Paleomagnetism of Proterozoic and Cambrian Strata, Adrar de Mauritanie, CRatonic West Africa

摘要: Four paleomagnetic poles are reported from red beds of the Adrar de Mauritanie, cratonic West Africa. Thirteen localities were occupied, and 224 samples collected in seven units a middle Proterozoic to early Paleozoic sedimentary section. Two late strata; third pole is Cambrian strata. The magnetizations for these reside stable high-temperature components, revealed by progressive thermal demagnetization analysis 675°C. fourth interpreted reflect Permian overprinting Cambrian-Ordovician sampled contained directions too scattered allow calculation any pole. strata (998±32 Ma; Rb-Sr date on argillite), derived four (52 samples, single polarity), plots at 48.7°N, 206.9°E (dp = 1.1°, dm 2.9°). (775 ± 52 date), two (15 mixed 34.0°N, 246.9°E 4.6°, 8.6°). Neither has correlatives age data set Africa, nor there obvious with remainder that we consider direction comes three (23 plotting 0.3°S, 249.3°E 5.7°, 11.5°). Its antiparallel corresponds one group Africa but differs markedly another poles. overprint obtained (50 localities, polarity) provides (reversed 47.2°S, 42.6°E 1.5°, 3.0°), which good agreement elsewhere In spite large number already additional needed before reliable apparent polar wandering path can be constructed