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848674 
Journal Article 
DETRITAL MONAZITE IN THE TIM MERSOI BASIN, NIGER: PROVENANCE AND CONTRIBUTION TO THE URANIUM BUDGET IN SILICICLASTIC SEDIMENTS 
Wagani, I; Pagel, M; Janots, E; Gnos, E 
2011 
Yes 
Canadian Mineralogist
ISSN: 0008-4476
EISSN: 1499-1276 
49 
2 
487-501 
English 
WOS:000291643500004 
A detailed study using back-scattered electron imaging and electron-microprobe analysis shows that grains of detrital monazite are present in the Carboniferous, Permian, Triassic and Jurassic sediments of the Tim Mersoi basin, Niger. Despite variations in the size and shape of monazite grains, the U-Th-Pb chemical ages obtained by electron microprobe fall in a narrow range, 425 to 650 Ma. These ages indicate that the monazite grains are issued from the erosion of Pan-African granites and metamorphic rocks from the Air Mountains, and probably also from the basement near Zinder and in Nigeria, a hypothesis in good agreement with paleocurrent reconstruction. The uranium content of monazite from sediments is high (up to 1.7 wt% UO(2)), but low in adjacent rhyolite. Some monazite grains from the sandstone show evidence of alteration, especially to florencite. We conclude that detrital monazite is a major reservoir of uranium in some sandstones from the Tim Mersoi Basin. 
monazite; electron-microprobe dating; Tim Mersoi Basin; Air Massif; Niger; U-PB; TUAREG SHIELD; RB-SR; FRANCEVILLE BASIN; RING COMPLEXES; K-AR; AGE; AIR; GEOCHRONOLOGY; GRANITES 
IRIS
• Uranium Toxicological Review
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