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

Abstract

The Grenada Basin is bounded to the east by the active Lesser Antilles Arc, to the west by the north-south trending Aves Ridge, commonly described as a Cretaceous-Paleocene remnant of the "Great Arc of the Caribbean" (Burke, 1988), and to the south by the transpressional plate boundary with South America (Figure 1). This setting led previous authors to propose various models for the origin of the Grenada Basin, most of them assuming the basin to be at least partly floored by oceanic crust that was formed during the

Deep Structure of the Grenada Basin From Wide‐Angle Seismic, Bathymetric and Gravity Data

“…The supra-crustal part of the wide-angle seismic velocity models presented here are closely consistent with the interpretation of coincident MCS lines GA01 ( Figure 12c) and GA02 ( Figure 12e) for the corresponding WAS profile, and MCS line GA06 for the western half of GA03 WAS profile (Figures 12a and 13a) (Garrocq et al, 2021). For the eastern part of the GA03 WAS profile, line 2B of the SISMANTILLES 1 cruise was used (Hirn, 2001) ( Figure 12b).…”

“…divided into two layers with a highly irregular top of the basement which is consistent with the numerous faults and vertical throws identified by Garrocq et al (2021). Crustal thinning takes place in a ∼100 km wide transition zone between the eastern flank of the Aves Ridge and the Grenada Basin.…”

“…The dotted black line in (a) symbolizes the probable location of the top of the subducted slab as extrapolated from MCS data (Laigle et al, 2013). divided into two layers with a highly irregular top of the basement which is consistent with the numerous faults and vertical throws identified by Garrocq et al (2021). Crustal thinning takes place in a ∼100 km wide transition zone between the eastern flank of the Aves Ridge and the Grenada Basin.…”

“…Here opening was accompanied by heavy volcanism leading to the deposition of large amounts of seaward dipping reflector (SDR) packages building a large part of the plateau (Museur et al, 2020;Reuber et al, 2016). Some volcanic edifices are identified in our study region (Garrocq et al, 2021) and the sedimentary sequences might contain volcano-sedimentary layers. Although dipping reflections identified in the MCS data are interpreted to correspond to lava flows, these do not have the same thickness as the SDR commonly identified along volcanic margins or at transform margin plateaus such as the Demerara plateau where they can reach a thickness of up to 21 km (Reuber et al, 2016).…”

“…The reflection seismic data were quality controlled using Ifremer's "SolidQC" software, and a first processing on Geovation CGG software included resampling to 4 ms, anti-alias filtering, multiple suppression by surface-related multiple elimination, predictive convolution, velocity analysis, stack and water-velocity migration (for a more detailed description see the companion manuscript by Garrocq et al, 2021).…”