Gabu Sandstone Fm
Period:
Ordovician
Age Interval:
Province:
Senegal Basin
Type Locality and Naming
Synonym: Gabu Sandstone, Gabu Fm
References: Brownfield and Charpentier, 2003
[Fig. 1. Generalized map of the central and southern parts of the Senegal Basin showing part of the Senegal Province, the Mauritania, Northern, and Casamance subbasins, the Mesozoic carbonate platform edge, the northern and southern salt basins, the Mauritanide Mountains, the Bové Basin, Deep Sea Drilling Project sites 367 and 368, the 2-second sediment isopach, and the onshore depth to basement isopachs (Brownfield and Charpentier, 2003)]
[Fig. 2: Generalized stratigraphic column for the Northern subbasin and the southern part of the Mauritania subbasins (Brownfield and Charpentier, 2003).]
Lithology and Thickness
The Ordovician Gabu Sandstone is the middle unit in the pre-rift section. It is about 1,400m thick and is made up entirely of sandstones that conformably transition into the overlying Buba Shales (Brownfield and Charpentier, 2003)..
Lithology Pattern:
Sandstone
Relationships and Distribution
Lower contact
Caium Sandstone Fm (conformable)
Upper contact
Buba Shale Fm (conformable)
Regional extent
Senegal Province, Mauritania, Senegal, The Gambia, and Guinea-Bissau, Northwest Africa
GeoJSON
{"type":"Feature","geometry":{"type":"MultiPolygon","coordinates":[[[[-17.78,22.85],[-17.27,22.83],[-16.61,22.77],[-16.26,22.7],[-16.51,21.78],[-16.1,21.53],[-16.08,20.98],[-15.36,20.16],[-14.12,18.91],[-13.34,17.94],[-13.71,17.32],[-13.18,16.63],[-13.28,15.95],[-12.62,14.69],[-12.62,13.65],[-13.04,12.95],[-13.55,12.66],[-14.54,12.5],[-15.05,12.07],[-15.15,11.59],[-14.9,11.26],[-14.97,10.14],[-15.32,9],[-16.36,9.09],[-17.58,9.35],[-17.88,9.5],[-17.58,10.73],[-17.8,12.09],[-17.97,14.06],[-18.09,14.74],[-17.86,15.58],[-17.47,15.8],[-17.35,16.21],[-17.18,17.8],[-17.72,18.86],[-18.64,20.42],[-18.33,21.18],[-17.78,22.85]]]]}}
Fossils
Age
Generalized as Ordovician
Age Span:
Beginning stage:
Tremadocian
Fraction up in beginning stage:
0.0
Beginning date (Ma):
486.85
Ending stage:
Hirnantian
Fraction up in the ending stage:
1.0
Ending date (Ma):
443.07
Depositional setting
Depositional pattern:
Additional Information
Compiler:
Enam O. Obiosio, Solomon Joshua Avong, Henry Nasir Suleiman, Rebecca Bobick (and Wen Du), modified from Brownfield, M.E. and Charpentier, R.R., 2003. "Assessment of the Undiscovered Oil and Gas of the Senegal Province, Mauritania, Senegal, The Gambia, and Guinea-Bissau, Northwest Africa", U.S. Geological Survey Bulletin 2207-A, 1-26.