Paleomagnetic results from Permian rocks of the northern Saharan craton and motions of the Moroccan Meseta and Pangea |
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| Authors: | P Morel E Irving L Daly A Moussine-Pouchkine |
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| Institution: | 1. Earth Physics Branch, Energy, Mines and Resources, Ottawa, Ont. , K1A 0Y3 Canada;2. Laboratoire de Géomagnétisme du Parc Saint-Maur, 4 Avenue de Neptune, 94100 Saint Maur des Fossés France;3. Centre Géologique et Géophysique, U.S.T.L., Place Eugène Bataillon, 34060 Montpellier CedexFrance |
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| Abstract: | The characteristic magnetization of redbed samples from the upper part of the Série d'Abadla (probably Early Permian 31°N, 2.7°W) has a mean direction derived from 13 sites of D=129°, I=11°, k=59, α95=6° and a corresponding south paleopole at 29°S, 60°E, A95=5°. All directions have reversed polarity. The paleolatitude of the northern fringe of the Saharan craton was 6°±3°S, which is in excellent agreement with that for the Moroccan Meseta. Therefore, in all probability, there has been no paleolatitudinal displacement greater than about 500 km of the Moroccan Meseta relative to Africa since Permian time. Comparison of results from sedimentary rocks shows no evidence for relative rotation of the Moroccan Meseta since Permian time. Small apparent rotations are indicated by evidence from massive trachyandesite lavas from Morocco, but we argue that these could have arisen from the incomplete averaging of secular variation and uncertainties in estimates of paleohorizontal, rather than from true tectonic rotations. The combined latest Carboniferous/Early Permian paleopole for the Saharan craton and the Meseta differs form the path of apparent polar wandering for North America when the continents are assembled in Wegener's Pangea (Pangea A, in which northwest Africa is opposite North America). It is in reasonable agreement when the continents are assembled in the Pangea B configuration (northwest Africa opposite Europe). |
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