Pre-Middle Cretaceous Geologic History of the Deep Southeastern Gulf of Mexico
R.L. Phair, R.T. Buffler, 1983. "Pre-Middle Cretaceous Geologic History of the Deep Southeastern Gulf of Mexico", Seismic Expression of Structural Styles: A Picture and Work Atlas. Volume 1–The Layered Earth, Volume 2–Tectonics Of Extensional Provinces, & Volume 3–Tectonics Of Compressional Provinces, A. W. Bally
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The University of Texas Institute for Geophysics (UTIG) has been conducting studies in the Gulf of Mexico for many years utilizing mainly multifold seismic data. One of the major areas now being studied is the deep southeastern Gulf of Mexico, where UTIG has collected an extensive grid of multifold seismic data (Figure 1). The study area lies north of Cuba between the Campeche and Florida Escarpments. The sea floor is shallower than the deep Gulf to the north and is characterized by erosional channels and large knolls.
Using the seismic data, a Deep Sea Drilling Project leg (DSDP Leg 77) was planned and carried out in December-January, 1980-81. The locations of the holes are shown on the map (Figure 1). Two sets of holes were drilled. Shallow basement was the objective of the three western sites (536, 537, and 538A), and penetration of a thick Mesozoic section was the objective of the eastern sites (535 and 540) (Schlager et al, in press).
Seismic and drilling results are being used to map the regional pre-middle Cretaceous structural and stratigraphic features and to interpret the geologic history of the area. This area is well suited for this type of study because the entire older sequence of rocks lies, in part, at shallow depths or is exposed by erosion at the sea floor. Because there is very little overburden of younger rocks, these older sedimentary sequences can easily be "seen" by the seismic data and reached by the D/VGlomar Challenger.
The purpose of this text is to describe briefly the gross structural and stratigraphic setting of the area (i.e., transitional crust overlain by a thick Jurassic to Lower Cretaceous sequence) and to show examples of seismic data that illustrate these aspects (Figures 2 through 5). Various line information for the seismic examples is included in the Appendix.