Eocene intra-plate shortening responsible for the rise of a faunal pathway in the northeastern Caribbean realm

Abstract

Intriguing latest Eocene land-faunal dispersals between South America and the Greater Antilles (northern Caribbean) has inspired the hypothesis of the GAARlandia (Greater Antilles Aves Ridge) land bridge. This landbridge, however, should have crossed the Caribbean oceanic plate, and the geological evolution of its rise and demise, or its geodynamic forcing, remain unknown. Here we present the results of a land-sea survey from the northeast Caribbean plate, combined with chronostratigraphic data, revealing a regional episode of mid to late Eocene, trench-normal, E-W shortening and crustal thickening by *25%. This shortening led to a regional late Eocene-early Oligocene hiatus in the sedimentary record revealing the location of an emerged land (the Greater Antilles-Northern Lesser Antilles, or GrANoLA, landmass), consistent with the GAARlandia hypothesis. Subsequent submergence is explained by combined trench-parallel extension and thermal relaxation following a shift of arc magmatism, expressed by a regional early Miocene transgression. We tentatively link the NE Caribbean intra-plate shortening to a well-known absolute and relative North American and Caribbean plate motion change, which may provide focus for the search of the remaining connection between 'GrANoLA' land and South America, through the Aves Ridge or Lesser Antilles island arc. Our study highlights the how regional geodynamic evolution may have driven paleogeographic change that is still reflected in current biology.

Genetic Relations Between the Aves Ridge and the Grenada Back‐Arc Basin, East Caribbean Sea

“…The onset of subsidence slowdown (Figure 9b) is synchronous with the late Eocene‐Oligocene compressional uplift that caused the emergence of the so‐called “GrANoLA” landmass (Greater Antilles‐Northern Lesser Antilles; Philippon et al., 2020). This subsidence slowdown also corresponds in time with the late Oligocene‐early Miocene tectonic inversion in the Grenada Basin, which preceded the emplacement of the Miocene to Recent southern southern Lesser Antilles Arc (see previous section).…”

Paleogene V‐Shaped Basins and Neogene Subsidence of the Northern Lesser Antilles Forearc

“…To the west, at the Saba Bank, two unconformities are observed in SB2 well, Oil company MCS lines (Church & Allison, 2004), and lines GA15B‐C‐GA08 (Figure 6) recorded during the GARANTI cruise (Cornée et al., 2019; Lebrun & Lallemand, 2017; Philippon, Cornée, et al., 2020; Philippon, van Hinsbergen, et al., 2020 #2812). From Church and Allison (2004), a late Eocene unconformity S3 separates an undrilled basement unit topped by middle Priabonian andesitic lavas flows overlaid by a very late Eocene to early Oligocene Lower Carbonate and Turbiditic unit.…”

“…A lower boundary age for U1 can be proposed. At St Barthélemy and in the backarc, compressional tectonic structures are sealed by a late Priabonian unconformity (Church & Allison, 2004; Philippon, Cornée, et al., 2020). Following this compression, the Kalinago Basin opening and extensive evidences in the Northern Anguilla Bank attest for a regional extension during the early Oligocene to early Miocene characterized by synsedimentary half‐grabens (Cornée et al., 2019; Legendre et al., 2018).…”

Lost islands in the northern Lesser Antilles: possible milestones in the Cenozoic dispersal of terrestrial organisms between South-America and the Greater Antilles

“…In this work, we study the palaeogeographic evolution of the northeastern part of the Lesser Antilles during the Cenozoic, as it may have constituted an episodic emerged area between the Aves Ridge to the southwest and the Greater Antilles to the North: the GrANoLA land -Greater Antilles-Northern Lesser Antilles land (Philippon et al, 2020a). Previous bathymetric reconstructions and offshore-onshore geological investigations have suggested that the Kalinago intra-arc rift basin (Figs.…”