Allen Lowrie¹, Luiz Somoza², Bradley M. Battista³, Susan J. Moffett¹, Ian Lerche⁴
(1) Consultant, Picayune, MS
(2) ITGE Geological Survey of Spain, Madrid, Spain
(3) Consultant, Slidell, LA
(4) University of South Carolina, Columbia, SC

Abstract: Hydrocarbon potential of the Gulf of Cadiz increases with greater thermal maturity

The Gulf of Cadiz is well-sedimented with a diffuse strike-slip/transverse fault system. this pattern results from a migrating plate boundary, caused by the Africa-Europe plate convergence. Subduction occurs as the Iberian continental and Atlantic oceanic crusts converge and diverge. Along the Spanish slope, east-west thrusts of crustal materials and salt occur caused by “escape tectonics” from convergence of these plates. Thrust origins are at depth beneath the Iberian Peninsula and are sites of elevated temperatures. The hot thrusts are heat sources injected into the sedimentary prism covering the continental margin. Associated salt provides conduits for further transport of heat within the sedimentary prism. Eastern equatorial Atlantic earthquakes are disseminated unevenly and straddle Portuguese-Spanish continental margins. Most have depths less than 70 km. this east-west trending arm of the Azores triple junction with magmatic emplacement produces Gorringe, Ampere Banks, Horseshoe Hills, and the Madeira Islands complex. West of Cadiz, the Neogene basin underlying the continental shelf is the site of natural gas production. Required thermal maturity of organic sediments necessary to create oil and gas is a fact. Present geothermal gradient is 2.4ºC/100m. The gradient is higher under the slope, rise, and plain so there is heat to elevate geothermal gradients. Known source and reservoir rocks with trapping mechanisms exist. A program of exploration wells and seismic is recommended to ascertain the richness of petroleum reserves.

AAPG Search and Discovery Article #90914©2000 AAPG Annual Convention, New Orleans, Louisiana