Next Article in Journal
Formation Mechanism of Granitic Basement Reservoir Linked to Felsic Minerals and Tectonic Stress in the Qiongdongnan Basin, South China Sea
Previous Article in Journal
New Insights into Graphite Deposits in Chisone and Germanasca Valleys (Dora-Maira Massif, Western Italian Alps): Scientific Advances and Applied Perspectives
 
 
Search for Articles:
Title / Keyword
Author / Affiliation / Email
Journal
Article Type
 
 
Advanced Search
 
Section
Special Issue
Volume
Issue
Number
Page
 
Journals
Minerals
Volume 15
Issue 5
10.3390/min15050456
minerals-logo
Submit to this Journal Review for this Journal Propose a Special Issue
► Article Menu

Article Menu

share Share announcement Help format_quote Cite question_answer Discuss in SciProfiles
first_page
settings
Order Article Reprints
Font Type:
Arial Georgia Verdana
Font Size:
Aa Aa Aa
Line Spacing:
Column Width:
Background:
Article

The Contribution of Evaporite Layers in the Formation of the Subvolcanic Type Fe Deposit in the Emeishan Large Igneous Province, Southwestern China: Insights from the S and O Isotopic Characteristics of the Kuangshanliangzi Deposit

by
Qiu Wan
1,2,3,
Chao Duan
1,*,
Yanhe Li
1,*,
Bin Hu
1,
Kejun Hou
1 and
Tianshun Wang
1
1
MNR Key Laboratory of Metallogeny and Mineral Assessment, Institute of Mineral Resources, Chinese Academy of Geological Sciences, Beijing 100037, China
2
Geological Survey of Anhui Province, Hefei 230001, China
3
The Coverage Area Deep Resource Exploration Engineering Technology Innovation Center of Ministry of Natural Resources, Hefei 230001, China
*
Authors to whom correspondence should be addressed.
Minerals 2025, 15(5), 456; https://doi.org/10.3390/min15050456
Submission received: 21 March 2025 / Revised: 19 April 2025 / Accepted: 24 April 2025 / Published: 27 April 2025
(This article belongs to the Special Issue Mineralization and Metallogeny of Iron Deposits)
Browse Figures
Versions Notes

Abstract

:
The Emeishan Large Igneous Province (ELIP) is one of the largest igneous provinces, containing some of the world’s richest mineral resources. It mainly comprises magmatic Fe-Ti-V deposits and Cu-Ni sulfide deposits, with minor subvolcanic-type Fe deposits related to mafic–ultramafic rocks. The evaporite layer is involved in the metallogenic system, yet its contribution has not been examined in detail. In this study, an integrated geological study, single-mineral S and O isotopic analysis, and in situ S isotope analysis were carried out on pyrite and magnetite from the Kuangshanliangzi (KSLZ) subvolcanic-type Fe deposit to examine the role of evaporite layers in Fe mineralization. The O isotopic values of magnetite and the S isotopic values of pyrite were abnormally high in the KSLZ deposit. This indicates that the ore-forming system of the KSLZ deposit is contaminated by 18O- and 34S-enriched evaporite layers, inferred from the Dengying Formation, which significantly increase the oxygen fugacity, sulfur fugacity, and water content of the metallogenic system via the basic–ultrabasic magma-upwelling process, thus promoting the formation of Fe ores. When the SO42− (from evaporite layers) oxidizes Fe2+ to Fe3+, the SO42− is reduced to S2−, and the ore-forming system can be changed from unsaturated sulfide to supersaturated sulfide, which also benefits the Cu-Ni sulfide deposit formation.

1. Introduction

The Emeishan Large Igneous Province (ELIP) is one of the largest igneous provinces, contains some of the world’s richest mineral resources, and is renowned for producing a large number of world-class magmatic vanadium–titanium magnetite deposits (Fe-Ti-V deposit), as well as magmatic Cu-Ni sulfide deposits and minor subvolcanic-type Fe deposits [1,2,3]. The Panzhihua–Xichang metallogenic region is an essential component of the ELIP. Two major metallogenic events have been identified [4,5,6,7,8,9]: (1) the Emeishan high-Ti basalts associated with the Panzhihua, Baima, and Hongge Fe-Ti-V deposit and (2) the low-Ti basalts associated with the Yangliuqing, Limahe, Zhubu, and Jinbaoshan Cu-Ni (-PGE) sulfide deposits and with subvolcanic-type Fe deposits, such as the Kuangshanliangzi (KSLZ), Daopingzi, and Lanzhichang deposits, which are characterized by low-Ti magnetite. One of the essential differences between the two ore-forming events is whether the basalts are contaminated by crustal material [5,8,9,10,11,12]. The assimilation and contamination of the evaporite layer is an important control factor for the formation of subvolcanic-type Fe deposits [13,14,15] and is also an essential enrichment mechanism for the formation of Ni-Cu-PGE sulfide ores [13,16,17,18,19,20,21,22]. While the evaporite layer is widely developed in the ELIP, it has not yet been examined in detail from a metallogenic viewpoint. The genetic relationship between subvolcanic-type Fe and Cu-Ni sulfide deposits has not yet been revealed.
In this study, the geological characteristics, oxygen, and sulfur isotopic compositions of the KSLZ deposit—as a classic large subvolcanic-type Fe deposit—were investigated and studied, and the contribution of the evaporite layers in the mineralization system is discussed. Moreover, the benefit of the evaporite layer in forming the Ni-Cu-PGE sulfide deposit is also discussed.

2. Regional Geology

The KSLZ deposit is a large-scale, high-grade subvolcanic-type Fe deposit located in the Pingchuan area in the western part of the Yangtze paraplatform (Figure 1), belonging to the Panzhihua–Xichang Metallogenic Belt, which is an essential component of the ELIP. The strata in the Pingchuan area are the Sinian–Triassic marine sedimentary formations formed by sedimentation on the pre-Sinian basement, with a total thickness of over 6000 m and a nearly SN–NNE trend. The exposed strata mainly include Sinian, Cambrian, Ordovician, Silurian, Carboniferous, Permian, and Triassic sedimentary rocks [23,24,25,26,27,28]. The Sinian Dengying Formation is distributed in the western part of the mining area and at the north and south ends of the Dabanshan intrusion, mainly consisting of dolomitic limestone, dolomite, mudstone, sandstone, and evaporitic layers. The Cambrian strata are composed of the Zhulinping and Gaojiaping Formations. The Zhulinping Formation is composed of argillaceous powder–crystal dolomite and carbonaceous siltstone. The Gaojiaping Formation is composed of thick-bedded massive dolomite. The Ordovician strata include silty mudstone and bedded sandstone of the Hongshiya Formation and limestone of the Qiaojia Formation. The Silurian strata comprise argillaceous limestone, quartz sandstone, and gravel-bearing quartz gritstone of the Longmaxi Formation and a thin layer of argillaceous siltstone and clayey shale of the Baizitian Group and Zhongcao Formation. The Carboniferous strata mainly include dark gray siliceous rock, argillaceous limestone, and siliceous banded crystalline limestone of the Weining Formation, and argillaceous limestone, marl, and crystalline limestone of the Maping Formation. The Permian strata mainly include calcareous gritstone and silty mudstone of the Liangshan Formation; gray layered banded limestone of the Qixia Formation; siliceous banded limestone and dolomitic limestone of the Maokou Formation; siltstone, mudstone, tuffaceous mudstone, and limestone of the Pingchuan Formation; and basalt, tuff breccia, basalt breccia, and basalt tuff lava of the Emeishan basalt. The Triassic strata include the Qingtianbao Formation, Yantang Formation, Baishan Formation, and Baiguowan Formation, mainly composed of quartz sandstone, siltstone, and mudstone. The Dabanshan intrusion is the largest intrusive body in the Pingchuan area, followed by the Dashanshu intrusion, both of which are Late Permian basic–ultrabasic plutons (Figure 2) [23,25,26,27,28]. The Dabanshan intrusion consists predominantly of gabbros, norite–gabbros, and lherzolites, formed from early to late. The gabbro occurs as a stratoid, with an exposed area of 27 km2, accounting for 70% of the exposed area of the Dabanshan intrusion. The norite–gabbro interrupts into the gabbro in a “finger” shape at the south side of the Dabanshan intrusion, with an exposure area of approximately 11 km2. The exposed area of lherzolite is small and distributed sporadically, occupying approximately 0.5 km2. Then, diabase gabbro, picrite porphyrite, and diorite dykes interrupt, which are considered to be associated with the KSLZ, Daopingzi, and Kuqiaodi subvolcanic-type Fe deposits. Among these dykes, picrite (porphyrite) dykes are concentratedly distributed in the KSLZ area as one rock type hosting the ore bodies [29]. The Dabanshan intrusion and picrite (porphyrite) dykes are derived from the same magma source and formed via different magmatic stages in the same magma activity period [8,30].
The geochronology of the Dabanshan intrusion yielded around 260 Ma [8,12,25,31], consistent with the age of Emeishan basalts. Zeng et al. (2013) [31] obtained a zircon U–Pb age of ~248 Ma for the picrite dike in the KSLZ deposit. Liu et al. (2015) [8] identified the Fe mineralization age of the Daopingzi deposit as 245 ± 26 Ma via apatite U–Pb dating, which could represent the Fe mineralization age in the Pingchuan area. Besides Fe deposits, disseminated Cu-Ni sulfide mineralization commonly appears in the Dabanshan intrusion, such as sparse disseminated Cu-Ni sulfide mineralization in the norite–gabbro and lherzolite of Nantiangou, which is a part of the Dabanshan intrusion [12]. Exploratory work on the Cu-Ni sulfide deposit is ongoing.
Minerals 15 00456 g001
Figure 1. Distribution of various magmatic deposits in the central zone of the Emeishan Large Igneous Province (Zeng, 2011 [32]).
Figure 1. Distribution of various magmatic deposits in the central zone of the Emeishan Large Igneous Province (Zeng, 2011 [32]).
Minerals 15 00456 g001
Minerals 15 00456 g002
Figure 2. Geological map of the Pingchuan area with the distribution of Fe deposits (Zeng, 2011 [32]). 1—gabbro; 2—gabbro–diorite; 3—gabbro–diabase; 4—porphyritic granite; 5—ultrabasic rocks; 6—olive gabbro; 7—fault; 8—stratigraphic boundary; 9—deposit; T—Triassic sedimentary rocks; P—Permian sedimentary rocks; P2β—Permian Emeishan basalt; C—Carboniferous sedimentary rocks; S—Silurian sedimentary rocks; O—Ordovician sedimentary rocks; Є—Cambrian sedimentary rocks; Z2d—sedimentary rocks of Dengying Formation.
Figure 2. Geological map of the Pingchuan area with the distribution of Fe deposits (Zeng, 2011 [32]). 1—gabbro; 2—gabbro–diorite; 3—gabbro–diabase; 4—porphyritic granite; 5—ultrabasic rocks; 6—olive gabbro; 7—fault; 8—stratigraphic boundary; 9—deposit; T—Triassic sedimentary rocks; P—Permian sedimentary rocks; P2β—Permian Emeishan basalt; C—Carboniferous sedimentary rocks; S—Silurian sedimentary rocks; O—Ordovician sedimentary rocks; Є—Cambrian sedimentary rocks; Z2d—sedimentary rocks of Dengying Formation.
Minerals 15 00456 g002

3. Deposit Geology

There are seven Fe deposits in the Pingchuan area, including the Daopingzi, KSLZ, Kuqiaodi, Lanzhichang, Laomaliangzi, Dashanshu, and Niuchang deposits from north to south, extending nearly 25 km (Figure 2). Among them, the KSLZ deposit is the largest one, containing 40 Mt of iron ores [8]. This deposit contains nine ore bodies, mainly occurring in the internal and external contact zone between intrusions (picrite porphyrite) and the surrounding sedimentary rocks, with some ores cutting through the sediment strata (Figure 3 and Figure 4). The ore bodies are tens to hundreds of meters long and tens of meters thick. Among them, the No. I ore body is the largest ore body in the mining area, with an average ore grade of 50% Fe [8]. Its northeast section occurs in the limestone of the Qixia Formation and Maokou Formation, and the southwest section occurs in the contact zone between picrite porphyrite (or diabase) and the tuffaceous siltstone of the Pingchuan Formation. The No. II ore body mainly occurs in the diabase and picrite porphyrite. The No. III ore body is hosted in the tuff breccia or the contact zone between basalt and picrite porphyrite. The No. IV ore body occurs in the contact zone between diabase gabbro and Permian limestone. The alterations are weakly developed, mainly carbonatization, chloritization, and serpentinization, with no distinctive zoning. The high-grade Fe ores bearing a relatively high sulfur content are predominant. The ore types developed (Figure 4d–g) include massive magnetite ores, breccia magnetite ores, siderite–magnetite ores, limonite–magnetite ores, pyrite ores, and siderite ores. The main ore mineral is magnetite, followed by martite, pyrite, siderite, and hematite, with gangue calcite, apatite, chlorite, phlogopite, diopside, barite, dolomite, and quartz (Figure 4 and Figure 5). The mineralization can be divided into four stages, from early to late: (1) magnetite–pyrite–carbonate, with phlogopite–serpentine–diopside–actinolite–apatite–chlorite, forming disseminated Fe mineralization; (2) magnetite–carbonate (ferro-dolomite–siderite)–pyrite–apatite (–hematite), forming massive Fe ores (Figure 4d–f and Figure 5b–d), as the main mineralization stage of the KSLZ deposit; and (3) vein pyrite–calcite (siderite); and (4) limonite–hematite in the supergene oxidation stage.

4. Analytical Methods and Results

4.1. Analytical Methods

In this study, eleven samples of massive Fe ores and wall rocks with Fe mineralization from the KSLZ deposit were selected for the single-mineral S and O isotope analyses (Table 1). For comparison, 11 samples of Fe ores from the Panzhihua Fe-Ti-V deposit were also selected for the single-mineral S and O isotope analyses (Table 1).
Magnetite and pyrite grains were separated from crushed samples using conventional magnetic and gravity techniques and were hand-picked under a binocular microscope. Single-mineral S and O isotopic analyses were performed at the Institute of Mineral Resources, the Chinese Academy of Geological Sciences (CAGS). The sulfur isotopic compositions were determined with a Thermo Fisher Flash 2000 HT unit coupled to a Thermo Fisher MAT-253 mass spectrometer (Thermo Fisher Scientific Inc., Waltham, MA, USA). The pyrite samples were oxidized to SO2 using O2 and WO3. All S-isotope data were expressed relative to Vienna-Canyon Diablo Troilite (V-CDT), with a precision of better than ±0.2‰ [39,40]. The oxygen isotope analyses used the BrF5 method [41], and the liberated CO2 was introduced into the inlet system of a Finnigan MAT-253 mass spectrometer (Thermo Fisher Scientific Inc., Waltham, MA, USA). The oxygen isotopic compositions were given in the standard notation and expressed relative to V-SMOW (‰). The analytical uncertainty was ±0.2‰.
In situ laser sulfur isotope analyses of the pyrite samples were performed using a Thermo Fisher Neptune Plus MC-ICP-MS (Thermo Fisher Scientific Inc., Bremen, Germany) equipped with a RESOlution-S155 excimer ArF laser ablation system (Applied Spectra Inc., Sacramento, CA, USA) at the LA-MC-ICP-MS laboratory in the Institute of Mineral Resources, CAGS. A circular 32 μm laser spot with a fluence of 5.0 J/cm2, a repetition rate of 6 Hz, and a duration of 40 s was used for the analysis. The reproducibility of the analytical results and mass spectrometer calibration were monitored using replicate measurements of an in-house primary standard JX (standard δ34S value: 16.9 ± 0.24‰) and a quality standard MXG (standard δ34S value: −0.35 ± 0.29‰; weighted average δ34S value of measured data: −0.29 ± 0.19‰, n = 15). The measured weighted average value was within the error of the recommended value. All the sulfur isotope compositions are reported using the standard delta notation relative to V-CDT.

4.2. Results

Pyrite in high-grade Fe ores from the KSLZ deposit had a wide range of δ34SV-CDT values, ranging from 3.3‰ to 23.6‰, with most values falling between 20‰ and 22‰ (Table 1). Combined with the published data, the average single-mineral δ34SV-CDT value of pyrite was 14.9‰ (n = 20; Table 1 and Figure 6). Similarly, 26 in situ S isotopic data were in a range of 13.4‰ to 22.7‰, with an average of 18.0‰ (Table 2).
The δ18O values of magnetite from the KSLZ deposit were abnormally high, ranging from 3.7‰ to 10.3‰ (Table 1). Meanwhile, the Panzhihua Fe-Ti-V deposit had lower δ34SV-CDT values, ranging from −0.4‰ to 5.5‰, and lower δ18O values, ranging from 0.3‰ to 2.3‰, with an average of 1.3‰.

5. Discussion

5.1. Involvement of Sedimentary Rocks in Fe Mineralization

5.1.1. Sources of Sulfur

The δ34SV-CDT values of pyrite from the KSLZ deposit (average δ34S value of 14.9‰, with a high-value peak of 21‰) were different from those of the Panzhihua Fe-Ti-V deposit (with a range of −0.4‰ to 2.3‰, with an average of 1.4‰; Figure 6b), which is a typical magmatic deposit and also much higher than the mantle-derived S isotope composition of basic–ultrabasic rocks. The sulfur isotope is a very effective origin tracer. The sulfate-reduced temperature and the proportion of original magma/sedimentary sulfur mainly control the variation in the sulfur isotopic composition of the deposits. The higher the temperature of the sulfate reduction reaction, the higher the δ34S value of sulfide. The higher the proportion percentage of the original magma sulfur, the lower the δ34S value of sulfide. Due to the low fractionations of the S isotopes among sulfides in the hydrothermal system [42,43] and the low δ34S value in the magma system (ca. 0‰), there must be a sulfur source of enrichment in 34S that endows the Fe mineralization, leading to the high δ34S isotope characteristics of sulfide in the KSLZ deposit. In the Pingchuan area, the basic–ultrabasic rocks intruded through all the strata from the Sinian to the Early Permian. Among them, the Sinian Dengying Formation is the most widely exposed sedimentary formation, and the dolomite and dolomitic limestone of the Dengying Formation contains abundant gypsum, which is the most important stratum hosting sedimentary gypsum deposits in Sichuan Province. The δ34S values of gypsum from the Dengying Formation fall in the range of 20.8‰ to 22.5‰, with an average value of 21.78‰ [37], similar to the high-value peak of the KSLZ deposit (Figure 6b). Considering the huge reserves of magnetite ores in the Pingchuan area, a large mass of oxidant is needed. It is inferred that the sulfur of the KSLZ deposit originates from the reduction of gypsum sulfate in the Dengying Formation, with a small amount coming from basic–ultrabasic magma. This high δ34SV-CDT value feature of the KSLZ deposit is similar to the volcanism or sub-volcanic intrusion-associated deposit in eastern China, such as the iron oxide–apatite deposit (IOA) from the Ningwu and Luzong ore districts [13,14] and skarn Fe deposits from the Edong ore district [20,44], which also involved evaporite layers in the ore-forming processes.

5.1.2. Oxygen Isotopes

Magnetite is a mineral with one of the lowest δ18O values in nature [36,45]. The magnetite from the KSLZ deposit had abnormally high δ18O values (>6.0‰); this was higher than that of the Panzhihua magmatic Fe deposit (0.4‰~5.0‰; Table 1) and relatively higher than the δ18O variation range (1.0‰~4.5‰) of magnetite crystallizing directly from silicate melt [46,47,48].
To trace the O isotope controller, it is first assumed that magnetite is crystallized directly from magma (basaltic rocks) with the O isotope fractionation between magnetite and ore-forming parent magma [45,49,50]. Based on the median O isotope value of magnetite (7.9‰), the magnetite precipitation temperature (ca. 470 °C, using the method proposed by Canil and Lacourse (2020) [51] and magnetite geochemistry data from Liu et al.’s study (2015) [8] to calculate), the calculated δ18O values of the parent magma were 14.0‰, which were much higher than the δ18O values of natural basalt (5.7 ± 0.3‰ [49]). Thus, this O isotope fractionation is not the major controller of the O isotope composition of the KSLZ deposit. It is implied that the mineralization system related to Fe mineralization underwent strong assimilation and contamination from the surrounding rocks, which are enriched with 18O (20‰–29‰; Dengying Formation [38]; Figure 6c).
Meanwhile, the high δ18O values were also related to the formation temperature of magnetite. Based on the δ18O values of magnetite (7.9‰) from the KSLZ deposit, the O isotope fractionation formula of magnetite–water (103lnαmagnetite-water = 3.02 × 106/T2 − 12.00 × 103/T + 3.31 [45]) was used to estimate and calculate the δ18O values of the ore-forming fluid, resulting in 15.3‰ at 470 °C and 13.2‰ at 800 °C, which are much higher than the δ18O values of natural magmatic–hydrothermal fluids, implying that the high O isotope composition was not caused by the formation temperature of magnetite in a closed mineralization system. This also indicates that the ore-forming system involved significant 18O enrichment from the surrounding sedimentary rocks.
Furthermore, the δ13C values of siderite from the KSLZ ores ranged from −2.6‰ to −1.6‰ [23], similar to the δ13C values of carbonate from the Dengying Formation (−2‰ to −4‰ [38]) and quite different from that of basalt (−3‰ to −8‰ [38]). The δ18O values of siderite from the KSLZ ores were 15.5‰~19.7‰, with an average value of 18.6‰, which was slightly lower than that of the Dengying Formation (22‰~29‰) but much higher than that of basalt. This evidence indicates the significant involvement of sedimentary rocks (evaporite layers) in the Fe ore-forming process.

5.2. Contribution of Evaporite Layers in Fe Mineralization

The ore-forming process of the KSLZ Fe deposit is believed to originate from basic–ultrabasic magma [8,26]. In a magma system, the liquid immiscibility between iron oxide and silicate melt could be developed under the promotion of phosphorus, chloride, carbonate, sulfate, and volatile matter, thus forming a Fe-rich melt and a Fe-poor silicate melt [52]. In the KSLZ deposit, the C, O, and S isotope compositions showed that basic–ultrabasic magma assimilated and/or was contaminated from the surrounding rocks, such as the evaporite layers, during the magma-upwelling process, which significantly increased the oxygen fugacity of the magmatic metallogenic system. A large amount of Fe2+ in the ore-forming magma was oxidized to form iron oxides, such as Fe3O4, and SO42− was reduced to S2−, forming sulfide (such as pyrite) [13,20]. Furthermore, evaporite layers can also provide Na, Ca, K, Cl, and other agents of mineralization, which could promote the Fe enrichment, transformation, and formation of Fe ores [14,53,54,55]. The Fe-bearing system continued to migrate upward and continuously reacted with the surrounding rocks, resulting in alterations including actinolitization, chloritization, and carbonatization. The Fe in the hydrothermal system precipitated in the form of hydrothermal magnetite, siderite, and pyrite.
The geochemical properties and precipitation conditions of magnetite, siderite, and pyrite differ. These three minerals can either precipitate successively in the same place or independently in different places, forming various types of ores. The ore-forming process of the KSLZ Fe deposit might be similar to that of IOA deposits, such as the Ningwu and Luzong ore districts in China, as well as IOA deposits, such as Kiruna in Sweden and El Laco in Chile, which are also similarly included evaporite layers [13,14,35,56,57,58,59,60].

5.3. Implications for Metallogeny of Fe and Ni-Cu Sulfide in Pingchuan Area

Magmatic Fe-Ti-V deposits associated with high-Ti basaltic rocks and magmatic Cu-Ni sulfide deposits and subvolcanic-type Fe deposits associated with low-Ti basaltic rocks occurred in the same period in the ELIP. Opposite to the magmatic Fe-Ti-V deposits, formations of magmatic Cu-Ni sulfide deposits and subvolcanic-type Fe deposits are closely related to the evaporite-bearing sedimentary rocks. In the Pingchuan area, the stratum is interrupted by the Dabanshan intrusion, including the evaporite layer-bearing Dengying Formation (Figure 2). During the oxidation by evaporite and formation of Fe3+, the S6+ in the SO42− is reduced, providing a large amount of reduced S2− to the metallogenic system. This promotes Fe accumulation and Fe ore formation. Meanwhile, this process could increase the sulfur fugacity in the metallogenic system, which might lead to sulfide saturation and supersaturation.
In the Pinchuan area, Liu et al. (2015) [8] found that the Fe content greatly decreased from gabbro to norite–gabbro very quickly, followed by the SiO2 reduction and MgO increase in lherzolite and picrate. The sudden drop in Fe2O3 was probably caused by the immiscibility of the low-Ti basaltic magma, and the isolated low-Ti Fe-rich melts can account for the mineralization of the Fe deposits in the Pingchuan area. The involvement of evaporite layers would trigger this mechanism [8,13,14,20].
Moreover, sparse disseminated Cu-Ni sulfide mineralization occurred in the norite–gabbro and lherzolite of Nantiangou, which is a part of the Dabanshan intrusion [12]. Most magmatic Ni-Cu-PGE sulfide deposits are formed by the crystallization differentiation and liquid immiscibility separation of basic–ultrabasic magma in magma chambers, forming disseminated/massive sulfide ores at the bottom or edges of basic–ultrabasic intrusions. The S concentration of most initial mantle-derived mafic–ultramafic magma is lower than 0.1 wt.%, and the magma is sulfide-unsaturated [19,61,62,63,64], making it difficult to accumulate a large amount of sulfides during magma evolution, forming large Ni-Cu-PGE sulfide deposits. The formation of Ni-Cu-PGE deposits requires significant supersaturation of sulfides. The addition of external sulfur from the surrounding rock is the most feasible mechanism for producing sulfides with a much higher proportion (Figure 6b). This is a key process for forming large-scale Ni-Cu-PGE sulfide deposits [19,65,66,67,68], such as Cu-Ni-PGE sulfide deposits at the Bushveld Complex area in South Africa [69], Cu-Ni-PGE sulfide deposits in the Norilsk region in Russia [18], and the Jianchaling deposit in China [34]. Wang et al. (2011) [25] determined the Cu/Zr ratio of the norite–gabbro as 0.88 to 5.56, implying that the norite–gabbro may have an S saturation or super-saturation condition. Combined with the evaporite layer’s involvement in this period, it is inferred that the southern parts of the Dabanshan intrusion may be a potentially favorable Cu-Ni-PGE metallogenic area.

6. Conclusions

The δ34SV-CDT value of pyrite and the δ18OV-SMOW value of magnetite in the KSLZ Fe deposit were significantly higher than those from the magmatic Fe-Ti-V deposit but similar to those in the IOA deposits, which were also associated with volcanism. During the magma’s ascent, the basic–ultrabasic magma assimilated evaporite layers, resulting in a significant increase in the oxygen fugacity and sulfur in the magmatic metallogenic system, which promoted the formation of subvolcanic-type Fe deposits and provided the conditions for the potential production of Co-Ni sulfide ores.

Author Contributions

Conceptualization, Y.L.; Investigation, C.D., Y.L. and K.H.; Data curation, C.D., B.H., K.H. and T.W.; Writing—original draft, Q.W. and C.D.; Writing—review & editing, C.D. and Y.L.; Supervision, Y.L. All authors have read and agreed to the published version of the manuscript.

Funding

This research was funded by the National Key Research and Development Program of China [grant number 2022YFC2903703] and the National Natural Science Foundation of China [grant numbers 42172102 and 41973022].

Data Availability Statement

The original contributions presented in this study are included in the article. Further inquiries can be directed to the corresponding authors.

Acknowledgments

We are grateful to Tong Hou and Meng Wang from the China University of Geosciences (Beijing) for their invaluable assistance during the fieldwork and insightful suggestions for improving this manuscript. We also thank two anonymous reviewers for their helpful suggestions for improving this manuscript.

Conflicts of Interest

The authors declare no conflict of interest.

References

  1. Ma, Y.; Ji, X.T.; Li, J.C.; Huang, M.; Kan, Z.Z. Mineral Resources of the Panzhihua Region; Sichuan Science and Technology Press: Chengdu, China, 2003; pp. 1–275. (In Chinese) [Google Scholar]
  2. Zhou, M.F.; Robinson, P.T.; Lesher, C.M.; Keays, R.R.; Zhang, C.J.; Malpas, J. Geochemistry, petrogenesis and metallogenesis of the Panzhihua gabbroic layered intrusion and associated V–Ti–Fe oxide deposits, Sichuan Province, SW China. J. Petrol. 2005, 46, 2253–2280. [Google Scholar] [CrossRef]
  3. Zhang, Z.C.; Hou, T.; Santosh, M.; Li, H.M.; Li, J.W.; Zhang, Z.H.; Song, X.Y.; Wang, M. Spatio-temporal distribution and tectonic settings of the major iron deposits in China: An overview. Ore Geol. Rev. 2014, 57, 247–263. [Google Scholar] [CrossRef]
  4. Xu, Y.G.; Chung, S.L.; Jahn, B.M.; Wu, G.Y. Petrologic and geochemical constraints on the petrogenesis of Permian–Triassic Emeishan flood basalts in southwestern China. Lithos 2001, 58, 145–168. [Google Scholar] [CrossRef]
  5. Zhou, M.F.; Arndt, N.T.; Malpas, J.; Wang, C.Y.; Kennedy, A.K. Two magma series and associated ore deposit types in the Permian Emeishan large igneous province, SW China. Lithos 2008, 103, 352–368. [Google Scholar] [CrossRef]
  6. Zhang, Z.C.; Mao, J.W.; Saunders, A.D.; Ai, Y.; Li, Y.; Zhao, L. Petrogenetic modeling of three mafic–ultramafic layered intrusions in the Emeishan large igneous province, SW China, based on isotopic and bulk chemical constraints. Lithos 2009, 113, 369–392. [Google Scholar] [CrossRef]
  7. Zhang, X.Q.; Song, X.Y.; Chen, L.M.; Yu, S.Y.; Xie, W.; Deng, Y.F.; Zhang, J.F.; Gui, S.G. Chalcophile element geochemistry of the Baima layered intrusion, Emeishan Large Igneous Province, SW China: Implications for sulfur saturation history and genetic relationship with high-Ti basalts. Contrib. Mineral. Petrol. 2013, 166, 193–209. [Google Scholar] [CrossRef]
  8. Liu, W.H.; Zhang, J.; Sun, T.; Zhou, L.; Liu, A.L. Low-Ti iron oxide deposits in the Emeishan large igneous province related to low-Ti basalts and gabbroic intrusions. Ore Geol. Rev. 2015, 65, 180–197. [Google Scholar] [CrossRef]
  9. You, M.X.; Zhang, Z.W.; Liu, J.M.; Zhang, J.W.; Wang, Y.L.; Qian, B. Geochemistry of mafic-ultramafic intrusion and Cu-Ni-(PGE) sulfide deposits in Panxi region, China. Northwest. Geol. 2017, 50, 146–161, (In Chinese with English Abstract). [Google Scholar]
  10. Wang, Y. Origin of the Permian Baimazhai magmatic Ni–Cu–(PGE) sulfide deposits, Yunnan: Implication for the relationship of crustal contamination and mineralization. Bull. Mineral. Petrol. Geochem. 2008, 27, 332–343, (In Chinese with English Abstract). [Google Scholar]
  11. Tang, Q.Y.; Ma, Y.S.; Zhang, M.J. The Origin of Ni-Cu-PGE Sulfide Mineralization in the Margin of the Zhubu Mafic-Ultramafic Intrusion in the Emeishan Large Igneous Province, Southwestern China. Econ. Geol. 2013, 108, 1889–1901. [Google Scholar] [CrossRef]
  12. Wang, M.; Zhang, Z.C.; Santosh, M.; Hou, T. Geochemistry of Late Permian picritic porphyries and associated Pingchuan iron ores, Emeishan Large Igneous Province, Southwest China: Constraints on petrogenesis and iron sources. Ore Geol. Rev. 2014, 57, 602–617. [Google Scholar] [CrossRef]
  13. Li, Y.H.; Duan, C.; Han, D.; Chen, X.W.; Wang, C.L.; Yang, B.Y.; Zhang, C.; Liu, F. Effect of sulfate evaporate salt layer for formation of porphyrite iron ores in the Middle-Lower Yangtze River area. Acta Petrol. Sin. 2014, 30, 1355–1368, (In Chinese with English Abstract). [Google Scholar]
  14. Duan, C.; Li, Y.H.; Mao, J.W.; Zhu, Q.Q.; Xie, G.Q.; Wan, Q.; Jian, W.; Hou, K.J. The role of evaporite layers in the ore-forming processes of iron oxide-apatite and skarn Fe deposits: Examples from the middle-lower Yangtze River metallogenic Belt, East China. Ore Geol. Rev. 2021, 138, 104352. [Google Scholar] [CrossRef]
  15. Xu, X.Y.; Bain, W.M.; Tornos, F.; Hanchar, J.M.; Lamadrid, H.M.; Lehmann, B.; Xu, X.C.; Steadman, J.A.; Bottrill, R.S.; Soleymani, M.; et al. Magnetite-apatite ores record widespread involvement of molten salts. Geology 2024, 52, 417–422. [Google Scholar] [CrossRef]
  16. Li, C.; Ripley, E.M.; Naldrett, A.J. Compositional variations of olivine and sulfur isotopes in the Noril’sk and Talnakh intrusions, Siberia: Implications for ore forming processes in dynamic conduits. Econ. Geol. 2003, 98, 69–86. [Google Scholar] [CrossRef]
  17. Li, C.; Ripley, E.M.; Naldrett, A.J.; Schnitt, A.K.; Moore, C.H. Magmatic anhydrite–sulfide assemblages in the plumbing system of the Siberian Traps. Geology 2009, 37, 259–262. [Google Scholar] [CrossRef]
  18. Ripley, E.M.; Li, C.; Moore, C.H.; Schmitt, A.K. Micro-scale S isotope studies of the Kharaelakh intrusion, Noril’sk region, Siberia: Constraints on the genesis of coexisting anhydrite and sulfide minerals. Geochim. Cosmochim. Acta 2010, 74, 634–644. [Google Scholar] [CrossRef]
  19. Ripley, E.M.; Li, C.S. Sulfide Saturation in Mafic Magmas: Is External Sulfur Required for Magmatic Ni-Cu-(PGE) Ore Genesis? Econ. Geol. 2013, 108, 45–58. [Google Scholar] [CrossRef]
  20. Li, Y.H.; Xie, G.Q.; Duan, C.; Han, D. Effect of sulfate evaporate salt layer over the formation of skarn-type iron ores. Acta Geol. Sin. 2013, 87, 1324–1334, (In Chinese with English Abstract). [Google Scholar]
  21. Li, Y.H.; Duan, C.; Fan, C.F.; Hu, B.; Wu, X.P. Effect of gypsum layer for formation of Ni-Cu-PGE sulfide deposits: A case of Noril’sk ores, Russia. Miner. Depos. 2020, 39, 619–630, (In Chinese with English Abstract). [Google Scholar]
  22. Malitch, K.N.; Latypov, R.M.; Badanina, I.Y.; Sluzhenikin, S.F. Insights into ore genesis of Ni- Cu- PGE sulfide deposits of the Noril’sk Province (Russia): Evidence from copper and sulfur isotopes. Lithos 2014, 204, 172–187. [Google Scholar] [CrossRef]
  23. Yang, S.H.; Que, M.Y. Magnetite Characteristics of Magnetite from Iron Deposits in the Xichang-Central Yunnan Region and the Genesis of the Deposits; Chongqing Press: Chongqing, China, 1987; pp. 1–105, (In Chinese with English Abstract). [Google Scholar]
  24. Yao, Z.D.; Yan, Y.Q. Re-understanding metallogenesis of the Kuangshan Liangzi-Niuchang magnitite ore deposits, Yanyuan, Sichuan. Acta Sichuan Geol. 1991, 11, 117–126, (In Chinese with English Abstract). [Google Scholar]
  25. Wang, M.; Zhang, Z.C.; Hou, T.; Luo, W.J. Geochronology and geochemistry of the Dabanshan intrusion in Panxi district and its constraints on the metallogenesis of Cu-Ni sulfide deposits. Acta Petrol. Sin. 2011, 27, 2665–2678, (In Chinese with English Abstract). [Google Scholar]
  26. Li, B.; Wang, S.Z.; Jing, W.C. The relationship between causing intrusions and Dabanshan mass of rock of the Pingchuan iron deposit in the Liangshan prefecture, Sichuan province. China Min. Mag. 2015, 24, 158–161, (In Chinese with English Abstract). [Google Scholar]
  27. Zeng, L.G.; Zhang, J.; Sun, T.; Li, B.; Zhu, G.H.; Jia, Z.C.; Fang, Q.; Chen, G.H. Geological characteristics, genesis, and its prospecting exploration enlightenment of Lanzhichang iron deposit in the Emeishan Large Igneous Province. J. Jilin Univ. 2016, 46, 412–424, (In Chinese with English Abstract). [Google Scholar]
  28. Liu, S.; Wang, S.Z.; Gao, L.F.; Jia, Z.W.; Ren, K.K.; Zhu, Y. The characteristics of ore fabric and its geological significance of Pingchuan iron deposit in the South of Sichuan province. China Min. Mag. 2018, 27, 182–184, (In Chinese with English Abstract). [Google Scholar]
  29. Sun, T.; Lu, X.S.; Zhou, X.N.; Liu, W.H.; Wang, J.; Zeng, L.G.; Fan, C. Geochemical characteristics and genesis of Daopingzi iron deposit in Panzhihuan-Xichang Region. Resour. Environ. Eng. 2021, 35, 408–417, (In Chinese with English Abstract). [Google Scholar]
  30. Li, H.M.; Chen, Y.C.; Li, L.X.; Wang, D.H. Metallogeny of the Iron Deposits in China; Geological Publishing House: Beijing, China, 2012; pp. 136–140, (In Chinese with English Abstract). [Google Scholar]
  31. Zeng, L.G.; Zhang, J.; Sun, T.; Guo, D.H. Zircon U-Pb age of mafic-ulreamafic rock from Pingchuan region in southern Sichuan and its geological implications. Earth Sci.-J. China Univ. Geosci. 2013, 38, 1197–1213, (In Chinese with English Abstract). [Google Scholar]
  32. Zeng, L.G. A Study on Pingchuan Iron Deposit in Metallogenic Regularity of Yanyuan County, Sichuan Province. Ph.D. Thesis, China University of Geosciences, Wuhan, China, 2011. [Google Scholar]
  33. Yu, S.Y.; Song, X.Y.; Ripley, E.M.; Li, C.S.; Chen, L.M.; She, Y.W.; Luan, Y. Integrated O-Sr-Nd isotope constraints on the evolution of four important Fe-Ti oxide ore-bearing mafic-ultramafic intrusions in the Emeishan large igneous province, SW China. Chem. Geol. 2015, 401, 28–42. [Google Scholar] [CrossRef]
  34. Jiang, X.D.; Wei, G.F.; Nie, J.T. Jianchaling nickel deposit: Magmatic or hydrothermal origin. Miner. Depos. 2010, 38, 1197–1213, (In Chinese with English Abstract). [Google Scholar]
  35. Tornos, F.; Velasco, F.; Hanchar, J.M. Iron-rich melts, magmatic magnetite, and superheated hydrothermal systems: The El Laco deposit, Chile. Geology 2016, 44, 427–430. [Google Scholar] [CrossRef]
  36. Li, Y.H.; Duan, C.; Han, D.; Liu, F.; Wan, D.F.; Wang, C.Y. Oxygen isotopic discriminant marker of magmatic iron deposits: Ningwu porphyrite iron ore as an example. Acta Petrol. Sin. 2017, 33, 3411–3421, (In Chinese with English Abstract). [Google Scholar]
  37. Zhu, G.Y.; Zhang, S.C.; Liang, Y.B.; Li, Q.R. Genesis and evidence of hydrogen sulfide in Weiyuan gas field, Sichuan Basin. Chin. Sci. Bull. 2006, 51, 2780–2788, (In Chinese with English Abstract). [Google Scholar]
  38. Xing, C.M.; Wang, C.Y.; Zhang, M.J. Volatile and C-H-O isotopic compositions of giant Fe-Ti-V oxide deposits in the Panxi region and their implications for the sources of volatiles and the origin of Fe-Ti oxide ores. Sci. China Earth Sci. 2012, 55, 1782–1795. [Google Scholar] [CrossRef]
  39. Wu, X.P.; Fan, C.F.; Hu, B.; Gao, J.F.; Li, Y.H. Measurements of sulfur isotope composition on ultrasmall (80 nanomole) sulfide and sulfate samples by a modified EA-IRMS. Acta Geol. Sin. Engl. Ed. 2022, 96, 1792–1799. [Google Scholar] [CrossRef]
  40. Li, Y.H.; Wan, D.F.; Zhao, X.Y. Geological and Mineral Industry Standards of the People’s Republic of China (DZ/T 0184.23-2024)—Isotope Analysis Methods for Geological Samples, Part 27: Determination of Oxygen Isotope Composition of Silicate and Oxide Minerals Using Bromine Pentafluoride Method; Geological Publishing House: Beijing, China, 2024. (In Chinese) [Google Scholar]
  41. Clayton, R.N.; Mayeda, T.K. The use of bromine pentafluoride in the extraction of oxygen from oxides and silicates for isotopic analysis. Geochim. Cosmochim. Acta 1963, 27, 43–45. [Google Scholar] [CrossRef]
  42. Rye, R.O.; Ohmoto, H. Sulfur and carbon isotopes and ore genesis: A review. Econ. Geol. 1974, 69, 826–842. [Google Scholar] [CrossRef]
  43. Ohmoto, H.; Rye, R.O. Isotopes of sulfur and carbon. In Geochemistry of Hydrothermal Ore Deposits, 2nd ed.; Barnes, H.L., Ed.; John Wiley and Sons: New York, NY, USA, 1979. [Google Scholar]
  44. Zhu, Q.Q.; Xie, G.Q. Sulfur isotopic character and geological implications for the Jinshandian Fe skarn ore field, Hubei Province. Acta Petrol. Sin. 2018, 34, 2518–2534, (In Chinese with English Abstract). [Google Scholar]
  45. Zheng, Y.F. Calculation of oxygen isotope fractionation in metal oxides. Geochim. Cosmochim. Acta 1991, 55, 2299–2307. [Google Scholar]
  46. Taylor, H.P. The oxygen isotope geochemistry of igneous rocks. Contrib. Mineral. Petrol. 1968, 19, 1–71. [Google Scholar] [CrossRef]
  47. Bindeman, I.N.; Valley, J.W. Oxygen isotope study of the long Valley-Glass Mountain magmatic system, California: Isotope thermometry, and t convection in large silicic magma bodies. Contrib. Mineral. Petrol. 2002, 144, 185–205. [Google Scholar] [CrossRef]
  48. Bindeman, I.N.; Valley, J.W. Rapid generation of both high- and low-δ18O, large volume silicic magmas at Timber Mountain/Oasis Valley caldera complex, Nevada. Bull. Geol. Soc. Am. 2003, 115, 581–595. [Google Scholar] [CrossRef]
  49. Taylor, H.P. Oxygen isotope studies of hydrothermal mineral deposits. In Geochemistry of Hydrothermal Ore Deposits; Barnes, H.L., Ed.; Holt, Rinehart & Winston Inc.: New York, NY, USA, 1967; pp. 109–142. [Google Scholar]
  50. Zhao, Z.F.; Zheng, Y.F. Calculation of oxygen isotope fractionation in magmatic rocks. Chem. Geol. 2003, 193, 59–80. [Google Scholar] [CrossRef]
  51. Canil, D.; Lacourse, T. Geothermometry using minor and trace elements in igneous and hydrothermal magnetite. Chem. Geol. 2020, 541, 119576. [Google Scholar] [CrossRef]
  52. Hou, T.; Charlier, B.; Holtz, F.; Veksler, I.; Zhang, Z.C.; Thomas, R.; Namur, O. Immiscible hydrous Fe–Ca–P melt and the origin of iron oxide-apatite ore deposits. Nat. Commun. 2018, 9, 1415–1423. [Google Scholar] [CrossRef]
  53. Whitney, J.A.; Hemley, J.; Simon, F.O. The concentration of iron in chloride solutions equilibrated with synthetic granitic compositions: The sulfur-free system. Econ. Geol. 1985, 80, 444–460. [Google Scholar] [CrossRef]
  54. Hemley, J.J.; Cygan, G.L.; Fein, J.B.; Robinson, G.R.; d’Angelo, W.M. Hydrothermal ore-forming processes in the light of studies in rock-buffered systems; I, iron-copper-zinc-lead sulfde solubility relations. Econ. Geol. 1992, 87, 23–43. [Google Scholar] [CrossRef]
  55. Borisov, A.; Behrens, H.; Holtz, F. Effects of strong network modifiers on Fe3+/Fe2+ in silicate melts: An experimental study. Contrib. Mineral. Petrol. 2017, 172, 34. [Google Scholar] [CrossRef]
  56. Sillitoe, R.H.; Burrows, D.R. New field evidence bearing on the origin of the El Laco magnetite deposit, Northern Chile. Econ. Geol. 2002, 75, 1101–1109. [Google Scholar]
  57. Tornos, F.; Velasco, F.; Hanchar, J.M. The magmatic to magmatic-hydrothermal evolution of the El Laco deposit (Chile) and its implications for the genesis of magnetite-apatite deposits. Econ. Geol. 2017, 112, 1595–1628. [Google Scholar] [CrossRef]
  58. Mungall, J.E.; Long, K.; Brenan, J.M.; Smythe, D.; Naslund, H.R. Immiscible shoshonitic and Fe-P-oxide melts preserved in unconsolidated tephra at El Laco volcano, Chile. Geology 2018, 46, 255–258. [Google Scholar] [CrossRef]
  59. Xie, Q.H.; Zhang, Z.C.; Hou, T.; Cheng, Z.G.; Eduardo, C.; Wang, Z.C.; Fei, X.H. New insights for the formation of Kiruna-type iron deposits by immiscible hydrous Fe-P Melt and high-temperature hydrothermal processes: Evidence from El Laco deposit. Econ. Geol. 2019, 114, 35–46. [Google Scholar] [CrossRef]
  60. Guo, D.; Li, Y.; Duan, C.; Fan, C. Involvement of Evaporite Layers in the Formation of Iron Oxide-Apatite Ore Deposits: Examples from the Luohe Deposit in China and the El Laco Deposit in Chile. Minerals 2022, 12, 1043. [Google Scholar] [CrossRef]
  61. Ripley, E.M.; Taib, N.I.; Li, C.; Moore, C.H. Chemical and mineralogical heterogeneity in the basal zone of the Partridge River intrusion: Implications for the origin of Cu-Ni sulfide mineralization in the Duluth Complex, Midcontinent Rift System. Contrib. Mineral. Petrol. 2007, 154, 35–54. [Google Scholar] [CrossRef]
  62. Keays, R.R. The role of komatiitic and picritic magmatism and S-saturation in the formation of ore deposits. Lithos 1995, 34, 1–18. [Google Scholar] [CrossRef]
  63. Naldrett, A.J.; Fedorenko, V.A.; Asif, M.; Lin, S.; Kunilov, V.A.; Stekhin, A.I.; Lightfoot, P.C.; Gorbachev, N.S. Controls on the compositions of Ni-Cu sulfide deposits as illustrated by those at Noril’sk, Siberia. Econ. Geol. 1996, 91, 751–773. [Google Scholar] [CrossRef]
  64. Naldrett, A.J. Magmatic Sulfide Deposits: Geology, Geochemistry, and Exploration; Springer: Berlin, Germany, 2004; pp. 1–727. [Google Scholar]
  65. Keays, R.R.; Lightfoot, P.C. Crustal sulfur is required to form magmatic Ni-Cu sulfide deposits: Evidence from chalcophile element signatures of Siberian and Deccan Trap basalts. Miner. Depos. 2010, 45, 241–257. [Google Scholar] [CrossRef]
  66. Godel, B.; Seat, Z.; Maier, W.D.; Barne, S.J. The Nebo-BabelNiCu-PGE sulfide deposit (West Musgrave block, Australia): Pt. 2. Constraintson parental magma and processes, with implications for mineral exploration. Econ. Geol. 2011, 106, 557–584. [Google Scholar] [CrossRef]
  67. Song, X.Y.; Zhu, D.; Xiao, J.F.; Zhu, W.G.; Chen, L.M. New insights on the formation of magmatic sulfide deposits in magma conduit system. Earth Sci. Front. 2010, 17, 153–163, (In Chinese with English Abstract). [Google Scholar]
  68. Song, X.Y. Current research status and important issues of magmatic sulfide deposits. Miner. Depos. 2019, 38, 699–712, (In Chinese with English Abstract). [Google Scholar]
  69. Mapiloko, M.; Yudovskaya, M.; McCreesh, M.; Velivetskaya, T.; Nex, P.; Kinnaird, J.; Montjoie, R.; Bekker, A. Contribution of the oldest Paleoproterozoic marine sulfate evaporites to Bushveld Complex Lower Zone mineralization. Geology 2025, 53, 355–359. [Google Scholar] [CrossRef]
Minerals 15 00456 g003
Figure 3. Geological section of the KSLZ deposit (Yang and Que, 1987 [23]). 1—Quaternary sandstone and mudstone; 2—massive siliceous nodular-bearing limestone; 3—thin-to-medium-thickness layer of siliceous nodule limestone; 4—muddy limestone containing quartz grains; 5—muddy limestone; 6—magnetite ore body with ore body number; 7—picrite porphyrite; 8—stratigraphic unconformity boundary; 9—fault; Q—Quaternary; P1p—Permian Pingchuan Formation; P1m—Permian Maokou Formation; P1q—Permian Qixia Formation; P1l—Permian Liangshan Formation; C2m—Carboniferous Maping Formation; C2w—Carboniferous Weining Formation.
Figure 3. Geological section of the KSLZ deposit (Yang and Que, 1987 [23]). 1—Quaternary sandstone and mudstone; 2—massive siliceous nodular-bearing limestone; 3—thin-to-medium-thickness layer of siliceous nodule limestone; 4—muddy limestone containing quartz grains; 5—muddy limestone; 6—magnetite ore body with ore body number; 7—picrite porphyrite; 8—stratigraphic unconformity boundary; 9—fault; Q—Quaternary; P1p—Permian Pingchuan Formation; P1m—Permian Maokou Formation; P1q—Permian Qixia Formation; P1l—Permian Liangshan Formation; C2m—Carboniferous Maping Formation; C2w—Carboniferous Weining Formation.
Minerals 15 00456 g003
Minerals 15 00456 g004
Figure 4. Photos of the relationship between KSLZ ores and picrite porphyrite. (a,b) Relationship between the picrite porphyrite and Fe ores in the KSLZ open pit; (c) picrite porphyrite intrudes along the layer, and magnetite ore bodies occur in its outer contact zone; (d) massive Fe ore; (e) breccia Fe ore; (f) massive magnetite ore bearing breccias and pyrite; (g) porous magnetite ore, with signs of supergene alteration; (h) Magnetite ore with chloritization and carbonitization (calcite vein); (i) altered wall rock with actinolite vein.
Figure 4. Photos of the relationship between KSLZ ores and picrite porphyrite. (a,b) Relationship between the picrite porphyrite and Fe ores in the KSLZ open pit; (c) picrite porphyrite intrudes along the layer, and magnetite ore bodies occur in its outer contact zone; (d) massive Fe ore; (e) breccia Fe ore; (f) massive magnetite ore bearing breccias and pyrite; (g) porous magnetite ore, with signs of supergene alteration; (h) Magnetite ore with chloritization and carbonitization (calcite vein); (i) altered wall rock with actinolite vein.
Minerals 15 00456 g004
Minerals 15 00456 g005
Figure 5. Photomicrographs of Fe ores and altered wall rocks. (a) Picrite porphyrite with magnetite mineralization, amphibolization, and serpentinization; (b) massive magnetite ore, with hematite and pyrite replacement; (c,d) magnetite ore; (e) sedimentary wall rock with minor disseminated magnetite and pyrite mineralization; (f) pyrite replaces magnetite. Abbreviations: Mag—magnetite; Py—pyrite; Cal—calcite; Ap—apatite; Hem—hematite; Ol—olivine.
Figure 5. Photomicrographs of Fe ores and altered wall rocks. (a) Picrite porphyrite with magnetite mineralization, amphibolization, and serpentinization; (b) massive magnetite ore, with hematite and pyrite replacement; (c,d) magnetite ore; (e) sedimentary wall rock with minor disseminated magnetite and pyrite mineralization; (f) pyrite replaces magnetite. Abbreviations: Mag—magnetite; Py—pyrite; Cal—calcite; Ap—apatite; Hem—hematite; Ol—olivine.
Minerals 15 00456 g005
Minerals 15 00456 g006
Figure 6. (a) Sulfur isotopic values of pyrite from the KSLZ deposit (data from this study and Yang and Que’s study (1987) [23]). (b) Sulfur isotope compositions for the KSLZ Fe deposit, Panzhihua Fe-Ti-V deposit, Jianchaling Cu-Ni deposit, and Dengying formation, with magma sulfur end member (data from this study and studies by Yang and Que (1987) [23], Yu et al. (2015) [33], Jiang et al. (2010) [34], and Zhu et al. (2006) [37]). (c) Oxygen isotope compositions for the KSLZ Fe deposit, Panzhihua Fe-Ti-V deposit, Gushan iron oxide–apatite deposit, El Laco iron oxide–apatite deposit, and Dengying formation (data from this study and the studies by Yang and Que (1987) [23], Yu et al. (2015) [33], Tornos et al. (2016) [35], Li et al. (2017) [36], and Xing et al. (2012) [38]).
Figure 6. (a) Sulfur isotopic values of pyrite from the KSLZ deposit (data from this study and Yang and Que’s study (1987) [23]). (b) Sulfur isotope compositions for the KSLZ Fe deposit, Panzhihua Fe-Ti-V deposit, Jianchaling Cu-Ni deposit, and Dengying formation, with magma sulfur end member (data from this study and studies by Yang and Que (1987) [23], Yu et al. (2015) [33], Jiang et al. (2010) [34], and Zhu et al. (2006) [37]). (c) Oxygen isotope compositions for the KSLZ Fe deposit, Panzhihua Fe-Ti-V deposit, Gushan iron oxide–apatite deposit, El Laco iron oxide–apatite deposit, and Dengying formation (data from this study and the studies by Yang and Que (1987) [23], Yu et al. (2015) [33], Tornos et al. (2016) [35], Li et al. (2017) [36], and Xing et al. (2012) [38]).
Minerals 15 00456 g006
Table 1. C-O-S isotopic data of the Kuangshanliangzi and Panzhihua deposits.
Table 1. C-O-S isotopic data of the Kuangshanliangzi and Panzhihua deposits.
Deposit/FormationSamplesLithologyMineralsδ18OV-SMOW (‰)δ13CV-PDB (‰)δ34SV-CDT (‰)References
KuangshanliangziKSLZ13-1Sulfide-bearing magnetite orePyrite 19.9This study
KuangshanliangziKSLZ13-2Sulfide-bearing magnetite oreMagnetite–pyrite7.9 3.3This study
KuangshanliangziKSLZ13-3Sulfide-bearing magnetite oreMagnetite8.6 This study
KuangshanliangziKSLZ13-4Picrite porphyrite with Fe mineralizationPyrite 20.6This study
KuangshanliangziKSLZ13-5Sulfide-bearing magnetite oreMagnetite–pyrite6.5 23.6This study
KuangshanliangziKSLZ13-7Near ore country rockPyrite 14.0This study
KuangshanliangziKSLZ13-14Sulfide-bearing magnetite oreMagnetite–pyrite3.7 21.2This study
KuangshanliangziKSLZ13-16Sulfide-bearing magnetite orePyrite 20.1This study
KuangshanliangziKSLZ13-17Picrite porphyrite with actinolite alterationMagnetite6.6 This study
KuangshanliangziKSLZ13-19Pyrite veinPyrite 11.8This study
KuangshanliangziKSLZ13-21Sulfide-bearing magnetite oreMagnetite–pyrite5.2 21.3This study
KuangshanliangziDF-4(1)Breccia magnetite oreMagnetite8.6 [23]
KuangshanliangziDF-4(2)Breccia magnetite oreMagnetite8.8 [23]
KuangshanliangziDF-12(1)Magnetite oreMagnetite8.5 [23]
KuangshanliangziDF12-(2)Magnetite oreMagnetite10.3 [23]
KuangshanliangziDF-22Magnetite oreMagnetite5.6 [23]
KuangshanliangziDF-3Siderite–magnetite orePyrrhotite 11.7[23]
KuangshanliangziDF-6Massive pyrite orePyrite 5.1[23]
KuangshanliangziDF-7(a)Siderite–magnetite orePyrite 14.8[23]
KuangshanliangziDF-7(b)Siderite–magnetite orePyrrhotite 16.0[23]
KuangshanliangziDF-8Siderite–magnetite orePyrite 18.0[23]
KuangshanliangziDF-9Breccia pyrite orePyrite 16.1[23]
KuangshanliangziDF-11Breccia pyrite orePyrite 20.6[23]
KuangshanliangziDF-14Near ore country rockPyrite 15.0[23]
KuangshanliangziDF-16Pyrite–magnetite orePyrite 10.6[23]
KuangshanliangziDF-17(a)Breccia pyrite orePyrite 5.5[23]
KuangshanliangziDF-17(b)Breccia pyrite orePyrrhotite 9.0[23]
KuangshanliangziDF-19(1)Magnetite oreSiderite18.4−1.6 [23]
KuangshanliangziDF-19(2)Magnetite oreSiderite15.5−1.8 [23]
KuangshanliangziDF-23Magnetite oreSiderite19.5−2.5 [23]
KuangshanliangziDF-24Magnetite oreSiderite19.0−2.5 [23]
KuangshanliangziDF-25Magnetite oreSiderite19.3−2.6 [23]
KuangshanliangziDF-26Magnetite oreSiderite19.7−1.7 [23]
PanzhihuaPZH13-15Magnetite oreMagnetite2.3 This study
PanzhihuaPZH13-16Magnetite oreMagnetite0.9 This study
PanzhihuaPZH13-17Sulfide-bearing magnetite oreMagnetite–pyrite1.4 5.5This study
PanzhihuaPZH13-18Sulfide-bearing magnetite oreMagnetite–pyrite2.0 1.1This study
PanzhihuaPZH13-19Magnetite oreMagnetite0.3 This study
PanzhihuaPZH13-24Sulfide-bearing magnetite oreMagnetite–pyrite1.3 2.3This study
PanzhihuaPZH13-29Magnetite oreMagnetite0.4 This study
PanzhihuaPZH13-39Sulfide-bearing magnetite oreMagnetite–pyrite1.5 0.4This study
PanzhihuaPZH13-40Sulfide-bearing magnetite oreMagnetite–pyrite1.6 −0.4This study
PanzhihuaPZH13-43Sulfide-bearing magnetite oreMagnetite–pyrite1.1 0.1This study
PanzhihuaPZH13-45Sulfide-bearing magnetite oreMagnetite–pyrite1.7 0.6This study
Panzhihua Magnetite oreMagnetite1.2~5.0 (2.7) [33]
Jianchaling Cu-Ni orePyrite 9.9~13.3 (11.68)[34]
El Laco, Chile Magnetite oreMagnetite4.3~5.0 [35]
Gushan Magnetite–hematite oreMagnetite–hematite−1.2~5.2 (1.81) [36]
Dengying Formation Evaporite layerGypsum 20.8~22.5 (21.8)[37]
Dengying Formation CarbonateLimestone; dolomite20~29−2~4 [38]
Note: The values in brackets are the average values.
Table 2. In situ S isotopic data of pyrite from the Kuangshanliangzi deposits.
Table 2. In situ S isotopic data of pyrite from the Kuangshanliangzi deposits.
Sampleδ34S2SESampleδ34S2SE
KSLZ13-6-119.68 0.13 KSLZ13-13-314.15 0.08
KSLZ13-6-220.31 0.18 KSLZ13-13-422.39 0.10
KSLZ13-6-313.67 0.10 KSLZ13-13-521.49 0.09
KSLZ13-6-420.10 0.06 KSLZ13-1-115.93 0.21
KSLZ13-6-519.82 0.10 KSLZ13-1-215.44 0.29
KSLZ13-3-118.78 0.07 KSLZ13-1-316.13 0.13
KSLZ13-3-221.74 0.08 KSLZ13-1-416.17 0.17
KSLZ13-3-322.25 0.09 KSLZ13-1-517.05 0.11
KSLZ13-16-113.93 0.08 KSLZ13-21-115.20 0.24
KSLZ13-16-218.95 0.10 KSLZ13-21-213.39 0.31
KSLZ13-16-320.72 0.09 KSLZ13-21-315.42 0.26
KSLZ13-13-122.68 0.07 KSLZ13-21-416.27 0.10
KSLZ13-13-221.37 0.09 KSLZ13-21-515.43 0.13
Disclaimer/Publisher’s Note: The statements, opinions and data contained in all publications are solely those of the individual author(s) and contributor(s) and not of MDPI and/or the editor(s). MDPI and/or the editor(s) disclaim responsibility for any injury to people or property resulting from any ideas, methods, instructions or products referred to in the content.

Share and Cite

MDPI and ACS Style

Wan, Q.; Duan, C.; Li, Y.; Hu, B.; Hou, K.; Wang, T. The Contribution of Evaporite Layers in the Formation of the Subvolcanic Type Fe Deposit in the Emeishan Large Igneous Province, Southwestern China: Insights from the S and O Isotopic Characteristics of the Kuangshanliangzi Deposit. Minerals 2025, 15, 456. https://doi.org/10.3390/min15050456

AMA Style

Wan Q, Duan C, Li Y, Hu B, Hou K, Wang T. The Contribution of Evaporite Layers in the Formation of the Subvolcanic Type Fe Deposit in the Emeishan Large Igneous Province, Southwestern China: Insights from the S and O Isotopic Characteristics of the Kuangshanliangzi Deposit. Minerals. 2025; 15(5):456. https://doi.org/10.3390/min15050456

Chicago/Turabian Style

Wan, Qiu, Chao Duan, Yanhe Li, Bin Hu, Kejun Hou, and Tianshun Wang. 2025. "The Contribution of Evaporite Layers in the Formation of the Subvolcanic Type Fe Deposit in the Emeishan Large Igneous Province, Southwestern China: Insights from the S and O Isotopic Characteristics of the Kuangshanliangzi Deposit" Minerals 15, no. 5: 456. https://doi.org/10.3390/min15050456

APA Style

Wan, Q., Duan, C., Li, Y., Hu, B., Hou, K., & Wang, T. (2025). The Contribution of Evaporite Layers in the Formation of the Subvolcanic Type Fe Deposit in the Emeishan Large Igneous Province, Southwestern China: Insights from the S and O Isotopic Characteristics of the Kuangshanliangzi Deposit. Minerals, 15(5), 456. https://doi.org/10.3390/min15050456

Note that from the first issue of 2016, this journal uses article numbers instead of page numbers. See further details here.

Article Metrics

Back to TopTop