Tectonic evolution of the Lufilian arc (Central Africa Copper belt) duringNeoproterozoic Pan African orogenesis

The Lufilian are of Central Africa (also called Katangan belt or Copperbelt ) is a zone of low- to high-grade metasedimentary land subsidiary igneous) rocks of Neoproterozoic age hosting high-grade Cu-Co-U and Pb-Zn mineraliza tions. The Lufilian are is located between the Congo and Kalahari cratons a nd defines a structure which is convex to the north. Three major phases of deformation characterize the construction of the Lufilian are. The first ph ase (D1) called the "Kolwezian phase" developed folds and thrust sheets wit h a northward transport direction. D1 deformation occurred in the Lufilian are between ca. 800 and 710 Ma, with a peak in the range 790-750 Ma. It is here correlated with the main deformation in the Zambezi belt. Southward-ve rging folds with the same trends as the D-1 structures were previously link ed to a second tectonic event named Kundelunguian phase of the Lufilian oro geny. We show in this paper that they are backfolds developed during D1 alo ng Katangan ramps and especially along the Kibaran foreland. The second pha se (D2) of the Lufilian orogeny is the "Monwezi phase" including several la rge left-lateral strike-slip faults which have been activated successively. During this deformation phase, the eastern block of the belt rotated clock wise, giving the present day NW-SE trend of D1 structures in this part of t he Lufilian are, and generating its convex geometry. The Mwembeshi dislocat ion, the major transcurrent shear zone separating the Zambezi and Lufilian are, was mostly active during the D2 deformation phase. D2 deformation occu rred between ca. 690 and 540 Ma. Such a long time interval is attributed to the migration of strike-slip faults developed sequentially from south to n orth, and probably to a slow convergence velocity during the collision betw een the Congo and Kalahari cratons. The third phase (D3) of the Lufilian or ogeny is a late event called the "Chilatembo phase", marked by structures t ransverse to the trends of the Lufilian are. This deformation and the post- D-2, uppermost Kundelungu sequence (Ks-3 Plateaux Group), are younger than 540 Ma and probably early Paleozoic.