La Désirade island (Guadeloupe, French West Indies): a key target for deciphering the role of reactivated tectonic structures in Lesser Antilles arc building

Abstract

In this paper we present and discuss new investigations performed on both the magmatic basement and the sedimentary formations of La Désirade. We report structural and sedimentary evidences for several episodes of deformation and displacement occurring prior to the present day tectonics. The main faults, respectively N130 ± 10 o , N040 ± 10 o and N090 ± 10 o , previously considered as marker of the current tectonic regime corresponds to reactivated tectonic structures developed first during late Cretaceous compression and second during Pliocene to early Pleistocene extension. We demonstrate also the importance of late Pliocene-early Pleistocene and middle-late Pleistocene vertical movements in this part of the Lesser Antilles fore-arc as well as the role of compressive tectonics in the over thickened character of the arc basement in the Guadeloupe archipelago. L'île de la Désirade (Guadeloupe, Antilles françaises) : Une clef pour comprendre le rôle de la réactivation tectonique dans l'édification de l'arc des Petites Antilles

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

“…La Désirade basement is affected by pervasive folding and thrusting and by development of a set of conjugated N130°and N°40 steeply dipping strike-slip shear zones. This tectonic is dated back to late early Cretaceous (Albian) and supports the subduction polarity inversion that leads to inception of the Antillean subduction during the Cretaceous Lardeaux et al, 2013;Pindell and Kennan, 2009).…”

“…U S6 deposits culminate at ca. 100 m bsl on the Flandre bank whereas coeval deposits are between 0 and +90 m elevation at La Désirade (late Pleistocene marine terraces; Lardeaux et al, 2013). This highlights rapid differential vertical movements between the submerged Karukéra spur and La Désirade Island after U S6 deposition.…”

“…This suggests that the spur experienced high amplitude vertical motions and that despite a reduced sediment thickness over the spur, these vertical motions are recorded during most of the Neogene time span (Andreieff et al, 1979;Bouysse and Guennoc, 1983;Bouysse and Westercamp, 1990). Onshore at La Désirade, the metavolcanic basement is capped by shallow water Pliocene-Pleistocene carbonate platform that culminate at 276 m above sea level (Lardeaux et al, , 2013Westercamp, 1980). Lardeaux et al (2013) highlighted that normal faults reactivated the inherited Albian N130°and N40°shear zones during the deposition of the Pliocene-Pleistocene platform.…”

“…Onshore at La Désirade, the metavolcanic basement is capped by shallow water Pliocene-Pleistocene carbonate platform that culminate at 276 m above sea level (Lardeaux et al, , 2013Westercamp, 1980). Lardeaux et al (2013) highlighted that normal faults reactivated the inherited Albian N130°and N40°shear zones during the deposition of the Pliocene-Pleistocene platform. Offshore, the spur is also affected by East-west and NW-SE tectonic structures interpreted by Feuillet et al (2002Feuillet et al ( , 2004 as resulting from the development of the MarieGalante graben.…”

“…7). Following this interpretation, the Karukéra basement is considered similar to the La Désirade one which is composed of Jurassic-lower Cretaceous Arc/ Back-arc metavolcanics (Cordey and Cornée, 2009;Corsini et al, 2011;Lardeaux et al, 2013;Neill et al, 2010). Tomographic data from wide angle seismic experiments over the spur and La Désirade did not reveal any crustal discontinuity or strong velocity gradient in the horizontal dimension Roux, 2007).…”