Over 700 km of industry seismic reflection data in the central Appalachians were reprocessed using both conventional and newly developed processing schemes. A new processing sequence, called dip projection, is introduced. The technique projects crooked-line processed CMPs onto a straight line oriented in the general dip direction for the area. The new stacked sections more closely approximate a dip line and hence are more migration-friendly and interpretable than the crooked-line stacks. Methods of determining the lateral continuity of subsurface density contrasts were also applied to gravity data from the study area. Known collectively as potential field attributes, the analytic signal, the tilt angle, and the gradient of the tilt angle (the potential field wavenumber ) proved valuable in the analysis of the gravity data. Comparison of reflection seismic data from the southern and central Appalachians revealed a dichotomy of seismic reflectivity from east to west. A highly reflective crust beneath the Piedmont in both the central and southern Appalachians contrasts with a general lack of reflectivity beneath the Blue Ridge and Valley and Ridge provinces where coherent reflections are restricted to the upper 3-4 seconds of the data. This difference in reflectivity is interpreted as a fundamental difference in the location and orientation of preexisting zones of weakness between the different crustal regions with respect to the tectonic events affecting the Appalachians since the early Paleozoic. The combination of the results of new methods of seismic and potential fields processing with deep well and geologic information allowed the lateral continuity of two major structures in the central Appalachians to be examined. The Blue Ridge in Virginia was found to overly a duplex of Cambrian-Ordovician carbonates formed in response to stresses during the Alleghanian Orogeny. A large thrust sheet of similar carbonate rocks was interpreted beneath the Nittany Anticlinorium in West Virginia. To the south in Virginia, this thrust sheet is replaced by imbrication of the carbonate package. The change in structural style may be related to the existence of a lateral ramp or it may reflect the overall change in structural style from the central to southern Appalachians. / Ph. D.

The rocks of the Appalachian orogen are world-class examples of collisional and extensional tectonics, where multiple episodes of mountain building and rifting from the pre-Cambrian to the present are preserved in the geologic record. These orogenic events produced plutonic rocks, which can be used as probes of the thermal state of the source region. SIMS (secondary ion mass spectrometry) U/Pb ages of zircons were obtained for ten plutons (Leatherwood, Rich Acres, Melrose, Buckingham, Diana Mills, Columbia, Poore Creek, Green Springs, Lahore and Ellisville) within Virginia. These plutons are distinct chemically, isotopically, and show an age distribution where felsic rocks are approximately 440 Ma, and Mafic rocks are approximately 430 Ma. Initial strontium isotopic ratios and bulk geochemical analyses were also performed. These analyses show the bimodal nature of magmatism within this region. In order to facilitate management of geologic data, including radiometric ages, strontium isotope initial ratios and major element geochemistry, a GIS based approach has been developed. Geospatially references sample locations, and associated attribute data allow for analysis of the data, and an assessment of the accuracy of field locations of plutons at both regional and local scales. The GIS based assessment of plutons also allows for the incorporation of other multidisciplinary databases to enhance analysis of regional and local geologic processes. Extending such coverage to the central Appalachians (distribution of lithotectonic belts, plutons, and their ages and compositions) will enable a rapid assessment of tectonic models. / Master of Science

Two threats to bats are especially pervasive in the central Appalachian Mountains of the eastern United States: a fungal disease called White-nose Syndrome (WNS) and wind energy development. White-nose Syndrome has caused the death of millions of bats in North America, and multiple hibernating bat species are affected in the central Appalachians. Wind energy is one of the most rapidly-growing energy sources in eastern United States, and bats are often killed when they fly near wind turbines. Fatality rates at wind turbines is highest in bat species that migrate instead of hibernate. There is limited data on bats during the autumn and spring seasons in the central Appalachian Mountains, and the impacts of WNS and wind energy development may be exacerbated during these seasons. Therefore, I sought to determine patterns and drivers of activity for hibernating bat species during autumn and spring around hibernacula. Similarly, I set out to determine patterns and drivers of activity for migratory bat species during autumn and spring along mountain ridgelines in the central Appalachians. Lastly, I searched for evidence of potential WNS-induced changes in the summer ecology of the once common northern long eared bat. This study can help elucidate patterns of bat activity during largely understudied seasons. Furthermore, it can provide useful information needed by land managers to implement actions that could help alleviate and/or avoid potential additive negative impacts on bat species with existing conservation concerns. / MS

Fire occurrence was widespread in the central Appalachians pre-European settlement due to Native American ignition and occasional lightning strikes, and continued through European settlement. During this time, low to mixed severity burns supported a suite of ecological communities that were fire adapted. In the mid-20th century, the frequency and intensity of fire decreased regionally, resulting in profound forest composition shifts. Land managers now are prioritizing prescribed fire as a restoration tool in current and transitioning fire dependent communities. However, it is unclear how the re-introduction of fire will affect bat community assemblages, particularly after the severe White-nose Syndrome related population declines of many cave-hibernating bat species. To address this concern we used acoustic detectors to sample bat activity levels in burned and unburned environments to examine habitat and temporal effects of fire on bat species in a repeatedly burned landscape. We found evidence for weak positive fire effects on the northern long-eared bat, Indiana bat, little brown bat, big brown bat/silver-haired bat group, high frequency phonic group, and total bat activity. Temporal effects of fire were only apparent for the big brown bat, where we observed a negative relationship between activity and time since fire. Additionally, historic wildfires may offer a suitable surrogate to assess long-term burn impacts on bats, which in turn can be used to better inform bat and prescribed fire relationships. To examine effects of historic fire on bats, we assessed bat presence using acoustic detections at 16 paired burned and unburned forest stands in Shenandoah National Park. Overall, we found few or mostly equivocal relationships of bat occupancy across species relative to burn condition or time since fire at SNP, indicating there is little evidence to support the concept that fire has a significant ecological effect on bats in this portion of the central Appalachians. Riparian areas are particularly important for bats, and serve as foraging and drinking areas, roost sites, and travel corridors. Because fire impacts dry upland and mesic riparian areas differently, is possible that fire will impact bats differently in burned and riparian habitats. To examine fire effects on bats in riparian and upland habitats, we used paired sampling to monitor bat activity in burned, unburned, riparian, and non-riparian areas. Burn and riparian variables had empirical support to explain activity of all bat species. However, coefficients for these species were small and confidence intervals overlapped zero indicating that differences between habitat configurations were marginal. Our results suggest bats have somewhat species-specific responses to fire that differ between upland and riparian habitats, but that large landscape level prescribed fire has a slightly positive to neutral impact on all bats species identified in at our study site post-fire suppression. / Master of Science

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