MESOZOIC BASALTIC MAGMATISM OF THE SIDI SAID MAACHOU BASIN (WESTERN MESETA, MOROCCO): PETROGRAPHY, GEOCHEMISTRY AND GEODYNAMIC IMPLICATIONS.

The late Triassic-early Jurassic volcanism of Sidi Sa?d Maachou basin belongs to the costalMeseta and the Central Atlantic Magmatic Province (CAMP). The volcanic pile conformably overlies the red siltstones of Machraa Boujamaa Formation. This set includes a stack of several lava flows 40 to 80 m thick. The petrographic study shows that the textures vary from porphyritic to microlitic porphyritic. These igneous rocks have the geochemical characteristics of an intra-continental tholeiitic series of an anorogenic context announcing the Triassic distension. On the basis of their petrographic and geochemical characteristics, the lava flows of Sidi Sa?d Maachou tholeiitic basalts approach those of the Triassic Basin of Berrechid-El Gara-Benslimane and the High Atlas. With these data, we attempt to place these volcanic rocks in global geodynamic context by making comparisons with other Upper Triassic?Early Jurassic volcanic rocks genetically related to the breakup of Pangea and the Central Atlantic Magmatic Province resulting from thinning of continental lithosphere.