Palaeogeographic and Palaeoclimatic Evolution of Tethyan and Atlantic Margin Basins and the Role of Earth Systems Modelling in the Predictive Mapping of Paleozoic and Mesozoic Source Rock Environments

Abstract

The basins of Western Tethys and the Central Atlantic occupied the core of Pangaea. Their stratigraphy and resource potential is controlled by Pangaeic assembly of the continents in the Paleozoic, their Mesozoic break-up history and the wholescale variations in palaeoclimate that accompanied these events. Given the complexities of this regional geohistory the distribution of source rocks and the lateral variation in source quality are significant difficulties for exploration in these basins. To construct a predictive tool designed to address this problem, deformable Plate Wizard reconstructions were used as the basis for global palaeogeographic mapping. Detailed gross depositional environment base maps were prepared using a global database of palaeoenvironmental and lithofacies data, the legacy of over 35 years of petroleum geological studies and an equally extensive source rocks database. A novel method relating topography and bathymetry to plate tectonic environments was used in the construction of palaeo digital elevation models (DEMs). The DEMs were coupled with state-of-the-art palaeo-Earth systems models (UK Met Office HadCM3 palaeoclimate model) and an unstructured mesh model to simulate palaeotides (Imperial College, UK, ICOM tide model). The database also includes climate proxies that were used to test the veracity of modelling results. In conjunction with the DEMs, palaeo-Earth systems were used to create a new predictive model of organic matter productivity, dilution and preservation. This model defines source facies depositional space for the broad range of marine source rock environments that developed during the Palaeozoic and Mesozoic in the basins of Western Tethys and the Central Atlantic and the gridded model results provide an objective assessment of lateral variability in source quality. This approach also provides an understanding of regional palaeogeographic and palaeoclimatic geohistory, drainage basin evolution, and the quantification of clastic sediment flux.

AAPG Datapages/Search and Discovery Article #90226 © 2015 European Regional Conference and Exhibition, Lisbon, Portugal, May 18-19, 2015