Arthur R I Cruickshank

Susan M. Gay

Academic paper

Journal of African Earth Sciences

21

1A

51-52

(Abstract only) A recent review of the Late Permian (Kungurian. Tatarian?) faunas from the Kawinga and Ruhuhu Formations, Songea District, Tanzania (Gay, 1 987, in prep. a, b) allows an updated comparison with the newly defined biozones of the Beaufort Group, South Africa (Rubidge, 1 995). The original survey of the Ruhuhu Valley sedimentary rocks (Stockley, 1 932) divided the sequence into eight horizons, ranging in age from the Permo-Carboniferous (KI) to the Middle Triassic (K8). Later workers refined the stratigraphical nomenclature and made brief attempts to interpret the depositional environments (Bishop, 1968; Charig, 1963). The Kawinga Formation (K6) contains faunal elements typical of the Tropidostoma, Cistecephalus and Dicynodon Assemblage Zones. The underlying Ruhuhu Formation (KS) fauna resembles that of the South African Pristerognathus Assemblage Zone (Table 1). No detailed sedimentological or palaeoenvironmental analyses exist for the Tanzanian Late Permian, but in the Karoo Basin evidence exists for an evolving sedimentary basin subject to aggradational processes resulting from the growth of the 'Cape Mountains' (Smith et al, 1993). Bishop's (1968) brief review of the Tanzanian sedimentary rocks suggests a predominantly lacustrine environment in a graben, whereas the Beaufort Group sediments were laid down on a broad flood-plain, richly supplied with moderately large river systems. It is concluded that the differences recorded in the faunal assemblages between these East and South African faunas reflect local facies changes in the tatter, whereas in the former there was a more varied local environment.

English