Element enrichment and U-series isotopic characteristics of the hydrothermal sulfides at Jade site in the Okinawa Trough

Abstract

The geochemical and U-series isotopic characteristics of hydrothermal sulfide samples from the Jade site (127°04.5′E, 27°15′N, water depth 1300-1450 m) at Jade site in the Okinawa Trough were analyzed. In the hydrothermal sulfide samples bearing sulfate (samples HOK1 and HOK2), the LREEs are relatively enriched. All the hydrothermal sulfide samples except HOK1 belong to Zn-rich hydrothermal sulfide. In comparison with Zn-rich hydrothermal sulfides from other fields, the contents of Zn, Pb, Ag, Cd, Au and Hg are higher, the contents of Fe, Al, Cr, Co, Ni, Sr, Te, Cs, Ti and U lower, and the 210 Pb radioactivity ratios and 210 Pb/Pb ratios very low. In the hydrothermal sulfide mainly composed of sphalerite, the correlations between rare elements Hf and U, and Hf and Mn as well as that between dispersive elements Ga and Zn, are strongly positive; also the contents of Au and Ag are related to Fe-sulfide, because the low temperature promotes enrichment of Au and Ag. Meanwhile, the positive correlations between Fe and Bi and between Zn and Cd are not affected by the change of mineral assemblage. Based on the 210 Pb/Pb ratios of hydrothermal sulfide samples (3.99×10 −5 -5.42×10 −5 ), their U isotopic composition ( 238 U content 1.15-2.53 ppm, 238 U activity 1.07-1.87 dpm/g, 234 U activity 1.15-2.09 dpm/g and 234 U/ 238 U ratio 1.07-1.14) and their 232 Th and 230 Th contents are at base level, and the chronological age of hydrothermal sulfide at Jade site in the Okinawa Trough is between 200 and 2000 yr.U-series isotope, Trace-element constituents, hydrothermal sulfide, Jade site, Okinawa Trough Jade site was first discovered on the northeast slope of the Izena Cauldron in the Okinawa Trough by the Deep-tow Ocean Floor Observing System (OFOS) during the "Sonne" SO-56 cruise in July, 1988 [1][2][3] . In August of 1988, by employing the deep-tow system of JAMSTEC and Shinkai 2000 ROV, hundreds of sulfide chimneys (0.1 m to several meters high) were observed at this site [4] .Since then, the mineralogy, geochemistry and fluid inclusions of hydrothermal sulfide at this site have been studied [5][6][7][8][9] . For example, previous studies suggest that the hydrothermal sulfides at this site are mainly composed of Fe-sulfide (pyrite, marcasite), Zn-sulfide (sphalerite, wurtzite), Cu-sulfide (chalcopyrite, isocubanite), cryptocrystalline silicon dioxide, sulfate (anhydrite, barite), Pb-sulfide (galenite, sulfonates), As-sulfide (dimorphine, realgarite), Cu-As-Sb-sulfide, (tennantite,

Hydrothermal Activity in the Okinawa Trough Back-Arc Basin: Geological Background and Hydrothermal Mineralization

“…Lead isotope data from ores, igneous rocks and sediments suggested that both surrounding sediments and volcanic rocks contributed comparable amounts of lead to the deposit (Halbach et al 1997). Zeng et al (2009) reported minor elements composition and U-series isotope data of sulfide/ sulfate deposits. Noguchi et al (2011) reported 87 Sr/ 86 Sr data for barite collected from the Jade and Hakurei fields, which suggest a significant contribution of sediment.…”

Evaluating Hydrothermal System Evolution Using Geochronological Dating and Biological Diversity Analyses

“…Age data of JADE site in Izena Hole were not obtained in this study. Consequently, the data range is in parenthesis and denoted by a "*" symbol (Zeng et al 2009) species (e.g. large animals have lower genetic diversity than small ones; Beebee and Rowe 2008), and the dating of vent activity with genetic diversity can only provide relative ages for many species.…”

Factors affecting the rare earth element compositions in massive sulfides from deep‐sea hydrothermal systems

“…[], and Zeng et al . []. The symbols indicate the ∑REE values in the sulfides from the EPR 13°N and 1°S–2°S, KHF, EHF, “A” area, S99HF, and LHF.…”

“…In addition, REE data may be used to evaluate the physicochemical conditions of hydrothermal fluids [Michard et al, 1983;Michard and Albarède, 1986;Michard, 1989;Klinkhammer et al, 1994;James et al, 1995;Douville et al, 1999;Bach et al, 2003;Mills and Elderfield, 1995]. As such, REE data provide important information about (1) the geochemical nature of ancient hydrothermal activity [Rimskaya-Korsakova and Dubinin, 2003;Schmidt et al, 2010;Cole et al, 2014]; (2) the impact of hydrothermal activity on the chemical mass balance of elements between sulfides and seawater [German et al, 1990;Mitra et al, 1994;Bau and Dulski, 1999;Sherrell et al, 1999]; (3) magmatic degassing in seafloor hydrothermal systems [Craddock et al, 2010]; and (4) the formation conditions and sources of seafloor sulfides, sulfates, and native sulfur balls and chimneys [e.g., Graf, 1977;Alt, 1988;Barrett et al, 1990;Gillis et al, 1990;Mills and Elderfield, 1995;Bach et al, 2003;Rimskaya-Korsakova and Dubinin, 2003;Zeng et al, 2007Zeng et al, , 2009Zeng et al, , 2010Zeng et al, , 2011.…”

“…Sources: sulfide data for TAG, Snake Pit (SP), EPR 138N, and New Brunswick (NB) fromMills and Elderfield [1995],Gillis et al [1990],Zeng et al [2010],and Graf [1977]. Green Seamount (GS) Si-rich sulfide, Southern Explorer Ridge (SER) sulfides-sulfates, and JADE sulfides-sulfates data fromAlt [1988],Barrett et al [1990], andZeng et al [2009]. The symbols indicate the P REE values in the sulfides from the EPR 138N and 18S-28S, KHF, EHF, ''A'' area, S99HF, and LHF.…”