Red Sea Brine Pool Research Articles

Isolation and characterization of a heavy metal-resistant, thermophilic esterase from a Red Sea Brine Pool

The Red Sea Atlantis II brine pool is an extreme environment that displays multiple harsh conditions such as high temperature, high salinity and high concentrations of multiple, toxic heavy metals. The survival of microbes in such an environment by utilizing resistant enzymes makes them an excellent source of extremophilic enzymes. We constructed a fosmid metagenomic library using DNA isolated from the deepest and most secluded layer of this pool. We report the isolation and biochemical characterization of an unusual esterase: EstATII. EstATII is thermophilic (optimum temperature, 65°C), halotolerant (maintains its activity in up to 4.5 M NaCl) and maintains at least 60% of its activity in the presence of a wide spectrum of heavy metals. The combination of biochemical characteristics of the Red Sea Atlantis II brine pool esterase, i.e., halotolerance, thermophilicity and resistance to heavy metals, makes it a potentially useful biocatalyst.

Autotrophic Microbe Metagenomes and Metabolic Pathways Differentiate Adjacent Red Sea Brine Pools

In the Red Sea, two neighboring deep-sea brine pools, Atlantis II and Discovery, have been studied extensively, and the results have shown that the temperature and concentrations of metal and methane in Atlantis II have increased over the past decades. Therefore, we investigated changes in the microbial community and metabolic pathways. Here, we compared the metagenomes of the two pools to each other and to those of deep-sea water samples. Archaea were generally absent in the Atlantis II metagenome; Bacteria in the metagenome were typically heterotrophic and depended on aromatic compounds and other extracellular organic carbon compounds as indicated by enrichment of the related metabolic pathways. In contrast, autotrophic Archaea capable of CO2 fixation and methane oxidation were identified in Discovery but not in Atlantis II. Our results suggest that hydrothermal conditions and metal precipitation in the Atlantis II pool have resulted in elimination of the autotrophic community and methanogens.

Unique Prokaryotic Consortia in Geochemically Distinct Sediments from Red Sea Atlantis II and Discovery Deep Brine Pools

The seafloor is a unique environment, which allows insights into how geochemical processes affect the diversity of biological life. Among its diverse ecosystems are deep-sea brine pools - water bodies characterized by a unique combination of extreme conditions. The ‘polyextremophiles’ that constitute the microbial assemblage of these deep hot brines have not been comprehensively studied. We report a comparative taxonomic analysis of the prokaryotic communities of the sediments directly below the Red Sea brine pools, namely, Atlantis II, Discovery, Chain Deep, and an adjacent brine-influenced site. Analyses of sediment samples and high-throughput pyrosequencing of PCR-amplified environmental 16S ribosomal RNA genes (16S rDNA) revealed that one sulfur (S)-rich Atlantis II and one nitrogen (N)-rich Discovery Deep section contained distinct microbial populations that differed from those found in the other sediment samples examined. Proteobacteria, Actinobacteria, Cyanobacteria, Deferribacteres, and Euryarchaeota were the most abundant bacterial and archaeal phyla in both the S- and N-rich sections. Relative abundance-based hierarchical clustering of the 16S rDNA pyrotags assigned to major taxonomic groups allowed us to categorize the archaeal and bacterial communities into three major and distinct groups; group I was unique to the S-rich Atlantis II section (ATII-1), group II was characteristic for the N-rich Discovery sample (DD-1), and group III reflected the composition of the remaining sediments. Many of the groups detected in the S-rich Atlantis II section are likely to play a dominant role in the cycling of methane and sulfur due to their phylogenetic affiliations with bacteria and archaea involved in anaerobic methane oxidation and sulfate reduction.

Sphalerite from the Sterling Hill Mine, New Jersey: Origin and History

The Sterling Hill and Franklin zinc-iron-manganese deposits, Sussex County, New Jersey, are sedimentary-exhalative in origin but were highly deformed and metamorphosed to granulite grade during the Mesoproterozoic Ottawan orogeny. They are unique because the major zinc minerals, zincite, franklinite, and willemite, are oxides and silicates rather than sulfides. However, at Sterling Hill minor granular sphalerite occurs in the central black willemite zone associated with loelling and graphite and sparsely elsewhere in the deposit. Based on textural observations and stable isotope geochemistry, sphalerite was present during metamorphism and was most likely part of the protolith mineral assemblage. It likely formed from a fluid containing seawater sulfate that circulated through volcanic rocks and reacted with igneous sulfides; some contribution from biological reduction of sulfate seems likely. This interpretation agrees with the generally accepted model that the protolith formed on the floor of an ancient rift in an environment similar to the present-day Red Sea brine pool sediments. The presence of loellingite and absence of pyrite or arsenopyrite in the black willemite zone requires that fAs2−/fS2− >1 during metamorphism. The position of the black willemite zone, occupying most of the central cross member of the deposit, and the more reduced mineral assemblages of the zone relative to the rest of the deposit are compatible with it being the feeder zone for the stratiform ores that make up the rest of the Sterling Hill deposit, indicating that the deposit is inverted relative to its original position. Pressure-corrected temperatures from fluid inclusion geothermometry and temperatures determined from carbon isotope fractionation factors between coexisting graphite and calcite suggest a postmetamorphic event that occurred at ∼360°–280°C at between ∼820 and 750 Ma. The fluid inclusion and mineral assemblage data also suggest that at least one additional postmetamorphic event affected the sphalerite and loellingite and their coexisting minerals. This event involved the development of secondary fluid inclusions in sphalerite and the formation of a secondary manganese arsenosilicate mineral and may correlate with the pervasive serpentinization-like alteration of the deposit. The complex sequence of vents indicated by the textures, isotopic ratios, and fluid inclusions is compatible with the history of prolonged cooling and uplift experienced by the New Jersey Highlands in the Neoproterozoic.

Geochemistry of the Furnace Magnetite Bed, Franklin, NewJersey, and the Relationship between Stratiform Iron Oxide Ores and StratiformZinc Oxide-Silicate Ores in the New Jersey Highlands

The New Jersey Highlands terrane, which is an exposure of the Middle Proterozoic Grenville orogenic belt located in northeastern United States, contains stratiform zinc oxide-silicate deposits at Franklin and Sterling Hill and numerous massive magnetite deposits. The origins of the zinc and magnetite deposits have rarely been considered together, but a genetic link is suggested by the occurrence of the Furnace magnetite bed and small magnetite lenses immediately beneath the Franklin zinc deposit. The Furnace bed was metamorphosed and deformed along with its enclosing rocks during the Grenvillian orogeny, obscuring the original mineralogy and obliterating the original rock fabrics. The present mineralogy is manganiferous magnetite plus calcite. Trace hydrous silicates, some coexisting with fluorite, have fluorine contents that are among the highest ever observed in natural assemblages. Furnace bed calcite has δ 13 C values of –5 ± 1 per mil relative to Peedee belemnite (PDB) and δ 18 O values of 11 to 20 per mil relative to Vienna-standard mean ocean water (VSMOW). The isotopic compositions do not vary as expected for an original siderite layer that decarbonated during metamorphism, but they are consistent with nearly isochemical metamorphism of an iron oxide + calcite protolith that is chemically and mineralogically similar to iron-rich sediments found near the Red Sea brine pools and isotopically similar to Superior-type banded iron formations. Other manganiferous magnetite + calcite bodies occur at approximately the same stratigraphic position as far as 50 km from the zinc deposits. A model is presented in which the iron and zinc deposits formed along the western edge of a Middle Proterozoic marine basin. Zinc was transported by sulfate-stable brines and was precipitated under sulfate-stable conditions as zincian carbonates and Fe-Mn-Zn oxides and silicates. Whether the zincian assemblages settled from the water column or formed by replacement reactions in shallowly buried sediments is uncertain. The iron deposits formed at interfaces between anoxic and oxygenated waters. The Furnace magnetite bed resulted from seawater oxidation of hydrothermally transported iron near a brine conduit. Iron deposits also formed regionally on the basin floor at the interface between anoxic deep waters and oxygenated shallower waters. These deposits include not only manganiferous magnetite + calcite bodies similar to the Furnace magnetite bed but also silicate-facies deposits that formed by iron oxide accumulation where detrital sediment was abundant. A basin margin model can be extended to Grenvillian stratiform deposits in the northwest Adirondacks of New York and the Mont Laurier basin of Quebec. In these areas iron deposits (pyrite or magnetite) are found basinward of marble-hosted sphalerite deposits, such as those in the Balmat-Edwards district. Whether the iron and zinc precipitated as sulfide assemblages or carbonate-oxide-silicate assemblages depended on whether sufficient organic matter or other reductants were available in local sediments or bottom waters to stabilize H2S.

Carbon and Oxygen Isotope Halo in Carbonates Related to the McArthur River (HYC) Zn-Pb-Ag Deposit, North Australia:Implications for Sedimentation, Ore Genesis, and Mineral Exploration

A study of carbon and oxygen isotope ratios in fine-grained sedimentary dolomite in the Barney Creek Formation of the McArthur basin demonstrates the presence of an extensive isotope halo surrounding the giant stratiform HYC Zn-Pb-Ag deposit. Dolomite within the halo shows an 18O-enriched and 13C-depleted isotope signature ( δ 18O = 23 to 26‰ SMOW, δ 13C = –2 to –3.5‰ PDB), relative to normal Proterozoic sedimentary dolomite beyond the halo ( δ 18O = 20–23‰ and δ 13C = 0 to –2‰). The C-O isotope halo within the dolomitic siltstones extends at least 15 km southwest of the HYC deposit and approximately coincides with a previously defined lithogeochemical halo of elevated Fe, Mn, Zn, Pb, and Tl. Dolomitic siltstone lamellae within the stratiform Zn-Pb-Ag ores at HYC exhibit an isotopic range similar to that of the halo dolomites, suggesting that the ore and halo equilibrated with the same hydrothermal fluid. Modeling of isotopic exchange accompanying fluid-rock interaction suggests that the halo dolomites equilibrated with low-temperature fluids (50°–120°C), which were enriched in 18O ( δ 18O = 5 ± 5‰) but with an average crustal carbon isotope signature ( δ 13C = –6 ± 1‰). Our preferred interpretation is that the oxygen and carbon isotope halo at HYC is related to the development of an extensive brine pool. This pool was deepest in the vicinity of the HYC deposit adjacent to the Emu fault, and it became shallower to the southwest away from the fault. Using the carbon isotope fractionation equation between dolomite and HC\batchmode \documentclass[fleqn,10pt,legalpaper]{article} \usepackage{amssymb} \usepackage{amsfonts} \usepackage{amsmath} \pagestyle{empty} \begin{document} \(O_{3}^{{\mbox{--}}}\) \end{document}, it is possible to estimate the temperature variation at the base of the brine pool during the accumulation of the Barney Creek Formation. Brine pool temperatures were highest in and adjacent to the HYC deposit (40°–70°C) and decreased to values of 17° to 30°C remote from the deposit. These temperatures are similar to those recorded in the Red Sea brine pool associated with the Atlantis II metalliferous sediment deposit. Based on our work at HYC and Lady Loretta, strata-bound 18O-enriched carbonate lithogeochemical halos may be a characteristic of the Proterozoic stratiform Zn-Pb-Ag deposits of northern Australia. These halos are more extensive than the narrow 18O-depletion halos recorded in dolomites surrounding skarn, Mississippi Valley-type and Irish-style Zn-Pb deposits. This fundamental difference in the isotopic halo characteristics of these groups of zinc deposits is probably related to the low-temperature, synsedimentary brine pool origin of the North Australian SEDEX deposits in contrast to the various replacement and open space fill origins of skarn, Mississippi Valley-type, and Irish-style deposits.

Submarine venting of brines in the deep Gulf of Mexico: Observations and geochemistry

Research Article| June 01, 1992 Submarine venting of brines in the deep Gulf of Mexico: Observations and geochemistry Paul Aharon; Paul Aharon 1Department of Geology & Geophysics, Louisiana State University, Baton Rouge, Louisiana 70803 Search for other works by this author on: GSW Google Scholar Harry H. Roberts; Harry H. Roberts 2Coastal Studies Institute, Louisiana State University, Baton Rouge, Louisiana 70803 Search for other works by this author on: GSW Google Scholar Ron Snelling Ron Snelling 1Department of Geology & Geophysics, Louisiana State University, Baton Rouge, Louisiana 70803 Search for other works by this author on: GSW Google Scholar Geology (1992) 20 (6): 483–486. https://doi.org/10.1130/0091-7613(1992)020<0483:SVOBIT>2.3.CO;2 Article history first online: 02 Jun 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation Paul Aharon, Harry H. Roberts, Ron Snelling; Submarine venting of brines in the deep Gulf of Mexico: Observations and geochemistry. Geology 1992;; 20 (6): 483–486. doi: https://doi.org/10.1130/0091-7613(1992)020<0483:SVOBIT>2.3.CO;2 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGeology Search Advanced Search Abstract Brine-issuing vents have been observed at 1920 m water depth on top of Green Knoll, an isolated salt diapir rising seaward of the Sigsbee Escarpment in the northern Gulf of Mexico. The brines are seven times saltier than ambient sea water. Their venting, both by lateral flow and by diffusion upward through the underlying sediments, gives rise to drainage patterns similar to braided streams. Brine transport pathways are floored by unindurated red-orange deposits similar to the iron oxide deposits of the Red Sea brine pools. The relations between major and minor constituents (Na, K, Cl, SO4, Br, and Li) and the δ18O compositions indicate that brines are formed by congruent sea-water dissolution of the underlying Louann salt containing a mixture of halite, sylvite, and anhydrite. Net removal of Mg corresponding to a proportional increase in Ca suggests that dolomitization is active in the subsurface. Ferrous iron is extracted from the salt diapir and precipitated as ferric hydroxide on floors of drainage networks during the venting and mixing of the brines with the oxygen-rich ambient water. The Green Knoll brines, whose chemistry is uncompromised by severe diagenetic overprints, could serve as an end-member analogue for formation waters that have acquired complex chemical histories during their long migration in sedimentary basins. This content is PDF only. Please click on the PDF icon to access. First Page Preview Close Modal You do not have access to this content, please speak to your institutional administrator if you feel you should have access.

Sedimentary-hosted polymetallic massive sulfide deposits of the Kebrit and Shaban Deeps, Red Sea

Massive sulfides recovered from the Kebrit Deep carbonaceous sedimentary succession represent black smoker fragments, novel to any Red Sea brine pool deposit. Chimneys, which were also observed in situ near the seawater/brine interface of the Kebrit Deep pool, are primarily comprised of Fe-, Zn- and Pb-bearing phases, and are often tar and asphalt impregnated. Cu-sulfides are virtually absent from parageneses, contrasting rift-related smoker and Red Sea metalliferous sediment deposits. Concentration of nickel in discrete bravoite points to a basalt/seawater leaching process as a source for most metals. The sedimentary package, which probably hosts Cu-mineralization in lower stockworks of the smoker deposit, is considered the major source of lead. Prevention of boiling of hydrothermal fluids, passing through a succession of organic-rich carbonate and clay horizons prior to discharge, is essential for smoker formation. Shaban Deep sedimentary-hosted massive sulfides are less frequent, with pyrite being the dominant ore mineral. Sulfur isotope data indicate both high temperature inorganic as well as biogenic sulfate (seawater and/or evaporite) reduction in sulfide-forming processes. Cogenetic sulfates formed from residual, bacteriogenically reduced seawater sulfate. Rather low sulfide/sulfate precipitation temperatures of 110–130 °C for the Kebrit brine pool and 100 °C for Shaban Deep massive sulfides are evident.

Petrology and stable isotope geochemistry of the metamorphosed zinc-iron-manganese deposit at Sterling Hill, New Jersey

The Sterling Hill deposit is an isoclinically folded sequence of zinc-, iron-, and manganese-rich strata surrounded by the Franklin Marble. The most metal-rich layers are composed of combinations of willemite, franklinitc, zincitc, and calcite; other layers contain calc-silicate minerals and calcite. Structural, petrologic, and geochronologic evidence indicates that the deformation and mineral assemblages observed today were produced during granulite-grade Grenville metamorphism of the deposit at about 1.0 Ga.In general, the oxygen isotope and chemical compositions of individual minerals vary from lithologic layer to lithologic layer but are uniform within layers which suggests that mineral compositions were controlled by the bulk compositions of the rocks. Important exceptions to this rule occur near faults and fractures where the deposit was infiltrated by retrograde metamorphic fluids. In these areas, the rocks commonly contain hydrous minerals which have replaced anhydrous assemblages, and the minerals have been exchanged to larger delta 18 O values.Willemite and zincite are stable at higher f (sub O 2 ) /f (sub S 2 ) than pyrite and pyrrhotite which implies that the ores are not chemically equilibrated with the surrounding Franklin Marble but are higher in oxidation state and/or lower in sulfidation state. The deposit also contrasts with the surrounding marble in oxygen isotope composition. Bulk delta 18 O values for ore layers range from about 6 to 13 per mil, and thin marble layers interbedded with the ores are consistently about 15 per mil. The Franklin Marble is 20 to 25 per mil.Models for the protolith are presented in which the bulk oxygen isotope compositions and bulk chemical compositions of the rocks are assumed to reflect protolith compositions modified by metamorphic devolatilization. The mineralogy of the protolith is inferred from the bulk chemical compositions of the rocks and by analogy with the mineralogy of other metal-rich oxidized rocks, and the minerals are assumed to have equilibrated isotopically with the fluid which formed them. The application of the models which require the fewest assumptions is to the marbles interbedded with the ore layers. Their isotopic compositions appear to require either equilibration with 18 O-depleted meteoric water at the earth's surface temperatures, or equilibration with a more 18 O-enriehed water at temperatures characteristic of hydrothermal or metamorphic processes. Application of the models to the ore layers suggests that the last fluid-dominated event took place at 150 degrees + or - 50 degrees C rather than at the earth's surface temperatures. Structural features of the deposit also support the higher temperature formation in that they appear to be incompatible with an origin by weathering.Exposure to seawater is the most plausible alternative to subaerial weathering for producing the high oxidation state-low sulfidation state of the protolith. An extremely large volume of seawater would have been required to oxidize the entire metal inventory of the deposit. Thus, the formation of the oxidized protolith is best inferred to have taken place on the Proterozoie sea floor or in shallowly buried sediments which were well irrigated by seawater. The closest modern analogues for Sterling Hill, and by analogy the nearby Franklin Furnace deposit, are the sulfide-poor strata in the metalliferous sediments beneath the Red Sea brine pools. There are, however, significant differences between the two occurrences.

Differences between Red Sea Brine Pools

Differences between Red Sea Brine Pools