New Insights into the mineralogy of the Atlantis II deep metalliferous sediments, Red Sea.

Laurila, Tea E., Hannington, Mark D., Leybourne, Matthew, Petersen, Sven , Devey, Colin W. and Garbe-Schönberg, Dieter (2015) New Insights into the mineralogy of the Atlantis II deep metalliferous sediments, Red Sea. Open Access Geochemistry, Geophysics, Geosystems, 16 (12). pp. 4449-4478. DOI 10.1002/2015GC006010.

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Abstract

The Atlantis II Deep of the Red Sea hosts the largest known hydrothermal ore deposit on the ocean floor and the only modern analog of brine pool-type metal deposition. The deposit consists mainly of chemical-clastic sediments with input from basin-scale hydrothermal and detrital sources. A characteristic feature is the millimeter-scale layering of the sediments, which bears a strong resemblance to banded iron formation (BIF). Quantitative assessment of the mineralogy based on relogging of archived cores, detailed petrography, and sequential leaching experiments shows that Fe-(oxy)hydroxides, hydrothermal carbonates, sulfides, and authigenic clays are the main “ore” minerals. Mn-oxides were mainly deposited when the brine pool was more oxidized than it is today, but detailed logging shows that Fe-deposition and Mn-deposition also alternated at the scale of individual laminae, reflecting short-term fluctuations in the Lower Brine. Previous studies underestimated the importance of nonsulfide metal-bearing components, which formed by metal adsorption onto poorly crystalline Si-Fe-OOH particles. During diagenesis, the crystallinity of all phases increased, and the fine layering of the sediment was enhanced. Within a few meters of burial (corresponding to a few thousand years of deposition), biogenic (Ca)-carbonate was dissolved, manganosiderite formed, and metals originally in poorly crystalline phases or in pore water were incorporated into diagenetic sulfides, clays, and Fe-oxides. Permeable layers with abundant radiolarian tests were the focus for late-stage hydrothermal alteration and replacement, including deposition of amorphous silica and enrichment in elements such as Ba and Au.

Document Type: Article
Additional Information: WOS:000368814000023
Keywords: Red Sea, Atlantis-II-Deep, metalliferous muds, hydrothermal sediments
Research affiliation: OceanRep > GEOMAR > FB4 Dynamics of the Ocean Floor > FB4-MUHS > Marine Mineralische Rohstoffe
OceanRep > The Future Ocean - Cluster of Excellence > FO-R03
Kiel University
Kiel University > Kiel Marine Science
OceanRep > The Future Ocean - Cluster of Excellence
OceanRep > GEOMAR > FB4 Dynamics of the Ocean Floor > FB4-MUHS
Refereed: Yes
Open Access Journal?: No
DOI etc.: 10.1002/2015GC006010
ISSN: 1525-2027
Projects: Future Ocean
Date Deposited: 05 Jan 2016 09:12
Last Modified: 23 Sep 2019 19:49
URI: http://oceanrep.geomar.de/id/eprint/30795

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