Palaeomagnetism of Upper Cretaceous volcanics and Nubian sandstones of Wadi Natash, SE Egypt and implications for the polar wander path for Africa in the Mesozoic
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Vols. 1-18 (1924-1944), ISSN 0044-2801
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Abstract
Eighteen sites (342 samples) from Upper Cretaceous Wadi Natash volcanics (24.5° N, 34.5° E) yield a mean direction of magnetization D = 345.4°, I = 16.7° with α95 = 8.5°, k = 21.4, N = 15 after AF cleaning resulting in a pole at 69.3° N, 258° E with A95 = 5.8° All sites have normal polarity consistent with their age and the magnetic stratigraphy in the Cretaceous. From 5 sites (85 samples) from Upper Cretaceous Nubian sandstone at Wadi Natasha mean direction D = 358.1°, I = 32.0° with α95 = 8.7°, k = 143 (mixed polarity) was obtained after thermal demagnetization. Combined with previous investigations on Nubian sandstone at other locations in Southern Egypt (Schult et al. 1978) this yields a pole at 81.8° N, 223° E with A95 = 3.3°, N = 23. 9 sites from Eocene Baharia iron ores (27.5° N, 29.0° E) yield a mean direction D = 188.0°, I = –43.6° and α95 = 6.4°, k = 65 with a pole at 83.5° N, 139° E and A95 = 7° In addition the palaeomagnetism of some Tertiary basaltic rocks in Northern Egypt was studied. The polar wander path for Africa in Mesozoic time is presented showing more mobility than in earlier papers. For appropriate reconstructions of South America with respect to Africa the polar wander paths of both continents are substantially in agreement.
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