Joseph P Smoot (Former Employee)

The High Point paleosol is 2.28-meters-thick aggradational soil developed in fining upward estuarine-alluvial sand and loess. The paleosol is exposed in a few shoreline cliff faces of Mason Neck, Virginia. Although a former A horizon is missing, the E, Bw, Bt, and C horizon sequence seen in the sediments indicates subaerial pedogenesis. Pedogenesis began with initial estuarine-alluvial floodplain

No abstract available.

The narrow-leaved cattail wetland known as Dyke Marsh formally became a land holding of George Washington Memorial Parkway (GWMP, a unit of the national park system) in 1959, along with a congressional directive to honor a newly-let 30-year commercial sand and gravel dredge-mining lease at the site. Dredging continued until 1974 when Public Law 93-251 called for the National Park Service and the U

Dyke Marsh, a distal tidal marsh along the Potomac River estuary, is diminishing rapidly in areal extent. This study documents Dyke Marsh erosion rates from the early-1860s to the present during pre-mining, mining, and post-mining phases. From the late-1930s to the mid-1970s, Dyke Marsh and the adjacent shallow riverbottom were mined for gravel, resulting in a ~55 % initial loss of area. Marsh los

We document frequent, rapid, strong, millennial-scale paleovegetation shifts throughout the late Pleistocene, within a 100,000+ yr interval (~ 115–15 ka) of terrestrial sediments from the mid-Atlantic Region (MAR) of North America. High-resolution analyses of fossil pollen from one core locality revealed a continuously shifting sequence of thermally dependent forest assemblages, ranging between tw

This report is a synthesis of the latest findings from an ongoing study of Dyke Marsh, an eroding freshwater tidal wetland that is scheduled for federal restoration. Its purpose is to provide an accurate and up-to-date temporal and geological framework for the marsh, of which most is new information (plus a compilation of historical and recent information), that is directly relevant to the restora

The geology of the Shenandoah National Park region of Virginia was studied from 1995 to 2008. The focus of the study was the park and surrounding areas to provide the National Park Service with modern geologic data for resource management. Additional geologic data of the adjacent areas are included to provide regional context. The geologic map can be used to support activities such as ecosystem de

A temporary exposure at the Midshore Regional Solid Waste Facility near Easton, MD, provided an opportunity to document the characteristics of the complex assemblage of surficial facies in that area. This unusually large cross section allowed interpretation of the changing processes that shaped the landscape in response to climate change through the late Pleistocene. Eight stratigraphic units were

The Culpeper basin is part of a much larger system of ancient depressions or troughs, that lie inboard of the Atlantic Coastal Plain, and largely within the Applachian Piedmont Geologic Province of eastern North America, and the transition region with the neighboring Blue Ridge Geologic Province. This basin system formed during an abortive attempt to make a great ocean basin during the Late Triass

No abstract available.

An outcrop of stratified slope deposits in Shenandoah National Park is described in detail. The Pleistocene age deposits are comprised of a mixture of clay to cobbles defining a series of offlapping wedges. Elongate clasts are oriented parallel to wedge boundaries except at the toe of the wedge, where they are oriented nearly vertical. The wedges represent sedimentation by freeze-thaw of ground ic

We constructed a radiometrically calibrated proxy record of Late Pleistocene and Holocene climate change exceeding 230,000 yr duration, using pollen profiles from two cores taken through age-equivalent dry lakes - one core having greater age control (via 230Th alpha mass-spectrometry) and the other having greater stratigraphic completeness. The better dated of these two serial pollen records (Sear