Mineralogy and geochemistry of hydrothermal sulphide from a submarine volcanic high at 18°36.4'S Central Lau Spreading Center, Southwest Pacific
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Abstract: We report the mineralogy and geochemistry of hydrothermal sulphide from the crater of a volcanic high near 18°36.4′S of the Central Lau Spreading Center. During 1990s, that volcanic structure was reported active and sulphide samples were collected by MIR submersible. A section of a chimney-like structure from the crater-floor was studied here. The Fe-depleted sphalerites, and Co-depleted pyrites in that chimney were similar to those commonly found in low to moderate temperature (<300℃) sulphides from sediment-starved hydrothermal systems. Bulk analyses of three parts of that chimney section showed substantial enrichment of Zn (18%–20%) and Fe (14%–27%) but depletion of Cu (0.8%–1.3%). In chondrite-normalized rare earth element-patterns, the significant negative Ce-anomalies (Ce/Ce*=0.27–0.39) and weakly positive Eu-anomalies (Eu/Eu*=1.60–1.68) suggested sulphide mineralisation took place from reduced low-temperature fluid. The depleted concentration of lithophiles in this sulphide indicates restricted contribution of sub-ducting plate in genesis of source fluid as compared to those from other parts of Lau Spreading Centre. Uniform mineralogy and bulk composition of subsamples across the chimney section suggests barely any alteration of fluid composition and/or mode of mineralisation occurred during its growth.
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Key words:
- Central Lau Spreading Center /
- hydrothermal sulphide /
- mineralogy /
- geochemistry
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Figure 1. Location of sulphide sampling site. a. Seafloor topography of the Lau Basin in the Southwest Pacific Ocean (modified after Paropkari et al. (2010)). The red box at the central part of the basin marks the location of the MIR diving site, A3 (dive No. M2231). b. The seafloor image of the Central Lau Spreading Center, displaying the sampling site over the volcanic high within the valley of the spreading axis. KTJ: Kings Triple Junction.
Figure 2. The sulphide deposit, M2231-10 from Central Lau Spreading Center, Lau Basin. a. The sulphide was sub-sampled into three sections, T31, G31 and B31; as marked by white lines. b. The cross-sectional view of the sub-sample G31, shows the openings of fluid channels (marked by the arrows).
Figure 3. Scanning electron microscope photographs and corresponding enegy dispersive X-ray spectroscopy (EDS) results of the surface of hydrothermal sulphide (M2231-10) from volcanic high at Central Lau Spreading Center (a); the magnified image of Fe-rich coating on B31 section (b); the inner surface of fluid channel in G31 section (c), and anhedral Zn-sulphide deposits in T31 section (d).
Figure 4. Back-scatter electrons microphotographs (obtained from EPMA) of mineral assemblages in polished sections of the layers, T31, and B31 of sulphide deposit, M2231-10. a. Sphalerite (white) and pyrite (light grey) embedded in silica (dark grey) in B31; b. colloform silica (grey) layered to concentric pyrite (off white) and sphalerite (white) in T31; c. pyrite embedded in amorphous silica in B31; d. pyrite and sphalerite in G31 section.
Figure 5. Comparison of cumulative concentration of Cu and Zn in relation to Cu/Zn ratios in hydrothermal sulphides from basalt and ultramafic hosted fields (modified after Fouquet et al. (2010)). CLSC: Central Lau Spreading Center; TAG: Trans-Atlantic Geotraverse; MAR: Mid-Atlantic Ridge; ODP: Ocean Drilling Program.
Figure 6. Spatial distribution of average Ba concentrations (wt%) of hydrothermal sulphides from vent fields along different spreading centres of the Lau Basin. The Ba contents in sulphides of Eastern Lau Spreading Center (ELSC) and Valu Fa Ridge (VFR) are obtained from Fouquet et al. (1991), Sun et al. (2012), and Evans et al. (2017).
Figure 7. Chondrite normalized REE-patterns of sub-samples from hydrothermal chimney, M2231-10. Those REE-patterns are compared with other sphalerite and pyrite-rich sulphides from Okinawa Trough (Hongo and Nozaki, 2001); Lau Basin (Paropkari et al., 2010); Mariana volcanic arc (Hein et al., 2014); Fiji Basin (Zeng et al., 2015) in the western Pacific.
Table 1. Mineralogical composition of three sections in hydrothermal sulphide sample, M2231-10 from the crater-floor of the volcanic high at Central Lau Spreading Center, Lau Basin
Top layer (T31) Middle layer around the central groove (G31) Bottom layer (B31) Major minerals sphalerite, opaline silica sphalerite, pyrite, opaline silica pyrite, sphalerite Trace minerals pyrite, galena marcasite galena, opaline silica 
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Table 2. The elemental composition of major minerals (e.g., pyrite, sphalerite, and opaline silica) in three sub-samples of hydrothermal sulphide, M2231-10 from the volcanic high at Central Lau Spreading Center, Lau Basin. The below detection limit (bdl) of microprobe analyses corresponds to the concentration <0.01%
Sample Pyrite Fe/% Co/% Ni/% Cu/% Zn/% Si/% S/% Cd/% Total/% T31 47.79 0.02 0.01 0.02 0.01 0.06 52.44 bdl 100.4 49.50 0.01 0.01 0.02 0.04 1.21 49.51 bdl 100.3 45.14 0.03 0.02 0.02 0.01 0.09 54.59 bdl 99.9 46.59 bdl bdl 0.03 bdl 0.05 53.86 bdl 100.5 47.30 0.02 bdl bdl bdl 0.02 53.42 bdl 100.8 47.13 bdl bdl bdl 0.04 0.02 53.52 bdl 100.7 Sample Sphalerite Fe/% Co/% Ni/% Cu/% Zn/% Si/% S/% Cd/% Total/% T31 4.54 0.02 0.06 0.03 53.11 0.13 33.92 0.41 92.2 3.65 0.02 0.06 0.04 55.47 0.02 33.76 0.21 93.2 3.62 bdl 0.02 0.01 52.94 1.35 32.66 0.42 91.0 3.04 bdl 0.05 bdl 59.45 0.49 33.39 0.59 97.0 Sample Opaline silica Al/% Fe/% Co/% Cu/% Zn/% Si/% S/% O/% Total/% T31 0.03 0.33 bdl bdl 0.01 46.66 0.13 53.28 100.4 0.14 0.38 0.01 bdl 0.08 46.51 0.14 53.22 100.5 G31 0.29 0.51 bdl bdl 0.04 46.01 0.18 53.05 100.1 0.30 0.35 0.02 bdl 0.09 46.24 0.13 53.14 100.3 0.08 0.31 0.02 bdl 0.07 46.55 0.21 53.26 100.5
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Table 3. The concentration of major and trace elements in three sub-samples of hydrothermal sulphide (M2231-10) from volcanic high at Central Lau Spreading Center (CLSC), Lau Basin
Elements Sections of hydrothermal sulphide from CLSC (M2231-10) T31 G31 B31 Major elements/wt% Mn 0.08 0.08 0.10 Fe 14.50 20.10 26.90 Cu 1.32 1.01 0.88 Zn 20.40 19.60 18.10 Cu+Zn 21.70 20.60 19.90 Cu/Zn 0.06 0.05 0.10 Trace elements/10−6 Sc 12.13 13.74 13.30 Ti 89.90 93.41 85.14 V 66.24 69.55 71.30 Ni 0.91 0.95 1.59 Rb 4.94 4.87 4.12 Sr 2.06 2.17 2.05 Y 0.26 0.17 0.31 Zr 4.77 5.51 4.65 Nb 0.38 0.40 0.41 Mo 13.87 14.56 17.15 Cd 1 319 1 230 856 Sn 20.12 19.51 20.98 Ba 27.68 29.07 34.86 Hf 0.11 0.23 0.22 W 1.59 1.13 1.07 Pb 906 1 029 1 082 Th 0.062 0.091 0.060 U 0.11 0.078 0.097 Ba/Nb 72.70 72.60 85.00
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Table 4. The concentrations of rare earth elements (×10−6) in three sub-samples of hydrothermal sulphide (M2231-10) collected from volcanic high at Central Lau Spreading Center (CLSC), Lau Basin
REEs Sections of hydrothermal sulphide
from CLSC (M223-10)T31 G31 B31 La 0.348 0.285 0.385 Ce 0.358 0.284 0.256 Pr 0.055 0.051 0.057 Nd 0.218 0.205 0.270 Sm 0.068 0.046 0.059 Eu 0.081 0.070 0.071 Gd 0.062 0.044 0.038 Tb 0.010 0.007 0.008 Dy 0.046 0.036 0.039 Ho 0.010 0.007 0.012 Er 0.027 0.028 0.033 Tm 0.005 0.004 0.004 Yb 0.037 0.029 0.027 Lu 0.009 0.007 0.007 ∑REE 1.334 1.103 1.265 (Nd/Yb)CN 2.06 2.46 3.48 (Eu/Eu*)CN 1.61 1.68 1.60 (Ce/Ce*)CN 0.39 0.34 0.27 Y/Ho (molar) 48.2 45.0 47.9 Note: CN=chondrite normalized values (from Sun and McDonough (1989)); (Eu/Eu*)CN=EuCN/(SmCN+GdCN)0.5 and (Ce/Ce*)CN=CeCN/(LaCN+PrCN)0.5.
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Anders E, Grevesse N. 1989. Abundances of the elements: meteoritic and solar. Geochimica et Cosmochimica Acta, 53(1): 197–214. doi: 10.1016/0016-7037(89)90286-X Barrett T J, Jarvis I, Jarvis K E. 1990. Rare earth element geochemistry of massive sulfides-sulfates and gossans on the Southern Explorer Ridge. Geology, 18(7): 583–586. doi: 10.1130/0091-7613(1990)018<0583:REEGOM>2.3.CO;2 Bau M, Mӧller P, Dulski P. 1997. Yttrium and lanthanides in eastern Mediterranean seawater and their fractionation during redox-cycling. Marine Chemistry, 56(1–2): 123–131 Bendel V, Fouquet Y, Auzende J M, et al. 1993. The White Lady hydrothermal field, north Fiji Back-Arc Basin, Southwest Pacific. Economic Geology, 88(8): 2237–2245. doi: 10.2113/gsecongeo.88.8.2237 Dekov V M, Lalonde S V, Kamenov G D, et al. 2015. Geochemistry and mineralogy of a silica chimney from an inactive seafloor hydrothermal field (East Pacific Rise, 18°S). Chemical Geology, 415: 126–140. doi: 10.1016/j.chemgeo.2015.09.017 Embley R W, Baker E T, Chadwick Jr W W, et al. 2004. Explorations of Mariana arc volcanoes reveal new hydrothermal systems. EOS, Transactions American Geophysical Union, 85(4): 37–40 Evans G N, Tivey M K, Seewald J S, et al. 2017. Influences of the Tonga Subduction Zone on seafloor massive sulfide deposits along the Eastern Lau Spreading Center and Valu Fa Ridge. Geochimica et Cosmochimica Acta, 215: 214–246. doi: 10.1016/j.gca.2017.08.010 Falloon T J, Malahoff A, Zonenshain L P, et al. 1992. Petrology and Geochemistry of back-arc basin basalts from Lau Basin spreading ridges at 15°, 18° and 19°S. Mineralogy and Petrology, 47(1): 1–35. doi: 10.1007/BF01165295 Fouquet Y, Cambon P, Etoubleau J, et al. 2010. Geodiversity of hydrothermal processes along the Mid-Atlantic ridge and ultramafic-hosted mineralization: a new type of oceanic Cu-Zn-Co-Au volcanogenic massive sulfide deposit. In: Rona P A, Devey C W, Dyment J, et al., eds. Diversity of Hydrothermal Systems on Slow Spreading Ocean Ridges. Washington: American Geophysical Union, 321–367 Fouquet Y, von Stackelberg U, Charlou J L, et al. 1991. Hydrothermal activity in the Lau back-arc basin: sulfides and water chemistry. Geology, 19(4): 303–306. doi: 10.1130/0091-7613(1991)019<0303:HAITLB>2.3.CO;2 Glasby G P, Iizasa K, Yuasa M, et al. 2000. Submarine hydrothermal mineralization on the Izu–bonin arc, south of Japan: an overview. Marine Georesources & Geotechnology, 18(2): 141–176 Glasby G P, Notsu K. 2003. Submarine hydrothermal mineralization in the Okinawa Trough, SW of Japan: an overview. Ore Geology Reviews, 23(3–4): 299–339 Grant H L J, Hannington M D, Petersen S, et al. 2018. Constraints on the behavior of trace elements in the actively-forming TAG deposit, Mid-Atlantic ridge, based on LA-ICP-MS analyses of pyrite. Chemical Geology, 498: 45–71. doi: 10.1016/j.chemgeo.2018.08.019 Hawkins Jr J W. 1995. The geology of the Lau Basin. In: Taylor B, ed. Backarc Basins: Tectonics and Magmatism. Boston: Springer, 63–138 Hein J R, de Ronde C E J, Koski R A, et al. 2014. Layered hydrothermal barite-sulfide mound field, East Diamante caldera, Mariana volcanic arc. Economic Geology, 109(8): 2179–2206. doi: 10.2113/econgeo.109.8.2179 Hongo Y, Nozaki Y. 2001. Rare earth element geochemistry of hydrothermal deposits and Calyptogena shell from the Iheya ridge vent field, Okinawa Trough. Geochemical Journal, 35(5): 347–354. doi: 10.2343/geochemj.35.347 James R H, Elderfield H. 1996. Chemistry of ore-forming fluids and mineral formation rates in an active hydrothermal sulfide deposit on the Mid-Atlantic Ridge. Geology, 24(12): 1147–1150. doi: 10.1130/0091-7613(1996)024<1147:COOFFA>2.3.CO;2 James R H, Green D R H, Stock M J, et al. 2014. Composition of hydrothermal fluids and mineralogy of associated chimney material on the East Scotia Ridge back-arc spreading centre. Geochimica et Cosmochimica Acta, 139: 47–71. doi: 10.1016/j.gca.2014.04.024 Karig D E. 1970. Ridges and basins of the Tonga-Kermadec island arc system. Journal of Geophysical Research, 75(2): 239–254. doi: 10.1029/JB075i002p00239 Keith M, Haase K M, Schwarz-Schampera U, et al. 2014. Effects of temperature, sulfur, and oxygen fugacity on the composition of sphalerite from submarine hydrothermal vents. Geology, 42(8): 699–702. doi: 10.1130/G35655.1 Keith M, Häckel F, Haase K M, et al. 2016. Trace element systematics of pyrite from submarine hydrothermal vents. Ore Geology Reviews, 72: 728–745. doi: 10.1016/j.oregeorev.2015.07.012 Kim J, Son S K, Son J W, et al. 2009. Venting sites along the Fonualei and Northeast Lau Spreading Centers and evidence of hydrothermal activity at an off-axis caldera in the northeastern Lau Basin. Geochemical Journal, 43(1): 1–13. doi: 10.2343/geochemj.0.0164 Koski R A, Jonasson I R, Kadko D C, et al. 1994. Compositions, growth mechanisms, and temporal relations of hydrothermal sulfide-sulfate-silica chimneys at the northern Cleft segment, Juan de Fuca Ridge. Journal of Geophysical Research, 99(B3): 4813–4832. doi: 10.1029/93JB02871 Lehrmann B, Stobbs I J, Lusty P A J, et al. 2018. Insights into extinct seafloor massive sulfide mounds at the TAG, Mid-Atlantic ridge. Minerals, 8(7): 302. doi: 10.3390/min8070302 Lisitzin A P, Lukashin V N, Gordeev V V, et al. 1997. Hydrological and geochemical anomalies associated with hydrothermal activity in SW Pacific marginal and back-arc basins. Marine Geology, 142(1–4): 7–45 Malahoff A, Falloon T. 1991. Preliminary report of the RV Akademik Mstislav Keldysh/ MIR cruise 1990, Lau Basin Leg (May 7−21), on behalf of the Keldysh/ Mir Science Team. http://pacific-data.sprep.org/dataset/preliminary -report-akademik-mstislav-keldyshmir-cruise-1990-lau-basin-leg-may-7-21-1[2022-5-1] Maslennikov V V, Cherkashov G, Artemyev D A, et al. 2020. Pyrite varieties at Pobeda hydrothermal fields, Mid-Atlantic ridge 17°07′–17°08′N: LA-ICP-MS data deciphering. Minerals, 10(7): 622. doi: 10.3390/min10070622 Maslennikov V V, Maslennikova S P, Large R R, et al. 2017. Chimneys in Paleozoic massive sulfide mounds of the Urals VMS deposits: mineral and trace element comparison with modern black, grey, white and clear smokers. Ore Geology Reviews, 85: 64–106. doi: 10.1016/j.oregeorev.2016.09.012 Meng Xingwei, Li Xiaohu, Chu Fengyou, et al. 2020. Trace element and sulfur isotope compositions for pyrite across the mineralization zones of a sulfide chimney from the East Pacific Rise (1–2°S). Ore Geology Reviews, 116: 103209. doi: 10.1016/j.oregeorev.2019.103209 Mills R A, Elderfield H. 1995. Rare earth element geochemistry of hydrothermal deposits from the active TAG mound, 26°N mid-Atlantic ridge. Geochimica et Cosmochimica Acta, 59(17): 3511–3524. doi: 10.1016/0016-7037(95)00224-N Mottl M J, Seewald J S, Wheat C G, et al. 2011. Chemistry of hot springs along the Eastern Lau Spreading Center. Geochimica et Cosmochimica Acta, 75(4): 1013–1038. doi: 10.1016/j.gca.2010.12.008 Münch U, Blum N, Halbach P. 1999. Mineralogical and geochemical features of sulfide chimneys from the MESO zone, Central Indian Ridge. Chemical Geology, 155(1–2): 29–44 Münch U, Lalou C, Halbach P, et al. 2001. Relict hydrothermal events along the super-slow Southwest Indian spreading ridge near 63°56′E—mineralogy, chemistry and chronology of sulfide samples. Chemical Geology, 177(3–4): 341–349 Paropkari A L, Ray D, Balaram V, et al. 2010. Formation of hydrothermal deposits at Kings Triple Junction, northern Lau back-arc basin, SW Pacific: the geochemical perspectives. Journal of Asian Earth Sciences, 38(3–4): 121–130 Parson L M, Pearce J A, Murton B J, et al. 1990. Role of ridge jumps and ridge propagation in the tectonic evolution of the Lau back-arc basin, Southwest Pacific. Geology, 18(5): 470–473. doi: 10.1130/0091-7613(1990)018<0470:RORJAR>2.3.CO;2 Pearce J A, Ernewein M, Bloomer S H, et al. 1994. Geochemistry of Lau Basin volcanic rocks: influence of ridge segmentation and arc proximity. Geological Society, London, Special Publications, 81(1): 53–75 Perrin A, Goes S, Prytulak J, et al. 2018. Mantle wedge temperatures and their potential relation to volcanic arc location. Earth and Planetary Science Letters, 501: 67–77. doi: 10.1016/j.jpgl.2018.08.011 Ray D, Banerjee R, Balakrishnan S, et al. 2017. S- and Sr-isotopic compositions in barite–silica chimney from the Franklin Seamount, Woodlark Basin, Papua New Guinea: constraints on genesis and temporal variability of hydrothermal fluid. International Journal of Earth Sciences, 106(5): 1723–1733. doi: 10.1007/s00531-016-1381-5 Ray D, Banerjee R, Mazumder A, et al. 2018. Mineralogical and geochemical variation in hydrothermal sulfides from Vienna Woods field, Manus Basin, Papua New Guinea: constraints on their evolution. Acta Oceanologica Sinica, 37(4): 22–33. doi: 10.1007/s13131-018-1194-4 Ray D, Kota D, Das P, et al. 2014. Microtexture and distribution of minerals in hydrothermal barite-silica chimney from the Franklin Seamount, SW Pacific: Constraints on mode of formation. Acta Geologica Sinica-English Edition, 88(1): 213–225. doi: 10.1111/1755-6724.12192 Scott S D. 1983. Chemical behaviour of sphalerite and arsenopyrite in hydrothermal and metamorphic environments. Mineralogical Magazine, 47(345): 427–435. doi: 10.1180/minmag.1983.047.345.03 Stoffers P, Worthington T J, Schwarz-Schampera U, et al. 2006. Submarine volcanoes and high-temperature hydrothermal venting on the Tonga arc, Southwest Pacific. Geology, 34(6): 453–456. doi: 10.1130/G22227.1 Sun Zhilei, Zhou Huaiyang, Yang Qunhui, et al. 2012. Growth model of a hydrothermal low-temperature Si-rich chimney: Example from the CDE hydrothermal field, Lau Basin. Science China Earth Sciences, 55(10): 1716–1730. doi: 10.1007/s11430-012-4485-1 Suzuki R, Ishibashi J I, Nakaseama M, et al. 2008. Diverse range of mineralization induced by phase separation of hydrothermal fluid: case study of the Yonaguni Knoll IV hydrothermal field in the Okinawa Trough back-arc basin. Resource Geology, 58(3): 267–288. doi: 10.1111/j.1751-3928.2008.00061.x Tivey M K. 1995. The influence of hydrothermal fluid composition and advection rates on black smoker chimney mineralogy: insights from modeling transport and reaction. Geochimica et Cosmochimica Acta, 59(10): 1933–1949. doi: 10.1016/0016-7037(95)00118-2 Wang Shujie, Li Huaiming, Zhai Shikui, et al. 2017a. Geochemical features of sulfides from the deyin-1 hydrothermal field at the southern Mid-Atlantic ridge near 15°S. Journal of Ocean University of China, 16(6): 1043–1054. doi: 10.1007/s11802-017-3316-6 Wang Shujie, Li Huaiming, Zhai Shikui, et al. 2017b. Mineralogical characteristics of polymetallic sulfides from the Deyin-1 hydrothermal field near 15°S, southern Mid-Atlantic Ridge. Acta Oceanologica Sinica, 36(2): 22–34. doi: 10.1007/s13131-016-0961-3 Wohlgemuth-Ueberwasser C C, Viljoen F, Petersen S, et al. 2015. Distribution and solubility limits of trace elements in hydrothermal black smoker sulfides: an in-situ LA-ICP-MS study. Geochimica et Cosmochimica Acta, 159: 16–41. doi: 10.1016/j.gca.2015.03.020 Zellmer K E, Taylor B. 2001. A three-plate kinematic model for Lau basin opening. Geochemistry, Geophysics, Geosystems, 2(5): 2000GC000106 Zeng Zhigang, Ma Yao, Yin Xuebo, et al. 2015. Factors affecting the rare earth element compositions in massive sulfides from deep-sea hydrothermal systems. Geochemistry, Geophysics, Geosystems, 16(8): 2679–2693 Zhang Xia, Zhai Shikui, Yu Zenghui, et al. 2018. Mineralogy and geological significance of hydrothermal deposits from the Okinawa Trough. Journal of Marine Systems, 180: 124–131. doi: 10.1016/j.jmarsys.2016.11.007 -
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