PALEOMAGNETISM OF THE KORAS GROUP, NORTHERN CAPE PROVINCE, SOUTH-AFRICA

Rocks of the Koras Group (ca. 1200-1000 Ma) near Upington, Namaqualand, mostly carry at least two components of NRM which have been distinguished by two stage a.f. plus thermal cleaning. Syngenetic or diagenetic NRM is identified in red sediments of the Kalkpunt Formation, in direction D = 170°, I = -7° with k = 67, α95 = 7.4° corresponding to a palaeomagnetic pole at 57°S, 183°E (dψ = 4°, dx = 7°). This result is corroborated by similar directions but opposite polarity in some immediately underlying basaltic andesites of the Florida Formation, and by soft components (anti-parallel to the hard component) in some specimens of both sediments and volcanics. NRM in the Ezelsfontein Formation, sampled at only one locality, may also be primary (D = 29°, I = -11°, k = 54, α95 = 16.9°). Some of the basaltic andesites appear to have been completely remagnetized in an easterly direction D = 95°, I = -10°, k = 55, α95 = 10.4°; the opposite polarity to this is found in soft components in some sedimentary specimens and both may reflect a mild magnetizing event at c. 800 Ma. © 1979.