The Pindiro Group (Triassic to Early Jurassic Mandawa Basin, southern coastal Tanzania): Definition, palaeoenvironment, and stratigraphy

This paper defines the Pindiro Group of the Mandawa Basin, southern coastal Tanzania based on studies conducted between 2006 and 2009 with the objective of understanding the evolution of this basin. This work draws upon field data, hydrocarbon exploration data, unconventional literature, and the scant published materials available. The paper focuses on the evolution, depositional environments, and definition of the lowermost sedimentary package, which overlies unconformably the metamorphic basement of Precambrian age. The package is described here as the Pindiro Group and it forms the basal group of the Mandawa Basin stratigraphy.The Pindiro Group sediments form part of the synrift sequences deposited during the initial stages of the rifting of Madagascar from East Africa. The Group comprises three formations, defined here in stratigraphic order from older to younger: the Mbuo, Nondwa and Mihambia Formations. Litho- and biofacies analyses from exploration wells suggest that Mbuo sediments were deposited in alluvial, fluvial, and lacustrine environments. The Nondwa Formation, which is principally an evaporitic formation, formed under a restricted marine environment. Palynological species recovered from the Nondwa Formation suggest Late Triassic to Early Jurassic age. The Mihambia Formation comprises sediments that indicate deposition in a shallow and marginal marine environment.The litho-biofacies of the Pindiro Group suggest various depositional environments, from lacustrine, alluvial, fluvial, deltaic, and restricted marine to shallow marine. © 2014 Elsevier Ltd.