Thermal History and Preservation Mechanisms of Porphyry-Cu Deposits: Evidence from Thermochronology, Mineral and Isotopic Geochemistry

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

Deadline for manuscript submissions: closed (31 March 2026) | Viewed by 7631

Special Issue Editors


E-Mail
Guest Editor
MNR Key Laboratory of Metallogeny and Mineral Assessment, Institute of Mineral Resources, Chinese Academy of Geological Sciences, Beijing 100037, China
Interests: preservation mechanism of deposit; thermochronology; mineral geochemistry; mineral exploration

E-Mail
Guest Editor
Chengdu Center, China Geological Survey, Chengdu 610081, China
Interests: geochronology; isotope geochemistry; mineral exploration

E-Mail Website
Guest Editor
College of Earth and Planetary Sciences, Chengdu University of Technology, Chengdu 610059, China
Interests: fluid inclusion in hydrothermal ore deposit; mineralogy; mineral exploration

Special Issue Information

Dear Colleagues,

The porphyry Cu deposit is one of the world’s largest and most valuable mines supplying much of the world’s copper, molybdenum, gold, silver, rhenium, tellurium, selenium, and mercury. It is the most explored and researched ore deposit over the last century. However, the preservation mechanisms of the ore body remain unclear, which severely inhibits the mineral exploration of the porphyry Cu deposit.

The distribution of mineral deposits is largely the result of the combined effects of burial, uplift, and erosion. Porphyry deposits worldwide have typical Phanerozoic ages, with the majority being Mesozoic Cenozoic deposits. The early-formed mineral deposits are likely to have been eroded and damaged, making them unable to be preserved. Geochronology, thermochronology, mineral geochemistry, and isotopic geochemistry are important ways to study the modification, telescoping, and preservation processes of the porphyry Cu deposit. Understanding the thermal history and preservation mechanisms is crucial for mineral exploration.

This Special Issue invites contributions that apply geochronology, thermochronology, mineral and isotopic geochemistry to study the formation, telescoping, modification, and preservation of porphyry Cu deposits and provide mineral exploration instructions. We encourage original and review papers covering novel techniques, developments, and applications in thermochronology, mineral and isotopic geochemistry.

Dr. Huanhuan Yang
Dr. Zhi Zhang
Dr. Yong Wang
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 250 words) can be sent to the Editorial Office for assessment.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Minerals is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2400 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • porphyry Cu deposits
  • geological characteristics of deposits
  • mineral system
  • thermochronology study
  • telescoping and modification process of deposits
  • preservation mechanisms
  • mineral exploration

Benefits of Publishing in a Special Issue

  • Ease of navigation: Grouping papers by topic helps scholars navigate broad scope journals more efficiently.
  • Greater discoverability: Special Issues support the reach and impact of scientific research. Articles in Special Issues are more discoverable and cited more frequently.
  • Expansion of research network: Special Issues facilitate connections among authors, fostering scientific collaborations.
  • External promotion: Articles in Special Issues are often promoted through the journal's social media, increasing their visibility.
  • Reprint: MDPI Books provides the opportunity to republish successful Special Issues in book format, both online and in print.

Further information on MDPI's Special Issue policies can be found here.

Published Papers (8 papers)

Order results
Result details
Select all
Export citation of selected articles as:

Research

18 pages, 12803 KB  
Article
Geochemistry of Chlorite from the North Zegulang Ore Block of the Jiama Deposit, Tibet: Implications for Fluid Evolution and the Mineralization Center
by Jun Zhong, Juxing Tang, Brant Wang, Pan Tang, Bin Lin, Yixuan Li, Mengdie Wang, Jing Qi, Zhichao Wang, Shuhui Xu and Yuke Xie
Minerals 2026, 16(5), 508; https://doi.org/10.3390/min16050508 (registering DOI) - 12 May 2026
Abstract
Jiama is a significant porphyry system in Tibet’s Gangdese Metallogenic Belt, characterized by a typical composite system with multicenter mineralization. The North Zegulang Ore Block, a recently identified mineralization center in the Jiama mining area, has remained understudied, particularly regarding its ore-forming fluid [...] Read more.
Jiama is a significant porphyry system in Tibet’s Gangdese Metallogenic Belt, characterized by a typical composite system with multicenter mineralization. The North Zegulang Ore Block, a recently identified mineralization center in the Jiama mining area, has remained understudied, particularly regarding its ore-forming fluid evolution. This study integrates microscopic identification, EPMA, and LA-ICP-MS to investigate the mineral chemistry of widely developed chlorite in the North Zegulang Ore Block, aiming to elucidate fluid evolution and its implications for identifying the mineralization center. Chlorite in the North Zegulang Ore Block is genetically classified into retrograde (Chl-1) and hydrothermal (Chl-2) types. Both are Fe-rich varieties, indicating formation under reducing conditions. Element substitution is dominated by Fe2+-Mg2+ exchange, accompanied by Tschermak and di-trioctahedral substitutions. The chlorite geothermometer yields formation temperatures of 260–400 °C and log fO2 values of −38 to −26 for Chl-1, while Chl-2 shows a wider temperature range of 220–400 °C and log fO2 values of −42 to −20, reflecting a medium-temperature, low-oxygen-fugacity environment. Outward from the granodiorite porphyry, fluid temperature decreases and Cu-Mo grades gradually decrease, confirming the intrusion as the mineralization center. With increasing distance from the mineralization center, chlorite Mg/Sr, Ti/Sr, and Ti/Pb ratios progressively decrease, whereas Th/U ratios and Sr, Th, U, and B contents increase. These systematic variations demonstrate that chlorite serves as an effective exploration tool in collisional-type porphyry systems. Full article
Show Figures

Figure 1

17 pages, 6348 KB  
Article
Geochemistry of Metal Sulfides from the Duolong Porphyry Cu-Au Deposit, Tibet: Implications for the Mineralization Process
by Qi Zhang, Huanhuan Yang, She Li, Qin Wang, Yujie Dong, Hongwei Li, Chao Yang, Changyun Gan, Rongkun Zhang, Xuelian Fu and Xinjuan Liang
Minerals 2026, 16(5), 478; https://doi.org/10.3390/min16050478 - 30 Apr 2026
Viewed by 232
Abstract
The Duolong porphyry copper–gold district, located in the northwestern segment of the Bangongco–Nujiang metallogenic belt on the southern margin of the South Qiangtang terrane (Tibet), hosts typical porphyry-style Cu-Au mineralization with well-defined alteration zoning from potassic through chlorite–sericite to propylitic assemblages. Based on [...] Read more.
The Duolong porphyry copper–gold district, located in the northwestern segment of the Bangongco–Nujiang metallogenic belt on the southern margin of the South Qiangtang terrane (Tibet), hosts typical porphyry-style Cu-Au mineralization with well-defined alteration zoning from potassic through chlorite–sericite to propylitic assemblages. Based on integrated in situ major/trace element and sulfur isotope analyses of pyrite and chalcopyrite from different alteration zones, we identify two discrete episodes of magmatic-hydrothermal activity that exerted distinct controls on metal endowment. Sulfur isotope signatures define a systematic evolution from the earliest, high-temperature potassic stage (δ³⁴S: Py-Ⅰ –3.70 to –1.16‰, mean –2.14‰; Cp-Ⅰ –4.92 to –0.90‰, mean –2.54‰) through propylitic alteration (Py-Ⅱ: 1.20–5.16‰, mean 3.06‰) to the later chlorite–sericite stage (Py-Ⅲ: –2.00 to 1.86‰, mean 0.06‰; Cp-Ⅱ: –2.50 to 0.58‰, mean –0.77‰), tracking progressive fluid cooling and changing fluid sources. Trace element systematics further discriminate these episodes: sulfides from potassic and chlorite–sericite zones are enriched in trace elements, whereas propylitic pyrite is depleted, with potassic pyrite recording the highest Cu concentrations (559–7256 ppm, mean 2302 ppm) and chlorite–sericite pyrite containing the lowest Au contents (0.01–0.59 ppm, mean 0.10 ppm). Gold mineralization occurs as native gold exsolved from chalcopyrite, and the markedly low Au concentrations in chlorite–sericite pyrite (0.01–0.59 ppm, mean 0.10 ppm) demonstrate that gold exsolution was largely completed during the first, high-temperature magmatic-hydrothermal stage. Collectively, these results establish a detailed geochemical framework linking sulfide composition to specific hydrothermal stages, providing new constraints on the processes of porphyry copper–gold mineralization in a collisional setting. Full article
33 pages, 18189 KB  
Article
Geochronology of the Magmatic Rocks in the Duobaoshan Porphyry Cu-Mo Deposit in the Great Xing’an Range: Implication for the Metallogenic Epochs and Related Geodynamics
by Baoshan Liu, Linlin Kou, Chunpeng Zhang, Renping Han, Wanbing Song and Ri Han
Minerals 2026, 16(4), 341; https://doi.org/10.3390/min16040341 - 24 Mar 2026
Viewed by 357
Abstract
The Duobaoshan porphyry copper–molybdenum deposit is located in the Great Xing’an Range, eastern segment of the Xing-Meng orogenic belt. It is the largest porphyry Cu-Mo deposit in NE China. Based on the contact relations of intrusive rocks and the results of LA-ICP-MS zircon [...] Read more.
The Duobaoshan porphyry copper–molybdenum deposit is located in the Great Xing’an Range, eastern segment of the Xing-Meng orogenic belt. It is the largest porphyry Cu-Mo deposit in NE China. Based on the contact relations of intrusive rocks and the results of LA-ICP-MS zircon U-Pb ages, we found that there were five stages of magmatism in the mining area, including the Early Ordovician (478.1 ± 3.2 Ma) granodiorite, the Middle Ordovician (462.1 ± 3.3 Ma, 459.5 ± 2.3 Ma) granodiorite porphyry, the Late Triassic (226.3 ± 0.4 Ma) oligoclase granite, the Middle Jurassic (170.1 ± 5.6 Ma) andesitic porphyrite, and the Early Cretaceous (118.1 ± 6.6 Ma) diorite. The Early and Middle Ordovician granodiorite and granodiorite porphyry are the principal host rocks for the mineralization in the deposit. However, Cu-Mo mineralization was also observed within the Late Triassic oligoclase granite, indicating that there are two stages of Cu-Mo mineralization in the Duobaoshan deposit. Combined with the previously reported Late Triassic skarn Cu mineralization occurring in the Xiaoduobaoshan deposit, and the Early Jurassic skarn Cu mineralization in the Sankuanggou and Yubaoshan deposits, we conclude that there are four metallogenetic stages in the Duobaoshan ore-concentration area. Regionally, there are five stages of Cu-Mo mineralization occurring in the northern Great Xing’an Range, including the Ordovician, Late Triassic, Early Jurassic, Late Jurassic, and Early Cretaceous. After discussing the tectonic setting for the generation of these deposits, we propose that the Duobaoshan ore-concentration area was influenced by the subduction of the Paleo-Asian Ocean, Mongol-Okhotsk, and Paleo-Pacific Plates during the Phanerozoic. Full article
Show Figures

Figure 1

31 pages, 6575 KB  
Article
Mineralogical Characteristics of Magnetite in the Duobuza Porphyry Copper (Gold) Deposit and Their Geological Implications
by Xuelian Fu, Changyun Gan, She Li, Qin Wang, Yujie Dong, Hongwei Xia, Qi Zhang, Rongkun Zhang and Xinjuan Liang
Minerals 2026, 16(3), 288; https://doi.org/10.3390/min16030288 - 9 Mar 2026
Viewed by 396
Abstract
Magnetite is extensively developed within various alteration zones of the mining district. Some magnetite is closely associated with copper mineralization, possessing significant research value. The Duobuza Cu (Au) deposit is a typical porphyry-type deposit within the Bangong Co-Nujiang metallogenic belt and was the [...] Read more.
Magnetite is extensively developed within various alteration zones of the mining district. Some magnetite is closely associated with copper mineralization, possessing significant research value. The Duobuza Cu (Au) deposit is a typical porphyry-type deposit within the Bangong Co-Nujiang metallogenic belt and was the first porphyry Cu-Au deposit discovered in the Duolong copper–gold ore district. Currently, this deposit contains copper resources exceeding 3 million tons @0.46%, with associated gold resources exceeding 80 tons @0.19 g/t. This study focuses on magnetite from the Duobuza deposit. Through field geological logging and microscopic identification combined with electron microprobe analysis (EMPA) and in situ LA-ICP-MS testing, mineralogical and mineral chemical research on magnetite is conducted. This research aims to elucidate the genesis of magnetite in the Duobuza deposit and its implications for mineral exploration. Five magnetite types with different occurrences can be distinguished in the Duobuza deposit: Mt1 is magmatic magnetite; Mt2, Mt3, Mt4, and Mt5 are hydrothermal magnetite, with Mt5 being closely associated with copper mineralization. Mt1 is relatively enriched in Ti, V, Al, and Cr but depleted in Mn and Si; Mt2 is relatively enriched in Ti and Al but depleted in Si and Cr; Mt3 is relatively enriched in Al but depleted in Mg; Mt4 is relatively enriched in Ti, Al, V, Zn, and Mn; and Mt5 is relatively enriched in Mg, Si, Ti, Al, Mn, and Zn but depleted in Cr. Based on the Al + Mn vs. Ti + V discrimination diagram, magnetite formed in a medium- to high-temperature environment, with hydrothermal magnetite Mt4 forming at the lowest temperature. Vanadium (V) content can be used to estimate the oxygen fugacity (fO2) during mineralization. Mt1 exhibits the highest V content, indicating relatively low oxygen fugacity, whereas Mt4 shows the lowest V content, suggesting relatively high oxygen fugacity. Mt5 has a higher V content compared to other early-stage hydrothermal magnetites, suggesting that a lower fO2 formation environment favors the precipitation of metal sulfides in the mining district. Trace element analysis of magnetite from the Duobuza, Bolong, and Naruo mining districts reveals that magnetite from all three deposits is enriched in Si and Al and depleted in Ca and Ni. Magmatic magnetite from the Naruo and Duobuza deposits exhibits similar elemental distribution patterns. Hydrothermal magnetite from the Duobuza deposit shows significantly higher Ti and V contents compared to magnetite from the Bolong and Naruo deposits. Full article
Show Figures

Figure 1

17 pages, 6008 KB  
Article
Small-Scale Porphyry Cu (Au) Systems in Collisional Orogens: A Case Study of the Xifanping Deposit with Implications for Mineralization Potential in Western Yangtze Craton, SW China
by Yunhai Hu, Mimi Yang, Xingyuan Li, Guoxiang Chi and Fufeng Zhao
Minerals 2025, 15(9), 1001; https://doi.org/10.3390/min15091001 - 20 Sep 2025
Viewed by 898
Abstract
The Xifanping Cu–(Au) deposit, a small-scale porphyry system in the central Jinshajiang–Red River tectonic belt (JSRR), formed in a Cenozoic collisional setting. This study integrates zircon U–Pb geochronology, Lu–Hf isotopes, whole-rock geochemistry, and zircon trace element analyses of ore-bearing and barren porphyries, combined [...] Read more.
The Xifanping Cu–(Au) deposit, a small-scale porphyry system in the central Jinshajiang–Red River tectonic belt (JSRR), formed in a Cenozoic collisional setting. This study integrates zircon U–Pb geochronology, Lu–Hf isotopes, whole-rock geochemistry, and zircon trace element analyses of ore-bearing and barren porphyries, combined with regional comparisons, to constrain magma sources, metallogenic controls, and genetic processes. Ore-bearing biotite quartz monzonite porphyries were emplaced at 32.15 ± 0.43 Ma and 32.49 ± 0.57 Ma, post-dating barren quartz monzonite porphyry (33.15 ± 0.51 Ma). These ages are consistent with molybdenite Re–Os ages (32.1 ± 1.6 Ma), indicating near-synchronous magmatism and mineralization. Both porphyry types belong to the shoshonitic, peraluminous series, enriched in LILE, depleted in HFSE, enriched in LREE, and lacking significant Eu anomalies. Their εHf (t) values (–2.94 to +3.68) and crustal model ages (TDM2 = 0.88–1.30 Ga) indicate derivation from Neoproterozoic subduction-modified lower crust. Ore-bearing porphyries, however, exhibit higher zircon Ce4+/Ce3+ ratios (average = 584 vs. 228 for barren porphyries) and elevated hydrous mineral contents (>10 vol.% amphibole + biotite), indicating more oxidized and water-rich parental magmas. Compared with large-scale porphyry systems (e.g., Dexing, northern Chile), the absence of adakitic signatures and only moderate oxidation limited the scale of mineralization. Overall, the Xifanping deposit formed through partial melting of Neoproterozoic subduction-modified lower crust in a post-collisional extensional regime: at ~33.2 Ma, melting of metasomatized ancient lower crust generated barren porphyries; at ~32 Ma, further evolution and differentiation of this lower crust magmas led to the extraction and enrichment of ore-forming materials from the thicken lower crust, producing hydrated, oxidized, ore-bearing magmas that intruded at shallow levels to form base and precious metal mineralizations. These results underscore the distinctive metallogenic characteristics of small-scale porphyry systems in collisional settings and provide new insights into how source composition and magma oxidation state constrain mineralization potential. Full article
Show Figures

Figure 1

24 pages, 7393 KB  
Article
Thermodynamic Modeling Constrains the Alteration and Mineralization Patterns of the Pulang Porphyry Cu-Au Deposits in Eastern Tibet
by Shaoying Zhang, Wenyan He, Huaqing Wang and Yiwu Xiao
Minerals 2025, 15(8), 780; https://doi.org/10.3390/min15080780 - 25 Jul 2025
Viewed by 1621
Abstract
Thermodynamic simulations of fluid–rock interactions provide valuable insights into mineral deposit formation mechanisms. This study investigates the Pulang porphyry Cu-Au deposit in the Sanjiang Tethys Orogen, employing both Gibbs energy minimization (GEM) and the Law of mass action (LMA) method to understand alteration [...] Read more.
Thermodynamic simulations of fluid–rock interactions provide valuable insights into mineral deposit formation mechanisms. This study investigates the Pulang porphyry Cu-Au deposit in the Sanjiang Tethys Orogen, employing both Gibbs energy minimization (GEM) and the Law of mass action (LMA) method to understand alteration overprinting and metal precipitation. The modeling results suggest that the ore-forming fluid related to potassic alteration was initially oxidized (ΔFMQ = +3.54~+3.26) with a near-neutral pH (pH = 5.0~7.0). Continued fluid–rock interactions, combined with the input of reduced groundwater, resulted in a decrease in both pH (4.8~6.1) and redox potential (ΔFMQ~+1), leading to the precipitation of propylitic alteration minerals and pyrrhotite. As temperature further decreased, fluids associated with phyllic alteration showed a slight increase in pH (5.8~6.0) and redox potential (ΔFMQ = +2). The intense superposition of propylitic and phyllic alteration on the potassic alteration zone is attributed to the rapid temperature decline in the magmatic–hydrothermal system, triggering fluid collapse and reflux. Mo, mainly transported as HMoO4 and MoO4−2, precipitated in the high-temperature range; Cu, carried primarily by CuCl complexes (CuCl4−3, CuCl2, CuCl), precipitated over intermediate to high temperatures; and Au, transported as Au-S complexes (Au(HS)2, AuHS), precipitated from intermediate to low temperatures. This study demonstrates that fluid–rock interactions alone can account for the observed sequence of alteration and mineralization in porphyry systems. Full article
Show Figures

Figure 1

21 pages, 8878 KB  
Article
Significance of Adakitic Plutons for Mineralization in Wubaduolai Copper Deposit, Xizang: Evidence from Zircon U-Pb Age, Hf Isotope, and Geochemistry
by Ke Gao, Zhi Zhang, Linkui Zhang, Peiyan Xu, Yi Yang, Jianyang Wu, Yingxu Li, Miao Sun and Wenpeng Su
Minerals 2025, 15(5), 500; https://doi.org/10.3390/min15050500 - 8 May 2025
Cited by 2 | Viewed by 1019
Abstract
The Wubaduolai copper deposit, a newly discovered porphyry-type deposit located in the western section of the Gangdese metallogenic belt, shows great potential for mineralization. Investigating the ore-bearing potentiality of the adakitic granite in this area is crucial for identifying concealed ore bodies and [...] Read more.
The Wubaduolai copper deposit, a newly discovered porphyry-type deposit located in the western section of the Gangdese metallogenic belt, shows great potential for mineralization. Investigating the ore-bearing potentiality of the adakitic granite in this area is crucial for identifying concealed ore bodies and assessing the metallogenic potential. This paper presents the zircon U-Pb dating, Hf isotope analysis, and whole-rock major and trace geochemical analysis of the plutons in the Wubaduolai mining area. The results indicate that the zircon U-Pb concordia age of the monzogranite is 15.7 ± 0.1 Ma, while the granodiorite porphyry has a concordia age of 15.9 ± 0.2 Ma, both corresponding to a Miocene diagenesis. The geochemical data show that both plutons belong to the high-K calc-alkaline series, characterized by a relative enrichment of large-ion lithophile elements (K, Rb, Ba, and Sr) and a depletion of high-field-strength elements (Nb, Ta, and Ti). Both plutons are characterized by low Y, low Yb, and high Sr/Y values, displaying the typical geochemical characteristics of adakites. Their mineral composition is similar to that of adakite. The εHf(t) values of the monzogranite and granodiorite porphyry range from −5.34 to −2.3 and −5.2 to −3.43, respectively, with two-stage model ages (TDM2) of 1246–1441 Ma and 1318–1432 Ma. Based on the regional data and this study, the plutons in the Wubaduolai mining area formed in a post-collision setting following the India–Asia continental collision. The magma source is identified as the partial melting of a thickened, newly formed lower crust. The above characteristics are consistent with the diagenetic and metallogenic ages, magma source, and dynamic backgrounds of the typical regional deposits. Full article
Show Figures

Figure 1

21 pages, 8306 KB  
Article
Magmatic–Hydrothermal Processes of the Pulang Giant Porphyry Cu (–Mo–Au) Deposit, Western Yunnan: A Perspective from Different Generations of Titanite
by Mengmeng Li, Xue Gao, Guohui Gu and Sheng Guan
Minerals 2025, 15(3), 263; https://doi.org/10.3390/min15030263 - 3 Mar 2025
Cited by 2 | Viewed by 2012
Abstract
The Yidun island arc was formed in response to the Late Triassic westward subduction of the Ganzi–Litang oceanic plate, a branch of the Paleo-Tethys Ocean. The Zhongdian arc, located in the south of the Yidun island arc, has relatively large number of porphyry [...] Read more.
The Yidun island arc was formed in response to the Late Triassic westward subduction of the Ganzi–Litang oceanic plate, a branch of the Paleo-Tethys Ocean. The Zhongdian arc, located in the south of the Yidun island arc, has relatively large number of porphyry (skarn) type Cu–Mo ± Au polymetallic deposits, the largest of which is the Pulang Cu (–Mo–Au) deposit with proven Cu reserves of 5.11 Mt, Au reserves of 113 t, and 0.17 Mt of molybdenum. However, the relationship between mineralization and the potassic alteration zone, phyllic zone, and propylitic zone of the Pulang porphyry deposit is still controversial and needs further study. Titanite (CaTiSiO5) is a common accessory mineral in acidic, intermediate, and alkaline igneous rocks. It is widely developed in various types of metamorphic rocks, hydrothermally altered rocks, and a few sedimentary rocks. It is a dominant Mo-bearing phase in igneous rocks and contains abundant rare earth elements and high-field-strength elements. As an effective geochronometer, thermobarometer, oxybarometer, and metallogenic potential indicator mineral, titanite is ideal to reveal the magmatic–hydrothermal evolution and the mechanism of metal enrichment and precipitation. In this paper, major and trace element contents of the titanite grains from different alteration zones were obtained using electron probe microanalysis (EPMA) and laser-ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) to define the changes in physicochemical conditions and the behavior of these elements during the process of hydrothermal alteration at Pulang. Titanite in the potassic alteration zone is usually shaped like an envelope. It occurs discretely or is enclosed by feldspar, with lower contents of CaO, Al, Sr, Zr and Hf; a low Nb/Ta ratio; high ∑REE + Y, U, Th, Ta, Nb, and Ga content; and high FeO/Al2O3 and LREE/HREE ratios. This is consistent with the characteristics of magmatic titanite from fresh quartz monzonite porphyry in Pulang and other porphyry Cu deposits. Titanite in the potassium silicate alteration zone has more negative Eu anomaly and a higher U content and Th/U ratio, indicating that the oxygen fugacity decreased during the transformation to phyllic alteration and propylitic alteration in Pulang. High oxygen fugacity is favorable for the enrichment of copper, gold, and other metallogenic elements. Therefore, the enrichment of copper is more closely related to the potassium silicate alteration. The molybdenum content of titanite in the potassium silicate alteration zone is 102–104 times that of the phyllic alteration zone and propylitic alteration zone, while the copper content is indistinctive, indicating that molybdenum was dissolved into the fluid or deposited in the form of sulfide before the medium- to low-temperature hydrothermal alteration, which may lead to the further separation and deposition of copper and molybdenum. Full article
Show Figures

Figure 1

Back to TopTop