Organisms are extremely sensitive to many parameters of the physical environment and their fossil remains may thus be used in the interpretation of ancient

End_Page 2176------------------------------

environments. Effective use of paleoecology depends first on determining what environmental parameters are of interest, second, on developing a model based on recent examples which can be tested on the fossil record, and third, testing the model on the fossil record. Following this procedure several methods for determining the depth of water in which deposition took place are considered. Though further testing is required, each of these procedures appears to offer promise for environmental reconstruction and for petroleum exploration. Additional techniques which consider the distribution of ocean currents across the continental shelves are also examined and appear to offer possibilities for the interpretation of ancient submarine topography which may be of significance in exploration. /P>

Climatic conditions strongly affect the distribution of certain stratigraphic traps, particularly such carbonate traps as reefs. Exploration for these traps is fruitless if climatic conditions at a particular time and place were such as to preclude their development. Determination of past climatic zones is, however, difficult if not impossible until the positions of the major continental masses in the past can be determined. Paleoecology with its ability to reconstruct depositional environment is in a strong position to examine both the question of continental drift and the question of polar wandering. A model which permits such an examination is developed and tested on the fossil record of the Permian. The test suggests that neither continental drift across latitude, nor polar wander ng is likely and that both the rotational poles and the latitudinal positions of continents probably have remained unchanged at least since the Permian. If this is true then the limits of tropical-subtropical conditions have varied widely through time controlling, as they varied, the area of the globe suitable for reef development and, in fact, for extensive carbonate development.

A modification of the model used to test the hypotheses of continental drift and polar wandering shows promise for reconstructing the pattern of surface oceanic currents. These currents are closely related to reef development which extends farther both toward the north and south on the east side of the continents than on the west because of these currents. The same technique suggests a possible means of learning more of the fundamental courses of glaciation if applied to glacial and interglacial patterns of oceanic circulation.

End_of_Article - Last_Page 2177------------