Natural Resources, School of
Date of this Version
TRANSACTIONS GULF COAST ASSOCIATION OF GEOLOGICAL SOCIETIES, VOLUME XLIII, 1993, pp. 121-129
Absolute-dated high frequency (Milankovitch cycles) marine climate/sealevel oscillatory stratigraphy can be correlated generally with continental stratigraphies. Improvements in absolute dating of Neogene formations across the North American Great Plains make this a candidate area in which to correlate marine and continental stratigraphies. Mid-latitude continental areas respond directly to climate variations. During glaciated/ cold climates, sealevel lowering results in steepened river gradients, increased erosion all along the river channel, and larger stress-bed loads. This, combined with glacial catastrophic flooding, produces greater cut-and-fill sequences along river systems than crevasse splays along the emergent coastal plain, deltas along the shelf, and submarine fans on the slope. Eustatic sea-level oscillations for the Tertiary are accepted as driven by glacial accumulations on the continents. Great Plains climate over the past 65 million years apparently has changed from generally nonseasonal, humid tropical to ever drier and cooler with seasonal variations accentuated. Absolute correlation between the available marine and continental is sufficiently tenuous, given the uncertainties of the various age dates, that only general pattern similarities may be recognized. Detailed verification must wait.
Copyright 1993 by the Gulf Coast Association of Geological Societies