The Paredão kimberlite, Western Minas Gerais, Brazil: field relations, chemical data and host rocks
Abstract:The Paredão kimberlite (Upper-Cretaceous) forms a circular-amoeboid depression of about 30 ha. It is emplaced in Neoproterozoic carbonates of the Bambuí Group (calcilutites, calcarenites and calcirudites of the Lagoa do Jacaré Formation) and shows a well-defined crater facies formed by pyroclastic deposits. The diatreme facies, not well observed, is deeply weathered, forming a homogeneous brown-greenish mass of clay material covered by soils. Field relations between the pipe and the host-rocks are marked by a significant difference in soil color and topography. Geological boundaries have been established through conventional geological mapping, enhanced by a radiometric prospecting using a total-count scintillometer. Furthermore, heavy-mineral prospecting was carried-out and the recovered kimberlite indicator minerals (pyrope, diopside, ilmenite and spinel) were analyzed. Chemical data placed the Paredão Kimberlite in the "non-diamondiferous" field.
Keywords: BRAZIL; CARBONATE HOST ROCKS OF KIMBERLITE; ILMENITE AND DIOPSIDE CHEMICAL DATA; KIMBERLITE; KIMBERLITE INDICATOR MINERALS; KIMBERLITE PYROCLASTIC FACIES; PYROPE; UPPER CRETACEOUS; WESTERN MINAS GERAIS
Document Type: Research Article
Publication date: 2009-07-01
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