Shedding New Light on an Enigmatic End Member of Back‐Arc Spreading: The Structure of the Grenada Basin in the Lesser Antilles

Abstract

AbstractAs one of only two subduction zones to consume slow‐spreading Atlantic oceanic crust, and with one of the slowest convergence rates of any subduction system globally, the Lesser Antilles arc is an important end member on the subduction spectrum. Back‐arc spreading is observed at many subduction zones. Yet, despite fulfilling many of the geodynamic requirements for spreading, the tectonic processes which may have led to the formation of the 500 × 150 km Grenada back‐arc Basin remain both enigmatic and controversial. In their new publication, Padron et al. (2021) (Padron, C., Klingelhoefer, F., Marcaillou, B., Lebrun, J.‐F., Lallemand, S., Garrocq, C., et al. (2021). Deep structure of the Grenada Basin from wide‐angle seismic, bathymetric and gravity data. Journal of Geophysical Research: Solid Earth, 126, e2020JB020472. https://doi.org/10.1029/2020JB020472) present the most expansive wide‐angle seismic data set acquired in the basin to date. In combination with other marine geophysical data the authors can map clear internal changes in crustal structure, proposing a model of oblique magmatic spreading in the southern basin. This study represents an important step, not only for understanding of the tectonic history of the eastern Caribbean region, but also toward understanding what the Lesser Antilles may be able to tell us about the complexities of back‐arc processes globally.