Showing papers in "Chemical Geology in 1976"

TL;DR: In this paper, it was shown that the presence of Fe(II)-containing solutions in recent sediments is necessary for the formation of the bidimensional orientation of SiO 4 tetrahedrons, leading to clay-mineral formation.

TL;DR: In this paper, it is suggested that the diffusion of dissolved organic material was important in sustaining microbiological activity, and that at least two different microbiological processes participated in concretionary growth.

TL;DR: In this article, an experimental determination has been made of the solubility of Ti in phlogopite, in the system K2OMgOTiO2Al2O3SiO2MgVIII, 2SiIV, MgVI ⇌ 2AlIV, TiVI Titanium substitutes in octahedral sites and does not replace Si4+ in tetrahedral sites.

TL;DR: In this article, the lipid constituents of three temperate lacustrine sediments (Rostherne Mere, Esthwaite Water and Grasmere, Great Britain) and three sub-tropical lagoonal/tidal flat sediments were analyzed.

TL;DR: In this paper, the same stanols as those found in the lake sediments were also determined in the diatom Melosira granulata, collected from this lake.

TL;DR: In this article, the distribution of the zeolites phillipsite and clinoptilolite with respect to geographic location, sedimentation rate, general sediment type, age of sediment, depth in core, and various aspects of the coexisting minerals.

TL;DR: In this paper, rare earth elements (REE) were analyzed for enrichment in iron-manganese concretions and their surrounding soil materials from six sites in New Zealand and the results showed that As is enriched in all the concretion samples.

TL;DR: In this paper, the authors used stepwise pyrolysis-gas chromatography to examine and characterize the carbonaceous matter in sedimentary rocks and determined the molecular sizes (chain length) of kerogens fragments.

TL;DR: In this article, the results for the dissociation constants of boric acid were derived from dilute sodium borate solutions with added alkali earth chlordie salts, and the average value from both methods is 0.22 ± 0.1 at 25°C.

TL;DR: In this paper, the optical configuration of amino acids in sediments and fossils has been reviewed and the results have been used to evaluate critically the reputed occurrence of original amino acid in ancient sediments of the Mesozoic, Palaeozoic and Precambrian eras.

TL;DR: Fluorine and chlorine are determined in geological samples following a sodium carbonate fusion and precipitation of interfering elements in the leach with ammonium carbonate using the Technicon Auto Analyser.

TL;DR: Elements resistent to alteration and metamorphism from metabasalts samples belonging to the north Apennine ophiolites have been determined in order to investigate the primary tectonic environment of these rocks.

TL;DR: In this paper, ten samples from drillcore of two rich oil-shale beds from the Parachute Creek Member of the Eocene Green River Formation, Piceance Creek basin, Colorado, and Uinta Basin, Utah were analyzed for 37 major, minor, and trace elements.

TL;DR: In this paper, mass absorption coefficients (A2) for a series of standard rocks, have been calculated in the wavelength region 0.492-3.03 View the MathML source; the data confirm the observations of Reynolds.

TL;DR: In this paper, a small portion of the labels was also incorporated into C 12 C 18 n -alkanoic acids in relative proportions approximating to the carbon-number distributions observed for the sediment itself.

TL;DR: In this paper, the authors measured the distribution coefficients between Mg and Fe in carbonates, based on the solubilities of magnesite and siderite as a function of pH and PCO2.

TL;DR: In this paper, the compositional range of phlogopite micas in the system K 2 OMgO ǫ mgO MgO 2 O 3 ε 2 O 2 SiO 2 H 2 O has been determined.

TL;DR: In this paper, the contents of Ni, Co and Cu in 63 alpine-type ultramafic rocks were determined, together with total Fe, FeO, MgO, MnO and SiO2.

TL;DR: In this article, a technique consisting of pyrolysis at 700°C in hydrogen, followed by catalytic hydrogenation and gas chromatography of the products, has been developed for studying the carbon-skeleton structure of coal or kerogen.

TL;DR: Abundances of fluorine and chlorine in thirty-two kimberlites and six ultrabasic inclusions from India, Greenland and Africa have been determined and shown to be held by apatite (mainly F) and phlogopite(mainly Cl).

TL;DR: In this paper, the action of various factors on the precipitation of apatite in seawater is studied: addition of Ca, addition of F, reduction of pH and simultaneous effect of reducing pH and addition either of F or of Ca.

TL;DR: In this paper, the mean values of Ca, Ba, and the estimated non-carbonate Ca are 0.46, 1.00 and 0.27%, respectively, for the celestites and their associated sediments.

TL;DR: In this article, a thermodynamic computer model simulating chemical reactions occurring during evaporation of waters is applied to the evolution of soils of the northeastern Lake Chad system, and the influence of oxido reduction and conditions of formation of calcite, gypsum, thenardite, trona and Mg-rich montmorillonite in salty and alkaline soils are discussed.

TL;DR: In this article, the potentiometric Karl Fischer titration method was adapted for the determination of combined water in chemical rock analysis, which appears to be superior in accuracy, precision and rapidity over the well-established Penfield method.

TL;DR: In this article, the isotopic compositions of various forms of nitrogen in silty clay sediments from the Bay of Quinte (Lake Ontario) have been determined and the total organic-N content is high throughout the sediment profiles and generally decreases with depth.

TL;DR: In this article, a method for bringing a sediment sample into solution and subsequently carrying out analysis for 210 Pb, 226 Ra and 137 Cs is described, where Silica is removed from the sample by cyclic HNO 3 HF treatments.

TL;DR: In this article, the authors show that basaltic rocks may be formed by anatexis of upper-mantle material with mineral assemblages containing either garnet (calc-alkaline rocks) or spinel (rocks of tholeiitic affinities).

TL;DR: The peralkaline Kaffo albite-riebeckite granite is an albitised, low-temperature intrusion in Liruei Complex, one of the oldest of the ring-complexes in the Younger Granite province of Nigeria.

TL;DR: In this paper, instrumental neutron activation was used to determine the rare-earth (REE) distribution patterns in eight kimberlites and inclusions from Greenland and Zambia.

TL;DR: The organic content of a number of sediments from the Carboniferous of northern England have been examined as a function of their depositional environment as mentioned in this paper, and a relationship between the amount of extract and the quantity of terrestrial plant material in the sediments has been established.