Palaeoclimatic Drivers of a Global Sequence Stratigraphic Model and Implications for Exploration

David Kemp, Alexander Brasier, Roger B. Davies, Ben Kilner, Melissa J. Oxford, Elizabeth V. Nunn, Peter R. Sharland, Michael D. Simmons, and Owen E. Sutcliffe
Neftex Petroleum Consultants Ltd, Abingdon, United Kingdom

Sharland et al. (2001; 2004) and Simmons et al. (2007) demonstrated a sequence stratigraphic model for the Phanerozoic of the Arabian Plate, which has been subsequently refined and shown to have global applicability. Here we concentrate on the drivers for two of the surfaces in the model and the important consequences for global exploration.

Pg30 Sequence Boundary (SB) occurs in the latest Eocene and can be recognized at, for example, the base of the Arida Formation in Libya, the base of the Horcones Formation in the Veracruz Basin of Central America, the East Java Sea, and the Santos and Campos Basins of Brazil. At many of these locations the SB is sedimentologically characterized by lowstand (and on the platform; transgressive) sandstones that form reservoir targets.

The occurrence of this SB is coincident with the marked growth of Antarctic ice sheets, likely caused by a combination of factors such as the opening of the Drake and Tasman Passages, uplift of the Himalayas, and changes in seasonality caused by astronomical forcing.

Our J10 MFS occurs in the early Toarcian, a period of supposed “greenhouse” climate. Isotopic data and direct climate proxies such as glendonites indicate that the preceding late Pliensbachian J10 SB was most likely associated with polar glaciation. The subsequent MFS probably resulted from deglaciation triggered by global warming from volcanic activity, astronomical forcing, and sudden gas hydrate dissociation. J10 MFS source rocks are recognized in multiple global locations.

A global sequence stratigraphic model and an understanding of its drivers can be a powerful tool in the prediction of source and reservoir rocks in frontier regions.

AAPG Search and Discovery Article #90078©2008 AAPG Annual Convention, San Antonio, Texas