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The Sheahan Diamond Literature Reference Compilation - Scientific and Media Articles based on Major Keyword - Kamafugite
The Sheahan Diamond Literature Reference Compilation is compiled by Patricia Sheahan who publishes on a monthly basis a list of new scientific articles related to diamonds as well as media coverage and corporate announcements called the Sheahan Diamond Literature Service that is distributed as a free pdf to a list of followers. Pat has kindly agreed to allow her work to be made available as an online digital resource at Kaiser Research Online so that a broader community interested in diamonds and related geology can benefit. The references are for personal use information purposes only; when available a link is provided to an online location where the full article can be accessed or purchased directly. Reproduction of this compilation in part or in whole without permission from the Sheahan Diamond Literature Service is strictly prohibited. Return to Diamond Keyword Index
Sheahan Diamond Literature Reference Compilation - Scientific Articles by Author for all years
Each article reference in the SDLRC is tagged with one or more key words assigned by Pat Sheahan to highlight the main topics of the article. In an effort to make it easier for users to track down articles related to a specific topic, KRO has extracted these key words and developed a list of major key words presented in this Key Word Index to which individual key words used in the article reference have been assigned. In most of the individual Key Word Reports the references are in crhonological order, though in some such as Deposits the order is first by key word and then chronological. Only articles classified as "technical" (mainly scientific journal articles) and "media" (independent media articles) are included in the Key Word Index. References that were added in the most recent monthly update are highlighted in yellow.
A kamafugite is an igneous intrusion that has a fair number of scientific references but is so obscure it does not even have a Wikipedia entry. Perhaps Roger Mitchell will be so kind as to pen a brief description and why it is is relevant to diamonds, ideally with a link to an online resource with greater detail.
Subcontinental lithospheric mantle origin of the Cenozoic kamafugite in western Qinling, China: evidence from helium isotopes in mantle derived xenoliths.
Geochimica et Cosmochimica Acta, Vol. 70, 18, p. 16 abstract only.
Melluso, L., Lustrino, M., Ruberti, E., Brotzu, P., Barros Gomes, C., Morbidelli, Morra, Svisero, Amelio
Major and trace element composition of olivine perovskite, clinopyroxene, Cr Fe Ti oxides, phlogopite and host kamafugites and kimberlites, Alto Paranaiba,
Canadian Mineralogist, Vol. 46, no. 2 Feb. pp. 19-40.
Su, B-X., Zhang, H-F., Ying, J-F., Xiao, Y., Zhao, X-M.
Nature and processes of the lithospheric mantle beneath the western Qinling: evidence from deformed peridotitic xenoliths in Cenozoic kamafugite from Haoiti, Gansu Pro
Journal of Asian Earth Sciences, Vol. 34, 3, pp. 258-274.
Su, B-X., Zhang, H-F., Ying, J-F., Xiao, Y., Zhao, X-M.
Nature and processes of the lithospheric mantle beneath the western Qinling: evidence from deformed peridotitic xenoliths in Cenozoic kamafugite from Haoti Province.
Journal of Asian Earth Sciences, Vol. 34, pp. 258-274.
Abstract: We have studied mineral-hosted melt, crystal and fluid inclusions from two ugandite, one mafurite and two katungite samples from the Toro-Ankole volcanic province in the East African Rift, which is the archetypal location for kamafugitic rocks. A main finding of our study is the presence of orthopyroxene as inclusions in an early generation of olivine from all three types of kamafugites, suggesting interaction of a carbonate-rich metasomatic agent with lithospheric peridotite mantle that may have caused almost complete dissolution of orthopyroxene. This process was preceded, accompanied or followed by the formation of phlogopite-clinopyroxene veins resulting from interaction of F-rich and low H2O/CO2 metasomatic fluids with the mantle rocks, which then became the source of the Toro-Ankole kamafugites. Pressure-temperature (P-T) estimates suggest that the parental kamafugitic melts last equilibrated with their source rocks at ?16?±?8?kbar and ?1160?±?130°C. This implies that they could have originated significantly below the solidus of dry, carbonated peridotite, but above the solidus of phlogopite-bearing clinopyroxenite. We conclude that the Toro-Ankole kamafugites originated by very low degrees of partial melting at moderately oxidized conditions (?FMQ = +2•2?±?0•4?atm log units, where FMQ is fayalite-magnetite-quartz buffer) under a high geothermal gradient of 60-80?mW?m?2, in response to lithospheric extension and probable association with an adjacent mantle plume. We estimate that differentiation of parental ugandite, mafurite and katungite magmas could have occurred at depths <12?km in the T range 1150-850°C. Laboratory-heated, homogenized melt inclusions trapped by a second generation of olivine and clinopyroxene are characterized by remarkable silica-undersaturation, compared with mid-ocean ridge basalt and ocean island basalt magmas, with high concentrations of alkalis, Ti, Ba, Sr and Zr, but varying to very low concentrations of Al and Ca. Such alkali-rich, strongly evolved melts might have resulted from extreme (>95%) fractional crystallization of the parental magmas, assuming their chemical compositions to be similar to those of the respective lavas. However, this estimate is about three times higher than the modal amount of phenocrysts in the lavas that could be reinforced by the presence of excess cognate crystals and/or xenocrysts in the lavas. Strong oxidation from FMQ?+?2 to FMQ?+?4 to +?5•2?atm log units of the evolved mafuritic magmas at ?900-1000°C has occurred during the final stage of magma evolution at very shallow crustal depths or possibly directly in the lava flow.
Brazil Journal of Geology, Vol. 47, 3, pp. 383-401. pdf
South America, Brazil
kimberlites, kamafugites, Tres Ranchos, Coromandel
Abstract: Magmatism associated with the Alto Paranaíba structural high comprises kimberlites, kamafugites, and alkaline complexes, forming an approximately 400 x 150 km NW-SE belt in the southern São Francisco Craton. Dating of some intrusions reveals ages between 120 and 75 Ma. Chemical analyses of garnet recovered in alluvium from traditional diamond digging areas indicate peridotitic garnet windows in Três Ranchos and Coromandel. Six hundred and eighty (680) diamonds acquired or recovered during mineral exploration in the digging areas of Romaria, Estrela do Sul, Três Ranchos and Coromandel show unique characteristics, certain populations indicating young, proximal and primary sources (YPP). Analyses of 201 stones from Santo Antônio do Bonito, Santo Inácio and Douradinho rivers alluvium, Coromandel, present no evidence of transport, characterizing a proximal source. Within these river basins, exposures of the Late Cretaceous Capacete Formation basal conglomerate contain mainly small rounded and/or angular quartzite pebbles and of basic and ultrabasic rocks, as well as kimberlite minerals (garnet, ilmenite, spinel, sometimes diamond). A magnetotelluric profile between the Paraná and Sanfranciscana basins shows that the thick underlying lithosphere in the Coromandel region coincides with the peridotitic garnet window and with a diamond population displaying proximal source characteristics. Diamond-bearing kimberlite intrusions occur in different areas of Alto Paranaíba.