Sulfur and lead isotopic compositions of massive sulfides from deep-sea hydrothermal systems: Implications for ore genesis and fluid circulation

Zeng, Zhigang; Ma, Yao; Chen, Shuai; Selby, David; Wang, Xiaoyuan; Yin, Xue‐Bo

doi:10.1016/j.oregeorev.2016.10.014

Cited by 50 publications

(20 citation statements)

References 114 publications

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“…The S sources in sediment-starved fields were mainly seawater-derived sulfate and magmatic sulfur [25]. Based on two-component mixing model (δ 34 S -mix = X × δ 34 S seawater + (1 − X) × δ 34 S basalt [25][26][27]). The δ 34 S seawater , δ 34 S basalt , and δ 34 S -mix represent 21 , 0 and the isotope values of the Wocan-1 and Wocan-2 samples, while, the unknown value (X) represents the amount of seawater component.…”

Section: The Contributions Of Hydrothermal Fluid Evidence From S Isomentioning

confidence: 99%

Mineralogical and Geochemical Signatures of Metalliferous Sediments in Wocan-1 and Wocan-2 Hydrothermal Sites on the Carlsberg Ridge, Indian Ocean

et al. 2019

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In this paper, we conduct a comparative study on the mineralogy and geochemistry of metalliferous sediment collected near the active hydrothermal site (Wocan-1) and inactive hydrothermal site (Wocan-2) from Wocan Hydrothermal Field, on the Carlsberg Ridge (CR), northwest Indian Ocean. We aim to understand the spatial variations in the primary and post-depositional conditions and the intensity of hydrothermal circulations in the Wocan hydrothermal systems. Sediment samples were collected from six stations which includes TVG-07, TVG-08 (Wocan-1), TVG-05, TVG-10 (Wocan-2), TVG-12 and TVG-13 (ridge flanks). The mineralogical investigations show that sediment samples from Wocan-1 and Wocan-2 are composed of chalcopyrite, pyrite, sphalerite, barite, gypsum, amorphous silica, altered volcanic glass, Fe-oxides, and hydroxides. The ridge flank sediments are dominated by biogenic calcite and foraminifera assemblages. The bulk sediment samples of Wocan-1 have an elevated Fe/Mn ratio (up to ~1545), with lower U contents (<7.4 ppm) and U/Fe ratio (<~1.8 × 10−5). The sulfide separates (chalcopyrite, pyrite, and sphalerite) are enriched in Se, Co, As, Sb, and Pb. The calculated sphalerite precipitation temperature (Sph.PT) yields ~278 °C. The sulfur isotope (δ34S) analysis returned a light value of 3.0–3.6‰. The bulk sediment samples of Wocan-2 have a lower Fe/Mn ratio (<~523), with high U contents (up to 19.6 ppm) and U/Fe ratio (up to ~6.2 × 10−5). The sulfide separates are enriched in Zn, Cu, Tl, and Sn. The calculated Sph.PT is ~233 °C. The δ34S returned significant values of 4.1–4.3‰ and 6.4–8.7‰ in stations TVG-10 and TVG-05, respectively. The geochemical signatures (e.g., Fe/Mn and U/Fe ratio, mineral chemistry of sulfides separates, and S-isotopes and Sph.PT) suggest that sediment samples from Wocan-1 are located near intermediate–high temperature hydrothermal discharge environments. Additionally, relatively low δ34S values exhibit a lower proportion (less than 20%) of seawater-derived components. The geochemical signatures suggest that sediment samples from Wocan-2 has undergone moderate–extensive oxidation and secondary alterations by seawater in a low–intermediate temperature hydrothermal environments. Additionally, the significant δ34S values of station TVG-05 exhibit a higher estimated proportion (up to 41%) of seawater-derived components. Our results showed pervasive hydrothermal contributions into station TVG-08 relative to TVG-07, it further showed the increased process of seafloor weathering at TVG-05 relative to TVG-10.

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Section: The Contributions Of Hydrothermal Fluid Evidence From S Isomentioning

confidence: 99%

Mineralogical and Geochemical Signatures of Metalliferous Sediments in Wocan-1 and Wocan-2 Hydrothermal Sites on the Carlsberg Ridge, Indian Ocean

et al. 2019

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“…Compared to sulfides from mid‐oceanic ridges, sulfides from the OT are notably enriched in Zn and Pb (Glasby & Notsu, ; Ishibashi, Ikegami, Tsuji, & Urabe, ). Studies on the rare earth elements (REEs), sulfur‐lead‐osmium‐zinc and noble gas isotopes, and the compositional characteristics of fluid inclusions of massive sulfides have shown that the endmembers of seawater, felsic volcanic rocks, and marine sediments may be the sources that formed the massive sulfides in the hydrothermal field of the OT (Halbach, Hansmann, Köppel, & Pracejus, ; Hongo & Nozaki, ; Hou, Zhang, & Qu, ; Lüders, Pracejus, & Halbach, ; Zeng et al, ; Zeng, Jiang, Qin, Zhai, & Hou, ; Zeng, Jiang, Zhai, & Qin, ; Zeng, Qin, & Zhai, ; Zeng, Zhai, & Du, ; Zhang, Zhai, Yu, Guo, & Wang, ). The Pb isotope compositions of galena in hydrothermal deposits in the middle OT also reflect that their metal sources originated from either the local volcanic rocks and/or the sediments via water–rock interactions (Totsuka et al, ).…”

Section: Geological Settingmentioning

confidence: 99%

Amphibole perspective to unravel the rhyolite as a potential fertile source for the Yonaguni Knoll IV hydrothermal system in the southwestern Okinawa Trough

Chen

Zeng

et al. 2019

Geological Journal

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Yonaguni Knoll IV is an active seafloor hydrothermal system containing massive Zn-Pb sulfides located in the southwestern OkinawaTrough. Previous research has suggested that the metal elements Zn and Pb were dominantly derived from the local volcanic rocks via water-rock interactions. However, it is not known whether or why the volcanic rocks are rich in these metals. Here, we performed a detailed in situ analysis of the major and trace elements in amphiboles in the rhyolite from the hydrothermal field to decipher the physical-chemical conditions of the silicic magma, including temperature (T), pressure (P), oxygen fugacity (fO 2 ), volatile contents (Cl, H 2 O) and metal contents (Pb, Zn), and investigate the behavior of the metals (Zn and Pb) during melt evolution. Our results show that the amphiboles are euhedral calcic magnesiohornblende and are in equilibrium with the hydrous and oxidized host rhyolitic melt characterized by high H 2 O melt (~5.8-6.5 wt.%), fO 2 (NNO +0.1 to +0.6) and SiO 2 melt (~71.73-72.62 wt.%) values at 761-797°C and 102-137 MPa, corresponding to an approximate depth of 3.9-5.2 km. In addition, the rare earth element (REE) patterns of the melt reconstructed from the amphiboles are analogous to those of cold-wetoxidized rhyolites. Thus, the amphiboles crystallized in a cold-wet-oxidized shallow silicic magma chamber. The high oxygen fugacity is inferred to have favored sulfur and metal enrichment in the melt. The most abundant metal in the amphiboles is Zn (237-294 ppm), and the concentrations of Pb are much lower (0.86-3.32 ppm), suggesting that Zn preferentially entered the amphibole and that Pb was retained in the melt. The Cl content of the amphiboles ranges from 0.11 to 0.25 wt.%, and accordingly, the Cl melt content estimated from the amphiboles varies from 0.15 to 0.28 wt. %. The low (Cl/H 2 O) melt ratios, which are <0.05 (i.e.,~0.02-0.04), suggest that the melt exsolved an H 2 O-rich vapor rather than a hydrosaline fluid with insufficient Cl to transport metals (e.g., Pb and Zn) into the vapor phase during degassing both in the magma chamber and during ascent. The lack of exsolved hydrosaline fluid and the high oxidation conditions resulted in the metal elements Pb and Zn remaining dissolved in the rhyolitic melt and/or partitioning into crystalline minerals upon eruption. Thus, the large volumes of rhyolitic magma that intruded into the upper crust of the Yonaguni Knoll IV hydrothermal field are a potential fertile source of these elements via leaching by heated seawater.

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“…It was suggested that the combination of the troctolite-alteration at the recharge zone near the oceanic core complex and subsequent basalt-alteration at the discharge zone under the Kairei is causing the distinct chemistry of the hydrothermal fluids [18,25]. Recent investigations have shown the presence of other hydrothermal deposits (Yokoniwa, and 25°09′S) in the area [26,28]. were optimized in order to provide a maximum in ion transmission, a low polyatomic cluster production rate (ThO/Th ≤ 0.03%; CuAr/Cu < 0.0025%) by hot plasma (normalized argon index NAI≈30; [33]) and a fast sample wash-out.…”

Section: Geological Backgroundmentioning

confidence: 99%

Trace Metals Distribution in Sulfide Minerals of the Ultramafic-Hosted Hydrothermal Systems: Example from the Kairei Vent Field, Central Indian Ridge

Wang¹,

Han²,

Petersen³

et al. 2018

Preprint

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The ultramafic-hosted Kairei vent field, located at 25°19′S, 70°02′E towards the northern end of the segment 1 of the Central Indian Ridge (CIR-S1) in a water depth of ~2450 m. This study aims to investigate the distribution of trace elements among sulfides of differing textures, and discuss the possible factors controlling the trace element distribution in those minerals by using LA-ICP-MS spot analyses as well as line scans. Our results show that there are distinct systematic trace element distributions throughout the different minerals：(1) Pyrite is divided into three types at the Kairei, including early-stage euhedral pyrites (py-I), sub-euhedral pyrites (py-II), and colloform pyrites (py-III). Pyrite is generally enriched in Mo, Au, As, Tl, Mn, and U. py-I have higher contents of Se, Te, Bi, and Ni, py-II are enriched in Au relative to py-I and py-III, but poor in Ni, py-III are enriched in Mo, Pb, and U but are poor in Se, Te, Bi, and Au. Variations in the concentrations of Se, Te, and Bi in pyrite are likely governed by the strong temperature gradient. Ni is generally lower than Co in pyrites, indicates that our samples precipitated at a high-temperature condition, whereas the extreme Co enrichment is likely from a magmatic heat source combined serpentinization reactions underlie the deposits. (2) Chalcopyrite is characterized by high concentrations of Co, Se, Te. The abundant of Se and Te in chalcopyrite cause by the high solubilities of Se and Te incorporated into chalcopyrite lattice at high temperature fluids. The concentration of Sb, As and Au is relatively low in chalcopyrite from the Kairei vent field. (3) Sphalerite from both the Zn-rich chimney is characterized by high concentrations of Sn, Co, Ga, Ge, Ag, Pb, Sb, As, and Cd, but depleted in Se, Te, Bi, Mo, Au, Ni, Tl, Mn, Ba, V, and U in comparison with the other minerals. The high concentration of Cd and Co is likely caused by the substitution of Cd2+ and Co2+ for Zn2+ in sphalerite. A high concentration of Pb accompanied by high Ag concentration in sphalerite indicating the Ag occurs in the microinclusions of Pb-bearing minerals such as galena. Au is generally low in sphalerite and strong correlate with Pb suggesting its presence in the microinclusions of galena. The strong correlation of As with Ge in sphalerite from Kairei suggests that they might precipitate under medium- to low-temperature with moderately reduced conditions. (4) Bornite-digenite is very low in most trace elements, except for Co, Se, and Bi. The high concentration of Se and Bi in all the sulfide minerals was observed in bornite-digenite can be explained by abundant Bi-selenide inclusions. Serpentinization in ultramafic-hosted hydrothermal systems might play an important role on Au enrichment in pyrite with low As contents. Compared with felsic-hosted seafloor massive sulfide (SMS) deposits, sulfide minerals from the ultramafic-hosted deposits show higher concentrations of Se and Te, but lower As, Sb, and Au concentrations attributed to the contribution of magmatic volatile input. Significant Se enrichment in chalcopyrite has been found from mafic-hosted SMSs indicate that the primary factor that controls the Se enrichment is its temperature-controlled mobility in fluids.

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Sulfur and lead isotopic compositions of massive sulfides from deep-sea hydrothermal systems: Implications for ore genesis and fluid circulation

Cited by 50 publications

References 114 publications

Mineralogical and Geochemical Signatures of Metalliferous Sediments in Wocan-1 and Wocan-2 Hydrothermal Sites on the Carlsberg Ridge, Indian Ocean

Mineralogical and Geochemical Signatures of Metalliferous Sediments in Wocan-1 and Wocan-2 Hydrothermal Sites on the Carlsberg Ridge, Indian Ocean

Amphibole perspective to unravel the rhyolite as a potential fertile source for the Yonaguni Knoll IV hydrothermal system in the southwestern Okinawa Trough

Trace Metals Distribution in Sulfide Minerals of the Ultramafic-Hosted Hydrothermal Systems: Example from the Kairei Vent Field, Central Indian Ridge

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