Zobrazeno 1 - 10
of 22
pro vyhledávání: '"K. S. Viljoen"'
Autor:
Sonja Aulbach, Alan B. Woodland, Richard A. Stern, Prokopiy Vasilyev, Larry M. Heaman, K. S. Viljoen
Publikováno v:
Scientific Reports, Vol 9, Iss 1, Pp 1-11 (2019)
Abstract Oxygen fugacity (ƒO2) is an intensive variable implicated in a range of processes that have shaped the Earth system, but there is controversy on the timing and rate of oxidation of the uppermost convecting mantle to its present ƒO2 around
Externí odkaz:
https://doaj.org/article/e1ecf0638965477ca8aae7a76173a079
Publikováno v:
International Kimberlite Conference Extended Abstracts: 1998.
Autor:
K. S. Viljoen, Sonja Aulbach
Publikováno v:
Earth and Planetary Science Letters. 431:274-286
Major- and trace-element compositions of eclogite and pyroxenite xenoliths of ≥2.5 Ga age (in situ Pb–Pb data on clinopyroxene) from the Lace kimberlite on the Kaapvaal craton were investigated in order to constrain: (1) the nature and evolution
Autor:
J.E. Westraadt, M.D.S. Lekgoathi, Patience Segonyane, Marco A.G. Andreoli, Vittoria Pischedda, Tshepo Ntsoane, David L. Block, Charles S. Montross, Maria Atanasova, Chris Franklyn, K. S. Viljoen, G.A. Belyanin, Chris Harris, Jan Kramers
Publikováno v:
Earth and Planetary Science Letters
Earth and Planetary Science Letters, Elsevier, 2013, 382, pp.21-31. ⟨10.1016/j.epsl.2013.09.003⟩
Earth and Planetary Science Letters, Elsevier, 2013, 382, pp.21-31. ⟨10.1016/j.epsl.2013.09.003⟩
We have studied a small, very unusual stone, here named “Hypatia”, found in the area of southwest Egypt where an extreme surface heating event produced the Libyan Desert Glass 28.5 million years ago. It is angular, black, shiny, extremely hard an
Publikováno v:
Lithos. 112:1002-1013
Eclogite xenoliths from the Kimberley diamond mine dumps were studied for major, trace elements and oxygen isotopes. The suite consists of typical garnet and clinopyroxene rocks as well as kyanite-eclogites and olivine- or orthopyroxene-bearing sampl
Autor:
K. S. Viljoen, Iain McDonald
Publikováno v:
Applied Earth Science. 115:81-93
Eclogite xenoliths recovered from kimberlites and alkali basalts are clinoproxene and garnet rich rocks formed at high pressures within the mantle. They are broadly 'basaltic' in composition and their genesis remains controversial. Early models sugge
Publikováno v:
Journal of Petrology. 46:2059-2090
Eclogite xenolith varieties at Kaalvallei include accessory-free bimineralic xenoliths, diamond-bearing eclogite, corundum-bearing eclogite, garnet-websterite, alkremite and spinel-bearing eclogite. The xenoliths can be accurately classified into pre
Autor:
Thomas Stachel, K. S. Viljoen, Ingrid Leost, Ralf Tappert, Jeff W. Harris, Sonja Aulbach, Gerhard P. Brey
Publikováno v:
Lithos. 77:1-19
On a global scale, peridotitic garnet inclusions in diamonds from the subcratonic lithosphere indicate an evolution from strongly sinusoidal REEN, typical for harzburgitic garnets, to mildly sinusoidal or “normal” patterns (positive slope from LR
Publikováno v:
Lithos. 77:155-179
Silicate and oxide mineral inclusions in diamonds from the geologically and historically important De Beers Pool kimberlites in Kimberley, South Africa, are characterised by harzburgitic compositions (>90%), with lesser abundances from eclogitic and
Publikováno v:
Contributions to Mineralogy and Petrology. 147:32-47
The Orapa and Jwaneng kimberlites are located along the western margin of the Kalahari Craton and the prevalence of eclogitic over peridotitic diamonds in both mines has recently been linked to lower P-wave velocities in the deep mantle lithosphere (