The Mekkam Inlier (Eastern Morocco): A Magmatic Domain with Mixed Characteristics: Contribution of Petrographic and Geochemical Data

Abstract

The Mekkam inlier is located 50 km southeast of the town of Taourirt, in northeastern Morocco. It offers a great opportunity for the study of Variscan magmatism in Morocco. This inlier is punctuated by small magmatic bodies which we will characterize through a petrographic and geochemical study to situate this inlier in its geotectonic context. The petrographic study revealed the existence of three trends: acidic, intermediate, and basic, which are represented by facies ranging from granites to basanites, including andesites, rhyolites, trachytes, dacites, quartz microdiorites, Aplite and microgranites. All these facies have a mineralogical assemblage dominated by quartz, plagioclase, oligoclase, potassium feldspar, pyroxene, and biotite; the most abundant accessory minerals are zircon and apatite. Green hornblende is found in microdiorites and dacites. The geochemical analysis, conducted through the examination of major elements, trace elements, and rare earth elements, has uncovered the presence of two distinct magmatic series: a calc-alkaline series of the island arc type or active continental margin, and another alkaline series of syn-collision. Based on this combined data, we propose that the Mekkam sector represents a magmatic arc developed within a compressional tectonic regime located above a subduction zone, which was later followed by an intracontinental collision phase.