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Lost islands in the northern Lesser Antilles: possible milestones in the Cenozoic dispersal of terrestrial organisms between South-America and the Greater Antilles
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.
Keyword(s)
Lesser Antilles, Cenozoic basins, Biostratigraphy, Seismic stratigraphy, Palaeogeography, Vertical motions
Full Text
File | Pages | Size | Access | |
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Author's final draft | 68 | 71 Mo | ||
Appendix A: Microphotographs of stratigraphically significant calcareous nannofossil taxa from the samples collected in the northern Lesser Antilles. | 2 | 3 Mo | ||
Appendix B: Microphotographs of stratigraphically significant foraminiferal taxa from the samples collected in the northern Lesser Antilles | 2 | 942 Ko | ||
Appendix C: Lithostratigraphical successions of Anguilla with depositional settings and microfossil content | 6 | 2 Mo | ||
Appendix D: Lithostratigraphical successions of St Martin with depositional settings and microfossil content | 7 | 3 Mo | ||
Appendix E: Lithostratigraphical successions of Tintamarre with depositional settings and microfossil content | 5 | 2 Mo | ||
Appendix F: Lithostratigraphical succession of the Highland Fm. of Barbuda with depositional settings and microfossil content | 1 | 537 Ko | ||
Appendix G: Lithostratigraphical successions of St Barthélemy and Antigua with depositional settings and microfossil content | 1 | 5 Mo | ||
Appendix H: Dredged samples in the northern Lesser Antilles; locations Fig. 2 | 3 | 338 Ko | ||
Appendix I: Samples dredged during the cruise GARANTI: facies, depositional settings and microfossil contents | 5 | 1 Mo | ||
Appendix J: Seismic lines CPEM 213 (Bouysse et al., 1994, re-interpreted) and GARANTI GA08 and 09 | 2 | 1 Mo | ||
Appendix K: Radiometric dating of a lava in St Martin, Terres Basses | 4 | 1 Mo | ||
Publisher's official version | 24 | 36 Mo |