loading page

Signature of Transpressional Tectonics in the Holocene Stratigraphy of Lake Azuei, Haiti: Preliminary Results From a High-Resolution Subbottom Profiling Survey
  • +13
  • Marie-Helene Cormier,
  • Heather Sloan,
  • Dominique Boisson,
  • Britta Brown,
  • Kelly Guerrier,
  • Casey Hearn,
  • Clifford Heil,
  • Roger Kelly,
  • John King,
  • Rachel Stempel,
  • Roberte Momplaisir,
  • Steeve Symithe,
  • Paul Knotts,
  • Oliver Lucier,
  • Sophia Ulysse,
  • Nigel Wattrus
Marie-Helene Cormier

Corresponding Author:[email protected]

Author Profile
Heather Sloan
Author Profile
Dominique Boisson
Author Profile
Britta Brown
Author Profile
Kelly Guerrier
Author Profile
Casey Hearn
Author Profile
Clifford Heil
Author Profile
Roger Kelly
Author Profile
Rachel Stempel
Author Profile
Roberte Momplaisir
Author Profile
Steeve Symithe
Author Profile
Paul Knotts
Author Profile
Oliver Lucier
Author Profile
Sophia Ulysse
Author Profile
Nigel Wattrus
Author Profile


The left-lateral Enriquillo-Plantain Garden Fault (EPGF) is one of two transform systems that define the Northern Caribbean plate boundary zone. Relative motion across its trace (~ 10 mm/yr) evolves from nearly pure strike-slip in western Haiti to transpressional in eastern Haiti, where the fault system may terminate against a south-dipping oblique reverse fault. Lake Azuei is a large (10 km x 25 km) and shallow (< 30 m deep) lake that lies in the direct extension of the EPGF in eastern Haiti. A single core previously collected in the lake suggests high sedimentation rates at its depocenter (~6 mm/yr). The shallow lake stratigraphy is therefore expected to faithfully record any tectonic deformation that occurred within the past few thousand years. In January 2017, we acquired a grid of high-resolution (~10 cm), shallow penetration (~4 to 5 m) subbottom seismic (CHIRP) profiles spaced 1.2 km apart across the entire lake. A new bathymetric map compiled from these CHIRP data and some prior echosounder survey reveals a flat lake floor (<0.01°) surrounded by steep (~5°) shoreline slopes. The CHIRP profiles highlight several gentle folds that protrude from the flat lakebed near the southern shore, an area where transpressional deformation is presumably focused. Thin (< 20 cm) horizontal strata from the lakebed can be traced onto the flanks of these gentle folds and pinch out in an upward curve. They also often pinch upward onto the base of the shoreline slopes, indicating that young sediments on the lakebed bypassed the folds as well as the shoreline slopes. We interpret this feature as diagnostic of sediments deposited by turbidity currents. The fact that young turbidites pinch out in upward curves suggests that the folds are actively growing, and that active contractional structures (folds and/or blind thrust faults) control much of the periphery of the lake. A few sediment cores were strategically located where beds are pinching out in order to maximize stratigraphic records. Two of these cores successfully penetrated strata imaged by the CHIRP profiles. On-going Pb210 dating of sediment samples from the cores should constrain sedimentation rates and thus help quantify the rates of the tectonic deformation.