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

Abstract

Our study aims to reconstruct the palaeogeography of the northern part of the Lesser Antilles in order to analyse whether emerged areas might have existed during the Cenozoic, favouring terrestrial faunal dispersals between South America and the Greater Antilles along the present-day Lesser Antilles arc. The stratigraphy and depositional environments of the islands of Anguilla, St Martin, Tintamarre, St Barthélemy, Barbuda and Antigua are reviewed in association with multichannel reflection seismic data acquired offshore since the 80's in the Saba, Anguilla and Antigua Banks and in the Kalinago Basin, including the most recent academic and industrial surveys. Seven seismic megasequences and seven regional unconformities are defined, and calibrated from deep wells on the Saba Bank and various dredges performed during marine cruises since the 70's in the vicinity of the islands. Onshore and offshore correlations allow us to depict an updated and detailed sedimentary organisation of the northern part of the Lesser Antilles from the late Eocene to the late Pleistocene. Paleogeographic reconstructions reveal sequences of uplift and emergence across hundredswide areas during the late Eocene, the late Oligocene, the early middle-Miocene and the latest Miocene-earliest Pliocene, interspersed by drowning episodes. The ∼200 km-long and ∼20 km-wide Kalinago Basin opened as an intra-arc basin during the late Eocene -early Oligocene. These periods of emergence may have favoured the existence of episodic mega-islands and transient terrestrial connections between the Greater Antilles, the Lesser Antilles and the northern part of the Aves Ridge (Saba Bank). During the Pleistocene, archipelagos and mega-islands formed repeatedly during glacial maximum episodes.

Colonizing the Caribbean: New geological data and an updated land‐vertebrate colonization record challenge the GAARlandia land‐bridge hypothesis

“…Such behaviour is often observed with some biotic components on remote islands/island groups that have never been connected to the mainland (e.g. Galápagos, Hawaii), or that were in the past were largely/wholly F I G U R E 1 Map of the Caribbean showing the physiographical features mentioned in the text plus the study areas of Garrocq et al, (2021), Cornée et al, (2020Cornée et al, ( , 2021 and Philippon et al, (2020). The base image was generated using GeoMapApp (Ryan et al, 2009).…”

Elongated Giant Seabed Polygons and Underlying Polygonal Faults as Indicators of the Creep Deformation of Pliocene to Recent Sediments in the Grenada Basin, Caribbean Sea

“…In sedimentary basins, σ1 is generally vertical and corresponds to the lithostatic vertical stress (σv) and we assume here that σ2 and σ3 are respectively perpendicular and parallel to the short axis of best fit ellipses obtained from the center-to-center method. In the north, the PFS abruptly ends at the toe of Saba Bank, a lithified reefal and red algal platform (Cornée et al, 2021) >The basement remains high in the NGB, reaching a maximum of about 4 s TWT in depth, although it is strongly deepening in the SGB, reaching a maximum of 10 s TWT (Figures 11a). The different subsidence histories have strongly influenced the architecture of both basins with the SGB deepening toward a curved depocenter more or less parallel to the volcanic arc whereas the NGB remains relatively flat and high (Figures 11b).…”

Evolution of a Shallow Volcanic Arc Pluton During Arc Migration: A Tectono‐Thermal Integrated Study of the St. Martin Granodiorites (Northern Lesser Antilles)

“…Ar ages Nagle et al, 1976Briden et al, 1979Davidson et al, 1993Cornée et al, 2021 This study structural measure observed fault well normal fault…”