Mohamed Khalil Bensalah

Morphology, internal architecture and emplacement mechanisms of lava flows from the Central Atlantic Magmatic Province (CAMP) of Argana Basin (Morocco)

Abstract The morphology, internal architecture and emplacement mechanisms of the Central Atlantic Magmatic Province (CAMP) lava flows of Argana Basin in Morocco are presented. The volcanic pile was produced by two volcanic pulses. The first, represented by the Tasguint Formation, corresponds to a succession of 3–13 individual flows created by 1–8 eruptions; the second, Alemzi Formation, is composed of 2–7 individual flows formed by 1–4 eruptions. These formations, geochemically distinct, are separated by thin silty or sandy horizons or by palaeosols. They include ‘compound pahoehoe flows’ and ‘simple flows’. The first type is almost exclusive of the lower formation, while the second type dominates the upper formation. The lava flows show clear evidence of endogenous growth or ‘inflation’. The characteristics of the volcanic pile suggest slow emplacement during sustained eruptive episodes and are compatible with a continental basaltic succession facies model.

Thermo-tectonic Evolution of the Central High Atlas during the Mesozoic

Analysis of the subsidence evolution of the Central High Atlas basin, coupled to geochemistry of some REE, shows that this rift “failed” in Late Jurassic times most probably due to differential extension, the mantle being more stretched than the crust as suggested by volcanism, leading to uplift as predicted by non-uniform extension models. The thermal dome may have been active since that time. The straightforward implications are that any thermal evolution models should take into account the lithospheric evolution and the complex geodynamic history of the CHA.