Geochemistry of diffuse low-temperature hydrothermal fluids in the North Fiji basin

Koschinsky, Andrea; Seifert, Richard; Halbach, Peter; Bau, Michael; Brasse, S.; Carvalho, Leandro Machado de; Fonseca, Nuno

doi:10.1016/s0016-7037(01)00855-9

Cited by 39 publications

(19 citation statements)

References 56 publications

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“…Secular facies variation of exhalites associated with deepwater, Cu-rich VMS deposits is from Slack and Cannon (2009). stratigraphic level of the Cu-rich VMS deposit to ensure that they formed from the same hydrothermal system and not as separate systems that existed during periods of different water depths. Third, exhalites must be laterally extensive for >100 m along strike, in order to reflect precipitation from hydrothermal fluids that mixed with bottom waters near a vent or in a hydrothermal plume, as in modern VMS systems (German and Von Damm, 2004); smaller occurrences of isolated exhalites that lack stratigraphic continuity were probably deposited from diffuse, low-temperature (<50°C) fluids (Hein et al, 1999;Koschinsky et al, 2002) that may not record the redox state of coeval deep seawater. Fourth, it is important to exclude from consideration magnetite-rich lenses that formed by subsea-floor replacement and not as true exhalites, such as in the Gossan Hill VMS deposit in Western Australia (Sharpe and Gemmell, 2002), possibly as a result of nonredox transformations by hydrothermal fluids beneath the sea floor (Ohmoto, 2003) or by phase separation into vapor and brine in hydrothermal system (cf.…”

Section: Secular Patterns In Precambrian Vms-related Exhalitesmentioning

confidence: 99%

Iron Formation: The Sedimentary Product of a Complex Interplay among Mantle, Tectonic, Oceanic, and Biospheric Processes

Bekker¹,

Krapež²,

Slack³

et al. 2010

Economic Geology

849

494

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Iron formations are economically important sedimentary rocks that are most common in Precambrian sedimentary successions. Although many aspects of their origin remain unresolved, it is widely accepted that secular changes in the style of their deposition are linked to environmental and geochemical evolution of Earth. Two types of Precambrian iron formations have been recognized with respect to their depositional setting. Algoma-type iron formations are interlayered with or stratigraphically linked to submarine-emplaced volcanic rocks in greenstone belts and, in some cases, with volcanogenic massive sulfide (VMS) deposits. In contrast, larger Superior-type iron formations are developed in passive-margin sedimentary rock successions and generally lack direct relationships with volcanic rocks. The early distinction made between these two iron-formation types, although mimimized by later studies, remains a valid first approximation. Texturally, iron formations were also divided into two groups. Banded iron formation (BIF) is dominant in Archean to earliest Paleoproterozoic successions, whereas granular iron formation (GIF) is much more common in Paleoproterozoic successions. Secular changes in the style of iron-formation deposition, identified more than 20 years ago, have been linked to diverse environmental changes. Geochronologic studies emphasize the episodic nature of the deposition of giant iron formations, as they are coeval with, and genetically linked to, time periods when large igneous provinces (LIPs) were emplaced. Superior-type iron formation first appeared at ca. 2.6 Ga, when construction of large continents changed the heat flux at the core-mantle boundary. From ca. 2.6 to ca. 2.4 Ga, global mafic magmatism culminated in the deposition of giant Superior-type BIF in South Africa, Australia, Brazil, Russia, and Ukraine. The younger BIFs in this age range were deposited during the early stage of a shift from reducing to oxidizing conditions in the ocean-atmosphere system. Counterintuitively, enhanced magmatism at 2.50 to 2.45 Ga may have triggered atmospheric oxidation. After the rise of atmospheric oxygen during the GOE at ca. 2.4 Ga, GIF became abundant in the rock record, compared to the predominance of BIF prior to the Great Oxidation Event (GOE). Iron formations generally disappeared at ca. 1.85 Ga, reappearing at the end of the Neoproterozoic, again tied to periods of intense magmatic activity and also, in this case, to global glaciations, the so-called Snowball Earth events. By the Phanerozoic, marine iron deposition was restricted to local areas of closed to semiclosed basins, where volcanic and hydrothermal activity was extensive (e.g., backarc basins), with ironstones additionally being linked to periods of intense magmatic activity and ocean anoxia.Late Paleoproterozoic iron formations and Paleozoic ironstones were deposited at the redoxcline where biological and nonbiological oxidation occurred. In contrast, older iron formations were deposited in anoxic oceans, where ferrous iron oxid...

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Section: Secular Patterns In Precambrian Vms-related Exhalitesmentioning

confidence: 99%

Iron Formation: The Sedimentary Product of a Complex Interplay among Mantle, Tectonic, Oceanic, and Biospheric Processes

Bekker¹,

Krapež²,

Slack³

et al. 2010

Economic Geology

849

494

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“…In the LHF, the hydrothermal sulfide deposit is associated with ultramafic rocks located in a debris flow consisting of heterogeneous ultramafic and mafic intrusive rocks, including serpentinized harzburgite, serpentinized dunite, gabbronorite, and olivine-bearing basalt (e.g., Petersen et al, 2009;Zeng et al, 2014Zeng et al, , 2015a. In addition, in the North Fiji Basin, the S99HF is located immediately south of the triple junction point at 16°50´S and is hosted by basaltic rocks, the trace element composition of which indicates that magma generation was influenced by two different sources: normal mid-ocean ridge basalt (N-MORB) and ocean island basalt (OIB)-related to enriched mid-ocean ridge basalt (E-MORB) Nohara et al, 1994;Koschinsky et al, 2002;Kim et al, 2006). Figure 1 show the sampling location, depth, and mineralogy of the hydrothermal sulfide samples.…”

Section: Geological Setting and Sample Mineralogymentioning

confidence: 99%

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

Zeng

Chen

et al. 2017

Ore Geology Reviews

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“…As it can be seen in Table 2, the presence of all the metals as contaminants in dialysis concentrate samples represents a serious contamination source for hemodialysis patients. Furthermore, the hydrothermal fluid samples have all the metals at concentrations higher than in normal seawater, due to the wellknown metal enrichment that occurs in these fluids [34]. The recovery values between 93.90 and 106.50% in dialysis concentrates, between 92.62 and 108.91% in seawater and between 93.51 and 98.76% in hydrothermal fluids prove the satisfactory accuracy and applicability of the proposed method for the simultaneous ASV determination of the metals in these saline samples.…”

Section: Analytical Applicationmentioning

confidence: 99%

Simultaneous Determination of Cadmium, Lead, Copper, and Thallium in Highly Saline Samples by Anodic Stripping Voltammetry (ASV) Using Mercury‐Film and Bismuth‐Film Electrodes

Carvalho¹,

Nascimento²,

Koschinsky³

et al. 2007

Electroanalysis

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This paper describes a comparative study of the simultaneous determination of Cd(II), Pb(II), Tl(I), and Cu(II) in highly saline samples (seawater, hydrothermal fluids, and dialysis concentrates) by ASV using the mercury-film electrode (MFE) and the bismuth-film electrode (BiFE) as working electrodes. The features of MFE and BiFE as working electrodes for the single-run ASV determinations are shown and their performances are compared with that of HMDE under similar conditions. It was observed that the stripping peak of Tl(I) was well separated from Cd(II) and Pb(II) peaks in all the studied saline samples when MFE was used. Because of the severe overlapping of Bi(III) and Cu(II) stripping peaks in the ASV using BiFE, as well as the overlapping of Pb(II) and Tl(I) stripping peaks in the ASV using HMDE, the simultaneous determination of these metals was not possible in highly saline medium using these both working electrodes. The detection limits calculated for the metals using MFE and BiFE (deposition time of 60 s) were between 0.043 and 0.070 mg L À1 for Cd(II), between 0.060 and 0.10 mg L À1 for Pb(II) and between 0.70 and 8.12 mg L À1 for Tl(I) in the saline samples studied. The detection limits calculated for Cu(II) using the MFE were 0.15 and 0.50 mg L À1 in seawater/hydrothermal fluid and dialysis concentrate samples, respectively. The methods were applied to the simultaneous determination of Cd(II), Pb(II), Tl(I), and Cu(II) in samples of seawater, hydrothermal fluids and dialysis concentrates.

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Geochemistry of diffuse low-temperature hydrothermal fluids in the North Fiji basin

Cited by 39 publications

References 56 publications

Iron Formation: The Sedimentary Product of a Complex Interplay among Mantle, Tectonic, Oceanic, and Biospheric Processes

Iron Formation: The Sedimentary Product of a Complex Interplay among Mantle, Tectonic, Oceanic, and Biospheric Processes

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

Simultaneous Determination of Cadmium, Lead, Copper, and Thallium in Highly Saline Samples by Anodic Stripping Voltammetry (ASV) Using Mercury‐Film and Bismuth‐Film Electrodes

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