Detection limits of CO₂in fluid inclusions using microthermometry and Raman spectroscopy and the spectroscopic characterization of CO₂

Simple item page
dc.contributor.authorRosso, Kevin M.en
dc.contributor.committeechairBodnar, Robert J.en
dc.contributor.committeechairZallen, Richard H.en
dc.contributor.committeechairHochella, Michael F. Jr.en
dc.contributor.departmentGeological Sciencesen
dc.date.accessioned2014-03-14T21:26:34Zen
dc.date.adate2009-01-05en
dc.date.available2014-03-14T21:26:34Zen
dc.date.issued1994en
dc.date.rdate2009-01-05en
dc.date.sdate2009-01-05en
dc.description.abstractIn many geologic environments, dominantly aqueous solutions contain low concentrations of CO₂. At ambient temperature, in fluid inclusions which trap these solutions, the typical phase assemblage consists of a CO₂-rich vapor (where P<sub>CO₂</sub> ≈ P<sub>internaI</sub>) and an aqueous phase containing dissolved salts and CO₂. In this study, the CO₂ minimum detection limits (MDLs) using microthermometry and laser Raman spectroscopy are established in terms of P<sub>CO₂</sub> using synthetic H₂O-CO₂ inclusions. The purpose of the microthermometric experiments was to examine the diagnostic CO₂ phase changes and determine the quantity of CO₂ necessary to result in observable solid CO₂ melting. The results of these experiments show that an observable solid CO₂ melting event requires P<sub>CO₂</sub> ≥ 45 bar at 25°C. The Raman spectroscopic detection limits were investigated using a multichannel Raman spectrometer. Because the Raman spectroscopic MDLs are a function of counts, the CO₂ MDLs were determined by collecting signal-to-noise ratios for both the upper and lower v₁-2v₂ bands as a function of CO₂ pressure (5-60 bars) and over a range of integration times and incident laser power to predict the optimal instrument settings. The resulting CO₂ MDLs are on the order of 1 bar for our instrument. The band splitting of the v₁-2v₂ diad as a function of CO₂ pressure was measured up to 500 bar at ambient temperature. The CO₂ pressures were converted to ρ<sub>CO₂</sub> and the results are given in terms of the frequency separation between the upper and lower bands. These results are compared to those of previous studies. An analysis of the estimated errors indicates that the technique can be used to determine CO₂ densities in fluid inclusions containing a homogenous, free CO₂ phase to a precision of approximately ± 0.02 g/cm³. The temperature dependence of the intensity ratio of the hot bands to the v₁-2v₂ diad was measured from 270 to 315 K. The close agreement between the calculated and observed results indicate that laser induced sample heating is not significant. The intensity ratio can be used to estimate the CO₂ temperature and, combined with the Raman density determination, allows calculation of the CO₂ pressure.en
dc.description.degreeMaster of Scienceen
dc.format.extentvii, 55 leavesen
dc.format.mediumBTDen
dc.format.mimetypeapplication/pdfen
dc.identifier.otheretd-01052009-091123en
dc.identifier.sourceurlhttp://scholar.lib.vt.edu/theses/available/etd-01052009-091123/en
dc.identifier.urihttp://hdl.handle.net/10919/40534en
dc.language.isoenen
dc.publisherVirginia Techen
dc.relation.haspartLD5655.V855_1994.R677.pdfen
dc.relation.isformatofOCLC# 32290488en
dc.rightsIn Copyrighten
dc.rights.urihttp://rightsstatements.org/vocab/InC/1.0/en
dc.subject.lccLD5655.V855 1994.R677en
dc.subject.lcshCarbon dioxideen
dc.subject.lcshFluid inclusionsen
dc.titleDetection limits of CO₂in fluid inclusions using microthermometry and Raman spectroscopy and the spectroscopic characterization of CO₂en
dc.typeThesisen
dc.type.dcmitypeTexten
thesis.degree.disciplineGeological Sciencesen
thesis.degree.grantorVirginia Polytechnic Institute and State Universityen
thesis.degree.levelmastersen
thesis.degree.nameMaster of Scienceen

Files

Original bundle
Now showing 1 - 1 of 1
Thumbnail Image
Name:
LD5655.V855_1994.R677.pdf
Size:
1.89 MB
Format:
Adobe Portable Document Format
Description:
Download

Collections

Masters Theses