ABSTRACT

The application of paleoecology and related stratigraphic studies in environmental interpretation is playing an increasingly important role in Gulf Coast petroleum exploration. Studies of the ecology of Recent Foraminifera of the Gulf of Mexico, both planktonic and benthonic, in the last 20 to 25 years have provided the basis for more accurate paleoecologic interpretations. Accurate paleoecologic interpretation also depends upon sufficient knowledge and consideration of the associated lithology, sedimentation, and tectonics, which are related components of stratigraphy.

In the interest of uniformity and a certain degree of standardization, the following eight depositional environments as proposed by the New Orleans paleoeological study group (1966) of the Gulf Coast Section of the Society of Economic Paleontologists and Mineralogists have been adopted herein: (1) Non-marine, (2) Transitional, (3) Inner Shelf (Inner Neritic), (4) Middle Shelf (Middle Neritic), (5) Outer Shelf (Outer Neritic), (6) Upper Slope (Upper Bathyal), (7) Lower Slope (Lower Bathyal), and (8) Abyssal. Recent and fossil Foraminifera characteristic of the various depositional environments are listed. Methods of paleoecological investigation are also presented, with a review of some of their limitations.

Oil and gas reservoirs were deposited in specific environments with a definite relation ship between petroleum occurrence and depositional history. The accurate reconstruction of depositional environments and the application of this knowledge in petroleum exploration will result in more successful exploration programs.