Fluid relationships in the Northern Gulf of Mexico using dissolved ion concentrations and strontium isotopes

dc.contributor.advisorDugan, Brandon
dc.contributor.advisorDickens, Gerald R.
dc.creatorHubbard, L. Ashley
dc.date.accessioned2018-12-03T18:31:54Z
dc.date.available2018-12-03T18:31:54Z
dc.date.issued2008
dc.description.abstractPore fluids from the slope in the Gulf of Mexico demonstrate specific ion enrichment and a range in concentration. Dissolved metal and halogen fluid concentrations and strontium isotope ratios from ten sites on the Gulf of Mexico (GoM) continental slope were compared to identify the variations in chemistry. Geochemical discrepancies are interpreted as coming from chloride sources, fluid mixing and fluid diagenesis at depth. We have adapted a grouping scheme developed by Fu and Aharon (1998) in order to highlight seep fluid relationships, including seep fluid from six additional locations. Chloride sources were assessed based on bromide to chloride and sodium to chloride trends and strontium isotope ratios. Chloride source end members include connate seawater, dissolved salt, and ancient evaporated seawater. Out of the sites examined, three sites are classified as having a chloride signal dominated by salt dissolution. Bromide to chloride ratios fall between 0.23 x 10 -3 and seawater (1.5 x 10 -3 ). Sodium to chloride ratios fall between 1.16 and seawater (0.85) and strontium ratios have a large distribution (0.707911-0.709220). Evidence of subaerially evaporated seawater is preserved in fluids from at least two or three sites. Bromide to chloride ratios fall between 2.47 x 10 -3 and seawater. Sodium to chloride ratios fall between 0.75 and seawater and strontium ratios demonstrate a narrow range of values in the least altered fluids (0.708662-0.709172). The majority of saline vent fluids demonstrate mixing between chloride source end members and a wide range of dissolved ion concentrations. Diverse ion enrichment behavior clearly indicates that the processes controlling GoM seep fluid chemistries are complicated and often site dependent resulting from differences in flux, early brine generation and fluid/sediment interactions.
dc.format.extent85 pp
dc.identifier.callnoTHESIS GEOL. 2008 HUBBARD
dc.identifier.citationHubbard, L. Ashley. "Fluid relationships in the Northern Gulf of Mexico using dissolved ion concentrations and strontium isotopes." (2008) Master’s Thesis, Rice University. <a href="https://hdl.handle.net/1911/103620">https://hdl.handle.net/1911/103620</a>.
dc.identifier.digital304511221
dc.identifier.urihttps://hdl.handle.net/1911/103620
dc.language.isoeng
dc.rightsCopyright is held by the author, unless otherwise indicated. Permission to reuse, publish, or reproduce the work beyond the bounds of fair use or other exemptions to copyright law must be obtained from the copyright holder.
dc.subjectGeochemistry
dc.subjectEarth sciences
dc.titleFluid relationships in the Northern Gulf of Mexico using dissolved ion concentrations and strontium isotopes
dc.typeThesis
dc.type.materialText
thesis.degree.departmentEarth Science
thesis.degree.disciplineNatural Sciences
thesis.degree.grantorRice University
thesis.degree.levelMasters
thesis.degree.majorNatural Sciences
thesis.degree.nameMaster of Science
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