Hydroxyl defects in garnets from mantle xenoliths in kimberlites of the Siberian platform
Article Abstract:
A study was undertaken to observe the hydroxyl defects in garnets from garnet-containing prageneses of mantle xenoliths found in different kimberlites at the Siberian platform. The garnet crystals gathered were of xenomorphic to hypidiomorphic types and sample analyses were done using electron microphobe and single-crystal infrared absorption methods. Results revealed that the defects were caused by internal factors and energetical specifications, intercrystalline distribution of hydrogen and external factors coupled with physicochemical conditions of garnet formation.
Publication Name: Contributions to Mineralogy and Petrology
Subject: Earth sciences
ISSN: 0010-7999
Year: 1998
User Contributions:
Comment about this article or add new information about this topic:
Graphite- and diamond-bearing eclogite xenoliths from the Bellsbank kimberlites, Northern Cape, South Africa
Article Abstract:
Eclogite xenoliths of Bellsbank kimberlites, Northern Cape, South Africa, contain graphite as separate grains in the form of tabular prisms and octahedral diamonds. Graphite is present in both Group I and II xenoliths while diamonds are present only in Group I xenoliths. The diamonds and carbon isotopes in the eclogites have a common source. The concentration of Nd isotopes in the xenoliths is higher than that in the bulk earth.
Publication Name: Contributions to Mineralogy and Petrology
Subject: Earth sciences
ISSN: 0010-7999
Year: 1995
User Contributions:
Comment about this article or add new information about this topic:
Diamondiferous garnet harzburgites from the Finsch kimberlite, Northern Cape, South Africa
Article Abstract:
The mineralogical results show that the two diamondiferous harzburgite xenoliths obtained at the Finsch kimberlite, South Africa are coarse peridotites exhibiting compositional equilibrium common in the diamond stability field. The xenoliths are found to be different from other inclusions in Finsch diamonds. The observed differences clearly state that the two recovered xenoliths originate from another diamond source.
Publication Name: Contributions to Mineralogy and Petrology
Subject: Earth sciences
ISSN: 0010-7999
Year: 1992
User Contributions:
Comment about this article or add new information about this topic:
- Abstracts: Petrography and geochemistry of eclogites from the Mir kimberlite, Yakutia, Russia. Petrogenesis of Variscan high-temperature Group A eclogites from the Moldanubian Zone of the Bohemian Massif, Czechoslavakia
- Abstracts: Distribution of trace elements during breakdown of mantle garnet: an examplefrom Zabargad. Distinct site preferences for heavy and light REE in amphibole and the prediction of (super Amph/L)D(sub REE)
- Abstracts: Carbonate-bearing mantle peridotite xenoliths from Spitsbergen: phase relationships, mineral compositions and trace-element residence
- Abstracts: Controls on the fractionation of isovalent trace elements in magmatic and aqueous systems: Evidence from Y/Ho, Zr/Hf, and lanthanide tetrad effect - a discussion of the article by M. Bau (1996)