Showing papers in "Earth and Planetary Science Letters in 1980"

TL;DR: In this paper, the effects of different types of bulk lower and upper crustal contamination of a within-plate alkali basalt on the Th, Hf, Ta and radiogenic isotope concentrations of the residual liquids are calculated in detail.

TL;DR: In this paper, it was shown that none of the analyzed meteorite samples deviated more than 0.5 e-units from a 4.6-AE reference isochron and defined an initial 4.5-AE value for CHUR using the Juvinas data of Lugmair.

TL;DR: The vertical profiles of Cd, Zn, Ni, and Cu have been determined at three stations in the North Pacific and in the surface waters on a transect from Hawaii to Monterey, California as discussed by the authors.

TL;DR: In this paper, the authors used a two-dimensional model with sediment units of varying thickness, radioactive heat production, and conductivity to calculate the temperature distribution within the sediments.

TL;DR: In this article, the estimation of errors and error correlations for various types of U-Pb isotope data, taking into account ion-beam instabilities, run-to-run variability in mass-discrimination, uncertainties in Pb and U concentrations, and uncertainties in initial Pb amount and isotopic composition, are derived.

TL;DR: In this paper, it was shown that biochemical processes are involved in the formation of the BaSO4 mineral in the water column, rather than purely chemical processes, which would not be anticipated for purely chemical interactions.

TL;DR: In this article, the dependence of the heat flow and subsidence histories on the rate of extension was determined using a time-dependent analytical model and constraints on the use of the latter were provided in terms of the duration and amount of stretching.

TL;DR: In this article, a variety of oxygen and strontium isotope mixing curves were calculated for this process of combined assimilation-fractional crystallization, and the positions and characteristics of the resultant curves on δ18O-87Sr/86Sr diagrams markedly diverged from simple two end-member mixing relationships.

TL;DR: In this article, the isotopic composition of neodymium in Atlantic Ocean seawater is compared with previous measurements of Pacific Ocean seafater and ferromanganese sediments from major ocean basins.

TL;DR: A radiotracer method that measures rates of oxidation of methane to carbon dioxide has been applied to anoxic marine sediments as discussed by the authors, and the results confirm the occurrence of anaerobic methane oxidation and agree with model predictions of a zone of intense anoxic methane oxidation at the base of the sulfate-reducing zone.

TL;DR: In this article, a model of the evolution and isotopic composition of ambient argon retained within the metamorphic host rocks during cooling was presented, based on a step-heating argon analysis of both neutron irradiated and unirradiated samples.

TL;DR: In this paper, the rare earth elements (REE) were potentially mobile during hydrothermal and supergene alteration of granitic rocks from southwest England, and they were removed from the system during K-silicate alteration, Eu was lost during sericitic alteration, all REE were lost during tourmalinization, and light and argillic alteration.

TL;DR: Using terrestrial osmium-enriched samples of known ages, this paper showed that the radioactivity of the earth's mantle varies with time in result of the 187 Re β − radioactivity.

TL;DR: A quantitative and precise method for determination of dissolved Mn at the nanomole(nmol)/kg level in seawater has been developed and used to study the distribution of Mn in the northeast Pacific as discussed by the authors.

TL;DR: The vertical distribution of dissolvable manganese at 13 stations in the Pacific has been studied in this paper, showing that surface water values range from about 3 to about 0.3 nmol/kg.

TL;DR: In this article, one-dimensional conductive relaxation models for the thermal evolution of continental crust which has undergone magmatic thickening in a predominantly recumbent tectonic regime are presented.

TL;DR: The results from these four sites suggest that the pore water profiles of these metals are controlled by processes involving the major oxidants (O2, NO3−, Mn and Fe oxides) as discussed by the authors.

TL;DR: From GEOSECS stations, largely, the 1974 distributions of Pu and of 137 Cs are described in the Pacific Ocean north of about 20°S latitude by the authors as mentioned in this paper.

TL;DR: In this article, the major tectonic elements of the Azores triple junction have been mapped using long-range side-scan sonar data and the data enable the Mid-Atlantic Ridge axis to be located with a precision of a few kilometres.

TL;DR: A serpentinite diapir made of altered plagioclase-bearing lherzolites, has been emplaced west of the Galicia Bank at the boundary between oceanic crust and the probable thinned continental crust, that underlies the Iberian margin this paper.

TL;DR: In this paper, the authors showed that the heat loss associated with a single vent of this type is three to six times the total theoretical heat loss for a 1-km segment of ridge out to 1 m.y.

TL;DR: In this paper, the authors extracted pore water samples from cores at three locations in the eastern equatorial Pacific and analyzed for nutrients, dissolved carbonate species, Mn and Fe.

TL;DR: In this article, isotopic data on pargasite Iherzolite inclusions, kaersutite megacrysts and their host alkali basalts are presented to clarify some questions regarding isotopic equilibration during mantle metasomatism and the role of metasomatic in basalt genesis.

TL;DR: In this article, densities calculated from glass compositions of observed mid-ocean ridge basalts show that the more primitive melts are likely to be buoyant in more evolved melts and that the most primitive basalts observed to erupt occupy a density minimum when compared to more primitive and more fractionated melts.

TL;DR: In this article, the earth's largest positive geoid height anomalies are associated with subduction zones and hotspots, and the expected geoid anomaly over subduction regions is calculated using the assumption that subducted lithospheric slabs are uncompensated and re-equilibrated with the asthenosphere at the maximum depth of earthquakes.

TL;DR: In this paper, vertical profiles and north-south sections for the distribution of the δ13C of total dissolved inorganic carbon are presented for the Atlantic stations of the GEOSECS program.

TL;DR: In this paper, vertical profiles of concentrations of iodate-and total-iodine have been measured at thirty stations in the Pacific, Atlantic and Antarctic Oceans, and the salinity-normalised iodine profiles are indicative of both iodine removal and iodate reduction in the euphotic zone.

TL;DR: In this article, a model for the closed system exchange of Sr and O is presented for estimating the water/rock ratio and subsequently used to evaluate the temperature of equilibration between the water and silicates from the O/O water-rock fractionation.

TL;DR: In this paper, the electron microprobe was used to investigate the geochemistry of accessory allanites, sphenes, apatites and zircons from a range of granitic, sedimentary and hydrothermally altered rocks from Skye.

TL;DR: In this paper, the solubility of fluorapatite in a wide variety of basic magmatic liquids was experimentally determined over a range of upper mantle P-T conditions (8-25 kbar, 1275-1350°C).