A characterisation of volumes and stratigraphic relationships within flood basalt units in order to access their potential environmental impact and onshore/offshore facies architectures

Michael Mawby,

University of Durham, Department of Earth Sciences,

Durham, UK,

[email protected]

This study aims to gain a better understanding of the crustal architecture of volcanic rifted margins, specifically focussing on large volume eruptions (1000s of cubic kilometres) which make up some of the largest known volcanic events on the planet. These volcanic units make up a significant component of volcanic rifted margins both onshore and offshore, and in the case of the Paraná-Etendeka flood basalt province, can be used to correlate stratigraphy either side of the rifted margin. This region is also important in terms of environmental impact, which relates to the potential gases erupted during emplacement. A better understanding of the stratigraphic makeup of volcanic rifted margins bears importance in areas of petroleum exploration where potential hydrocarbon targets lie beneath significant flood basalt cover. Detailed field measurements, mapping of the stratigraphic units, and the building of a 3-D model of the stratigraphic architecture in a well constrained onshore exposure of flood volcanics has now begun. This will be used to constrain individual volumes of lava flows which will enable estimates of gas inputs and the environmental impact from such eruptions to be deduced as well as better constraining the internal ‘make-up’ of the basalt cover in volcanic rifted margins.

AAPG Search and Discovery Article #90060©2006 AAPG Foundation Grants-in-Aid