▼ Ground water flow and contaminant transport patterns are largely controlled by the distribution of high- and low-permeability sediments. Therefore, an accurate description of the aquifer architecture is paramount to producing a representative ground water model. Models of contaminant fate and transport in the aquifer near Woburn, Massachusetts, have previously been created by others using a deterministic approach. As a complement to these prior studies, the proportions, geometry, and juxtaposition of the different lithofacies of the aquifer were statistically characterized for developing stochastic models for the aquifer system. The descriptions of lithology from boreholes were separated into eleven categories based primarily on grain size. Hydraulic conductivity values were available for some of the categories and their frequency distributions were analyzed. However, it was not possible to conclusively divide the categories into facies based on permeability because of the overlap in the values. As a result, three classifications (termed A, B, and C) were devised to explore the effect of different classifications. The classifications were designed to represent both the worst- and best-case scenarios with respect to the volumetric proportion of low-permeability facies. In each classification, the study area was divided into three sections: the northern section, the central section, and the southern section. The proportion of low-permeability facies was found to be highest in northern section and lowest in central section. The vertical range of the low-permeability facies was characterized using the transition probability models while the variogram model characterized the lateral range of the low-permeability facies. The results of the stochastic characterization were utilized with a sequential indicator simulator code to produce visualizations under each classification. Using previous results of Ritzi et al., (2000) from transport studies of contamination in simulations of areas similar to this study, an assessment of the likelihood of contamination still residing in the aquifer was made. Ritzi et al. (2000) found that residence time for contamination that encountered low-permeability facies was several orders several orders of magnitude greater than the residence time for contamination that did not encounter low-permeability facies. In addition, they demonstrated that the probability of contamination entering the low-permeability regions increased as the proportion of low-permeability facies increased. Using these results, an estimate of the probability that contamination encountered low-permeability regions was made for each section. The results indicate that the section with the highest proportion of low-permeability facies, the northern section, would be the most likely to still contain contamination while the central section, which had the lowest proportion, would have the least likelihood. Thus, the aquifer may appear to be clean while contamination still persists in small proportions in the low-permeability facies. Over time, contamination could leach out of the northern section and migrate toward the lower regions. Remediation would then have to continue indefinitely if contamination is to be fully removed from the area. Advisors/Committee Members: Ritzi, Robert.

▼ This research was undertaken to determine the amount of time between transgressive and regressive sequences. One of the methods used to determine the amount of missing time in an unconformity is the 87Sr / 86Sr ratio. The 87Sr / 86Sr ratio will be high around brackish and freshwater environments while it will be lower in open marine conditions. Limestones and their constituent parts are susceptible to diagenetic processes that can contaminate or obliterate isotope values contained within the rocks. The purpose of this research was to discover if reliable isotope information could be pulled from Pennsylvanian aged shark teeth. Nine teeth from the shark, Petalodus ohioensis, were analyzed to find the value of the 87Sr / 86Sr ratio contained within the teeth. The values of the ratio from the teeth were found to be much higher than what was expected. Contamination was thought to be the cause behind the high ratio values. From the literature, P. ohioensis was thought to be an open marine dwelling shark. The remains of P. ohioensis have been found in rocks interpreted to be of marine origin. The high values found in teeth were similar to the values found in brackish and freshwater environments. The limestones the teeth were found in, however, showed a 87Sr / 86Sr ratio that matched open marine conditions. The Calcite in the limestones is more susceptible to alteration than the Apatite that composes the teeth. So contamination of the ratio in the teeth does not appear to be the cause of the higher than expected values. If the limestones had not been altered then the teeth should have not been altered. Research was then conducted into shark evolutionary history to see if the high values could be explained by brackish / freshwater tolerant sharks. If P. ohioensis lived in these conditions rather than open ocean, it would explain the values found in its teeth. This researcher found that several modern species of shark could tolerate freshwater habitats and that some of the ancestors of these sharks were freshwater dwelling as well. It was then found that P. ohioensis was related to the lineage of sharks that also contained the brackish / freshwater tolerant sharks. The conclusions reached by this research indicate that the literature has the habitat of P. ohioensis wrong and that it was indeed a brackish / freshwater tolerant species of shark. Advisors/Committee Members: Slattery, William.

▼ Hurley, Angela Lorraine. M.S., Department of Geological Sciences, Wright State University, 2003. Identification of Gypsy Moth Defoliation in Ohio Using Landsat Data. The gypsy moth is one of the most devastating forest pests in North America. In late spring, gypsy moth larvae hatch from eggs laid the previous summer. During the next forty days, tens of thousands of these caterpillars eat up to one square foot of foliage each. The gypsy moth has established populations in several states, and dangerously fast-growing populations in several others. The state of Ohio is a critical area in the suppression of the gypsy moth because the front of gypsy moth advance passes through the state. Besides diminishing the aesthetic value of Ohio’s forests, gypsy moths also cause substantial economic damage to the Ohio timber industry, which is estimated to be a $7 billion per year industry. The Ohio Department of Agriculture currently uses aerial sketchmapping each year to assess the damage done by the gypsy moth. This procedure is difficult, time-consuming, and somewhat imprecise. The results obtained from Landsat 5 and Landsat 7 data can be compared to locations determined by aerial sketchmapping to locate gypsy moth infestations in Ohio. Since vegetation reflects infrared light and absorbs visible light, the health of vegetation can be assessed using a haze-adjusted ratio of Landsat spectral band 4 (near-infrared) to Landsat spectral band 3 (visible red). To determine the change that has occurred between two dates, the ratio values from two dates are subtracted. To identify change that has been caused by the gypsy moth, an area should exhibit defoliation between early June and late June and subsequent refoliation between late June and late July. This type of change results in large positive ratio subtraction values between early June and late June and large negative ratio subtraction values between late June and late July. Pixels that exhibit these attributes are candidates for locations of gypsy moth damage. These ratio subtraction values are further analyzed using change vector analysis to more effectively isolate areas where change has been caused by the gypsy moth. The use of three frames to analyze both defoliation and subsequent refoliation results in a stronger, less ambiguous signal of gypsy moth damage and pinpoints the locations of the most severe defoliation. The most severe defoliation often marks the location of egg masses. Although the use of three frames reduces the ambiguity caused by agricultural anomolies, this procedure also detects areas with significant wild grapevine infestations. Advisors/Committee Members: Watts, Doyle R.

▼ A distinct sequence of orange-brown, fossiliferous grainstones with interbedded blue mudstones exists in the upper portion of the Silurian-aged (Llandoverian) Brassfield Formation exposure at Oakes Quarry Park, Fairborn, Ohio. The unit is locally referred to as the cephalopod marker bed as it can be easily identified and is continuous throughout the quarry. The unit varies considerably in thickness (0.3m-0.9m) and contains a variety of sedimentary structures and fossils indicative of a warm, shallow marine environment subject to wave action. Dominant fossils within the unit include echinoderms, cephalopods, bryozoans, abraded mollusks, gastropods, brachiopods, and trilobites. Less-common fossil organisms within the unit include ostracodes, foraminifera, algae, and stromatoporoids. Mollusk chambers are commonly filled with micrite that contain traces of microbial life, including cement in the shape of bacterial filaments and micropeloids. Samples of the cephalopod marker bed were taken in a vertical sequence at two locations and from several locations along a north-south transect. Thin-sections were created from the samples; these were then point-counted using 300 counts to attain a quantitative analysis of the rock composition. Fossil abundance and diversity increases from the bottom to the top of the sequence and lateral variations within the top two, most-fossiliferous layers were also observed. Petrographic analysis of the cephalopod marker bed revealed that on average, bioclasts represent ~75% of the rock volume, cement is the next most-abundant constituent, and dolomite composes ~9% of the the rock volume. Dolomitization is preferential: it occurs most often in micrite within mollusk shells and might be driven by microbial processes; skeletal grain replacement occurs most easily within bryozoans. Advisors/Committee Members: Carney, Cindy K.

▼ Mohamud, Yussuf N. M.S., Department of Geological Sciences, Wright State University, 2007. Seasonal Variation in the Redox Zones and Biogeochemical Processes within the Constructed Wetland This research investigation focuses on the vertical distribution of dissolved inorganic species in the pore-water affected by redox processes and seasonal changes within a small constructed wetland located at the Wright-Patterson Air Force Base. This is a follow up study to an earlier investigation (Lach, 2004) at this site in 2003. Water samples were collected from influent, effluent and three layers of the constructed wetland through a network of nested piezometers in the vertical flow wetland from June 2005 to June 2006. Onsite analysis of temperature, pH and conductivity were carried out onsite. Major anions and cations were measured by ion chromatography and ferrous iron was analyzed by spectrophotometer. In addition, the alkalinity titration was conducted. The results of this research indicate a strong likelihood of anaerobic processes such as nitrate, Fe(III) and sulfate reduction in lower and middle layers of the constructed wetland, and a potential for oxidative processes within the upper layer of the wetland. The efficiency of this system in reducing or oxidizing redox-sensitive species(electron acceptors) is affected by factors including temperature, vegetation and availability of electron donors. Advisors/Committee Members: Agrawal, Abinash.

▼ The reprocessing of the WSU2002 seismic line indicates the presence of a Precambrian half-graben. Also observed through this reprocessing is the possible presence of Paleozoic structures. Although Paleozoic features have been interpreted, variations in glacial drift thickness evidenced by glacial drift maps also may have contributed to a lower quality of stacked section in comparison to other seismic lines. WSU2002 was originally processed by Lauren Geophysical. The Lauren processing resulted in an image that was of much lower quality than corresponding seismic lines. The Lauren Geophysical processed section revealed many horizontal Paleozoic reflections, with no prominent reflectors beneath the Paleozoic. This prompted a study to be done to reprocess the data and determine if other reflections could be found. As a result of the processing undertaken in this study new reflectors have been found beneath the Paleozoic reflections. There are multiple interpretations of the sub-Paleozoic reflections which lead to a half-graben interpretation. Also new in this study is topography in the usually flat lying Paleozoic reflections. A low coherency in reflections is assumed to be the result of glacial drift thickness variations. At one point in the lower Paleozoic reflections is interpreted above a reactivated fault. This anticline could also be the result of variations in glacial drift. Advisors/Committee Members: Hauser, Ernest.

▼ Zerkel, Brent M.S., Department of Earth and Environmental Sciences, Wright State University, 2007. Geophysical Reconnaissance of Karst Features Associated With Sinkholes on the Antioch University Campus in Yellow Springs, Ohio: Western Area Antioch University is located in Yellow Springs, OH. This study was conducted on the Antioch University Campus in the commons area and is concentrated on the area west of the easternmost sinkhole. The primary purpose of this study is to locate and identify buried anomalous karst features, such as joints and collapses that may be hazardous to nearby buildings on the Antioch University Campus. The secondary purposes of this study are to identify remaining features in the geophysical data that may be related to manmade structures, and to identify areas for future studies. It is known that an 8-inch steel sewer pipe runs east-west, and a 1-inch water line runs southeast-northwest, through the survey area. This steel sewer pipe and the water line may be the cause of two of the anomalous features discovered. There is, however, a feature in the ground penetrating radar data that seems to be related to the sinkholes in the study area. This feature is most likely a joint or collapse that is related to the karst topography in the study area. At least one sinkhole has been visible since 1975 when an Antioch University chemistry professor noticed the geological feature. Since that time the sinkholes have been filled in with rocks, dirt and similar materials. Preliminary electrical resistivity studies by Wright State University geophysics students in 2004 indicated a low resistivity anomalous feature in the subsurface. Five geophysical methods were used in this study to locate the extent of known anomalous features in the area. These five methods are: electrical resistivity, magnetic surveying, ground penetrating radar, electromagnetic surveying, and seismic refraction. Anomalous features were discovered with each method employed. Electrical resistivity produced low resistivity anomalous features in each line. These features vary in shape and size. Low resistivity features are found near the sinkholes. These features are most likely the result of a steal water line. The magnetic surveying method produced mixed results. Some magnetic anomalous features were discovered that correlate with other methods in this study, and some features did not correlate as well with the other methods. High amplitude responses in the ground penetrating radar data correlate very well with low resistivity anomalous features. Electromagnetic data correlates well with the known extent of the 8-inch steel sewer pipe, and the 1-inch steel water pipe. Seismic surveying produced excellent results in relation to the known sinkholes. Seismic energy was greatly attenuated at the middle sinkhole exactly where it was expected. This high attenuation is most likely the result of a joint in the bedrock, and not likely the result of the buried steel pipe. A steel pipe would create some impedance but not as much as displayed in the seismogram. The seismic attenuation found near the middle sinkhole is found in the same location as a probable collapse feature in the GPR data, a low resistivity anomalous feature in the resistivity data, an anomalous feature in the magnetic data, and an anomalous feature in the electromagnetic data. Advisors/Committee Members: Hauser, Ernest.