~1400 Ma, and ~1650 Ma, suggesting most of the detritus of Malieziken Group from the South Kunlun Terrane (SKT) itself. However, the source of the ~1650 Ma peak is not found in the Tarim block, and the ~1400 Ma and the ~1650 Ma peak are absent in the middle of the three samples, which implied that there is an exotic source. The Paleoproterozoic sediment strata in the Albany–Fraser belt shows dominant peaks at ~1400 Ma and ~1650 Ma may have been transported to SKT and redeposited in the Malieziken Group during the Ordovician. The Malieziken Group shows detrital zircon age patterns resembling those of East Sumatra, Lhasa, and Western Australia which, in combination with the Albany–Fraser belt provenance, enables us to propose that the Tarim block has a close linkage with Western Australia, East Sumatra, and Lhasa in East Gondwana. Full article
(This article belongs to the Special Issue Microbeam Analysis Characterization in Petrogenesis and Ore Deposit)
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15 pages, 3324 KiB  
Article
A Study on the Raman Spectral Characteristics of Garnet from the Jiama Copper Polymetallic Deposit in Tibet
by Minghai Fu, Jingjing Dai and Longxian Zhao
Minerals 2022, 12(12), 1578; https://doi.org/10.3390/min12121578 - 9 Dec 2022
Cited by 2 | Viewed by 1804
Abstract
Raman spectroscopy is an important method to analyze and measure mineral composition and structure, which has the advantages of being non-destructive and rapid. This study considered garnet from the Jiama copper polymetallic deposit in Tibet to carry out micro-Raman spectrum and electron microprobe [...] Read more.
Raman spectroscopy is an important method to analyze and measure mineral composition and structure, which has the advantages of being non-destructive and rapid. This study considered garnet from the Jiama copper polymetallic deposit in Tibet to carry out micro-Raman spectrum and electron microprobe research to analyze the Raman spectrum characteristics of garnet with different components to reveal its indicative significance for garnet composition and skarn mineralization. The results showed that the Raman peaks T, X, A1, A2, and A3 shift toward lower wavenumber with the increase in andradite (And) content. The variations in T, X, and A2 are more obvious than those of A1 and A3. When And > 50%, the three Raman peaks (T, X, and A2) range are 173–174, 234–239, 513–525 cm−1; when And < 50%, they are 177–178, 240–244, 527–543 cm−1. The Raman peaks also shift with the cation radius and relative atomic mass. Different peaks moved in the low-frequency direction with the increase in the X2+ and Y3+ radius, and the X2+ atomic mass. The Raman spectrum can indicate the composition change in garnet. Raman spectrum analysis of garnet is of great significance for skarn zoning and prospecting. Full article
(This article belongs to the Special Issue Microbeam Analysis Characterization in Petrogenesis and Ore Deposit)
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