Paleomagnetism of some late Precambrian and lower Paleozoic sediments from L'Adrar de Mauritanie, West Africa

Palaeomagnetic results are reported from three formations from the late Precambrian to lower Paleozoic sedimentary sequence of L'Adrar de Mauritanie, on the West African Craton. Each of the formations recorded complex magnetizations, the sequence of which could only be resolved after detailed thermal and chemical cleaning. Most of these complexities have arisen from post depositional hematite coating on both magnetic and non-magnetic grains. Formation I 2 with a probable age of 1020 Ma records an early, presumably original remanence directed along D = 034°, I = +60° (α 95  = 6°) and a later remanence D = 336°, I = +37° (α 95  = 11°). Specimens from formations CO 8 and CO 10 (Cambro–Ordovician boundary) record a common late phase remanence at D = 128°, I = +24° (α 95  = 8°). The CO 10 early phase remanence is D = 033°, I = +61° (α 95  = 7°), whereas the poorly isolated early phase remanence of CO 8 approximates D = 060°, I = +51° (α 95  = 20°).