CONTINENTAL COLLISION AND METALLOGENIC RESULTS IN NORTHEST OF ALGERIA

The territory of North Algeria is part of Maghrebides which represent the southeastern part of the west Mediterranean alpine orogen. It was formed during an oblique continental collision between Africa an Mesomediterranean plate.

In the North-East of Algeria, the crystalline Edough Massif exhibits characteristics of the so-called "metamorphic core complexes", in close relationships with the opening of the Western Mediterranean Sea (Algiers-Provence Basin).

Presently, it is a N50°E antiform basement with a tectonic cover of flysch nappes. These nappes were emplaced in two stages: (i) during Eocene, a first stage of collisional tectonics in the Maghrebides led to the emplacement of a complex of Cretaceous flysch nappes "; (ii) in Late Burdigalian, following a second collisional stage, the Numidian (Oligo-Miocene) siliceous flysch nappe was emplaced.

Antiformal structures are sealed by the emplacement of Langhian (magmatic rocks granite (17 Ma), microgranite (16 Ma) and rhyolite (15 Ma). Magmatism and hydrothermalism occurred under shallower conditions with time, indicating continuous uplift from the onset of magmatism and hydrothermalism in Late Burdigalian. In the Aïn-Barbar area, the uplift rate was estimated to be 0.5 mm.a-1 (Marignac, 1988).

The magmatic and hydrothermal activities have induced several kind of mineralizations (W, Cu-Pb-Zn, Sb, Au) in strong relationship with the continuous uplift.