Abstract
Supralittoral coarse-clast deposits along the shores of Bonaire (Netherlands Antilles) as well as increased hurricane frequency during the past decade testify to the major hazard of high-energy wave impacts in the southern Caribbean. Since deducing certain events from the subaerial coarse-clast record involves major uncertainties and historical reports are restricted to the past 500 years, we use a new set of vibracore and push core data (i) to contribute to a more reliable Holocene history of regional extreme-wave events and (ii) to evaluate their impact on shoreline evolution. Multi-proxy palaeoenvironmental analyses (XRF, XRD, grain size distribution, carbonate, LOI, microfossils) were carried out using nearshore sedimentary archives from the sheltered western (leeward) side of Bonaire and its small neighbour Klein Bonaire. In combination with 14C-AMS age estimates the stratigraphy reflects a long-term coastal evolution controlled by relative sea level rise, longshore sediment transport, and short-term morphodynamic impulses by extreme wave action, all three of which may have significantly influenced the development of polyhaline lagoons and the demise of mangrove populations. Extreme wave events may be categorized into major episodic incidents (c. 3.6 ka [?] BP; 3.2–3.0 ka BP; 2.0–1.8 ka BP; post-1.3 ka [?] BP), which may correspond to tsunamis and periodic events recurring on the order of decades to centuries, which we interpret as severe tropical cyclones. Extreme wave events seem to control to a certain extent the formation of coastal ridges on Bonaire and, thus, to cause abrupt shifts in the long-term morphodynamic and ecological boundary conditions of the circumlittoral inland bays.
Highlights
A broad spectrum of potential triggering mechanisms of tsunamis exists throughout the Caribbean region
On the island of Bonaire in the southern Caribbean (Fig. 1), the lack of historical accounts of tsunamis (O’Loughlin and Lander, 2003) stands in a remarkable contrast to the massive circumlittoral boulder deposits some of which have been associated with tsunamigenic dislocation (Scheffers, 2004, 2005)
The stratigraphy of Salina Tam at the leeward coast of Bonaire reflects an interplay of long-term sea-level rise, gradual sediment dynamics as well as periodic and episodic wave impacts
Summary
A broad spectrum of potential triggering mechanisms of tsunamis exists throughout the Caribbean region. These include (i) earthquake-triggering tectonic movement (strikeslip motion, oblique convergence) along the boundary of the Caribbean and North American Plates (Grindlay et al, 2005) or the Venezuelan coast (Audemard et al, 2005); (ii) the Lesser Antilles subduction zone with earthquakes and various sources of explosive and effusive volcanism On the island of Bonaire in the southern Caribbean (Fig. 1), the lack of historical accounts of tsunamis (O’Loughlin and Lander, 2003) stands in a remarkable contrast to the massive circumlittoral boulder deposits some of which have been associated with tsunamigenic dislocation (Scheffers, 2004, 2005). The interpretation of these boulders as storm or tsunami deposits has been ques-
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.