Oblique Collision of the Bahamas Platform at the Northern Boundary of the Caribbean Plate Recorded by the Late Cenozoic Coastal Terraces of SE Cuba

Abstract

The southeastern tip of Cuba Island is limited to the south by the N‐Caribbean boundary. By revisiting the impressive sequences of coastal terraces of this region, we decipher the Quaternary deformation pattern of this plate boundary. We present a detailed mapping of coastal terraces uplifted over a hundred kilometers of coastline, and U/Th dating. At Punta de Maisí, the deformation pattern shows (a) a faster uplift close to the transform boundary and (b) a northward propagation of folding produced by the convergence of the Bahamas platform toward the Caribbean plate. Along the southern coast of Punta de Maisí, the sequence displays 29 coastal terraces up to 520 m in elevation and a upper Pleistocene uplift rate of 0.23 ± 0.07 mm yr−1. We interpret this deformation as resulting from an offshore north‐dipping reverse fault near the coast. This uplift rate corresponds to 3% to 1.6% of the short‐term horizontal slip rate of Septentrional Oriente Fault Zone (10 ± 0.1 mm yr−1). Along the northern coast of Punta de Maisí, the sequence displays height coastal terraces up to 220 m in elevation and the uplift rates amount to 0.1 ± 0.05 mm yr−1 and likely result from the reverse faulting and folding associated with the offshore North Hispaniola Fault Zone. Uplift rates quickly decrease to the West, in agreement with the westward decrease in the activity of the North Hispaniola Fault Zone due to the docking of the Bahamas Platform against Cuba, while the platform more gently underthrusts Cuba to the East.

The Protracted Evolution of a Plate Boundary: Eastern Cuba Block and Old Bahamas Channel

“…This occurrence is supported by seismic sections, which depict the cessation of tectonic activity through horizontal seismic reflections in the topmost layer, known as Unit E (refer to Figure 12). Nevertheless, some faults affect relatively recent seismic reflections, suggesting the possibility of ongoing tectonic activity localized on the deformation front as shown by seismic activity and the still active uplift of the Cuba coast (Authemayou et al., 2023; Calais et al., 2023) (refer to Figures 4b, 5, 8, and 9).…”