Répertoire du personnel
Stijn DEWAELE
Sciences de la Terre
Géodynamique et ressources minérales
Géodynamique et ressources minérales
Détails
Decrée , S., Deloule, E., De Putter, Th., Dewaele, S., Mees, F., Yans, J. & Marignac, Ch. 2011. ‘SIMS U-Pb dating of uranium mineralization in the Katanga Copperbelt: constraints for the geodynamic context’. Ore Geology Reviews 40: 81-89. DOI: 10.1016/j.oregeorev.2011.05.003. (PR).
Article dans une revue scientifique / Article dans un périodique
The Katanga Copperbelt, in the southeastern part of the Democratic Republic of the Congo (DRC), occurs within
the Pan-African Lufilian fold-and-thrust belt and hosts numerous uraniferous mineral occurrences in addition to
the world-class sediment-hosted copper and cobalt ore deposits. In the 1950s and 1960s, Cahen et al. gave a
relatively wide range of U mineralization ages, using U–Pb dating on whole-rock samples. Although these ages
nowadays appear as inaccurate because of large error ranges, they were frequently used to discuss the regional
geodynamic events. This paper offers a reappraisal of the age range previously published, using in-situ SIMSU–Pb
analyses. Based on these analyses, two ages are regarded as analytically reliable and significant (652.3±7.3 Ma
and 530.1±5.9 Ma), and hence as having implications for the understanding of geological and geodynamic
context in the study area.
In the Katanga Copperbelt, the siliciclastic rocks of the Lower Roan Group are slightly enriched in uranium. A
major U mineralization/(re-)mobilization episode took place at ~652 Ma, during proto-oceanic rift basin
development. This phase took place in an extensional tectonic regime and led to the (re-)mobilization of U
within fractures and voids. Such deposits are observed along the ~250 km-long Kalongwe–Luishia tectonic
lineament.
This metal concentration was reworked at ~530 Ma, at the occasion of the climax of Lufilian deformation and
metamorphism. This event gave rise to the U deposits in the southern border of the Katanga Copperbelt (and in
Northern Zambia). The Kolwezi deposit is a deposit located further to the North. Notwithstanding its initial
position further to the south, the deposit is heavily faulted and the thrusts and faults could have focused the
fluids associated with the deformation, at ~530 Ma.