A geochemical study of the concentration process of tungsten and tin in the “Taourirts” granites of central Ahaggar, Algeria

Abstract

The here presented geochemical study of the granite of three intrusions in the Central Ahaggar (Algeria) was carried out in an effort to discriminate between W- and Sn-bearing intrusions. In the Nahada intrusion, W is not correlated with the other elements. As this intrusion is linked to a large W deposit, the correlation of W should be made with the elements of the fluid phase. However, this has not been taken into account in the present study. Although the Tamazaror intrusion was also affected by a strong fluid phase, only a minor W deposit was observed, due to the fact that the W remained partially absorbed in a ferruginous phase caused by an extensive crustal contamination. In the El Bema intrusion, accompanied by intrabatholitic Sn veins, W is correlated with a lithophile factor characterizing a fractional crystallization process, which is recognized as an indicator of granite specialization for Sn. The chemical features of the intrusive granites allow a lithogeochemical approach to the prospection problems for W and Sn in the Central Ahaggar.