Showing papers in "Geochimica et Cosmochimica Acta in 1985"

TL;DR: The major ion data are consistent with the estimates based on extrapolation of the original measurements made on the hot springs from the Galapagos Spreading Center ( Edmond et al., 1979a).

TL;DR: In this article, the authors measured radiogenic 40Ar loss from sized biotite (56% annite) samples following isothermalhydrothermal treatment have provided model diffusion coefficients in the temperature interval 600°C to 750°C, calculated on the assumption that Ar transport proceeds parallel to cleavage.

TL;DR: In this paper, the surface complexation-site binding model of Davis et al. was used to predict uranyl adsorption from aqueous electrolyte solution onto well-characterized goethite, amorphous ferric oxyhydroxide and hematite sols at 25°C.

TL;DR: The first profiles of rare earth elements in the Pacific Ocean were reported in this paper, showing that the distribution of the rare earth groups is consistent with two simultaneous processes: 1) cycling similar to that of opal and calcium carbonate 2) adsorptive scavenging by settling particles and possibly by uptake at ocean boundaries.

TL;DR: The chemistry of the hydrothermal waters is distinctly different from that characteristic of sediment-starved, open ocean ridge axes in that the solutions are alkaline, contain ammonium as a major ion and are strongly depleted in the “ore-forming” metals.

TL;DR: In this article, DH ratios of tree sap can be used to determine the source water for a tree, and trees can be classified into three categories: those which rely solely on summertime rainfalls, those which depend solely on groundwaters and those which utilize both water sources.

TL;DR: The phase equilibria in the system H2O-NaCl have been determined to 1000°C and 1500 bars using synthetic fluid inclusions formed by healing fractures in inclusion-free Brazilian quartz as mentioned in this paper.

TL;DR: In this paper, a time-space continuum model for transport of hydrothermal fluids in porous media is presented which provides for simultaneous, reversible and irreversible chemical reactions involving liquids, gases and minerals.

TL;DR: In this paper, the chemistry and leaching patterns of soluble humic substances in forested watersheds of the Adirondack region were examined in conjunction with the Integrated Lake-Watershed Acidification Study (ILWAS).

TL;DR: N abundance and isotopic compositions can differentiate existing taxonomic groups with close to 100% reliability and there are hints that both CI and CM groups may each be divisible into two subgroups.

TL;DR: In this paper, alder, alder and oak wood were compared with their modern counterparts by quantification of individual neutral sugars and lignin-derived phenols as well as by scanning electron microscopy, 13C NMR and elemental analysis.

TL;DR: In this article, a quantitative model is calculated which enables the balance of both processes to be taken into account, and two extreme models can account for the observed variations: an internally driven model, in which variable quantities of mantle material are added to the crust, and an externally driven model in which the rate of crustal recycling is low in the Archean but increases rapidly at the onset of the atmospheric oxygen buildup and development of soil supported life.

TL;DR: Significant amounts of SO42−, Na+, and OH− are incorporated in marine biogenic calcites as discussed by the authors, which increases the unit cell size of calcites and increases the solubility.

TL;DR: The Ronda peridotite in southern Spain is a large exposure of upper mantle which provides direct information about mantle processes on a scale much larger than that provided by mantle xenoliths in basalt.

TL;DR: In this article, the distributions of di- and trimethylnaphthalenes in two sedimentary sequences from Western Australia have been examined by capillary gas chromatography and combined GC-MS spectrometry.

TL;DR: In this paper, the authors explored the possibility of establishing Nd isotopic variations in seawater over geologic time by examining calcite, aragonite, and apatite as possible phases recording seawater values of ϵ_(Nd).

TL;DR: In this paper, the results of a water column of a permanently anoxic basin, Framvaren Fjord, Norway, were determined in order to better understand the geochemical processes operating on metals in anoxic marine waters.

TL;DR: The rate of 4 He accumulation in the groundwaters of the J-aquifer of the Great Artesian Basin, Australia has been determined using 14 C and hydrologic ages as mentioned in this paper.

TL;DR: In this paper, low-Ti lavas from the Bonin-Mariana arc system, Cape Vogel, New Caledonia, Cyprus, Newfoundland and SE Australia have been analysed for Pd, Ir, Au, Cu, S and Se.

TL;DR: A petrographic and transmission electron microscopy study of the Mighei, Murchison and Murray carbonaceous chondrites showed that much of the CM matrix material was probably produced by aqueous alteration of olivine, pyroxene, sulfide, and metal.

TL;DR: In this article, the authors compared the results obtained from oxic lake sediments and the in situ measurement of trace metal concentrations in the associated pore waters in the area of Sudbury, Ontario, to those obtained for the adsorption of the trace metals onto amorphous iron oxyhydroxides in a NaNO3 medium.

TL;DR: The most likely natural product precursors for the tetracyclic diterpene hydrocarbons are considered to be the TPDP-derived diterpanes which occur widely in the leaf resins of conifers.

TL;DR: In this paper, the occurrence and significance of hydrocarbons present in two bituminous marl layers and one distinct gypsum layer from a Messinian sedimentary basin, where hypersaline conditions prevailed, was described.

TL;DR: The initial solid phase oxidation products formed during the oxidation of aqueous Mn(II) at 25°C were studied as a function of time in this paper, where the analyses included morphology (TEM), mineralogy (x-ray diffraction), OMn ratio (iodometric method), and dissolved manganese.

TL;DR: Germanium is enriched in the following geologic environments: 1) iron meteorites and terrestrial iron-nickel; 2) sulfide ore deposits, particularly those hosted by sedimentary rocks; 3. iron oxide deposits; 4. oxidized zones of Ge-bearing sulfide deposits; 5. pegmatites, greisens, and skarns; and 6. coal and lignitized wood.

TL;DR: In this paper, the isotope exchange rate between dissolved sulfate and water was experimentally determined at 100, 200 and 300°C, and it was shown that the exchange reaction proceeds through collision between H2SO04 and H2O at low pH and between HSO−4 and H 2O at intermediate pH.

TL;DR: In this paper, the authors investigated the relationship between foraminiferal shell chemistry and solution composition and found that the ratios of Li and Sr to Ca in the shells are a function of these ratios in the culture solutions.

TL;DR: The adsorption of Pu(IV) and Pu(V) on goethite (αFeOOH) from NaNO3 solution shows distinct differences related to the different hydrolytic character of these two oxidation states as discussed by the authors.