New Moscovian palaeomagnetic pole from the Edjeleh fold (Saharan craton, Algeria)

M. E. M. Derder , B. Henry (1) , B. Bayou , H. Djellit , M. Amenna

1 IPGP (UMR_7154) - Institut de Physique du Globe de Paris

A palaeomagnetic study was carried out in the Moscovian (~305Ma) formation in the Edjeleh anticline, the only area where important dips can be observed in the Upper Palaeozoic series of the Illizi basin (Algeria). This study shows the existence of three magnetization components. Two of them are interpreted as Cenozoic and Permian remagnetizations; their poles are 88.8°N, 164.0°E, K=262, A₉₅=3.3° and 43.4°S, 61.7°E, K=93, A₉₅=5.9°, respectively. The third component is determined by both well-defined ChRMs and remagnetization circles analysis. Its associated fold test is positive and significant. Because the folding started before or during the Autunian, this third component was acquired very early and is very probably the primary magnetization. Its corresponding palaeomagnetic pole (28.3°S, 58.9°E, K=157, A₉₅=4.2°) is close to the poles from the Saharan platform obtained from neighbouring periods. The positive fold test of this study thus validates these previous Upper Palaeozoic poles.

This new result is in agreement with the geodynamical model (Matte 1986; Henry et al. 1992), which proposed the occurrence of a large clockwise rotation of Africa during the Carboniferous; such a motion agrees with the Permian Pangaea A2 reconstruction.

Mots clés: Africa; apparent polar wander path; fold test; Moscovian; palaeomagnetic pole; Saharan craton

Domaines: Planète et Univers [physics]

M. E. M. Derder, B. Henry, B. Bayou, H. Djellit, M. Amenna. New Moscovian palaeomagnetic pole from the Edjeleh fold (Saharan craton, Algeria). Geophysical Journal International, 2001, 147, pp.343-355. ⟨10.1046/j.0956-540X.2001.01530.x⟩. ⟨insu-03597748⟩