دانلود کتاب Cretaceous and Tertiary Stratigraphy of the Elk Neck Area, Northeastern Maryland: Elk Neck State Park, Maryland, July 12, 1989

About The ProductPublished by the American Geophysical Union as part of the Field Trip Guidebooks Series. Elk Neck is a small peninsula which lies at the northern end of the Chesapeke Bay. This peninsula is an erosional remnant of a once more widespread Coastal plain. The peninsula is relatively small, approximately 13 miles long and 5.5 miles wide at its widest point. Elevations within the peninsula range from sea level to just over 300 feet above sea level. The west side of the peninsula is characterized locally by steep bluffs and numerous landslides. Because of the continued sluffing in the land slide areas, the exposures continually are alternately covered or uncovered, and the sections shown in this report may not be the same when the field trip is run. The east side of the peninsula is less precipitous than the west side. Here the land surface descends more gradually to the Elk River. The field trip will concentrate for the most part on the exposures along the west side of the peninsula in the vicinity of Mauldin Mountain near Elk Neck State Park. Of particular interest here will be the exposures of the Potomac Formation of late Early to early Late Cretaceous age. As much as 135 feet of the Potomac Formation are intermittently exposed at this locality which is an unusually thick exposure of the Potomac Formation. The Potomac Formation is overlain by a thin series of deeply weathered marine and marginal marine units. If access is available to the top of the bluff, these formations will also be examined briefly in order to illustrate the differences in bedding style between the non-marine beds of the Potomac Formation and the marine-influenced younger Cretacious formations. The field trip will also visit the southermost part of the peninsula at Turkey Point. Here a channel of the middle Miocene Pensauken Formatin has eroded deeply into the underlying Potomac Formation. The Pensauken like the Potomac Formation is a fluvial unit. The Pensauken deposits on Elk Neck Peninsula mark the western boundary of a highly eroded gravel sheet which caps the northern part of the Delmarva Peninsula to the east. The central bedding styles and perticularly the compositional differences between the Potomac and Pensauken formations will be discussed. Content: