Basic Rocks of Texenna (Northeastern Algeria): Petrography and Geochemistry: A Metallogenic Approach Its Correlation with Perimediterranean Orogenic Belts

This petrographic, metallogenic, and geochemical study focuses on the oceanic basic rocks of the Texenna volcano-sedimentary complex (Petite Kabylie, Algeria), compared to the western Perimediterranean orogen. Analysis of 13 thin sections and 3 polished sections reveals four facies (pillow lavas, porphyritic basalts, dolerites, and gabbros). The pillow lavas (~250 m) range in size from 0.5 to 3 m. Intense spilitization (green schist to amphibolite facies) has pseudomorphosed the primary minerals into chlorite, actinote, epidote, albite, and calcite, with textural zoning. Disseminated mineralization includes pyrite, chalcopyrite, pyrrhotite, covellite, hematite, chromite, and magnetite, indicating hydrothermal circulation. The major elements show high mobility (SiO¿: 19-55%; MgO: 0.09-12.82%). Immobile elements (Zr: 324 ppm) and trace element ratios (Ta/Nb = 0.07; Ta/La = 0.05) confirm an N-MORB to T-MORB affinity. Anomalies in Rb, Zr, and Pb indicate crustal contamination. The Texenna rocks are relics of the Tethysian oceanic crust, consistent with the Mediterranean ophiolites.