Showing papers in "Chemical Geology in 1984"
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TL;DR: The abundance of rare-earth elements (REE's) in francolite increases with increasing age as a result of post-depositional enrichment as discussed by the authors, and the abundance is higher in pelletal samples than in non-pelletal ones because the higher surface/mass ratio of pelletal francolites promotes enrichment during diagenesis.
221 citations
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TL;DR: The cause of the climatically controlled fluctuations in the carbonate content of deep-sea sediments remains the subject of uncertainty and debate as discussed by the authors, and three variables are involved: supply of biogenic carbonate, loss by dissolution, and dilution by non-carbonate phases.
212 citations
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TL;DR: In this paper, deep-water sediment cores from 32 Scandinavian and 19 northern New England, U.S.A., lakes were analyzed for 137Cs; 210Pb was analyzed in cores from 16 and 14 of these lakes, respectively.
199 citations
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TL;DR: In this article, the distributions of steroidal and triterpenoidal alkanes and aromatic hydrocarbons in nine oils, nine coals and three shales from the Mahakam Delta have been examined by gas chromatography-mass spectrometry.
186 citations
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TL;DR: In this article, the rate of dissolution of calcite in aqueous solutions can be conveniently discussed in terms of three pH regimes: low pH ( 5.5), high pH (5.5) and mixed kinetics (H+-independent) regimes.
159 citations
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TL;DR: In this article, the authors analyzed the ether-soluble fraction of Baltic amber (Succinite) and found a pattern of monoterpenoids similar to that encountered in fossil kauri resin, sesquiterpenoids and many other compounds including terpenol succinate and hemisuccinate esters.
138 citations
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TL;DR: Detailed results are presented for the distributions of triterpenoid alkanes, acids and alcohols of the hopane family in ten samples of peat from three environments, and of contributing organisms in the case of Lyne of Skene, Scotland.
134 citations
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TL;DR: In this article, the range of trace-element concentrations in the rock before and after alteration must be known with confidence; and the absolute abundances and the ratios of the mobile trace elements should vary between altered and unaltered rocks.
122 citations
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TL;DR: In this article, coprecipitation of sodium and potassium with calcite was investigated at pH's 7.38-10.60 and 20°C, and the relationship satisfactorily explained the correlation of Na contents of natural calcites with salinity, and suggested that Na+ and K+ are located at interstitial positions between carbonate ions and CaO6 octahedra in calcite.
114 citations
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TL;DR: In this paper, a strong positive correlation has been found between formation-water salinity and Ra activity, resulting from the interaction of formation water with aquifer matrix, and the process of transferring Ra from matrix to formation water are chemical leaching and alpha-particle recoil.
105 citations
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TL;DR: Sedimentation rates have been measured in three reservoirs in northeastern Ohio, U.S.A., by means of 137Cs and 210Pb geochronologies, volumetric surveys and varve counting as mentioned in this paper.
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TL;DR: In this article, the formation of apatite from calcite and RNA in fresh water was obtained, after a latency period which depends on organic matter and not on the nature of carbonate.
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TL;DR: In this article, two separate gradient strong-acid cation exchange chromatography procedures were characterized and the major elements as well as those elements thought to provide the greatest interference for the determination of the rare-earth elements (REE) and yttrium in geologic materials were tested for separation from the REE.
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TL;DR: Sediment accumulation rates obtained from 39 cores in 10 tributaries of the western shore of Chesapeake Bay average 0.30 cm yr.−1 since European settlement as discussed by the authors.
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TL;DR: The concordia method introduced by G.W. Wasserburg and modified by F. Tera and G.J. Wetherill can be extended to the measured total Pb isotope ratios by a three-dimensional discordia plane.
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TL;DR: In a series of 19 runs, the partition coefficient for barium into calcite, k Ba 2+ calcite, was determined to be 0.06 ± 0.01 at 25°C and 1 bar.
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TL;DR: In this article, Humic substances were isolated from Penwhirn Reservoir (PR) and Esthwaite Water (EW) and their removal from solution by centrifugation was studied as a function of pH, humic concentration and molecular weight, and CaCl 2 concentration.
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TL;DR: Oxygenation of Mn(II)-rich water samples taken from two English lakes (Esthwaite Water, Cumbria, and Rostherne Mere, Cheshire) during the summer months caused the precipitation of Mnoxide, the process being catalysed by particulate matter as discussed by the authors.
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TL;DR: In this paper, three suites of volcanic rocks from Radicofani, Mts. Cimini and Mt. Amiata (south Tuscany, Italy) were analyzed for major and trace element contents and Sr isotopic composition.
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TL;DR: In this article, water-rock interaction on a local scale is interpreted as the result of extensive waterrock interaction, and it suggests that there is no single age for such brines, but it may be possible to date stages in the water's evolution by determining the age of secondary minerals that equilibrated with the water.
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TL;DR: The vertical distribution of 20 elements in a 12.5m thick laterite profile from Suriname, South America, has been investigated using neutron activation analysis, atomic absorption spectrometry and X-ray fluorescence as mentioned in this paper.
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TL;DR: In this paper, the CRS (constant flux) model provides a sound basis for establishing recent chronology, despite major changes in sedimentation rates as a result of lake or catchment disturbance.
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TL;DR: In this article, it was shown that within 10 A of the biotite surface pH can be several orders of magnitude lower than in the bulk fluid, and [ Na + ] [ Ca 2+ ] ratios may be more than three times higher than the bulk fluids.
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TL;DR: In this article, the hydrogen isotope fractionation factor between kaolinite and water was determined at temperatures between 200° and 352°C, assuming equilibrium between exchanged hydrogen and water.
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TL;DR: In this paper, Desulfovibrio desulfuricans produces a change in the chemistry of the surrounding fluids, such as carbonate dissolution reactions and diagenetic reactions involving silica.
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TL;DR: The Early Mesozoic North Mountain basalts of Nova Scotia, Canada, are continental tholeiites similar in composition to numerous Triassic diabase dykes of the northern Appalachians as discussed by the authors.
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TL;DR: The flux of Pb, Zn, Cu, Ni and Cd into ten remote lakes in the Algonquin Provincial Park of Ontario has been determined as discussed by the authors, showing that there is an overall 2-fold enrichment for Ni, Cu and Zn in surficial sediments together with a 25fold increase for Pb.
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TL;DR: In this paper, nine glauconite samples with relatively high K concentrations and which appear to be well crystallized using normal X-ray diffraction techniques have been studied using the 40 Ar 39 Ar method.
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TL;DR: In this paper, it was suggested that the necessary HS−-rich solutions stem from near-surface hydrothermal convection cells set up by nearby granitic intrusions, which caused a decrease in temperature, an interruption of calcite deposition and sulphide mineralization.
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TL;DR: The Phalaborwa Complex (South Africa) has been dated by UPb analysis of uranothorianite and baddeleyite yielding an age of 2047 + 11/−8 Ma for caronatite and phoscorite magmatism.