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Volcanic Glass As A Paleoenvironmental Proxy: Comparing Preparation Methods On Ashes From The Lee Of The Cascade Range In Oregon, Usa, Tessa Boe Carlson

Dissertations and Theses

Deuterium ratios (δD) of hydrated volcanic glass have been used to reconstruct paleoenvironments, although the reliability and proper sample preparation protocol have been debated. In this study, hydrated volcanic ash samples from the lee of the Cascades were prepared using two separate methods. Method 1 involves sonicating and rinsing samples with hydrochloric acid (HCl) followed by hand-selection of glass shards (125-212µm). Method 2 requires hydrochloric acid (HCl) and hydrofluoric acid (HF) abrasion as well as heavy liquid separation of shards (70-150µm). Method 2 produced more consistent results with decreased intra-replicate variability in both water content (-0.92 wt. %) and deuterium …

A Theoretical And Experimental Examination Of Sodium Chloride Hydration, Debra Conway Modra

Dissertations and Theses

A Hitachi Hu 125C transmission electron microscope in which the standard specimen holder was replaced by an environmental cell was used to observe the hydration of sodium chloride crystals. To observe Kelvin curvature and solubility effects sodium chloride crystals which were 0.1u or smaller were of special interest. An electrohome video system attached to the electron microscope was used to record the sodium chloride hydration for subsequent particle measurement and viewing.

A theoretical model was also developed. Thermodynamic properties such as the Kelvin curvature and solubility effects were considered as well as the kinetic expressions for salt dissolution/recrystalization and water …