Showing papers in "Chemical Geology in 1983"

TL;DR: In this article, an alternative zeta (ζ) calibration approach is described, which circumvents absolute φ and λf evaluation: each dosimeter glass is calibrated repeatedly against zircon age standards from the Fish Canyon and Bishop tuffs, the Tardree rhyolite and Southern African kimberlites, to obtain empirical calibration factors ζ.

TL;DR: In this article, the 18O fractionation between CO2 and H2O at 10 − 60°C was determined by measuring the ratio of 18O/16O ratio in water and CO2 equilibrated with this water.

TL;DR: In this paper, the same authors investigated the effect of radium on amorphous ferric oxyhydroxide (FerO) and showed that radium radium sorption data fit a Dubinin-Radushkevich sorption isotherm with radium distribution coefficients ranging from a low of ∼1100 ml g−1 at 60°C to a high of >20,000 ml g −1 at 25°C, much lower than comparable uranium distribution coefficients.

TL;DR: The 40Ar/39Ar incremental-heating dating method has been applied to metamorphic biotite containing excess 40Ar in this article, which shows generally well defined plateaus with apparent ages within analytical uncertainty of those previously determined by conventional K-Ar.

TL;DR: Fifty-six samples of ophiolitic rocks from various Late Cretaceous-Eocene suture zones in Iran have been analyzed for major and trace elements in order to assess their petrogenetic affinity and to determine their original tectonic setting.

TL;DR: In this article, the authors compared the composition of a shale oil to the petrology of the parent organic matter and the mineralogy of the inorganic matrix using gas chromatography and found that the retort oils were both highly aliphatic (H C = 1.7 ).

TL;DR: In this article, the authors described partly successful attempts to determine emplacement ages of kimberlites by U−Pb and Pb−PB methods, involving groundmass minerals with high U content (notably perovskite) and whole-rock kimbersite samples.

TL;DR: The Ordovician quartz-rich greywackes of the Snowy Mountains region are essentially mixtures of two components: quartz and clay minerals as discussed by the authors, and the chemistry of any rock is largely determined by its proportions of clay minerals.

TL;DR: In this paper, the authors measured δ 13 C- and δ 18 O-values of atmospheric CO 2, extracted from air by condensation in liquid nitrogen, have to be corrected for the presence of N 2 O.

TL;DR: In the chott El Jerid basin of southern Tunisia, waters are strongly concentrated by evaporation under an arid climate as discussed by the authors and the diluted waters are of the Ca/1bMg/ 1bSO4 type whereas the brines are of Na/1 bCl type, relatively concentrated in K and Mg.

TL;DR: The isotopic compositions of dissolved uranium in groundwaters of age up to 36,000 a from the East Midlands Triassic Sandstone, and in saline fluids from deep geothermal boreholes in the Wessex Basin, have been investigated as discussed by the authors.

TL;DR: In this article, an accurate water balance was obtained for the pumice aquifer catchment and the mass recharge to the aquifer, and it was shown that 95% of the phosphorus and some of the sodium, calcium and magnesium in the spring waters are derived from within the rhyolitic substrate with recharge water, acidic due to dissolved carbon dioxide.

TL;DR: In this paper, the structure of dissolved marine humic material and the intracellular and extracellular material from the diatom Phacodactylum tricornutum has been investigated by 1H- and 13C-NMR spectroscopy.

TL;DR: In this paper, the authors used the 40Ar/39Ar age spectrum technique to resolve the internal Ar isotope distribution in crystals for the purpose of placing constraints on the timing of thermal events.

TL;DR: In this article, the authors used immobile element abundances to characterize chemically amphibolite facies shear zones in meta-basic sequenes in the Ben Hope sill suite of northern Scotland and found that the immobile group of elements (TiO 2, P 2 O 5, Zr, Y, Nb, light REE) did not appear to have been markedly disturbed during metasomatism.

TL;DR: In this article, the top 30 cm section of a contemporary lacustrine sediment (Rostherne Mere, Cheshire, England), of age 0-150 yr. present variations which can be correlated with changes in input of organic material as well as the effects of early diagenesis.

TL;DR: In this paper, it was shown that even for extractions at 1670°C for 40 min, a small but measurable amount of residual gas remains behind. But this quantity can be detected readily by remelting an extracted sample together with basalt, and it is clear that inadequate experimental conditions rather than diffusive loss of radiogenic Ar can be responsible for erroneously young feldspar ages.

TL;DR: In this paper, seasonal variations and the influence of vegetation on the δ 13C and CO2 concentration of soil gases were found in the Tucson aquifer during the summer and winter months.

TL;DR: In this paper, the authors investigated the geochemistry of waters and sediments associated with shallow-water submarine hydrothermal activity within Santorini Caldera and showed that the distribution of the minor elements can be related to both their rate of supply in the hydro-thermal fluids and their removal to the sediments by scavenging, although other controls on their abundance such as detrital and biogenic supply are of variable importance at increasing distances from the vents.

TL;DR: In this article, the relation between the isotopic composition and various synoptic parameters is discussed, based on deuterium excess values, the rain samples can be separated into three groups.

TL;DR: In this paper, the composition of the initial basalt magma in equilibrium with the residual phase is extrapolated to be FM = 0.40-0.48. And the importance of apatite introduced from the parental peridotite for the incompatible elements (REE, F and P2O5) within various basalt differentiation series is demonstrated.

TL;DR: In this article, the levels of Cd, Pb and Cu were determined along a transect of stations in the Atlantic, Caribbean and particularly in the Western Pacific during cruise OS-04 with R.V. "Sonne" in the summer of 1978.

TL;DR: The source of the salts in the groundwater from the arid crystalline complex of the southern Sinai has been traced by the Sr isotopic composition of the waters and their major chemical components as mentioned in this paper.

TL;DR: Oxygen, hydrogen and carbon isotope analysis of minerals, whole rocks and fluid inclusions were performed on pegmatites and associated wall rocks from ten pegmatite districts and individual occurrences of Precambrian-Late Cretaceous age.

TL;DR: In this article, mixed plankton samples collected from both the East Pacific and nearshore areas off southern California were analyzed for the elements Na, Mg, Cl, K, Ca, Sc, V, Cr, Mn, Fe, Co, Zn, Se, Br, Sr, Ag, Sb, I, Ba, La, Ce, Sm, Eu, N., Eu and U. Principal components analysis identified members of sea salt, detrital silicate and authigenic element groups.

TL;DR: In this article, a preliminary study of the Eolian Islands is concentrated on zero-age rocks, and measured Th/U ratios ( κ m ) are compared with those deduced from Th (π Th ) and Pb (π Pb ) isotopes.

TL;DR: The first-order rate constant for exchange of 18 O between benzoic acid and water under these conditions is (1.4 ± 0.1) · 10 −3 min −1.

TL;DR: The distribution of n-alkanes and fatty acids, the composition of the kerogen and the content of tetrapyrrole pigments of the bituminous chalks of the Campanian-Maastrichtian Ghareb Formation in Israel differ in the Horon, Nebi Musa, Ef'e and Ein Boqeq basins.