The Holocene drowned reef of Les Saintes plateau as witness of a long-term tectonic subsidence along the Lesser Antilles volcanic arc in Guadeloupe

Tectonic and sedimentary architecture of the Karukéra spur: A record of the Lesser Antilles fore-arc deformations since the Neogene

“…6 in Münch et al, 2013). Such geometries of the latest submerged deposits along ancient platforms margins have been described elsewhere in the Guadeloupe Archipelago and were interpreted as reefal terraces of the last Holocene sea level rise (Leclerc et al, 2014). Samples CR25, CR26 and Arcante1 sample 33 V (Andreieff et al, 1979) from the Flandre Bank provided unconsolidated sediments with encrusting red algae, rhodoliths and bryozoans with minor Mussidae corals and Halimeda fragments, suggesting Holocene deposits.…”

The reef platform of Martinique: Interplay between eustasy, tectonic subsidence and volcanism since Late Pleistocene

“…Adey et al (1977) drilled the reef barrier of Martinique at several places (Pinsonnelle ridge, Vauclin Point, Ramville island, Figure 1-c) down to 13 m at most, and inferred the presence of a Pleistocene reef basement (estimated at about 30-40 m bsl beneath Pinsonnelle ridge) post-LGM reef. The pre-existing paleo-barrier, dissected by passes, may have focused post-LGM reef growth, as seen in the seismic profile Mr08_12/Mr08_13 (Figure 8) and also proposed byBattistini et al (1978).Finally, the unit U3 (and terrace M3) likely grew during a previous sea-level highstand, such as MIS7, the major interglacial high stand preceding MIS5.5.VI-2 Subsidence rate of Martinique platformThe morphology, thicknesses, and succession of reef strata on the Martinique platform require tens of meters of tectonic subsidence to create sufficient vertical accommodation space to account for the deposits observed(Rooney et al, 2008;Leclerc et al, 2014). Subsidence allowed the post-LGM transgression to superimpose the Late Pleistocene to Holocene reef on the surface of the MIS5.5 reef platform, which in turn was deposited on the surface of even older interglacial reefs.…”

“…The morphology and stratigraphy of the platform indicate that Martinique Island is subsiding, at a rate similar to, though a bit slower than, Les Saintes plateau (Leclerc et al, 2014). This subsidence is observed at the scale of each island, but could also be regional; the entire Lesser Antilles volcanic arc could be subsiding.…”

“…Farther west, Les Saintes archipelago, located 180 km west of the subduction backstop and along the active volcanic arc, is surrounded by a 20 km wide submarine carbonate platform whose stratigraphy and morphology indicate it has grown in a context of subsidence. Leclerc et al (2014) propose that Les Saintes archipelago has been subsiding since at least 125 ka at a maximum rate of about 0.4 m/ky.…”

“…The inner bank barrier corresponds to Adey and Burke (1976)'s outer system, while the outer bank barrier imaged here with bathymetry has never been identified before. Such a double bank barrier morphology is rare but has already been observed elsewhere, for instance in New Caledonia(Coudray 1976; Andréfouët et al 2009) and on Les Saintes drowned Holocene reef plateau(Leclerc et al, 2014). The processes leading to the development of multiple barriers are still not understood.…”