Testing the Continuity of Lesser Antilles Forearc Provinces Based on Gravity Modeling and a Compilation of Radiometric Age Dates

Authors: Benjamin Miller (presenter), Paul Mann, University of Houston

The Lesser Antilles arc is a largely submarine feature covered by thick, marine sedimentary rocks and locally by 19 active, stratovolcanoes, and small, carbonate platforms formed on bathymetric highs and extinct volcanic highs. Gravity data therefore provide a useful tool for understanding the continuity and relationships of crustal provinces along the 800-km-long, north-south-trending, intra-oceanic arc of early Cretaceous to recent age. There is no question from gravity data that the remnant arc (Aves Ridge) and the active volcanic arc forms two continuous ridges along the length of the arc. Ages from the remnant arc range from 86 to 65 Ma while those from the active arc range from 38 to 0 Ma. Gravity data reveals a prominent bifurcation in the volcanic arc north of Martinique with the active arc to the west ranging in age in this area from 3.5 to 0 Ma and the inactive “Limestone Caribees” ranging in age from 38 to 25 Ma and capped by a carbonate platform of 15 Ma to recent age. Gravity data reveals that the obliquely subducting St. Lucie fracture zone marks the zone of bifurcation of the northern arc near Martinique. To the south, the Tobago-Barbados ridge extends over a distance of 300 km and is underlain at Tobago Island by arc rocks ranging in age from 160 to 140 Ma. The Limestone Caribees ridge in the north and the TBR to the south appear unrelated arc crustal provinces because: 1) the TBR is located 100 km east of the bifurcation point of the northern arc near Martinique; 2) the TBR and Limestone Caribees exhibit strongly contrasting gravity signatures; and 3) the known ages of the two ridges differ with the Limestone Caribees being much younger.

Bio:

Benjamin Miller, University of Houston

Benjamin has double degree in Geology and Geophysics at the University of Houston. He currently is research assistant at Conjugate Basins, Tectonics, and Hydrocarbons (CBTH) Consortium working on the investigation of the structures in the Northeastern Caribbean plate on the Saba Bank by interpreting stratigraphic sequences on vintage seismic data, examining volcanic history and the impact of the regional plate tectonics, and modelling potential fields.

His past experience includes the AAPG UH IBA Team, Finance Departments Payroll and Department Specialist, Landslide Research in China using GPS and LiDar, and Entech Sales and Services Intern.

Benjamin is a member of SEG Wavelets, AAPG and HGS.