OS33A-1039 and Channel: New Insights About two Tectonic Gateways of the Northern Caribbean

Marie-Helene Cormier1, Ruth Elaine Blake2, Dwight F. Coleman1, Kelly Guerrier3, Nicole Raineault4, Nixon Saintilus5, Sharon L Walker6, Steven Auscavitch7 and Jamie Wagner8 (1) U. Rhode Island, Graduate School of Oceanography, Narragansett, RI, USA; (2) Yale U., Dept. Geology and Geophysics, New Haven, CT, USA; (3) U. d’Etat de , URGeo-FDS, Port-au-Prince, Haiti,; (4) Ocean Exploration Trust, Graduate School of Oceanography - U. Rhode Island, Narragansett, RI, USA, (5) SEMANAH (Haiti maritime and Navigation Service), Delmas, Haiti, (6)NOAA/PMEL, Seattle, WA, USA, (7) U. Maine, Orono, ME, USA, (8)Duke U., Durham, NC, USA

In August 2014, The E/V NAUTILUS of the OCEAN EX- PLORATION TRUST explored the region delimited by two deep straits of the northern Caribbean, the Wind- ward passage and the Jamaica Channel. The morphology Windward passage C - Thrust fold of these straits is controlled by two transform faults: The Gonave microplate CUBA Septentrional fault, which stretches between Cuba and B Haiti (slip rate: ~13 mm/yr), and the Enriquillo-Plantain Garden Fault (EPGF), which stretches between Jamaica and Haiti (slip rate: ~9 mm/yr). Together, these faults Septentrional Fault Cap Haitien bound the Gonave microplate, an elongated platelet caught between the North America plate and Caribbean plates. The Septentrional fault ruptured in 1842, devastat- HAITI ing the town of Cap Haitien. The EPGF ruptured cata- strophically in 2010 near Port-au-Prince (death toll > 100,000). Tsunamis were associated with both earth- A C quakes. Oblique slip on these two faults is presumably Eric Calais, http://www.nsf.gov/news/mmg/media/images/haiti5_h.jpg Port-au-Prince controlling the history of uplift and subsidence of the sea- AAA floor, and has therefore also been regulating the water ex- changes between the north central Atlantic and the Carib- JAMAICA Enriquillo Plantain- bean Sea. Multibeam bathymetric data acquired with the Garden Fault E/V NAUTILUS and direct observation made with the ROV HERCULES provide new information about the Red lines: Ship tracks Jamaica Channel Seafloor is jointed near the fold physiography of the plate boundary. axis, and beds are upturned on This project was funded by the Ocean Exploration Trust. We gratefully acknowledge the crew and the entire team that ROV Hercules south side. sailed aboard the E/V Nautilus during cruise NA050.

A - B - Windward passage

Lobated lava flows? Tortue Island

Septentrional Fault Lava flow exposed Septentrional Fault at base of Navassa Island ?

Rifted volcanics?

Landslide

A tectonized seafloor characterizes the central section of the Septentrional fault. South of Tortue Island, the fault trace is heavily sed- Enriquillo Plantain-Garden Fault mented, but near the top of the northern fault escarpment, the steep wall displays a fractured surface.

A landslide 7 km-wide and 10 km-long has cut into the lower terrace that surrounds Navassa Island. It is unclear how young this landslide is, and whether it may have been triggered by an earthquake on the nearby Enriquillo-Plantain Garden fault. Volcanics may be exposed at the base of the north side of Navassa island, which may have been emplaced as part of the Caribbean Oceanic plateau, or be relict from the volcanic arc that migrated eastward through the area.