The chemistry of hydrothermal mounds near the Galapagos Rift

Corliss, John B.; Lyle, Mitchell W; Dymond, Jack; Crane, Kathleen

doi:10.1016/0012-821x(78)90070-5

Cited by 265 publications

(131 citation statements)

References 28 publications

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“…Marine hydrothermal nontronites commonly are low in A1 (Table 2). Similar low A1 contents were reported by Corliss et al (1978) and more recently by McMurtry et al (1983) for nontronite from the Galapagos hydrothermal mound. The Fe content of the clay from core KL9 is high.…”

Section: Chemical Compositionsupporting

confidence: 89%

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Nontronite in a Deep-Sea Core from the South Pacific

Singer

Stoffers

Heller-Kallai

et al. 1984

Clays and clay miner.

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Abstract--Smectite close to the pure Fe end member of the nontronite-beidellite series was found in the fine clay separated from a 354-cm deep sediment core in the southwestern Pacific Basin. The mineral has a b-axis of 9.09/~ and an unusually low dehydroxylation temperature of 454~ and is composed of sheaves of fibers less than 50/~ wide. Its charge density is 5.09 x 10 -4 esu/cmL The charge originates mainly from the presence of 18% of the total Fe in tetrahedral positions, as determined by Mrssbauer analysis. Slight deviations of the infrared spectra from those reported for nontronites are probably due to the presence of more octahedral Mg. The presence of authigenic quartz in the same sample permits some speculation on the concentration of dissolved silicon during nontronite genesis. A 6~80 value of 26 + 0.3%o indicates a temperature of formation of about 22~ The Sr isotope ratio suggests that the nontronite formed at least 12 million years ago.

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Section: Chemical Compositionsupporting

confidence: 89%

“…Marine clays of hydrothermal origin, however, have been reported to approach the pure Fe end member (Corliss et al, 1978;Hoffert et al, 1978;Schrader et al, 1980;Moorby and Cronaw, 1983;McMurtry et al, 1983).…”

Section: Introductionmentioning

confidence: 99%

Nontronite in a Deep-Sea Core from the South Pacific

Singer

Stoffers

Heller-Kallai

et al. 1984

Clays and clay miner.

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“…Nontronite deposits have been described with sulphur deposits near active high temperature black and white smokers (Bischoff, 1972;Thompson et al, 1985;Köhler et al, 1994), but also in lower temperature off-axis hydrothermal systems (Corliss et al, 1978;Moorby and Cronan, 1983).…”

Section: Introductionmentioning

confidence: 99%

“…Such tests were conducted on an Fe(III)-rich deposit from the Galapagos hydrothermal mounds where biogenic calcareous sediment alternates with iron-rich clays. Initially these deposits were described as nontronite, based on bulk wet chemical analyses (Corliss et al, 1978;Moorby and Cronan, 1983), but these methods do not allow accurate characterization of the clay mineral structure. A detailed crystallochemical characterization using TEM-AEM (transmission analytical electron microscopy) analyses and Mossbauer spectroscopy was conducted on these Fe(III)-rich clays, revealing the presence of iron-rich montmorillonite and goethite (Buatier et al, 1989(Buatier et al, , 1993.…”

Section: Introductionmentioning

confidence: 99%

Conditions and mechanism for the formation of iron-rich Montmorillonite in deep sea sediments (Costa Rica margin): Coupling high resolution mineralogical characterization and geochemical modeling

Charpentier

Buatier

Jacquot³

et al. 2011

Geochimica et Cosmochimica Acta

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Wheat. Conditions and mechanism for the formation of iron-rich Montmorillonite in deep sea sediments (Costa Rica margin): Coupling high resolution mineralogical characterization and geochemical modeling. Geochimica et Cosmochimica Acta, Elsevier, 2011Elsevier, , 75 (6), pp.1397Elsevier, -1410Elsevier, . 10.1016Elsevier, /j.gca.2010 Conditions and mechanism for the formation of iron- AbstractIron-rich smectite is commonly described in the diagenetic fraction of deep-sea sediment, as millimeter to centimeter aggregates dispersed in the sediment, or as a coating on sedimentary particles or nodules. This study examines several factors to elucidate formation mechanisms of a particular iron-rich smectite and its potential transformation to glauconite. The study combines a detailed mineralogical investigation on natural samples and a chemical modeling approach to assess mineralogical reactions and pathways.Transmission electron microscopy (TEM) observations and analytical electron microscopy (TEM-AEM) analyses were conducted on microtomed samples of millimeter-to centimeter-long green grains. These grains are widespread in pelagic calcareous sediment from the Costa Rica margin. They are composed of pyrites that are partially dissolved and are surrounded by amorphous or very poorly crystallized iron-rich particles. Iron-rich montmorillonite grows from an amorphous precursor and its formation requires the input of Si, O, Mg, K, Na and Ca; our results suggest that these inputs are supported by the dissolution of sedimentary phases such as volcanic glasses, siliceous fossils and silicates.Thermodynamic modeling of fluid-sediment interactions was conducted with the geochemical computer code PhreeqC, using mineralogical and pore fluid compositions from sediment samples and calculated estimates for thermodynamic constants of smectites that are not maintained by the computer code. Simulations confirm the possibility that the green grains are the product of pyrite alteration by seawater under oxidizing conditions. The extent of smectite production is controlled by the kinetics of pyrite dissolution and fluid migration. The absence of aluminum in the Costa Rica margin system explains the formation of an iron-rich montmorillonite instead of glauconite, whereas the presence of calcite that buffers the system explains the formation of an iron-rich montmorillonite instead of iron oxides.

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“…The growth of these two types of deposits requires very slow or no sedimentation in the deep-sea basin or on old seamounts over a long geological time interval (on the order of millions of years). In contrast, recent hydrothermal manganese deposits have been observed only around the volcanically active areas, such as mid-oceanic ridges, backarc spreading centers, and submarine volcanos (Corliss et al, 1978;Lonsdale et al, 1980;Moorby et al, 1984;Usui et al, 1989).…”

Section: Introductionmentioning

confidence: 98%

Hydrothermal Manganese Minerals in Leg 126 Cores

Usui¹

1992

Proceedings of the Ocean Drilling Program

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During Ocean Drilling Program Leg 126, which drilled in the forearc and backarc areas of the Izu-Bonin Arc, three substantial manganese deposits were recovered from deep stratigraphic levels. The characteristics of the fossil manganese deposits are similar to those of modern submarine hydrothermal manganese deposits occurring on the seafloor in this area. Two of these manganese deposits-a coating on Pliocene pumice at Site 788 and a fracture infilling in Oligocene volcanic rock at Site 792-are clearly hydrothermal. They have high Mn/Fe ratios, lack divalent stabilizing interlayer cations, have large crystal sizes, and have 10 A d-spacings that are resistent to heating. Both of the manganese deposits were presumably deposited near the volcanic front during the initial rifting phases in the backarc and forearc areas. The third deposit consists of manganese minerals in semiconsolidated Miocene claystones at Site 793. This deposit may be the result of primary early-diagenetic manganese deposits that evolved into more stable hydrothermal-like minerals during later diagenesis after burial.

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The chemistry of hydrothermal mounds near the Galapagos Rift

Cited by 265 publications

References 28 publications

Nontronite in a Deep-Sea Core from the South Pacific

Nontronite in a Deep-Sea Core from the South Pacific

Conditions and mechanism for the formation of iron-rich Montmorillonite in deep sea sediments (Costa Rica margin): Coupling high resolution mineralogical characterization and geochemical modeling

Hydrothermal Manganese Minerals in Leg 126 Cores

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