Fluvial sand, Wouri River, Cameroon
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Glass bead is 200µ in diameter |
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Location |
Shore of the Wouri river (25 km from the Atlantic ocean), City of Douala (long. 9 42'; Lat. 4 3'), Cameroon |
Depositional facies |
River shore |
Provenance |
Mix of (1) ?volcanic source rich in quartz with (2) ?basaltic gas-rich lava; also, (3) some arid-climate components |
Composition |
Dominant typically blocky, highly angular transparent and clear, occasionally slightly yellowish quartz (volcanic or high-grade metamorphic provenance ?). Significant (~5%) component of fresh black glassy bubbly lava (resembling pumice), few wind-abraded grains with desert varnish; very few grains of chlorite/epidote minerals. Interesting incongruent composition. Traces of well rounded quartz grains and recent plant seeds |
Texture |
Coarse-grained (cU, median ca. 1000µ); poorly sorted, angular |
Petrographic thin section:
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Sample number |
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Collector |
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Date of sampling |
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Comments:
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