rdf-syntax-grammar
mods:
  schema location: http://www.loc.gov/mods/v3 http://www.loc.gov/standards/mods/v3/mods-3-2.xsd
  title info:
    title: Uranium and thorium series isotopes as indicators of geochemical processes in recent Venezuela Basin sediments
  name:
    name part: Cole, Kathleen Hicks
    name part: 1951-
    role:
      role term: creator
  name:
    name part: Grossman, Ethan L.
    role:
      role term: degree committee member.
  name:
    name part: Presley, Bobby J.
    role:
      role term: degree committee member.
  name:
    name part: Rowe, Marvin W.
    role:
      role term: degree committee member.
  name:
    name part: Schink, David R.
    role:
      role term: degree supervisor.
  name:
    name part: Scott, Martha R.
    role:
      role term: degree committee member.
  name:
    name part: Texas A & M University
    role:
      role term: degree granting institution.
  type of resource: text
  genre: bibliography
  genre: Academic theses
  origin info:
    place:
      place term: xx
    date issued: 1988
    issuance: monographic
  language:
    language term: eng
  physical description:
    form: print
    extent: xiii, 265 leaves : illustrations ; 29 cm
  abstract: Several uranium and thorium series isotopes are important indicators of abyssal geochemical and physical processes. These processes, in concert, control the timing and intensity of early sedimentary diagenetic changes. Important among these processes are sedimentation, bioturbation, compaction, dissolution and precipitation. This research was designed to investigate the relative importance of each of these on early sediment diagenesis in different abyssal environments. Sediment samples were collected from three different sedimentary environments from the Venezuela Basin. Samples were designated as pelagic carbonate, hemipelagic and turbidite-rich, based on bulk sediment characteristics. Selected members of the 238U and 232Th radioisotope series (238U, 234U, 230Th, 226Ra, 210Pb and 232Th) 14C, and anthropogenic 239,240Pu were determined on selected intervals. Other sedimentary parameters, including porosity, calcium carbonate content, stable isotopes, macrofaunal abundances, organic carbon and grain size, were measured or available from the literature. Nearly constant carbonate-free 232Th activities with respect to depth and location are indicative of a constant terrigenous sediment source throughout the basin. Uranium activities at two sites correspond to activities in Amazon River particulates, while sediments from the turbidite site appear enriched in uranium. 230Th activities are low at all sites and display considerable variability with depth, suggesting a high but variable sedimentation rate. A large 226Ra peak occurs just below the redox boundaries in the turbidite and hemipelagic sediments. No redox boundary is observed for the pelagic carbonate sediments nor is a 226Ra peak observed. Excess 210Pb and 239,240Pu activities are confined to the upper 10 to 15 cm of the sediment columns and are highly variable both between sites and between subcores. A model, based on the constancy of 230Th production in sea water, was developed to determine fine-scale sedimentat…
  note: "Major subject: Oceanography."
  note: Typescript (photocopy).
  note: Vita.
  note: Ph. D. Texas A & M University 1988
  note: Includes bibliographical references.
  subject:
    geographic code: s-ve---
  subject:
    topic: Basins (Geology)
    geographic: Venezuela
  subject:
    topic: Isotope geology
  subject:
    topic: Sedimentation and deposition
    geographic: Venezuela
  subject:
    topic: Uranium enrichment
  subject:
    topic: Major oceanography
  subject:
    topic: Basins (Geology)
  subject:
    topic: Sedimentation and deposition
  subject:
    geographic: Venezuela
  classification: QE501.4.N9 C65 1988a
  identifier: http://proxy.library.tamu.edu/login
  identifier: https://hdl.handle.net/1969.1/DISSERTATIONS-993505
  related item:
    location:
      url: http://proxy.library.tamu.edu/login
  related item:
    location:
      url: https://hdl.handle.net/1969.1/DISSERTATIONS-993505
  record info:
    record content source: TXA
    record creation date: 900214
    record change date: 20220104090441.0
    record identifier: in00000883002
    language of cataloging:
      language term: eng