Section III: Earth & Atmospheric Sciences.
8:45 INVESTIGATION OF METAMORPHIC CONDITIONS ASSOCIATED WITH THE GROWTH OF CENTIMETER-SCALE GARNET PORPHYROBLASTS AT THE GARNET HILL LOCALITY, WEST-CENTRAL GEORGIA**, Nelson Spratt IV* and C.A. Berg, University of West Georgia, Carrollton, GA 30118. Samples collected from the Garnet Hill locality contain idiomorphic garnet porphyroblasts up to two centimeters in diameter that have grown in a fine-grained phyllitic matrix. This study is a preliminary assessment of the metamorphic conditions associated with the development of this texture, and an investigation of how changes in pressure, temperature, fluid composition, and/or deformation during garnet growth may be manifested in the internal textures and chemical zoning of these porphyroblasts. Thin-sections cut approximately through the centers of the large garnet porphyroblasts were oriented orthogonal to the dominant matrix foliation, and either parallel or orthogonal to the weakly-developed mineral stretching lineation in these samples in order to identify metamorphic mineral assemblages and deformational fabrics preserved in the matrix and within the garnet porphyroblasts themselves. Analysis on the SEM-EDS instrument at UWG will identify important accessory phases and microscopic inclusions and to determine the spatial distribution of inclusion assemblages. Chemical mapping using the SEM-EDS provides preliminary data on garnet chemistry and internal chemical zonation. Crystallographic orientation of subcrystals within the garnet porphyroblasts, the degree of development of low-energy grain boundaries, and deformationa! fabrics preserved within the matrix will be examined using electron backscatter diffraction (EBSD) mapping.
9:00 PRELIMINARY RESULTS FROM HIGH-RESOLUTION MAGNETIC SURVEY OVER LARAMIDE AND BASIN AND RANGE STRUCTURE, BIG BEND NATIONAL PARK, TEXAS, John Allison*, C. Parham* and C. Poppeliers, Augusta State University, Augusta, GA 30904. We present results of a ground-based magnetic survey of two Tertiary-aged intrusions in the northern portions of Big Bend National Park, TX. Ongoing field mapping of Cretaceous sedimentary rocks has identified numerous intrusions that appear to be cross cut by Laramide and post-Laramide deformation in the South Persimmon Gap Laccolith (SPGL) and Dagger Mountain areas. We use the results of several magnetic profiles to test hypothesis about fault/fold timing based on cross cutting NW-trending of these structures with the intrusions. The SPGL is crosscut by at least two NW-trending high-angle faults. Stratigraphic relationships suggest that the SPGL may be cross-cut by a large, Basin and Range normal fault to the east of the main outcrop, however, alluvium prevents direct observation. Pending isotopic age-dating of the intrusive rocks as well as modeled subsurface structure of the intrusions help to constrain the age and extent of faulting and folding in this area. Dagger Mountain is a large map-scale anticline south of the Dog Canyon area. Previous work suggests that the topographic expression of Dagger Mountain is due to purely structure deformation of the Cretaceous-aged rocks. However, an alternate hypothesis is that Dagger Mountain is cored by a map-scale intrusion of Tertiary aged rocks similar to those seen in nearby outcrops. Two magnetic profiles help to support the latter hypothesis.
9:15 MINERLOGY AND CRYSTALLIZATION SEQUENCE OF INCLUSIONS WITHIN TOPAZ CRYSTALS OF THE TOPAZ BEARING RHYOLITE OF TOPAZ MOUTNAIN, JUAB COUNTY, UTAH,** kIMBERLY E. Cook* and Curtis L. HoIIabaugh, Department of Geosciences, University of West Georgia, Carrollton, GA 30118. Topaz Mountain located in the Thomas Range of Juab County, Utah contains extensive F-rich rhyolite lava flows formed approximately 6.5 million years ago. The flow banding of the rhyolite provided pathways for the transportation of vapors and the crystallization of vapor phase minerals within vugs located along the distinctive bands. Over the years, several specimens were collected for the purpose of research at UWG. From the samples several topaz crystals were collected and analyzed. A series of orthogonal thin sections were created, examined under a polarizing microscope for initial mineral identification and then placed on a scanning electron microscope to create an elemental map of the inclusions within the topaz. Inclusions found within the topaz include quartz, bixbyite, and psuedobrookite. We hypothesize that a correlation exists between the crystallization of quartz and bixbyite. We plan to obtain a quantitative x-ray diffraction using the reference intensity ratio method (RIM)
to identify elemental compositions of the minerals in question, and create additional thin sections of topaz crystals in an attempt to verify this correlation.
9:30 EVIDENCE FOR DEEP EVAPORATION WITHIN SAND DUNES AND THE INABILITY OF NORMAL PRECIPITATION EVENTS TO RECHARGE GROUNDWATER AT THE GREAT SAND DUNES NATIONAL PARK & PRESERVE IN COLORADO, Dion Stewart (1) and Andrew Valdez (2), (1) Georgia Perimeter College, Atlanta, GA 30338 and (2) Great Sand Dunes National Park and Preserve, Mosca, CO 81146. A 1,000,000 [cm.sup.3] volume of water covering an area of 9.3 [m.sup.2] was forced to uniformly infiltrate an active sand dune over a 24-hour period. The infiltration of this non-saturated water slug, which simulated a maximum 11cm. precipitation event, was monitored for seven days by a chain of buried moisture sensors at depths of 0.2 m., 0.5 m., 1.2 m., 2.75 m. and 4.3 m. within a dune where the water table was approximately 10 m below the surface. A 3 by distributed slug of infiltration water, allowing the sensors to experience no lateral outflow to a depth of 2.75 m., and the deepest sensor should receive 92% of the initial water if infiltration losses were due solely to lateral flow. The hydraulic conductivity varied from a maximum of 1.4 m/day near the surface to 1.0 m/day at a depth of 1.2 m., well below the saturated value of 10 m/day. This slug of soil moisture was funicular in nature, coexisting with air in the pores during its movement through the vadose zone. The passage of this slug of soil moisture showed a 30% decline in soil moisture between 0.2 m and 0.5 m and an additional 30% decline between 0.5 m and 1.2 m. the slug of infiltrating of pendular water occurs at depths greater than 3 meter within the dunes and that infiltration from normal precipitation events will not reach the water table The source of pendular water in the vadose may relate to evaporation at the shallow water table.
9.45 CREATING A HISTORICAL STORM SURGE DATA WEB SITE, Andrew J. Maloof* and Rochelle F. Legaspi*, University of West Georgia, Carrollton, GA. Researchers of hurricane impacts often encounter roadblocks when trying to evaluate storm surge history. The National Hurricane Center's Tropical Cyclone Reports contain comprehensive information on each storm, including synoptic history, meterological statistics, casualties and damages, and the post-analysis best track (six-hourly positions and intensities) dating back only to 1958. Federal agencies, private companies, and academic institutions have unpublished reports for some storms but not for all; and especially not for older hurricanes. Access to reports is difficult, and even for archived storms the data is often sketchy at best. For early hurricanes a combination of lack of understanding of the importance, lack of reliable surveying devices, and the overwhelming need to concentrate on rescue and recovery efforts probably led to poor storm surge data. For more recent hurricanes, very precise storm surge measurements are available, but often there are not enough of them or they are in error. A georeferenced database is being created of all storm surge measurements in the southeastern United States. All data are established to reports, photos, and other pertinent documents. It is hoped that the database will provide the basis for statistical evaluation of the various factors impacting coastal storm surge. In addition, it will be a critical resource for numerical modelers who are in need of such data for model calibration and verification of predictive coastal flooding models. The web site is undergoing constant updating. The web address is www.stormsurgedatabase.org.
10.00 Section business meeting
10.30 HISTORICAL CHANGES OF GOULDS INLET, GEORGIA, FROM GEO-SPATIAL ANALYSIS OF AERIAL PHOTOGRAPHS, Rochelle Petruccelli*, University of West Georgia, Carrollton, GA 30118. Goulds Inlet is a relatively small Gerogia inlet running between St. Simons and Sea Islands. Typically, inlet dynamics cause adjacent shorelines to experience varying degrees of erosion and accretion as hydrographic. conditions vary seasonally or at longer temporal scales. Goulds Inlet, though seemingly stable, has historically migrated south, hugging the St. Simons shoreline, allowing the Sea Island spit to follow suit, building out towards the south. The relative persistence of the channel against St. Simons Island creates shoreline accretion/erosion processes driven by complex linkages between the movements of the ebb channel, asymmetry of the ebb-tidal delta, and migration of the swash bars. Georectified aerial photos of the study area spanning roughly sixty years (1942-2003) were used within ArcGIS to delineate the high-water line (HWL) shoreline, ebb delta shoals, and the middle of the inlet channel and stored as shapeflles. Measurements of spatial and temporal changes of these features were performed within ArcGIS using ArcToolbox and in-house scripts. Preliminary results of the shoreline change analyses suggest net long-term accretion along the adjacent shorelines. However, a small segment on the St. Simon's inlet shoulder was identified that has net long-term erosion (~ - 1.5 m/yr). This portion of the shoreline appears to be less influenced by the ebb delta morphology and more so with the position ebb channel's thalweg and periodic advance and retreat of the Sea Island spit. A few hundred meters south of this shoreline segment, net accretion is occurring along a "bulge" in the shoreline associated with inlet swash bar welding. Cursory inspection of the aerial photos suggests the shoreline position along this region also tends to fluctuate in response to the movement/orientation of the ebb channel and changes in ebb delta symmetry (~ +1 to 7 m/ yr). More aerial photos and historical maps are being added to the GIS database to better ascertain long and short-term trends.
10:45 CONTAMINANT TRENDS IN LAKE CORE SEDIMENTS OF LAKE PALMER AND LAKE HARRIET, MINNEAPOLIS, MN, Ellie L. Busse*, USGS Austin, TX 78754. Lake coring and paleolimnology have been used to better understand how water quality has changed within watersheds. This project focused on two lakes in Minneapolis, MN: Lake Palmer and Lake Harriet. Each lake has very different land usages and urban development impacting its watershed. Lake Palmer is composed of two lobes, referred to as the east and west lobe. The east lobe has a pristine watershed with no urban development; this lobe represents a "reference" lake. In contrast, the watershed of the west lobe has undergone rapid urban sprawl over the past 50 years, representing "new urban." Lake Harriet was urbanized in the early 20th century; this watershed represents "old urban". The two lakes are used in this study to compare the impact of different amounts and timing of urbanization. Lake cores were retrieved from Lake Harriet and both lobes of Lake Palmer in 1997. The deposited sediment was analyzed for organo-chlorine compounds (OCs), metals, radionuclides, and polycyclic aromatic hydrocarbons (PAHs) to investigate trends with land use and urbanization. The results demonstrate that water quality in Lake Harriet and the west lobe of Lake Palmer have been impacted by urban growth. Levels of DDT, PCBs, and lead increased with urbanization. The decrease in concentrations resulted from bans on leaded gasoline and use of DDT and PCBs. In contrast, concentrations of metals and chemicals in the east lobe of Palmer are low and unchanging, correlating to the lack of urbanization in the watershed.
11:00 CONTAMINATION POTENTIAL FOR CAVES IN THE SUWANNEE RIVER BASIN, FLORIDA **, Krystalynn Batts *, Valdosta State University, Valdosta, GA 31698. The Floridan Aquifer is one of the largest aquifers in the world making it a very valuable resource. The potential for contamination of this karstic aquifer is a study of great importance. The goal of this project is to analyze the vulnerability of caves in the Suwannee River Basin to various pollutants. Many potential means of contamination will be examined throughout this project. Land use practices, and distances from hazardous material and superfund sites have been evaluated using GIS in order to help determine the individual cave susceptibility. The depth to the cave is also being evaluated using GIS in order to help determine the vulnerability to contamination.
11:15 SPATIAL AND TEMPORAL CHANGES OF WETLAND AREAS IN THE COASTAL PLAINS REGION**, GA, John Ray*, Valdosta State University, Valdosta, GA 31698. Wetlands during the time periods of 1974, 1985, 1991, and 2001 are spatially analyzed through GIS (Geographic Information System) to determine the loss in wetlands. Areas of lost wetlands were further analyzed to determine the replacing land cover and percentages of land use/land cover taken over the wetlands are obtained. GIS was also used to analyze fragmentation of wetlands during this time period.
11:30 CONSTRUCTED WETLANDS: AN INVESTIGATION OF FILTRATION QUALITY AND EFFICIENCY**, Cameron G. Wolfe* and Curtis L Hollabaugh, Department of Geosciences. University of West Georgia, Carrollton, GA 30118. The United States Fish and Wildlife Service estimated in 2004 that there are 107.7 million acres of wetlands in the continental United States. The majority of these wetlands serve only as wildlife refuges, green space and unwanted areas for urbanization. Technologies utilizing wetlands as groundwater filters are becoming more prevalent outdating the process of land application of treated sewage. Constructed wetlands manufactured primarily to filter treated sewage also become natural habitats, green spaces and wildlife refuges for communities. Wetland sewage reclamation facilities are extremely versatile, able to service a small community of ten or less homes or able to provide enough drinking water for a county with a population over 250,000 several systems of constructed wetlands. As constructed wetlands become a more prominent treated sewage filtration system research must be done to improve filtration quality and efficiency. A model will be created designed after a small scale, freshwater constructed wetland and will be used for testing multiple parameters affecting the filtration quality and efficiency. The variables to be tested include grain size, roundness, soil type, and plants.
11:45 EVALUATION OF PROPOSED LONG-TERM SOLUTIONS FOR FUTURE GEORGIA DROUGHTS, Curtis L. Hollabaugh, University of West Georgia, Carrollton, GA 30118. Proposed long-term solutions for droughts during 2010 to 2050 include conservation/rain water harvesting, sewage to wetland to drinking water supply, well fields, local reservoirs, redefinition of Lake Lanier as a drinking water reservoir and West Point Lake as supply reservoir for lower Chattahoochee River, and aqueducts from Tennessee and Savannah Rivers to metro Atlanta. Each proposed solution is evaluated on a 0 to 10 scale with 0 least support and 10 maximum support. The evaluation is based on seven factors; (1) environmental issues, (2) effectiveness, (3) time required for implementation, (4) cost, and state support from (5) Georgia, (6) Alabama and (7) Florida. A perfect favorable score would be 70. It is proposed that water conservation coupled with small scale rain water harvesting has the highest score of 60. It is considered that resistance to conservation within Georgia is because of lack of its perceived effectiveness and need for more reservoirs. The least favorable (25) solution is the aqueduct plan to purchase and transport water from the Tennessee River near Chattanooga, Tennessee to metro Atlanta and water from the Savannah River to Athens, Georgia. Such a plan would have high environmental problems, be very expensive, take decades to complete, and require cooperation of Tennessee and South Carolina. Redefinitions of Lake Lanier (41) and West Point Lake (26) have unfavorable evaluation because of state opposition, the long time that would be required, and the uncertainty of the environmental effect.
RIDGE AND SWALE MICROTOPOGRAPHY IN THE ST. JOSEPH'S BAY STATE BUFFER PRESERVE**, Antonio Cano* and Donald M. Thieme, Valdosta State University, Valdosta, GA 31698. The St. Joseph's Bay State Buffer Preserve occupies over 50,000 km2 on several parcels of land in Gulf County, Florida. Ridge and swale features were mapped in the field at two very different locations within the preserve. The first location is along the bayshore south of the preserve office where the local relief is less than 70 cm and the land surface has been modified by construction of County Road 30A and private homes. The other field location was along the bayshore at Richardson Hammock on St. Joseph's Peninsula. Local relief there is more than 2 m and has been modified primarily by prehistoric Native American habitation which began at least 1500 years ago. Contour maps prepared using ArcGIS from field mapping with a Sokkia SET 600 total station show differences in spacing, orientation, and relief of features on the land surface at the two locations. The results of the study provide some indications of effects which tropical storms and other external factors have had in shaping the coast of the Florida panhandle.
COMMUNITY DEVELOPMENT ALONG HIGHWAY 41**, Stevee Edwards* and Michael G. Noll, Valdosta State University, Valdosta, GA 31698. Within the past couple decades, communities throughout Georgia have changed dramatically. Family owned stores, that once dominated Main Street USA, were driven to bankruptcy, as strip malls and retail giants like Wal-Mart conquered the popular shopping culture. More recently, a growing influx of Hispanic immigrants has reshuffled old neighborhoods, created new ones, and introduced a new bilingual reality to our state, ranging from store fronts and ATM machines, to church services and TV programs. This research focuses on yet another aspect of change, which began to transform parts of Georgia in the 1960s. Until then, US Highway 41 was a major route for people traveling north or south through the Peach State, and many businesses along its path depended on the regular flow of customers. By utilizing information from AAA and various Chambers of Commerce within the state, and by a careful analysis of its cultural landscapes, the community development along Highway 41 will be analyzed. For instance, the Dixie Motel in Adel was a popular place for travelers to stop, and other ventures in town, such as gas stations, retail stores and restaurants, too, profited from these overnight stays. However, when the Interstate system was introduced in the 1960s, communities along Highway 41 were irreversibly transformed, as businesses used to a steady flow of travelers, saw a decline in their number of customers, were forced to relocate to 1-75, or were closed down altogether. Thus, by focusing on Valdosta, Hahira, Adel, Tifton, Ashburn, Perry, and Macon, this poster will analyze and illustrate the effects 1-75 has had on communities along Highway 41.
A NEW OCCURRENCE OF BALD CYPRESS IN A PALEOSOL ON THE SILVER BLUFF FORMATION EXPOSED ON THE BEACH OF JEKYLL ISLAND, GA, Timothy M. Chowns, University of West Georgia, Carrollton, GA 30118. Jekyll Island consists of a nucleus of Pleistocene sands and clays deposited during the Silver Bluff highstand, questionably dated around 35-50 ka. This nucleus underlies most of the northern part of the island with the exception of the area north-east of Clam Creek, which is Holocene. The southern half of the island is a Holocene spit. Shoreline retreat and beach erosion has recently begun to expose the easternmost part of this Pleistocene core as a wave-cut platform. Coastal erosion is evidently accelerating as a consequence of rising sea levels and the beach is being starved of sand by a rip-rap sea wall. The top of the Pleistocene is characteristically capped by a thick iron-humate paleosol (spodosol), which currently forms pinnacles up to about 1 m high on the beach. Within this paleosol are the roots of at least six well preserved specimens of Bald Cypress (Taxodium distichum). An age of 3290 +/- 40 BP is indicated by 14C. Similar fossils with radiometric ages ranging from about 2.4-3.1 ka have been reported from various localities close to the coast, generally beneath Holocene marsh. Apparently, freshwater cypress swamps were abundant immediately prior to the time the Silver Bluff deposits were inundated by the Holocene transgression. The age of these trees effectively dates the time the Holocene transgression first reached Jekyll Island.
Section III: Earth & Atmospheric Sciences
Science Center, Room 134
Donald Thieme, Presiding
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|Publication:||Georgia Journal of Science|
|Date:||Mar 22, 2009|
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