GEOCHEMICAL JOURNAL

The graphic method of analysis of discordant potassium-argon data

A. G. Rublev, Lev K. Levsky

1978 Volume 12 Issue 2 Pages 69-74
Published: June 20, 1978
Released on J-STAGE: April 08, 2008

DOIhttps://doi.org/10.2343/geochemj.12.69

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The loss of argon from various minerals by thermal event is semi-quantitatively discussed by a graphic method based on diffusion model. The way of estimating the primary age of a rock or rock massif is presented using real samples of Kidjimitskii and Vitimkanskii complexes in Zabaikalie.

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Rock volatility — Some initial experiments

Georges Desaedeleer, E. D. Goldberg

1978 Volume 12 Issue 2 Pages 75-79
Published: June 20, 1978
Released on J-STAGE: April 08, 2008

DOIhttps://doi.org/10.2343/geochemj.12.75

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Volatile elements from a basalt and from an obsidian were identified following slow neutron irradiation of the samples and a gamma ray spectroscopic assay of the room temperature distillate. The covariance of the enrichment factors for a variety of metals in the distillate and in atmospheric aerosols suggests that natural volatilization is responsible in part for the metal burdens in the atmosphere.

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Application of settling model to the vertical transport of soluble elements in the ocean

Shizuo Tsunogai

1978 Volume 12 Issue 2 Pages 81-88
Published: June 20, 1978
Released on J-STAGE: April 08, 2008

DOIhttps://doi.org/10.2343/geochemj.12.81

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The vertical flux of chemical elements in the ocean is expected to be related to that of carbon from the settling model proposed by TSUNOGAI and MINAGAWA (1978) where chemical elements settle by forming large particles with organic material. The enrichment of concentration in the deep water is explained by introducing this vertical flux into a box model. The ratio of concentration for a constituent between the deep and surface waters is expressed by (1 + 2 × 10^-5E)/(1 + 7 × 10²/T) where E is the enrichment factor in the particle relative to seawater and T is the residence time in the ocean. The observed concentration ratios for various elements usually lies between the calculated ratios from E of suspended particles and of plankton and the settling particles from the surface to deep water are expected to be similar to suspended material rather than planktonic material. This model also predicts that analytical methods having errors less than 0.03% are necessary to detect enrichments for Na, Mg and K in the deep water and further that the material decomposing in the deep water has the following relationship; P : N : Si : C : O (oxygen used) = 1 : 14 : 60 : 110 : 276.

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Rare earth element abundances in Caledonian metavolcanics from the island of Leka, Norway

Tore Prestvik, Elen Roaldset

1978 Volume 12 Issue 2 Pages 89-100
Published: June 20, 1978
Released on J-STAGE: April 08, 2008

DOIhttps://doi.org/10.2343/geochemj.12.89

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Fourteen rare-earth elements (REE) have been determined in metavolcanics and metagabbros from the island of Leka, Norway. The overall REE content of these rocks ranges from about 3 ppm, with strong light REE depletion, for the metagabbros to 170ppm with light REE enrichment, for porphyritic greenstones and pillow lavas. Based on regional geological features, lithology, and the REE abundances it is concluded that rocks of the island Leka constitute a part of an ophiolite complex.

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A simple method of estimating the binodal surface

Lawrence M. Barron

1978 Volume 12 Issue 2 Pages 101-105
Published: June 20, 1978
Released on J-STAGE: April 08, 2008

DOIhttps://doi.org/10.2343/geochemj.12.101

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Calculated binodal and spinodal relations for Ganguly's ternary Ca (Al, Fe, Cr) garnet model are used to calibrate an empiricial equation which permits the estimation of a binodal surface from its spinodal surface. The equation also works satisfactorily in the quaternary model of Ganguly and Kennedy for aluminous (Ca, Mn, Fe, Mg) garnets. The equation is generalized so that asymmetric multicomponent solutions can be similarly treated. The calculated ternary results in the Ca (Al, Fe, Cr) garnet model indicate that binodal tie-lines can be estimated from the properties of the spinodal.

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Multivariable correlation method for calculation of magmatic rocks weathering budget

G. Sarazin

1978 Volume 12 Issue 2 Pages 107-113
Published: June 20, 1978
Released on J-STAGE: April 08, 2008

DOIhttps://doi.org/10.2343/geochemj.12.107

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The author built up a multivariable correlation method in order to explain stoichiometric relations observed between water soluble species and rock composition during the weathering process. This method allows to define four parameters of unequal importance. Two of them are closely related to the type of newly formed secondary mineral. Application in a complex volcanic environment gives quite satisfactory results.

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Synthesis of protodolomite from aqueous solution at normal temperature and pressure

Shigeru Ohde, Yasushi Kitano

1978 Volume 12 Issue 2 Pages 115-119
Published: June 20, 1978
Released on J-STAGE: April 08, 2008

DOIhttps://doi.org/10.2343/geochemj.12.115

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To estimate the conditions of the protodolomite formation, laboratory syntheses from simple aqueous solutions have been carried out under normal temperature and pressure conditions. Protodolomites have been synthesized from CaCl₂ + MgCl₂ + (NaCl) + NaHCO₃ solutions. This paper shows the concentrations of calcium and magnesium ions in the parent solution, which are required for the protodolomite formation. The synthesis experiment indicates that concentrated seawater is favorable to the protodolomite formation. That is, the high value of [Mg²⁺] / [Ca²⁺], and the high concentrations of sodium and chlorine ions in a parent solution are favorable to the protodolomite formation.

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D/H and ¹⁸O/¹⁶O fractionation factors in evaporation of water at 60 and 80°C

Osamu Matsubaya, Hitoshi Sakai

1978 Volume 12 Issue 2 Pages 121-126
Published: June 20, 1978
Released on J-STAGE: April 08, 2008

DOIhttps://doi.org/10.2343/geochemj.12.121

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The isotopic fractionation factors in evaporation of water at 60° and 80°C were determined from the isotopic ratios of water under steady-state balance between inflow and evaporation. The results at 60° and 80°C are 1.0501 ± 0.0029 and 1.0431 ± 0.0022 for H₂O/HDO and 1.0176 ± 0.0010 and 1.0156 ± 0.0008 for H₂¹⁶O/H₂¹⁸O, respectively. Oyunuma, isotopically the heaviest geothermal pond in Japan, is enriched by 40.3‰ in D/H and by 16.5 ‰ in ¹⁸O/¹⁶O, respectively, relative to its meteoric inflow and may be a natural example of such steady-state evaporation pans.

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Geochemistry and petrology of some volcanic rocks dredged from the Gulf of California

Margarita Lopez M., Jose Perez R., Jaime Urrutia F., Surendra Pal, Dav ...

1978 Volume 12 Issue 2 Pages 127-132
Published: June 20, 1978
Released on J-STAGE: April 08, 2008

DOIhttps://doi.org/10.2343/geochemj.12.127

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This work is based on the study of three rocks dredged from the mouth of the Gulf of California. Chemical and petrographic analyses of these samples show their association as tholeiitic basalts. The three samples contain finely dispersed olivine and are composed mainly of basic glass and plagioclase microliths. They show chlorite too as evidence of alteration. Tectonic implications of their chemical and petrographic characteristics are briefly discussed.

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Effect of continuous self-resorption of solid particles formed in the melt on rare-earth pattern: a possible backward fractionation

Akimasa Masuda

1978 Volume 12 Issue 2 Pages 133-135
Published: June 20, 1978
Released on J-STAGE: April 08, 2008

DOIhttps://doi.org/10.2343/geochemj.12.133

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