Effects of inherited structures on inversion tectonics: Examples from the Asturian Basin (NW Iberian Peninsula) interpreted in a Computer Assisted Virtual Environment (CAVE)

Map shows mid-nineteenth century Texas counties, major cities, towns, roads, railroads, and areas of Native American habitation. Includes detailed notes on map. Insets: "Plan of Sabine Lake," "Plan of the Northern Part of Texas," and "Plan of Galveston Bay." Relief shown by hachures. Depths shown by soundings on inset. Scales [ca. 1:2,350,000], [ca. 1: 529,000], [ca. 1:3,800,000], and [ca. 1:887,000]

Episodic folding inferred from syntectonic carbonate sedimentation: the Santaren anticline, Bahamas foreland

Sedimentation coeval with growth of the Santaren anticline provides an excellent opportunity to study the relationships between sedimentation and anticline uplift through time. The Santaren anticline is a kilometre-scale, NW–SE trending fold offshore of Cuba, in the Bahamas foreland of the Cuban fold and thrust belt. The growth strata associated with this anticline consist of a thick package of carbonate sediments that were deposited without major interruptions from Neogene (and perhaps before) to present day. The excellent seismic resolution and age control of a number of seismic horizons within the growth strata allowed us to define 25 growth beds, each of them representing between 0.1 and 3.2 Ma. An analysis of the thickness of these beds allowed us to determine accurate quantitative values of cumulative decompacted thickness and crestal structural relief at the time of their deposition. In addition, for the same periods, sedimentation and fold uplift rates were calculated. Moreover, some information on relationships between sedimentation and fold uplift rates was inferred from the growth stratal geometry. Growth beds that overlap the fold crest and thin over it indicate that sedimentation rates outpaced fold growth rates during their deposition. Some overlapping beds have constant thickness indicating that no fold uplift occurred during their sedimentation. The rest of the growth beds exhibit onlap/offlap geometries that do not indicate a unique sedimentation/fold uplift rate relationship. Only in those cases in which the geometry of the underlying bed at the end of its deposition is known is it possible to infer a specific sedimentation/fold uplift rate relationship. As a result of this analysis, we have been able to (1) illustrate that the geometry of the growth strata associated with the Santaren anticline results from competition between sedimentation and tectonic fold uplift, (2) document the episodic and non-steady nature of fold growth, and (3) show that short-term rates (at the scale of hundreds of thousands years) provide much insight into the interplay between sedimentation and tectonic fold uplift that control the growth stratal patterns

Palaeogene-Neogene/Present Day (?) Growth Folding in the Bahamian Foreland of the Cuban Fold and Thrust Belt

The Santaren Anticline constitutes the frontal termination of the Cuban fold and thrust belt within the Bahamian foreland. New well and seismic data allow us to constrain in detail the evolution of this anticline. Pre-growth and syntectonic (partly post-tectonic?) units, separated by a major unconformity, are associated with the Santaren Anticline. Their geometrical features are consistent with a detachment fold. The precise age of the beginning of fold growth remains unknown. However, the complete record of well-dated syntectonic sediments documents its kinematic evolution from Mid-Eocene to Pliocene/present day, and reveals an approximately constant and very slow growth rate from Early Miocene to Pliocene/present day. The timing of evolution of the Santaren Anticline is not consistent with previous models that postulate that deformation associated with the Cuban fold and thrust belt ended in the Eocene. Our data suggest that the most external part of the Cuban fold and thrust belt was still being deformed under a compressional regime during the late Palaeogene, Neogene and probably during the Quaternary. We propose that this folding may result from compressive stresses transmitted approximately 400 km northwards from the actual plate boundary, as a result of slow convergence between the N and S American plates