16 Result(s)

Article

Editorial

T. L. Grove, J. Hoefs in Contributions to Mineralogy and Petrology (2006)

Chapter

Stable Isotope Characteristics of Recent Natrocarbonatites from Oldoinyo Lengai

Carbon and oxygen isotopic compositions of nyerereite and gregoryite phenocrysts and wholerock samples of natrocarbonatite lavas from the June 1988 eruption of Oldoinyo Lengai lie within restricted ranges of δ¹³C...

J. Keller, J. Hoefs in Carbonatite Volcanism (1995)

Chapter

Isotopic Mineralogy

Among the 340 isotopes of the 98 chemical elements occurring in the minerals of the Earth, Moon, Mars, and meteorites, the majority are nonradioacitive. Many of them are absolutely stable in accordance with th...

Yu. A. Shukolyukov, K. Wetzel, H. J. Lippolt… in Methods and Instrumentations: Results and … (1995)

Article

O, H, C isotope study of rocks from the KTB pilot hole: crustal profile and constraints on fluid evolution

The pilot hole of the Continental Deep Borehole (KTB) drilling project is located in the Bavarian Oberpfalz at the western margin of the Bohemian Massif. The 4-km deep borehole penetrated various paragneisses ...

K. Simon, J. Hoefs in Contributions to Mineralogy and Petrology (1993)

Article

Carbon and oxygen isotopic covariations in hydrothermal calcites

Isotopic covariations of carbon and oxygen in hydrothermal calcites are quantitatively modeled in terms of the following three mixing processes: (1) mixing between two different fluids which leads to the preci...

Y. -F. Zheng, J. Hoefs in Mineralium Deposita (1993)

Article

Stable isotope (O, H, S) relationships in Tertiary basalts and their mantle xenoliths from the Northern Hessian Depression, W.-Germany

¹⁸O/¹⁶O, ³⁴S/³²S, and D/H ratios as well as vacuum-fusion H₂O⁺ contents were measured for late Tertiary volcanic basaltic rocks ranging in composition from quartz tholeiites and alkali olivine basalts to melilit...

R. S. Harmon, J. Hoefs, K. H. Wedepohl in Contributions to Mineralogy and Petrology (1987)

Article

Stable isotope relations in an open magma system, Laacher See, Eifel (FRG)

¹⁸O/¹⁶O and D/H ratios have been measured for matrix glasses and phenocrysts from the zoned phonolitic Laacher See tephra sequence (11000 y.b.p., East Eifel volcanic field, FRG) to study open-system behaviour of...

G. Wörner, R. S. Harmon, J. Hoefs in Contributions to Mineralogy and Petrology (1987)

Chapter

Isotope geothermometers

The best available isotope thermometers of the elements oxygen, sulfur, carbon and hydrogen are summarized, and some applications to metamorphic rocks, to sulfide ore deposits and to geothermal systems are dis...

J. Hoefs in Paleogeothermics (1986)

Chapter

Oxygen Isotope Ratios in Late Cenozoic Andean Volcanics

O-isotope ratios for 127 Cenozoic volcanic rocks from the Andean Cordillera between 5°N and 4°S range from +5.2 to +14.0‰ (SMOW). Lavas from eight volcanoes in the SVZ between 36–42°S exhibit a very narrow ran...

R. S. Harmon, J. Hoefs in Andean Magmatism (1984)

Article

The oxygen isotope composition of Hercynian granites and pre-Hercynian gneisses from the Schwarzwald, SW Germany

The oxygen isotope composition of 56 Hercynian granites and 42 pre-Hercynian gneisses has been investigated. In addition some mineral δ ¹⁸O data and 5 δD values of whole rocks have been obtained. The granites fro...

J. Hoefs, R. Emmermann in Contributions to Mineralogy and Petrology (1983)

Article

Very high CO₂ cordierite from Norwegian Lapland: Mineralogy, petrology, and carbon isotopes

The most CO₂-rich cordierite thus far encountered in nature with about 2.2 wt.% CO₂ and 0.3 wt.% H₂O occurs as large poikiloblasts in a strange non-foliated “reaction rock” that dissects well-foliated granulites ...

Th. Armbruster, W. Schreyer, J. Hoefs in Contributions to Mineralogy and Petrology (1982)

Article

Constraints on the origin of Damaran granites by Rb/Sr and δ¹⁸O data

The mean (⁸⁷Sr/⁸⁶Sr) and mean (⁸⁷Rb/⁸⁶Sr) ratios of the intrusive granites from the North and South of the Orogen's Central Zone plot on straight lines. These are interpreted as areal isochrons indicating the tim...

U. Haack, J. Hoefs, E. Gohn in Contributions to Mineralogy and Petrology (1982)

Article

The sulfur and carbon isotope composition of scapolite-rich granulites from southern Tanzania

Sulfur and carbon isotope data are presented of 15 granulite samples from the Furua Complex, southern Tanzania, in which scapolite is a primary and major rock-forming constituent (up to 30 vol%). From these da...

J. Hoefs, J. J. M. Coolen, J. Touret in Contributions to Mineralogy and Petrology (1982)

Article

Fluid inclusion and carbon isotope study from bamble granulites (South Norway)

The carbon isotopic composition of CO₂ from fluid inclusions in granulite facies rocks has been determined. The “primary” carbonic fluid — most probably being of Upper Mantle origin — appears to have δ ¹³C-values...

J. Hoefs, J. Touret in Contributions to Mineralogy and Petrology (1975)

Article

Die Isotopenzusammensetzung von Dolomiten und Kalken aus dem süddeutschen Malm

On dolomites and calcites from the Malm (Upper Jurassic) formation of Southern Germany δ ¹³C and δ ¹⁸O-determinations have been done. The most striking feature of our results is that the dolomites are isotopicall...

W. Bausch, J. Hoefs in Contributions to Mineralogy and Petrology (1972)

Article

Geochemische Untersuchungen an Travertinen der Slowakei

Travertines are characterized by high rates of deposition. Waters from which travertines are precipitated have more than ten times the calcium concentration of mean continental surface waters. Calcium has been...

R. Demovič, J. Hoefs, K. H. Wedepohl in Contributions to Mineralogy and Petrology (1972)