Paleomagnetism of the Nuanetsi Igneous Province and its bearing upon the sequence of Karroo igneous activity in southern Africa

Further sites have been collected in the Marangudzi ring complex and the results confirm the presence of one normally magnetized site among seven reversely magnetized sites. A new paleomagnetic pole position is given for Marangudzi at 70.2°S, 105.1°E, with A95 = 8.9°. This pole is 15.6° away from the pole previously found for the nearby ring complexes at the Mateke Hills (58.6°S, 79.7°E, A95 = 8.3°). The difference is shown to be significant, and the two poles must therefore be quoted separately. The difference in pole position probably corresponds to a difference in age which recent radiometric age determinations reveal. A limited collection in the Nuanetsi lavas showed reversed magnetization in the first 2000 meters of the sequence, and this is correlated with the reversed magnetization found at Marangudzi. Data on ages and polarities for the whole of southern Africa are summarized, and a simple reversal sequence is suggested. A comparison is made with results from rocks of a similar age in other continents.