Print this pageSnowball Earth and the Search for Neoproterozoic Petroleum Systems in Angola and Namibia
Exploration for Neoproterozoic gas petroleum systems in the interior basins of Angola and Namibia is a truly challenging new frontier.
Global climate change has occurred throughout geological time with alternating periods of greenhouse and icehouse climate with durations lasting over many millions of years. The earliest known glaciations occurred in the Neoproterozoic (1000-550 Ma). It is in the Late Neoproterozoic (i.e. Late Cryogenian and Ediacaran Periods) that “Snowball Earth” occurred. “Snowball Earth” is the commonly used term for that period in Earth’s history that experienced two extensive glaciations; the “Sturtian Glaciation” (740-700Ma) and “Marinoan Glaciation” (665-635Ma).
This presentation will examine the efforts to gain a better understanding of the petroleum prospectivity of the Neoproterozoic interior basins of Angola and Namibia as the basis for future exploration programmes.
The exploration approach is two-fold.
Firstly, an investigation of the plate tectonic setting in the Neoproterozoic in a mega-regional Pangea context. In particular, this will include the integration of the geological evolution of the Sao Francisco Basin in Brazil with that of the interior basins of Angola, Namibia, and also Zaire and Congo. These areas were juxtaposed in Pangea.
A tectono-stratigraphic framework is being established that will facilitate the understanding and prediction of depositional systems for the key play elements.
Primary focus is on the identification of possible source horizons to ascertain source type, level of maturation and timing of migration.
Potential reservoirs include glaciogenic clastics derived from the Sturtian and Marinoan glaciations, and platform and reefal carbonates of pre- and post-“Snowball” times.
The second exploration approach is to leverage knowledge of global analogues. Neoproterozoic petroleum systems are proven, but relatively poorly understood, in many parts of the world. These include the glaciogenic petroleum systems of the Infracambrian of North Africa, e.g. Mauritania; the Middle East, e.g. Oman; and Russia, e.g. East Siberia. Studies in these other areas are then integrated into an overall better understanding of “Snowball Earth”.
Can this better understanding of “Snowball Earth” lead to the discovery of giant gas fields?
AAPG Search and Discover Article #90100©2009 AAPG International Conference and Exhibition 15-18 November 2009, Rio de Janeiro, Brazil