Showing papers by "Gerhard P. Brey published in 2013"
TL;DR: In this paper, the partitioning of a number of trace elements (LILE, HFSE, REE, Cu, Pb, Co, Ni) between mantle minerals (olivine, pyroxenes and garnet) and silico-carbonate melts was experimentally studied at 6-12-GPa and 1300-1700°C.
78 citations
TL;DR: In this article, the authors used single garnet grains from heavy mineral concentrates from the Kaapvaal craton (Roberts Victor and Lace mine) to determine the major and trace elements and the Sm−Nd and Lu−Hf isotope systematics of these highly depleted members of the peridotitic suite.
36 citations
TL;DR: In this article, an analytical transmission electron microscopy and electron probe micro-analysis (EPMA) was used to characterize the temperature-dependent ratio of Fe2+/ΣFe in garnet and clinopyroxene.
Abstract: Samples with eclogitic composition in the system CaO–FeO–Fe2O3–MgO–Al2O3–SiO2 were produced from various kinds of starting materials held in graphite-lined Pt capsules at a pressure of 2.5–3.0 GPa and temperatures of 800–1,300 °C using a piston-cylinder or Belt apparatus. Garnets and clinopyroxenes were characterized by analytical transmission electron microscopy and electron probe micro-analysis (EPMA). Fe3+/ΣFe ratios determined by electron energy-loss spectroscopy (EELS) decrease in clinopyroxene from 22.2 ± 3.4 % at 800 °C to 13.3 ± 5.4 % at 1,300 °C, while in garnet, they vary between 10.8 ± 1.5 and 15.4 ± 4.7 %, respectively. Temperature estimates according to Krogh (Contrib Mineral Petrol 99:44–48, 1988) reproduce the experimental temperature to ±60 °C without systematic deviations if total iron is used in the calculation. If only the Fe2+ content is used, which was obtained by combining EPMA and EELS results, the experimental temperature is underestimated by 33 °C on average at 800–1,200 °C and overestimated by 77 °C on average at 1,300 °C. These systematic deviations can be explained by the temperature-dependent ratio of Fe2+/ΣFe in garnet divided by that in clinopyroxene. Since the difference between the calculated and experimental temperature is relatively small, a Fe2+-based recalibration of the thermometer appears not to be necessary for the investigated system in the range of pressure, temperature and composition covered by the experiments of this study.
20 citations
TL;DR: In this paper, major and trace elements and the Sm-Nd and Lu-Hf isotope systematics in minerals of 19 garnet peridotites from the Gibeon Townlands and Hanaus kimberlite pipes were determined.
13 citations