Mea Fm
Type Locality and Naming
Kalahari Basin (NE). Named after the Mea Pan area in the Makgadikgadi region of northeastern Botswana. It is mapped from both borehole data and limited surface/pan-margin exposures in the region. Middle formation in Ecca Gr in Kalahari Basin (NE).
Synonym: Mea Arkose Fm
Lithology and Thickness
Predominantly a coarse arenaceous (sandy) succession. It is characterized by massive, cross-bedded, coarse- to medium-grained white to buff feldspathic sandstones (arkose). It is highly micaceous and frequently contains gritty, pebbly layers, and basal conglomerates. Thin, localized lenses of carbonaceous shale and thin coals can occasionally occur in the upper sections.
Relationships and Distribution
Lower contact
Typically rests conformably to disconformably on the glaciogenic sequences of the Dukwi Fm (Dwyka Group equivalent). Where the Dukwi was eroded or not deposited due to paleo-topographic highs, the Mea Arkose rests with a profound unconformity directly upon the Archean granitic basement (Zimbabwe Craton).
Upper contact
Conformably and transitionally overlain by the thick, coal-bearing carbonaceous mudstones of the Tlapana Fm (Upper Ecca Gr equivalent).
Regional extent
Widespread across the northern and northeastern sub-basins of the Kalahari Basin in Botswana, acting as a significant regional aquifer. Lower to Middle Ecca Gr equivalent. It correlates chronostratigraphically with the basal Ecca arenaceous units across Botswana (such as the Kweneng Fm in the central/southern basins) and broadly with the Vryheid Fm in the Main Karoo Basin of South Africa.
GeoJSON
Fossils
Age
Depositional setting
High-energy continental braided river and fluvio-deltaic environments.
Additional Information