--> Abstract: Foraminifera as Indicators of Slope Environments in the Northern Gulf of Mexico, by S. J. Culver; #91004 (1991)

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Foraminifera as Indicators of Slope Environments in the Northern Gulf of Mexico

CULVER, STEPHEN J., Old Dominion University, Norfolk, VA

Paleobathymetric reconstructions of the northern Gulf of Mexico are based mainly on models derived from distribution patterns of modern benthic foraminiferal taxa. This method of paleoenvironmental analysis is commonly supplemented by information derived from species diversity patterns, planktonic/benthonic ratios, and shell-type ratios. Based on these lines of evidence, environment subivision of the northern Gulf slope in the 1960s recognized two zones, upper bathyal (200 to 500 m) and lower bathyal (500 to 2000 m). Later studies defined three bathyal depth zones: upper bathyal (200 to 500 m), middle bathyal (500 to 1000 m), and lower bathyal (1000 to 2000 m). Both qualitative and quantitative analyses indicate that this tripartite pattern is the natural subdivision of the slope that can be recognized in foraminiferal assemblages at both the species and generic level.

The movement of exploration onto the slope in the 1980s stimulated attempts to further subdivide the bathyal realm. For example, a recent study defined a model consisting of seven a priori bathyal depth zones and statistically investigated zone membership on the basis of generic assemblages. Another approach involved analysis of the depth distribution of assemblages defined by shape of test rather than taxonomic composition. The pattern of intra-specific morphologic

is expected to reach the House in 1991. This bill in its present form requires the EPA to study oil and gas waste-management practices and prepare standards for regulation of the states.

Additional industry regulation occurs for the storage of oil products via the Underground Storage Tank (UST) regulations by the EPA. The UST allows the EPA authority to compel response actions for substances that otherwise fall within the "petroleum exclusion" of CERCLA.

To minimize liability exposure under CERCLA, UST, and the other environmental laws discussed above, it is recommended that lessees, operators, buyers, and sellers of interests in real property obtain environmental audits to document the status of the site at the time of the activity or transaction. Parties to a transfer of ownership interest should allocate amongst themselves liability for future environmental clean up. Be aware, however, that governmental commissions are not parties to any contractual contribution or indemnification agreements. Therefore, state or federal regulations regarding proper operations, disposal of substances, and plugging and abandonment of wells will prevail to establish liability on an operator, regardless of contractual agreements of the parties.

In order to preclude statutory destruction of the existing oil and gas exemptions, forestall the EPA from exercising the full regulatory control it possesses, and minimize liability exposure, the oil and gas industry must continually monitor its protection of the environment.

 

AAPG Search and Discovery Article #91004 © 1991 AAPG Annual Convention Dallas, Texas, April 7-10, 1991 (2009)