Emilia Torrellas, honors thesis, 2018. Relationship Between Precipitation and Stream Baseflow Isotopic Signatures in Charlotte, NC Urban Forest Streams.
Relationship Between Precipitation and Stream Baseflow Isotopic Signatures in Charlotte, NC Urban Forest Streams
Naturally-occurring chromium and vanadium in Charlotte Terrane rocks: A source of trace elements to groundwater?
Geochemical evolution of the Critical Zone across variable time scales informs concentration-discharge relationships: Jemez River Basin Critical Zone Observatory
McIntosh, J.C., Schaumberg, C., Perdrial, J., Harpold, A., Vázquez-Ortega, A., Rasmussen, C., Vinson, D., Zapata-Rios, X., Brooks, P.D., Meixner, T., Pelletier, J., Derry, L., and Chorover, J., 2017. Geochemical evolution of the Critical Zone across variable time scales informs concentration-discharge relationships: Jemez River Basin Critical Zone Observatory. Water Resources Research, v. 53, p. 4169–4196. doi: 10.1002/2016WR019712.
Microbial methane from in situ biodegradation of coal and shale: A review and reevaluation of hydrogen and carbon isotope signatures
Vinson, D.S., Blair, N.E., Martini, A.M., Larter, S., Orem, W.H., and McIntosh, J.C., 2017. Microbial methane from in situ biodegradation of coal and shale: A review and reevaluation of hydrogen and carbon isotope signatures. Chemical Geology, v. 453, p. 128–145. doi: 10.1016/j.chemgeo.2017.01.027.
Presentation at Goldschmidt conference, Boston, August 12-18, 2018
Presentation at Goldschmidt conference, Boston, August 12-18, 2018:
Vinson D, Kiker T & Clinton S
Dissolved organic carbon and dissolved inorganic carbon along an urbanization gradient in Charlotte, North Carolina
Taylor Kiker, 2018, MS Thesis: Dissolved organic carbon and dissolved inorganic carbon along an urbanization gradient in Charlotte, North Carolina
Isotope hydrology and sustainability of High Plains groundwater in northeastern New Mexico
Victoria Blumenberg, 2018, MS Thesis: Isotope hydrology and sustainability of High Plains groundwater in northeastern New Mexico
Naturally-occurring boron in NC Coastal Plain groundwater: Contrast in sources or mobilization between confined Cretaceous and Pliocene aquifers
Presentation given at N.C. Water Resources Research Institute annual conference, March 18-19, 2015, Raleigh, NC (co-authors: Gary Dwyer and Avner Vengosh, Duke University)
Abstract:
As a natural trace element that is enriched in specific materials (e.g. wastewater, coal, marine clays), boron (B) has attracted interest in diverse natural and engineered environments. Boron has distinctive concentration in seawater (4.6 mg/L), imparting boron to marine-derived aquifer material such as the Atlantic Coastal Plain (ACP) of NC. In groundwater, expected behavior of B can yield (1) low B concentration and relatively high B-11/B-10 isotope ratio (adsorption) during salinization; or (2) high B concentration and relatively low B-11/B-10 (desorption) during freshening.
Naturally-occurring boron was examined in groundwater of the confined Cretaceous Upper and Lower Cape Fear aquifer of the ACP in NC. 14 monitoring wells were sampled from fresh, Na-bicarbonate to brackish Na-Cl water (Cl concentration 5-4680 mg/L). Several wells exhibited elevated boron (overall 0.4-6.6 mg/L). A large range of B-11/B-10 was observed (8.5‑51.8‰, as δ11B relative to NBS951 standard). Observed B/Cl ratios (0.003-0.255 mol/mol) are ~10‑1000 higher than seawater, implying B desorption from clays. However, observed groundwater δ11B >39‰ is consistent with the residual, unreacted B after adsorption occurs.
This pattern differs from the overlying Pliocene Yorktown aquifer, in which groundwater δ11B (20.9‑34.7‰) is consistent with desorption of seawater-derived B having δ11B of about 39‰ (Vinson et al. 2011, Hydrogeology Journal, v. 19 p. 981). In the Cape Fear, the pattern of B concentration vs. δ11B could indicate: (1) episodes of partial adsorption and desorption have disrupted the boron isotope mass balance; and/or (2) the boron originally adsorbed to clays had δ11B >39‰ (e.g. marine brine).