Spring 2003 Abstracts for Georgia Southern University Geology and Geography Students and Faculty

Clark R. Alexander, Skidaway Institute of Oceanography, 10 Ocean Science Circle, Savannah, GA 31411, clark@skio.peachnet.edu

Estuaries are important geologic repositories containing the signatures of the latest sea level rise, large natural events and anthropogenic inputs to the coastal zone. For the past three decades, long-lived, naturally occurring radionuclides (210Pb and 137Cs) have been applied to the study of estuarine sediment accumulation on 100-y timescales. Within the past decade, new approaches with short-lived radionuclides (7Be and 234Th) have been developed that allow us to examine sedimentary processes on much shorter timescales (days to months).

Because particles are dynamically remobilized and redistributed within the estuarine environment, sediment distribution and accumulation patterns exhibit spatial and temporal heterogeneity on a variety of scales that can be highlighted by the application of radiochemical tools with a range of half-lives. Work during the past decade in the fluvial and saltmarsh estuaries of the Georgia and South Carolina coasts documents the short- and long-term signatures of sedimentary processes in the estuarine stratigraphic record. In South Carolina, both Winyah Bay and the Ashepoo River in the ACE Basin National Estuarine Research Reserve exhibit extremely rapid fine-grained sediment deposition at rates over 10 cm/month as documented by the distribution of the 234Th and 7Be, although 210Pb rates are orders of magnitude lower. These deposits in the ACE Basin are removed each year and widely distributed into the extensive salt marshes. The residual deposits, a black, low-porosity mud overlain by a few centimeters of sand, represents the stratigraphic signature of this massive deposition. In Winyah Bay, harbor dredging annually creates accommodation space that is quickly filled by muddy deposits within at most a few months, necessitating annual maintenance dredging. In the Satilla River estuary, sediment distribution and accumulation patterns exhibit variability on tidal to decadal timescales and on broad spatial scales as well. Redistribution of mobile sediments as evidenced by high-concentration mud suspensions (up to 5 g/L) occurs with each tide but sediment accumulation as documented with Pb-210 accumulation rates is discontinuous on decadal timescales.

ASHER, PRANOTI M., Department of Geology and Geography, Georgia Southern University, Statesboro, GA 30460-8149, PAsher@GaSoU.edu, VANCE, ROBERT K., Department of Geology and Geography, Georgia Southern University, Statesboro, GA 30460-8149, RKVance@GaSoU.edu, Cook, H. Patrice, Department of Geology and Geography, Georgia Southern University, Statesboro, GA 30460-8149, greyjade1@yahoo.com.

Numerous diabase dikes intrude the Piedmont in Georgia. They are part of the system of Mesozoic dikes, sills, and flood basalts that occur in eastern North America from Nova Scotia to Alabama. The petrography and geochemistry of three such dike exposures in central and eastern Georgia are the subject of this study. Field localities include dike outcrops near Sparta, Clark Hill Reservoir, and Macon. A diabase dike near Sparta intrudes the Pennsylvanian Sparta Granite and surrounding amphibolite facies metamorphic rocks of the Kiokee Belt. The dikes near Macon intrude amphibolite facies metamorphic rocks of the Charlotte Belt.

Low water levels in Clark Hill Reservoir provide rare exposures of diabase dikes that strike N250W across the NE striking foliation of greenschist facies metavolcanic and metasedimentary rocks of the Neoproterozoic to Cambrian Persimmon Fork and Richtex Formations (Carolina Slate Belt). The near vertical dikes range in width from < 1 m to > 10-m thick and limited exposure suggests discontinuous, en echelon segments.
At Clark Hill the texture is diabasic to subophitic with subhedral plagioclase (An51-60) composing 50-60% of the rock. A range of An29-54 was determined in grains that exhibited oscillatory zoning. Anhedral to subhedral olivine make up 20-25% of the diabase and have a bimodal size distribution (grain diameter < .1 mm and 1.5-2.5mm). The larger grains exhibit zoning with serpentine-talc alteration on rims and in fractures. Anhedral clinopyroxene comprises nearly 20 % of the rock and opaques make up around 2 % of the rock. The mineralogy of the Sparta and Macon dikes is similar to that from Clark Hill except that pervasive alteration of olivine and pyroxene to chlorite, serpentine, and iron oxides is quite noticeable at Sparta
Geochemically, the Macon and Clark Hill diabase resemble other Southeastern US diabases reported in South Carolina (Warner et al., 1985 and 1992) and Virginia (Cummins, 1987 and Cummins et al. 1992). The diabase is olivine normative and lies in the olivine normative group proposed by Weigand and Ragland (1970). The Sparta diabase, however, is comparable to the high-Fe quartz tholeiites from west central Georgia (Milla and Ragland, 1992).

BISHOP, G.A.., South Dakota School of Mines and Technology, Museum of Geology and Paleontology, O'Harra Building, 501 E. St. Joseph Street, Rapid City, SD 57701,

Decapod assemblages occur in the Upper Cretaceous Coon Creek Formation of the Mississippi Embayment. The Blue Springs Dakoticancer australis Assemblage resembles the South Dakota Dakoticancer Assemblages in faunal composition, mode of preservation and distribution, but differs significantly in taxonomic composition and taphonomic fabric. The Avitelmessus Assemblage may consist of the single decapod taxon, Avitelmessus grapsoideus, or of A. grapsoideus associated with a molluscan assemblage, and is preserved as repeated, discrete assemblage, a biocoenosis, in near shore shale-rich or clay-rich and muddy-sand lithosomes of the Coon Creek and Ripley Formations. The Blue Springs Dakoticancer australis Assemblage, preserved in an off shore facies, consists of at least two preservational cycles over-printed on a molluscan thanatocoenosis. Both decapod assemblages represent preserved Cretaceous crab community fractions and occupy intermediate positions in Late Cretaceous marine food chains and food webs. Hypothetical food chains and food webs are presented for these community fractions and their cohorts.

Gale A. Bishop
South Dakota School of Mines and Technology
Director, SD Museum of Geology and Paleontology
Rapid City, South Dakota, 57701

The St. Catherines Sea Turtle Conservation Program integrates conservation, applied research, and science education for K-12 teachers on a Georgia barrier island where 14 teachers per year spend eight days in total immersion conserving nests of loggerhead sea turtles.

Abstract

The St. Catherines Island Sea Turtle Conservation Program was instituted in 1990 to conserve loggerhead sea turtles nesting on the beaches of St. Catherines Island, Georgia. The holistic program integrates conservation of threatened and endangered sea turtles with applied research and conservation education. Fourteen teachers per year are trained in conservation of loggerhead sea turtles and practice while in residence on the Island for seven days. These teachers take the learned content and real-world experiences back to their classrooms to teach school children about sea turtle conservation. The program has impacted over 100 teachers and 100,000 school children.

The summer internship necessitates residing on St. Catherines Island and working daily for seven days to conserve sea turtle nests being deposited on the beaches. The work is grueling, intense, and often entails long hours even in inclement weather. Interns must be willing to drive an open ATV (Kawasaki Mule 2500) monitor beaches at dawn, work long hours on the beach, and complete all mandated tasks on a daily basis. Knowledge of computers, maintenance of two Georgia DNR Microsoft Excel spreadsheets, and keeping a detailed daily journal are essential to the program. Raccoon trapping and selective hog hunting may be required and observed by the interns. Modern housing, tuition at Georgia Southern University, funds for food, and training are provided. The successful applicants must be capable of responsible, independent work, maintain a clean, safe work environment, and be able to positively interact with other programs and persons on St. Catherines Island.

Active role modeling of integrated science is provided as teacher-interns learn conservation skills, processing skills, field triage, and apply critical thinking in the field in an exceptional hands-on, real-world conservation project.

Gale A. Bishop
Director, South Dakota Museum of Geology and Paleontology
South Dakota School of Mines and Technology
Rapid City, SD 57701
Gale.Bishop@sdsmt.edu

The South Dakota Museum of Geology and Paleontology hopes to serve K-12 Educators by an active outreach program, an interpretive web site, and museum-based mini-classes and exercises.

Abstract

The Museum of Geology and Paleontology was established in 1885 to " collect, conserve, curate, interpret, exhibit, and disseminate knowledge of geologically significant objects and serve as the repository for such objects from South Dakota and the Northern Great Plains, as well as from other areas that enhance our understanding of South Dakota geology."

The Museum of Geology conserves approximately 300,000 geological artifacts consisting of major collections of minerals, rocks, and fossils, both vertebrate and invertebrate, and meteorites. Some 3200 of these are exhibited in the Museum Exhibit Hall and are available for public scrutiny. A new Museum web site has been developed (and will evolve) to enable Internet access to some of these specimens and other information about the Geology of South Dakota and Northern Great Plains, eventually including aspects of our specimen database. Three research libraries are present for use of students, staff, and visiting scientists.

The Museum serves local educational needs with an undergraduate program in Geology (specialization in Paleontology) with 20 students, a Masters of Science in Paleontology with 17 graduate students, and a Ph.D. in Geology with 3 students, all studying paleontologic resources of the Museum.

The Museum is attempting to serve the educational needs of all South Dakota constituents as far as possible within constraints of conservation of specimens and budgets. General educational needs are served through Museum tours, web-based learning, summer field expeditions, and direct outreach programs in the museum and classroom. A model of the expected evolution of this outreach is provided by the St. Catherines Island (Ga) Sea Turtle Program that has developed an integrated model for delivery of holistic science to learners of all ages.

Fire compartments are a central concept of landscape-level fire ecology. A fire compartment is a unit of the landscape having continuous fuel and no natural fire breaks, such that an ignition would be likely to burn the entire compartment barring changes in weather or fuel moisture. We hypothesized that presettlement (potential/natural) distributions of fire-dependent longleaf pine (Pinus palustris) communities could be accurately mapped using a new environmental variable, presettlement fire compartment size. We quantify the average fire probability index (AFPI) for any point within a fire compartment using topographic features and compartment size. GIS layers with watershed information were used with slope-class maps derived from DEMs to map fire compartments in the Uwharrie National Forest, North Carolina. The AFPI for points in this landscape was predicted using a GIS and an algorithm that included distances to firebreaks and prevailing wind direction during fire season. AFPI values were assigned to one of five topographic fire regime (TFR) classes, from class 1 (the most fire protected areas) to class 5 (the most fire exposed areas). TFR classes were comparatively assessed using 209 'witness trees', mapped in a GIS layer from county survey plats of the study area ca. 1700-1800. Trees were assigned to vegetation fire regime (VFR) classes based on species characteristics. The most fire refugial species were assigned to VFR class 1 and the most fire-dependent species were assigned to class 5. Correspondence between VFR and TFR classes was 86%. Our hypothesis that presettlement fire-dependent communities could be accurately mapped using fire compartment size was generally supported by our results. Our weighting scheme also appears to be realistic for this landscape. The AFPI for a particular site may be the most ecologically meaningful environmental variable for understanding and managing remnant natural areas to maintain original levels of biodiversity in fire-dependent landscapes.

Policies for Place Attachment: Forestry Initiatives and Aboriginal Communities in British Columbia
SOREN C. LARSEN, Georgia Southern University

This presentation examines recent forestry initiatives among Dakelh communities in the province's central interior, concentrating on the role of place in aboriginal forestry management. During the 1990s, British Columbia's New Democratic Party (NDP) sought to improve the chronic privations of resource-dependent and First Nations communities by implementing new policies in the forestry sector. For example, the Jobs and Timber Accord enabled local groups to lease, manage, and harvest large tracts of land known as community forests. Other policies encouraged the formation of public-private partnerships that generated locally owned sawmills and processing facilities. Frustrated by a lack of progress in the provincial treaty process, several First Nations communities have used these forestry initiatives to advance their own visions of economic and cultural revitalization. In the process, they have strengthened their relationships to place by harvesting and processing local forest resources. As their place attachments are intensified, they confront both internal and external complications. In particular, community members struggle over the meanings invested in their ancestral territories as they forge partnerships with non-native and non-local individuals and firms. Only recently have forestry scientists begun to debate the role of such place attachments in the sustainable development of forested land. In light of these debates, the aboriginal experience in British Columbia illustrates the interconnections between place identity and forest management as local communities implement policies originally designed to promote sustainable development.

Asteroid 4 Vesta is a target of the upcoming DAWN spacecraft mission under NASA's Discovery program. Experience gained from the NEAR mission demonstrates that a firm understanding of an asteroid's geology prior to the mission permits more sophisticated questions to be addressed during the mission. Our recent work shows that much can be learned about Vesta by studying genetically related asteroids in the Vesta region of the main belt.

The depth, width, and spectral placement of the 1- and 2-mm mafic silicate absorption features in the ground-based reflectance spectrum of 4 Vesta (the archetype V-class asteroid) indicate that orthopyroxene is a major phase in its surface mineralogy. Hubble Space Telescope observations confirmed albedo differences across Vesta's surface, and produced shape and topographic information about Vesta. Dynamical studies previously revealed that a family of mainbelt asteroids is associated with 4 Vesta. Taxonomic surveys have found numerous, smaller asteroids with Vesta-like 1-mm spectral absorption features.

Until recently, work on the surface mineralogy of Vesta was the definitive analysis for one of these V-class asteroids since no complete near-infrared spectrum of another V-type existed. The case for a Vesta-HED meteorite connection has a firm mineralogical foundation. Previou spectral data have suggested a link to additional V-class asteroids, but until now that supposed association had not been mineralogically tested.

Analysis of our near-infrared reflectance spectrum for asteroid 1929 Kollaa, which includes the critical 1- and 2-mm spectral absorption features, allowed us not only to determine that this mainbelt asteroid is a daughter of 4 Vesta, but also to constrain the location of its formation within Vesta and establish its connection to the cumulate eucrites. This is the first mineralogical link to be made between the HED meteorites and an asteroid other than Vesta, and between Vesta and another asteroid.

We recently obtained near-IR reflectance spectra for several additional Vesta region asteroids, including 3494 Purple Mountain. Reduction and analysis of these data are continuing and the results will allow us to apply a mineralogic (genetic) test to their possible connection with 4 Vesta and the HED meteorites.