Record Details
Deconvolving the sedimentary phases of barium using flow-through time-resolved analysis
ScholarsArchive at Oregon State University
| Field | Value |
|---|---|
| Title | Deconvolving the sedimentary phases of barium using flow-through time-resolved analysis |
| Names |
Hsieh, Chih-Ting
(creator) Torres, Marta E. (advisor) Klinkhammer, Gary . (advisor) |
| Date Issued | 2009-06-26T17:27:24Z (iso8601) |
| Note | Graduation date: 2010 |
| Abstract | The distribution of barite (BaSO₄) in marine sediments has long been studied as a proxy for paleoproductivity. While pure barite is known to be a stable mineral in oxic sediments, it is also known that variations in the Sr/Ba ratio influence its solubility and liability during early diagenesis. To extract this information we developed Flow-Through Time-Resolved Analysis (FT-TRA) technique coupled with Inductively Coupled Plasma Optical Emission Spectroscopy (ICP-OES) to continuously monitor the dissolution process using sequential leaching with deionized water (DIW), acidic acid (HNO₃), acidic hydroxylamine (NH₂OH) and diethylene triamine pentaacetic acid (DTPA) at controlled flow rate and temperature. We applied this technique to the analyses of barite samples and sediments from two contrasting basins in the California borderlands. To further understand various barium-carrying phases we analyzed foraminifera recovered from core tops from various locations around the world, using FT-TRA coupled with Inductively Coupled Plasma Mass Spectrometry. Combined with available pore water data, our results provide a set of data that illuminates the nature (e.g. barite, carbonate, oxyhydroxide) and composition (e.g. relative concentrations of Sr, Ba and Ca) of barium-carrying phases to the sediment. We found the presence of a barium-carrying carbonate phase, hitherto unrecognized, which is present both as disseminated carbonates in the sediment as well as overgrowths in foraminifera. This phase has various compositions, but in general contains significantly more barium than biogenic carbonate, and may be responsible or early diagenetic remobilization of barium as the pH of the sediment is lowered during oxic respiration. The analytical technique and the results presented in this thesis provide the foundation for further investigations that can be used to constrain the barium geochemistry so as to fully exploit its application in a wide realm of studies. |
| Genre | Thesis/Dissertation |
| Topic | barite |
| Identifier | http://hdl.handle.net/1957/11941 |
