University of SaskatchewanHARVEST
  • Login
  • Submit Your Research
  • About
    • About HARVEST
    • Guidelines
    • Browse
      • All of HARVEST
      • Communities & Collections
      • By Issue Date
      • Authors
      • Titles
      • Subjects
      • This Collection
      • By Issue Date
      • Authors
      • Titles
      • Subjects
    • My Account
      • Login
      JavaScript is disabled for your browser. Some features of this site may not work without it.
      View Item 
      • HARVEST
      • Electronic Theses and Dissertations
      • Graduate Theses and Dissertations
      • View Item
      • HARVEST
      • Electronic Theses and Dissertations
      • Graduate Theses and Dissertations
      • View Item

      SEDIMENTOLOGY, ICHNOLOGY, AND SEQUENCE STRATIGRAPHY OF THE MIOCENE OFICINA FORMATION, ORINOCO OIL BELT, EASTERN VENEZUELA BASIN

      Thumbnail
      View/Open
      RODRIGUEZ-THESIS-2017.pdf (13.75Mb)
      Date
      2017-02-01
      Author
      Rodriguez, Williams
      ORCID
      0000-0001-5865-3635
      Type
      Thesis
      Degree Level
      Masters
      Metadata
      Show full item record
      Abstract
      ii ABSTRACT The Lower Miocene Oficina Formation is widely distributed in the subsurface of the Orinoco Oil Belt of eastern Venezuela. Despite its economic importance as one of the most important hydrocarbon reservoirs worldwide, little is known about its sedimentologic, ichnologic and sequence-stratigraphic aspects. Sedimentary facies, trace fossils, depositional environments, stratal stacking patterns and surfaces of sequence stratigraphic significance have been analyzed in the Junín and Boyacá areas. The Oficina Formation is subdivided here into three members: Lower, Middle, and Upper. The Lower Member consists mainly of lowstand fluvial braidedchannel deposits filling an incised valley. No evidence of marine conditions is present and the only biogenic structures detected are root trace fossils present at the top of a few fining- and thinning- upward channelized units. The Middle Member is much more heterogeneous, both vertically and laterally, comprising high-sinuosity estuarine-channel, tidal-flat, tidal-creek and tidal-sandbar deposits, stacked to form a retrogradational package and representing the transgressive systems tract. The Middle Member is characterized by widespread evidence of tidal influence (e,g, inclined heterolithic stratification) and by the presence of the impoverished Cruziana Ichnofacies and the Skolithos Ichnofacies, both reflecting brackish-water conditions. This member is thought to represent deposition in an estuarine system. The Upper Member consists predominantly of highstand delta-plain deposits, stacked forming a progradational pattern. These deposits locally show intense bioturbation with a predominance of continental trace fossils, illustrating the Scoyenia Ichnofacies. Deltaic deposits display a mixed influence of tides and river processes. Previous studies invariably assumed a deltaic model for the whole Oficina Formation. However, integration of sedimentologic, ichnologic, and sequencestratigraphic datasets suggests a more complex depositional evolution, comprising a fluvioestuarine valley incised during a fall in sea level that became filled during the lowstand and subsequent transgression, culminating with deltaic progradation during the highstand.
      Degree
      Master of Science (M.Sc.)
      Department
      Geological Sciences
      Program
      Geology
      Supervisor
      Buatuois, Luis
      Committee
      Mangano, Gabriela; Robin W. Renaut, Robin; Hawkes, Christopher
      Copyright Date
      January 2017
      URI
      http://hdl.handle.net/10388/7731
      Subject
      Fluvioestuarine, Orinoco Oil Belt , Oficina Formation
      Collections
      • Graduate Theses and Dissertations
      University of Saskatchewan

      University Library

      © University of Saskatchewan
      Contact Us | Disclaimer | Privacy