Academic Affiliation: Alfred University
Crystal grew up in New York City, New York. Her passion in geoscience began on a class camping trip in the 7th grade, where learning how flint can be used to start a fire sparked her interest in rocks and their applications. Since then she has focused her interests on soil science and hydrology. She hopes to contribute to these fields by filling in gaps and challenging discrepancies in existing research. For her RESESS project, Crystal is examining whether carbonates in fossilized soils from the Meade Basin, Kansas, have been chemically altered after original soil formation. Because these carbonates hold clues about past environmental conditions, her results will be combined with other data to help interpret environmental impacts on the evolution of rodents in the region.
2015- Detection of Diagenesis in Paleosol Carbonate Nodules Using Optical and Cathodoluminescence Microscopy
This study is part of a project evaluating the environmental conditions that affected the evolution of rodent fauna in the Meade Basin, Kansas during the Miocene-Pleistocene. Prior to this study, a suite of isotopic analyses was measured in paleosol carbonates that were previously collected from the region. The stable isotopic values of these pedogenic carbonates can be used to track changes in the relative abundance of plants that used C3 photosynthetic pathway versus C4. However, diagenetic events may change the chemical composition of a carbonate’s isotopic signature, making the isotope values a potentially unreliable reflection of paleoclimatic conditions. To investigate this, we used Cathodoluminescence (CL) and optical microscopy to determine the extent of diagenetic alteration in carbonate nodules collected from the Meade Basin. The CL and petrographic images reveal a range in the extent of preservation and diagenesis throughout the samples. We placed each sample in one of three categories based on the degree of diagenetic fabrics present. The observed fabrics suggest some recrystallization from secondary fluids, likely groundwater. We also found paleoenvironmental proxies in the carbonate nodule samples that suggest that at least one sample formed in a shallow lacustrine environment, rather than in a paleosol. Overall, the addition of CL images to previous stable and clumped isotope analyses helps us to determine the diverse range of fluids (both original and secondary) that affected Meade Basin paleosol carbonates. These findings help us better interpret paleoenvironmental conditions in the region.
2016- Temporal Pattern of Naturally Occurring Methane Levels in Domestic Water Wells, Overlying the Marcellus Shale in New York
Increasing unconventional gas extraction, particularly in the Marcellus Shale, has led to concern over the risk of groundwater contamination from faulty well casings. However, since there is little data on baseline methane levels and natural methane variability prior to drilling, it is difficult to differentiate natural groundwater methane from methane caused by unconventional drilling.
To develop a time series of methane concentrations prior to unconventional drilling in the Marcellus Shale formation, we sampled methane in 137 domestic drinking water wells in the southern tier of New York, where drilling is currently banned, and then resampled 28 of the wells with the highest methane concentrations in 2014 and 2016. Methane concentrations in 2013, 2014 and 2016 were all positively correlated with one another, with correlation coefficients > 0.8. In all three years, >10% of observed methane concentrations (in the subsample of 26) were above warning levels (>10 mg/L).
To improve predictions of natural methane occurrence in New York, as well as regions with similar hydrogeology overlying the Marcellus shale, we also analyzed correlations between methane concentrations and two major aquifer characteristics coincident with methane presence: Na-rich water chemistry, and/or valleys. Although confined aquifers are closely related to the presence of methane, we were not able to explore aquifer confinement as a characteristic due to limited stratigraphic records at the well locations. Understanding the natural conditions favorable to methane occurrence will help identify the differences between methane migrations due to unconventional drilling versus natural occurrence.