Grootegeluk Fm
Type Locality and Naming
Ellisras Basin / Waterberg Coalfield (Limpopo Province, South Africa). Named after the farm Grootegeluk in the Lephalale (formerly Ellisras) district of the Limpopo Province. It is the most economically significant unit in the basin and lends its name to the massive Grootegeluk Coal Mine (one of the largest open-pit coal mines in the world), which operates on this farm. Upper formation in Ecca Gr in Ellisras Basin
Synonym:
Lithology and Thickness
A highly carbonaceous, economically vital succession ranging from 70 to 110 meters in thickness. Unlike the underlying units which feature thick, discrete coal seams separated by massive sandstones, the Grootegeluk Formation is characterized by rapid, cyclic intercalations (fining-upward cycles) of bright coal, carbonaceous shale, and dark grey mudstone. It contains very little to no sandstone.
Relationships and Distribution
Lower contact
Conformably and transitionally overlies the coarser, sandstone-dominated and discrete-seam-bearing Swartrant Fm (the local Middle Ecca / Vryheid Fm equivalent).
Upper contact
Conformably, but abruptly, overlain by the brightly colored, non-carbonaceous, barren mudstones of the Eendragtpan Fm (Beaufort Gr equivalent).
Regional extent
Restricted entirely to the subsurface of the Ellisras Basin (Waterberg Coalfield) in northwestern South Africa. It hosts roughly 50% of South Africa's remaining recoverable coal reserves. Upper Ecca Gr equivalent. In the context of the Waterberg Coalfield, it is frequently referred to informally as the "Upper Coal Zone." It broadly correlates chronostratigraphically with the Volksrust Fm in the Main Karoo Basin.
GeoJSON
Fossils
Age
Depositional setting
Extensive, long-lived paludal (peat swamp) and shallow, restricted lacustrine environments.
Additional Information