Physical Sciences and Mathematics Commons^™

Lithofacies Of The Pliocene Yorktown Formation In The Vicinity Of Kingsmill On The James River, Virginia, Michael David Lawless

OES Theses and Dissertations

The Yorktown Formation beds which crop out along the James River in southeastern Virginia near Kingsmill and Carter's Grove are lithologically described in order to compare them with the "typical" Yorktown beds upriver in the area of Fort Boykins, Rushmere, and Cobham Wharf. Thirty-four stratigraphic sections are constructed of the bluffs along the river. The Yorktown beds in the area of Kingsmill and Cobham Wharf are divided into ten lithofacies: the silty sand facies (B), the Chesapecten facies (C), the Glycymeris facies (D), the Chama facies (E), the glauconitic biofragmental sand facies (F), the laminated silty clay facies (G), the …

Nonlinear Solutions To A Two-Layer Quasi-Geostrophic Model Of The Gulf Stream, Eiichi Oka

OES Theses and Dissertations

The Gulf Stream shows a large meander off Cape Hatteras. This is driven by an energy conversion process known as baroclinic instability and observations suggest that nonlinearity is an important part in this process. In order to understand the fundamental role of nonlinearity in baroclinic instability, an inviscid 2-layer quasi-geostrophic model is studied.

The linear solution is obtained by methods of normal mode and Fourier-Laplace transforms. It is found that the set corresponding to the continuous spectrum is null and the set corresponding to the discrete spectrum is complete.

The nonlinear solution is expanded in terms of the complete set …

A Geophysical Study Of The Easternmost Piedmont: Brunswick County, Virginia, Mark A. Corbin

OES Theses and Dissertations

Gravity and magnetic models indicate that a steeply dipping, mylonitic shear zone recognized by reconnaissance mapping in the easternmost Piedmont of Brunswick County, Virginia is a listric fault. A pronounced 3 to 5 mgal Bouguer anomaly high is associated with the fault zone. A band of N10° trending aeromagnetic anomalies delineate the areal extent of the fault zone. The fault zone flattens eastward over a short distance to a depth of 15 kms where it joins a near horizontal surface that cuts across the region. This surface is herein interpreted to be a decollement. The fault zone of this study …

The Geomorphology And Surficial Geology Of The West Flank Of The Blue Ridge, Sherando Area, Virginia, Derek Weston Ryter

OES Theses and Dissertations

The west flank of the Blue Ridge near Sherando, Virginia (Augusta County) consists of many landforms including talus slopes, bedrock cliffs, boulder streams, colluvial slopes, residual knobs, and debris fans. The purpose of this study is to describe the geomorphic history of the area by understanding the spatial and temporal relationships between landforms on the hillslopes.

Boulder streams (maximum 30 m wide, 400 m long, 6.1 m thick) exhibit a gently dipping imbricated fabric and basal shear stresses of 0.1 to 0.4 bars.

Debris fans in Group L (lower) and Group U (upper) are distinguished by topographic position, degree of …

The Temporal And Spatial Distribution Of Blue Crab Larvae On The Mid-Atlantic Bight Adjacent To The Chesapeake Bay, 1982-1983, Lyle Michael Varnell

OES Theses and Dissertations

Recruitment processes are important information for the management of commercially and recreationally exploited marine species. Recruitment processes of the Chesapeake Bay's most important commercial and recreational species, the blue crab, are unknown, due in part to the lack of knowledge of the processes directly preceeding recruitment.

The present study was undertaken to investigate and explain the movement and developmental patterns of blue crab larvae while offshore. Interannual and intraseasonal variations of these patterns were also examined.

Sampling occurred from May to November during 1982 and 1983. Larvae were collected at three depths (neuston layer (upper 10 cm), one meter and …

Picoplankton/Phytoplankton Dynamics In Hampton Roads, Virginia, Leslie E. Dorworth

OES Theses and Dissertations

The biomass distribution of the three main size components of the phytoplankton (net, nano, and picoplankton) was examined in the lower Chesapeake Bay. Work was done at two stations during the spring and neap tidal cycles when freshwater flow into the bay was at its seasonal minimum and maximum. Emphasis was placed on how the picoplankton ( < 2.0 μm, > 0.2 μm) reacted during the sampling period.

Picoplankton made up approximately 13% of the total biomass, during the observed time period, at the more oceanic station. The picoplankton fraction contributed up to 16% of the total biomass at the estuarine station. From this …

Population Variation In The Mitochondrial-Dna Of Two Marine Organisms: The Hard Shell Clam Mercenaria Spp. And The Killifish, Fundulus Heteroclitus, Bonnie Lynn Brown

OES Theses and Dissertations

The two major topics are covered in this dissertation: the integration of molecular genetic tools with applied aquacultural research and short-term evolutionary dynamics. The first study investigated the extent of geographic differentiation of native clam stocks along the U.S. east and Gulf coasts. Clam mitochondrial DNA (mtDNA) demonstrated size polymorphism (16.5-19.0 kb) and restriction site heteroplasmy. Size heteroplasmic individuals occurred at a frequencies of 0-89% in clam populations. Restriction site heteroplasmy occurred in 12% of the 317 individuals assayed. Results of the study indicated that although harbouring a wealth of genetic variation, clams from northern regions were similar and lacked …