Structural and tectonic evolution of western Cuba fold and thrust belt

Abstract

We present balanced and restored cross sections across the western Cuba fold and thrust belt to illustrate its structure and tectonic evolution, based on the interpretation of multichannel seismic profiles, field data and balancing techniques. The NNW–SSE trending Soroa cross section intersects, from south to north, (1) the Los Palacios Basin, (2) the Sierra del Rosario antiformal stack, (3) the Bahía Honda thrust unit, (4) the frontal ∼3‐km‐thick imbricated thrust sheets, and (5) the foredeep basin. At depth, a duplex that links the Sierra del Rosario unit and the frontal imbricates is defined using the thickness of the cover thrust sheets of the imbricated North American margin. The minimum calculated shortening is of 130 km in a SSE or south direction to fit large‐scale plate tectonic reconstructions. However, a more allochthonous alternative using thinner cover sequences is also discussed, which restores the Bahía Honda unit 220 km to the south of its present position. Syntectonic deposits in combination with a forward kinematic model provide a good constraint for the tectonic evolution of the orogen. The internally deformed Bahía Honda unit overthrusted the North America margin cover successions during Danian and Selandian times (∼65.5–60 Ma), before the stacking of these cover rocks during Selandian and Thanetian times (∼60–56 Ma). The growth of a large antiformal stack beneath the Sierra del Rosario occurred at early middle Eocene (∼56–45 Ma), generating about 4 km of structural relief between the paleoisland of Cuba and the synorogenic seafloor before the final infill of the foredeep.

Comment on “Structural and tectonic evolution of western Cuba fold and thrust belt” by Eduard Saura et al.

“…In fact, Iturralde-Vinent [1994,1998], PszczóJkowski [1999], and Pindell et al [2006] believed that the Sierra del Rosario successions belonged to the eastern Yucatán margin within the Proto-Caribbean Sea. As concerns the Sierra del Rosario units, the above cited conclusion of Saura et al [2008] is not supported by stratigraphy and facies development. In general, the Jurassic deposits of the southern tectonic units of the Sierra del Rosario are similar to those of the Sierra de los Organos and probably belonged to the same paleogeographic domain [PszczóJkowski, 1978[PszczóJkowski, , 1994b.…”

“…In these papers, Saura et al [2008] could find also information on the San Cayetano Formation outcrop in the Soroa area [see PszczóJkowski, 1994b, Figure 6, p. 78]. The remark (paragraph 16) concerning the thrust sheets ''displaying slightly different stratigraphic successions'' narrows the probable range of their ''own field data'' (see below).…”

“…As a matter of fact, the continuity proved much earlier is the transition between the Sierra de los Organos and the Sierra del Rosario stratigraphic successions. This continuity which is apparent in the thrust units exposed in the Guaniguanico megaunit was, however, not mentioned by Saura et al [2008]. They totally ignored the Los Organos isochronous stratigraphic section, which represents a distinct set of facies in the same North American continental margin [PszczóJkowski, 1999].…”

“…PszczóJkowski et al, Texto explicativo para el mapa geológico a escala 1: 250,000 de la provincia de Pinar del Río, unpublished report, 1975). As a matter of fact, Gordon et al [1997] proposed that the Pinar fault was active since early Eocene time (not ''since late Eocene times'' as incorrectly cited by Saura et al [2008]). …”

“…[1] The paper by Saura et al [2008] is rich in claims and conclusions; some of them are certainly acceptable, although not always quite new. Unfortunately, the paper contains also inaccurate information and some unfounded claims; moreover, there are frequent omissions in this publication.…”