PI will study the stratigraphy and depositional history of several Mississippian-age formations in southern New Mexico, along an ancient carbonate ramp to basin, during a period of paleoclimate transition of "greenhouse" to "icehouse." Excellent exposures and biostratigraphic control will allow detailed sequence stratigraphy, and elucidation of depositional processes and of controls on slope and platform morphology. Interregional comparison will allow the test of sequence stratigraphic concepts and of models for carbonate platform/slope evolution.