STRUCTURAL EFFECTS OF CHICXULUB AND CHESAPEAKE-TOMS RIVER ASTEROID IMPACT EVENTS: RISKS TO HYDROCARBON ENTRAPMENTS- SOUTHEASTERN BAHAMAS

Punctuated tectonic equilibrium describes the sudden effects of impact events altering the steady-state tectonic process. Impact-tectonic far-field (ITFF) crustal-strain fields are caused by refracted and reflected shock waves off acoustic boundaries returning to the surface at remote distances off the asthenosphere (660km.), lower mantle (1600km.), and outer Core (2900km.). Chicxulub and Chesapeake Impacts generated calculated seismic events of 10.3 and 9.1 respectively. (ITFF) of the Chicxulub (1600km.) and Chesapeake Bay) overlap the Bahamas.

Strewn fields are documented in cores as micro-tektites spherules from 1) Cretaceous/Paleogene (65-66) Ma the Chicxulub impact, DSDP 603, ODP Leg 174 AX, Bass River, Cuba, Northeastern Mexico, Northern Gulf of Mexico, Texas, Mississippi, Alabama, and Tunisa.2) and the Chesapeake Bay Impact Late Eocene (35 Ma) DSDP 612, 902,903, Texas.

In the Bahamas, a structural belt sub-paralleling Cuba and attributed to Cretaceous subduction and transform movements has solely been the principal mechanism affecting the system. Seismic profiles demonstrate deformation up to the K/P boundary. The Chicxulub impacts may have enhanced fault networks, accelerated over thrusting, transform movement, tectonic motion, and volcanism, resulting in the migration of entrapped hydrocarbons generated and emplaced by the end of the Cretaceous ( 65 Ma).An ophiolite belt present along the Caribbean islands may have been caused by the event. Cuban and Southern Bahamas hydrocarbon maturation modelling demonstrate Jurassic age rocks capable of peak generation from 120 to 70 Ma. . The most recently drilled exploration wells drilled in a seismically mapped structural belt encountered immature Cretaceous age hydrocarbons with sub economic quantities derived from deeper origins. Impact structurally related deformation may have breached Cretaceous hydrocarbon reservoirs , in some case demonstrating 1000 m of throw by reverse faulting and reservoir depletion. Preserved accumulations would be present at deeper depth closer to source reservoir packages with continued recharge and resealing of traps.