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Full-Text Articles in Physical Sciences and Mathematics

An Investigation Into Transitions In Clay Mineral Chemistry On Mars, Seth Gainey Aug 2015

An Investigation Into Transitions In Clay Mineral Chemistry On Mars, Seth Gainey

UNLV Theses, Dissertations, Professional Papers, and Capstones

This dissertation is comprised of three studies investigating clay mineralogy on, or near the martian surface, with an introductory chapter, introducing and linking the three studies. Chapter two is on the subject of clay mineral synthesis, including Fe/Mg clay minerals which have been detected at multiple locations across the southern highlands. These Fe/Mg clay minerals have been previously interpreted as forming in anoxic/reducing environments, conducive to the preservation of organic matter. The results of this study suggest that the previous interpretation of Fe/Mg-rich clay as requiring anoxic/reducing conditions may not be accurate, as the minor presence of Mg (below what …


Use Of Esi-Fticr-Ms To Characterize Dissolved Organic Matter In Headwater Streams Draining Forest-Dominated And Pasture-Dominated Watersheds, Yuehan Lu, Xiaping Li, Rajaa Mesfioui, James E. Bauer, R. M. Chambers, Elizabeth A. Canuel, Patrick G. Hatcher Jan 2015

Use Of Esi-Fticr-Ms To Characterize Dissolved Organic Matter In Headwater Streams Draining Forest-Dominated And Pasture-Dominated Watersheds, Yuehan Lu, Xiaping Li, Rajaa Mesfioui, James E. Bauer, R. M. Chambers, Elizabeth A. Canuel, Patrick G. Hatcher

Chemistry & Biochemistry Faculty Publications

Electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (ESI-FTICR-MS) has proven to be a powerful technique revealing complexity and diversity of natural DOM molecules, but its application to DOM analysis in grazing-impacted agricultural systems remains scarce. In the present study, we presented a case study of using ESI-FTICR-MS in analyzing DOM from four headwater streams draining forest-or pasture-dominated watersheds in Virginia, USA. In all samples, most formulas were CHO compounds (71.8-87.9%), with other molecular series (CHOS, CHON, CHONS, and CHOP (N, S)) accounting for only minor fractions. All samples were dominated by molecules falling in the lignin-like region (H/C …