Stratigraphy, chronology and palaeontology of the Tertiary rocks of the Cheringoma Plateau, Mozambique

Abstract

The discovery of fossil plants, marine molluscs and mammals in the Mazamba Formation, Cheringoma Plateau, Mozambique, opens a new chapter in the study of this part of the African Rift System. The evidence suggests that the Mazamba Formation is older than previously reported, probably late Eocene rather than Miocene. The fossil wood and stems indicate a frost-free tropical humid environment and a high water table soon after deposition, and the marine molluscs and mammals indicate proximity to the sea. There is also evidence for the occurrence of pans in the area during the late Eocene which also suggest a near-surface water table. This paper discusses the history of interpretation of the geology of the Cheringoma Plateau and describes and interprets the fossil plants, molluscs and mammals collected in 2012 and 2013. It is concluded that the Mazamba Formation, which overlies the fully marine Lutetian-Bartonian Cheringoma Limestone, is a coastal facies (fluvio-deltaic, lagoonal and onshore deposits) that accumulated on top of the marine limestones as sea level dropped late in the Bartonian. Mammalian bones from the White Patch sites represent a heavily built species about the dimensions of a pygmy hippopotamus, probably belonging to the order Embrithopoda. If so, then the Mazamba Formation is likely to correlate to the latest Bartonian or early Priabonian rather than to the Miocene as previously assumed.