J.L. Masaferro¹, J. Poblet², M. Bulnes², G. Eberli³
(1) Shell International Exploration and Production, Rijswijk, Netherlands
(2) Universidad de Oviedo, Oviedo, Spain
(3) University of Miami, Miami, FL

Abstract: Timing, kinematics and exploration significance of growth detachment folding in the Cuban fold-thrust belt

In this presentation, we analyse the evolution of the Santaren anticline, which is a seismically well-imaged growth detachment fold located in the outermost part of the Cuban fold-thrust belt in the Bahamas foreland. Carbonate sedimentation coeval to anticline growth provides an excellent opportunity to study the relationships between sedimentation and anticline uplift through time.

A complete record of well-dated carbonate syntectonic sediments documents fold kinematic evolution from Middle Eocene to Pliocene/present day, and reveals an approximately constant and very slow growth rate from Lower Miocene to Pliocene/present day. Average fold-growth rates were extremely slow, at least for the last 19 Ma, ranging between 0.006 and 0.014 mm/a for the variation of crestal structural relief, and 0.001 mm/a for the shortening. A detailed geometrical analysis of the architecture of the growth beds allowed us also to document the nature of fold growth and the major controls that sedimentation and fold uplift have on the origin of lapout geometries. The results revealed the episodic nature of anticline growth implying that the amplification of the Santaren anticline was a discontinuous process characterised by several tectonic uplift pulses of different duration and intensity interrupted by periods of variable duration in which no fold growth occurred.

Detailed quantification of the fold growth has critical importance from an exploration point of view since it provides with an accurate record of the timing of trap formation in relation to hydrocarbon migration in the offshore Cuban/Bahamas region.

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