PhD, University of Cincinnati, 2018, Arts and Sciences: Geology

Plant wax hydrogen isotopes (dDwax) are important archives of water isotopes in the geologic past. Plant waxes are common in lacustrine sediments, providing widely distributed terrestrial records of hydrologic change in locations where other water isotope proxies (e.g., ice sheets, cave deposits) do not exist. However, application of dDwax to reconstruct past precipitation hydrogen isotopes (dDp) is subject to uncertainties resulting from modification of original water isotope signals in plants and sediments. This dissertation addresses several of these uncertainties through a series of studies that identify controls on this proxy system at increasing spatial scales, from individual plants to a single bog catchment to a regional survey of multiple lake catchments. Chapter 2 examines the seasonal timing of leaf wax production for two commonly used paleohydrology proxies, n-alkanes and n-alkanoic acids. The goals of this project are to constrain the drivers of seasonal dDwax variability among tree species and to determine whether leaf waxes in temperate forests record seasonally-biased precipitation. This study monitors the dD of environmental and plant waters and resulting leaf waxes as they evolve over a growing season from bud break to leaf fall at Brown's Lake Bog (BLB), Ohio, USA. This is the first study to track seasonal changes in both n-alkanes and n-alkanoic acids, and offers novel insight into systematic differences in water isotope fractionation and the timing, duration and amount of wax production between compound classes. Chapter 3 compares the abundance, molecular distribution and isotopic composition (dD and d13C) of n-alkanes and n-alkanoic acids in bog sediments with all major plant species growing in the catchment of BLB. This project aims to identify factors that influence the integration of leaf waxes from source (plants) to sink (sediments) in a single catchment. Results of this study offer insight into sediment bias toward particular plant (open full item for complete abstract)

Committee: Aaron Diefendorf Ph.D. (Committee Chair); Brooke Crowley Ph.D. (Committee Member); Thomas Lowell Ph.D. (Committee Member); Broxton W. Bird Ph.D. (Committee Member); Dylan Ward Ph.D. (Committee Member) Subjects: Geochemistry

PhD, University of Cincinnati, 2017, Arts and Sciences: Geology

Long-chain leaf wax carbon (δ13;Cwax) and hydrogen (δDwax) isotopic compositions in geologic archives are important tools for assessing Earth's climate perturbations through time as they record vegetation and hydrologic conditions during plant growth, respectively. Interpreting sedimentary leaf wax isotopes requires modern calibration studies to identify and constrain vegetation and climate controls on leaf waxes and their carbon and hydrogen isotopes. Calibrations have been carried out for numerous sites worldwide to characterize the biological and environmental controls on leaf wax isotopes. However, uncertainties still exist including i) seasonal and canopy controls on (δ13;Cwax) values, and ii) integration and transport of leaf waxes from catchment to sediment sink. This lack of information confounds interpretations of leaf wax isotopes in geologic archives. In this dissertation, I present three related research projects that address uncertainties in forest-level (δ13;Cwax) variations to basin-level leaf wax integration to paleoclimate applications. In the first study (Chapter 2), I identified and quantified temporal and canopy variation in n-alkane (δ13;C values (δ13;Calk) from buds to leaves among different tree species in a single temperate deciduous forest. I then constrained how canopy height and openness affect n-alkane production and(δ13;Calk) values. The results from seasonal and canopy variations were then compared to leaf litter (δ13;Calk) values to verify if canopy leaves dominate the leaf litter as commonly assumed. In the second study (Chapter 3), I constrained controls on integration and transport of leaf waxes from Mississippi River Basin (MRB) catchment to the Gulf of Mexico (GOM) using GIS-enabled mixing model. Spatial distribution of carbon and hydrogen leaf wax isotopes (i.e. isoscapes) were developed in the MRB for the Holocene without human interferences removed. Production and transport parameters such as runoff, net primary productivit (open full item for complete abstract)

Committee: Aaron Diefendorf Ph.D. (Committee Chair); Brooke Crowley Ph.D. (Committee Member); Heather Graham Ph.D. (Committee Member); Thomas Lowell Ph.D. (Committee Member); Yurena Yanes Ph.D. (Committee Member) Subjects: Paleoclimate Science

Master of Science, University of Akron, 2012, Geology

Shoveleater Cave of the Hellhole System is located in Germany Valley, Pendleton County, West Virginia. The Wills Mountain Anticline is breached here, exposing Ordovician limestones. Although currently dry, Shoveleater Cave retains evidence of its genesis and history that can help develop a thorough understanding of karst, both past and present in Germany Valley. This study investigated structural controls of cave formation, present day hydrology, and paleohydrology. It was hypothesized that the development of the vertical shafts of Shoveleater Cave is controlled by fracturing of the rock that hosts the cave. This was explored by comparing the locations of shafts with fractures measured in the field or found through aerial photography interpretation. Shafts coincided with fracturing in two cases. Bedding and fracture measurements taken in and above the cave were compared to the orientations of cave passages. Statistically, two times more passage length was bedding-controlled than fracture-controlled. It was hypothesized that the existence of a kink in the Wills Mountain Anticline is responsible for fracturing the rock that hosts Shoveleater Cave. Bedding was measured along the anticline limbs to determine if a bend in the ridge line of North Fork Mountain, which bounds Germany Valley to the east, was evidence of a structural kink in the anticline. A minor change in bedding strike near the bend did not account for the 9° horizontal bend in the ridge line. Instead, a slight change in bedding strike and dip, due to the anticline plunging at both ends of Germany Valley, caused inconsistent erosion of the ridge line. Dip was steeper to the north, possibly resulting in differential weathering along the ridge line. The present hydrology in Germany Valley precludes Shoveleater Cave from receiving allogenic recharge. Surface streams sink into swallets feeding Silent Stream of Hellhole prior to reaching Shoveleater Cave. It was hypothesized that paleo water flow in the souther (open full item for complete abstract)

Committee: Ira Sasowsky Dr. (Advisor); John Senko Dr. (Committee Member); W. Ashley Griffith Dr. (Committee Member) Subjects: Geology; Geomorphology

Master of Science, University of Akron, 2012, Geology

Caves have the potential to provide insight to landscape evolution. Defining the genesis of the cave in the context of the broader hydrologic system, and dating cave growth, can accomplish this. The present study employed paleohydrologic and sediment studies to construct a relationship between discontinuous sediments preserved in a cave, and paleomagnetic analysis for dating. Haynes Cave exists in the Big Levels karstified limestone upland, in the Appalachian Plateaus physiographic province in Monroe County, West Virginia. The entrance is at 670 m. Current local base level is Second Creek, which has steeply incised to 530 m. The cave is currently dry, with insignificant present catchment. The cave passage shape indicates initial development was phreatic, followed by further development from vadose recharge. The main branch of the cave has two stacked and intertwining levels. These passages trend north-south and end in a gravel choke to the south. A small, sinuous lower level (the Basement) runs 400 m northeast, and 15 m below, the middle section of the main branch. There are multiple episodes of sedimentation and incision. Bedrock scallops and pebble imbrications indicate that drainage in the main level was northwards (toward the present entrance). Flow originated from allochthonous sources that fed into the southern end of the cave, and discharged from a paleospring into Second Creek through the main branch at the northern end of the cave. The recharge area is uncertain, but might have been an upstream reach of Second Creek, or via large sinkholes that are developed on an unnamed major fracture trace. Drainage in the Basement was northeastward, and was fed by vadose water from the main branch. The minimum age of the sediments in the cave exceeds 990 ka, yielding a maximum incision rate of 0.14 m/ka for Second Creek. This rate is much higher than rates calculated in other parts of the Appalachians. Using those rates and elevation above the present base level suggest (open full item for complete abstract)

Committee: Ira Sasowsky Dr. (Advisor); John Peck Dr. (Committee Member); W. Ashley Griffith Dr. (Committee Member) Subjects: Geology; Geomorphology

Master of Science, University of Akron, 2010, Geology

The West African monsoon is an important component of the Earth's atmospheric system because the monsoon redistributes heat and moisture in the tropics. In addition, West Africa is densely populated and has an ecosystem controlled by monsoon rainfall. Therefore, a better understanding of past monsoon variability has social relevance. The hydrologically-closed Lake Bosumtwi occupies a 1.07 Ma meteorite impact crater located in Ghana, West Africa. The lake lies beneath the seasonal passage of the ITCZ; hence, the lake's sediment record is well suited for studies of past monsoon variability. This thesis research identifies down-core mineralogic variations in a 291-m long sediment core from Lake Bosumtwi using X-Ray diffraction (XRD). Scanning electron microscope and calcium carbonate measurements were also performed to support the XRD results. X-ray diffraction measurements were performed on more than 410 samples at a 1-meter spacing; and at a resolution of 50-cm or less, above 67 m.Lake Bosumtwi mineralogy is shown to provide an interpretable proxy of paleoclimate variability. During several well-documented lake level lowstands (at 3.2 kyr and 16.3 to 20 kyr when the lake was 30 m and 60 m below the present lake level, respectively), increases in calcite, Mg-calcite and total carbonate content indicate carbonate precipitation by evaporative enhancement during arid climate conditions. During the lake-level highstand of the Holocene African Humid Period, calcite is completely absent and Mg-calcite is present in low abundance reflecting the diluted lake water during this moist climate period. In general, detrital (i.e., quartz), carbonate (i.e., calcite, Mg-calcite, ankerite, dolomite) and diagenetic (i.e., analcime) minerals are more abundant during times of low boreal summer insolation when the West Africa summer monsoon is weak. The source of quartz to Lake Bosumtwi include both the bedrock of the crater walls and wind-blown dust from the Sahel, both of which increase (open full item for complete abstract)

Committee: John A. Peck Dr. (Advisor) Subjects: Environmental Science; Geology; Mineralogy; Oceanography

Master of Science, University of Akron, 2007, Geology

Hellhole is an extensive (32 kilometer) cave system developed within Germany Valley (Pendleton County, West Virginia) on the flank of the Wills Mountain Anticline. The area can be described as a mature karst aquifer on the transitional margin of the Appalachian Plateau and Valley and Ridge physiographic provinces. Hellhole is the most extensive and deepest (158 meters) of several mapped caves in the area (others include Memorial Day Cave and Schoolhouse Cave). The upper bounding lithology is the McGlone Limestone. The cave penetrates through the Big Valley Formation and in to the New Market Limestone, a high purity unit that is mined locally. Faulting and folding are prominently exposed in several passages, but did not affect passage development in a noticeable way. The entrance sinkhole opens in to a large room, however, the morphology of the room suggests that the room formed the entrance by the intersection of passages followed by a vertical shaft intersecting from the surface. Passage orientation and strike of the bedrock are nearly identical (N25°E). Lower passages are generally down dip from upper (older) passages. Cave sediment and paleomagnetic analysis reveals that the minimum age of sediments analyzed are 1.070 million years old. Three hundred measurements of wall scallops show that paleowaters in the Western section flowed southwest (1.1 cubic meters per second). Paleoflow from the Southern portion of the cave flowed northward (0.94 meters cubic meters per second), and flow in the Northern section flowed southward (1.0 cubic meters per second). Most passages are 50 to 100 meters below the present land surface. Most of the cave appears to have formed under phreatic conditions, but the presence of thick clastic sediments in some locations attests to vadose invasion.

Committee: Ira Sasowsky (Advisor) Subjects: Geology