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Some comparative marine chemistries of rhenium, gold, silver and molybdenum
OLR (1987)34 (12)
C. Chemical Oceanography
87:6817 Koide, M. et al., 1986. Some comparative marine chemistries of rhenium, gold, silver and molybdenum. Appl. Geochem., 1(6):705-714. Four metals, Re, Au, Ag and Mo, were measured in hydrothermal sulfides, coastal sediments, and phosphorites depositing under anoxic conditions. These elements were also determined in ferromanganese minerals and pelagic sediments which accumulated under oxidizing conditions. Rhenium appears unique for identifying reducing depositional environments, where enrichments more than three orders of magnitude above crustal concentrations are found. Molybdenum follows Re in these sediments but is enriched also in those that accumulate under oxidizing conditions. Reported Mo crustal concentrations appear low in comparison to measured sedimentary values. Gold and Ag are concentrated in hydrothermal deposits and sulfides appear to be involved in their precipitation. Understanding of the mobilities and sinks of these metals in the marine environment during the major weathering cycle is sought, and anthropogenic contributions to their sedimentary concentrations are identified. Scripps Inst. of Oceanogr., La Jolla, CA 92093, USA. 87:6818 Matthews, Elaine and Inez Fung, 1987. Methane emission from natural wetlands: global distribution, area, and environmental characteristics of s o u r c e s . Global biogeochem. Cycles, 1(1):61-86. The global wetland area derived in this study is approximately twice that previously used in methane-emission studies. Emission was calculated using methane fluxes for major wetland groups, and simple assumptions about the duration of the methane production season. Annual emission from wetlands is well within the range of previous estimates. Peat-poor swamps from 20°N-30°S account for ~30% of the global wetland area and ~25% of total methane emission. About 60% of total emission comes from peat-rich bogs concentrated from 50 °70°N, suggesting that this highly seasonal emission is the major contributor to large annual oscillations observed in atmospheric methane concentrations at these latitudes. M-COM Sigma Data, NASA Goddard Space Flight Center, Inst. for Space Studies, 2880 Broadway, NY, NY 10025, USA. 87:6819 Meybeck, Michel, 1987. Global chemical weathering of surficial rocks estimated from river dissolved loads. Am. J. Sci., 287(5):401-428. Representative water analyses for major rock types outcropping on the continents, weighted according to their occurrence at the surface, are used to obtain
1041
a theoretical average composition for fiver water which compares well with measured values reported in the literature. A breakdown of the dissolved mineral and rock components shows that crystalline rocks contribute 17.2% of the material in solution, whereas carbonates make up 50%. Using these results, chemical erosion rates relative to granite weathering are estimated at 1.0 for granite, gneiss and mica schist; 1.3 for gabbro and sandstone; volcanic rocks 1.5; shales 2.5; 5 for serpentine and amphibolite; carbonate rocks 12; gypsum 40; and rock salt 80. Inst. de Biogeochimie Mar., Ecole Normale Superieure, 1, rue Maurice Arnoux, 92120 Montrouge, France. (hbf) 87:6820 Schimmelmann, Amdt and M.J. DeNiro, 1986. Stable isotopic studies on chitin. II. The ~3C/~2C and tSN/~4N ratios in arthropod chitin. Contr. mar. Sci. Univ. Texas, 29:113-130. Analysis of D-glucosamine hydrochloride from exoskeletal chitin (collected from 70 arthropod species in 59 geographical areas) revealed a distinct difference in 8~3C values, but not 8~5N values, between marine and terrestrial species. Both 8~3C and 8JSN values are altered by coastal pollution, and 8~N also reflects the trophic level of marine crustaceans. Scripps Inst. of Oceanogr., La Jolla, CA 92093, USA. (gsb) 87:6821 Slater, J.M. and D.G. Capone, 1987. Denitrification in aquifer soil and nearshore marine sediments influenced by groundwater nitrate. Appl. environ. Microbiol., 53(6): 1292-1297. Mar. Sci. Res. Center, SUNY, Stony Brook, NY 11794, USA. 87:6822 Tlig, S., A. Sassi, H. Belayouni and D. Michel, 1987. Uranium, thorium, zirconium, hafnium and rareearth element (REE) distributions in size fractions of sedimentary phosphates. Chem. Geol., 62(3-4):209-221. (In French, English abstract.) Lab. de Geochimie, Dept. des Sci. de la Terre, Faculte des Sci. de Tunis, 1060 Tunis, Tunisia. 87:6823 Wakeham, S.G., B.L. Howes, J.W.H. Dacey, R.P. Schwarzenbach and J. Zeyer, 1987. Biogeochemistry of dimethylsulfide [DMS] in a seasonally stratified coastal salt pond. Geochim. cosmochim. Acta, 51(6):1675-1684. In summer, maximum DMS concentrations of up to 60 nmol/L were found in the oxygen-deficient metalimnion of Salt Pond, Cape Cod, Massachusetts. Concentrations in the epilimnion were an order
C. Chemical Oceanography
87:6817 Koide, M. et al., 1986. Some comparative marine chemistries of rhenium, gold, silver and molybdenum. Appl. Geochem., 1(6):705-714. Four metals, Re, Au, Ag and Mo, were measured in hydrothermal sulfides, coastal sediments, and phosphorites depositing under anoxic conditions. These elements were also determined in ferromanganese minerals and pelagic sediments which accumulated under oxidizing conditions. Rhenium appears unique for identifying reducing depositional environments, where enrichments more than three orders of magnitude above crustal concentrations are found. Molybdenum follows Re in these sediments but is enriched also in those that accumulate under oxidizing conditions. Reported Mo crustal concentrations appear low in comparison to measured sedimentary values. Gold and Ag are concentrated in hydrothermal deposits and sulfides appear to be involved in their precipitation. Understanding of the mobilities and sinks of these metals in the marine environment during the major weathering cycle is sought, and anthropogenic contributions to their sedimentary concentrations are identified. Scripps Inst. of Oceanogr., La Jolla, CA 92093, USA. 87:6818 Matthews, Elaine and Inez Fung, 1987. Methane emission from natural wetlands: global distribution, area, and environmental characteristics of s o u r c e s . Global biogeochem. Cycles, 1(1):61-86. The global wetland area derived in this study is approximately twice that previously used in methane-emission studies. Emission was calculated using methane fluxes for major wetland groups, and simple assumptions about the duration of the methane production season. Annual emission from wetlands is well within the range of previous estimates. Peat-poor swamps from 20°N-30°S account for ~30% of the global wetland area and ~25% of total methane emission. About 60% of total emission comes from peat-rich bogs concentrated from 50 °70°N, suggesting that this highly seasonal emission is the major contributor to large annual oscillations observed in atmospheric methane concentrations at these latitudes. M-COM Sigma Data, NASA Goddard Space Flight Center, Inst. for Space Studies, 2880 Broadway, NY, NY 10025, USA. 87:6819 Meybeck, Michel, 1987. Global chemical weathering of surficial rocks estimated from river dissolved loads. Am. J. Sci., 287(5):401-428. Representative water analyses for major rock types outcropping on the continents, weighted according to their occurrence at the surface, are used to obtain
1041
a theoretical average composition for fiver water which compares well with measured values reported in the literature. A breakdown of the dissolved mineral and rock components shows that crystalline rocks contribute 17.2% of the material in solution, whereas carbonates make up 50%. Using these results, chemical erosion rates relative to granite weathering are estimated at 1.0 for granite, gneiss and mica schist; 1.3 for gabbro and sandstone; volcanic rocks 1.5; shales 2.5; 5 for serpentine and amphibolite; carbonate rocks 12; gypsum 40; and rock salt 80. Inst. de Biogeochimie Mar., Ecole Normale Superieure, 1, rue Maurice Arnoux, 92120 Montrouge, France. (hbf) 87:6820 Schimmelmann, Amdt and M.J. DeNiro, 1986. Stable isotopic studies on chitin. II. The ~3C/~2C and tSN/~4N ratios in arthropod chitin. Contr. mar. Sci. Univ. Texas, 29:113-130. Analysis of D-glucosamine hydrochloride from exoskeletal chitin (collected from 70 arthropod species in 59 geographical areas) revealed a distinct difference in 8~3C values, but not 8~5N values, between marine and terrestrial species. Both 8~3C and 8JSN values are altered by coastal pollution, and 8~N also reflects the trophic level of marine crustaceans. Scripps Inst. of Oceanogr., La Jolla, CA 92093, USA. (gsb) 87:6821 Slater, J.M. and D.G. Capone, 1987. Denitrification in aquifer soil and nearshore marine sediments influenced by groundwater nitrate. Appl. environ. Microbiol., 53(6): 1292-1297. Mar. Sci. Res. Center, SUNY, Stony Brook, NY 11794, USA. 87:6822 Tlig, S., A. Sassi, H. Belayouni and D. Michel, 1987. Uranium, thorium, zirconium, hafnium and rareearth element (REE) distributions in size fractions of sedimentary phosphates. Chem. Geol., 62(3-4):209-221. (In French, English abstract.) Lab. de Geochimie, Dept. des Sci. de la Terre, Faculte des Sci. de Tunis, 1060 Tunis, Tunisia. 87:6823 Wakeham, S.G., B.L. Howes, J.W.H. Dacey, R.P. Schwarzenbach and J. Zeyer, 1987. Biogeochemistry of dimethylsulfide [DMS] in a seasonally stratified coastal salt pond. Geochim. cosmochim. Acta, 51(6):1675-1684. In summer, maximum DMS concentrations of up to 60 nmol/L were found in the oxygen-deficient metalimnion of Salt Pond, Cape Cod, Massachusetts. Concentrations in the epilimnion were an order