Karoo basalts in the Ellisras sub-basin, Northern Province

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Authors:Reid, D. L.; Rex, D. C.; Brandl, G.
Author Affiliations:Primary:
University of Cape Town, Department of Geological Sciences, Rondebosch, South Africa
Other:
University of Leeds, United Kingdom
Council for Geoscience, South Africa
Volume Title:South African Journal of Geology
Source:South African Journal of Geology, 100(2), p.151-156. Publisher: Bureau for Scientific Publications at the Foundation for Education, Science and Technology, Pretoria, South Africa. ISSN: 1012-0750
Publication Date:1997
Note:In English with Afrikaans summary. 21 refs.; illus., incl. 4 tables
Summary:Jurassic basalts cap the Karoo stratigraphic sequence in the Ellisras sub-basin of the Northern Province. The 75-metre section of basalt flows, obtained from a borehole, is probably a remnant of a thicker accumulation of unknown thickness. K-Ar ages of flows from top and bottom of the profile average 179±5 Ma, which is similar to ages obtained for the Lebombo and Lesotho lavas. Little geochemical variation can be detected in the lava section, and the basalts appear to represent another occurrence of the voluminous low Ti-Zr (or LTZ) type, which characterizes the Springbok Flats, central Botswana, and Lesotho. None of the Ellisras basalts resemble those of northern Lebombo, Nuanetsi, Tuli, and the area east of Soutpansberg, thereby providing a western limit to the geochemically enriched magma type (high Ti-Zr or HTZ) that appeared to have been erupted from the Lebombo-Soutpansberg/Tuli-Nuanetsi triple junction. The Ellisras basalts represent part of the margins of a vast basalt lava field consisting of the LTZ magma type that was erupted from a separate centre (or centres) in Lesotho and/or Botswana.
Subjects:Absolute age; Basalts; Boreholes; Chemical composition; Chemical ratios; Dates; Igneous rocks; Jurassic; K/Ar; Karoo Supergroup; Major elements; Mesozoic; Petrography; Spatial distribution; Thickness; Trace elements; Volcanic rocks; Africa; Limpopo South Africa; South Africa; Southern Africa; Ellisras Basin; Igneous activity; Northern Province South Africa
Abstract Numbers:98M/856
Record ID:1997068291
Copyright Information:GeoRef, Copyright 2019 American Geosciences Institute.
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