• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 1
  • Tagged with
  • 2
  • 2
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Lake Cycles and Sediments: Locality 80, Olduvai Gorge, Tanzania

Berry, Patricia A 07 August 2012 (has links)
Studies have shown that Bed I and Lower Bed II (1.92Ma- 1.76Ma) of Paleolake Olduvai at Locality 80 are primarily composed of the authigenic lacustrine clay minerals illite, smectite, and interlayered illite-smectite. X-ray fluorescence analysis and the sedimentation rates of Hay and Kyser (2001) were used to identify four apparent lake cycles beginning and ending with saline alkaline phases. Peaks in Al2O3/MgO ratios, and TiO2 and P2O5 abundances occur at approximately the same elevations within the stratigraphic section. Low values in these three parameters indicate saline alkaline conditions whereas high values represent fresh water conditions. Lake Cycles (LC) 1 and 4 completed in approximately 44,000 years and 42,000 years respectively, which is similar to the 41k.y. year cycle associated with Earth’s obliquity. Lake Cycles 2 and 3 span approximately 24,000 years and are similar to the 21k.y. precession cycle.
2

Petrochemistry and geochronology of Ngorongoro Volcanic Highland Complex (NVHC) and its relationship to Laetoli and Olduvai Gorge, Tanzania

Mollel, Godwin F. January 2007 (has links)
Thesis (Ph. D.)--Rutgers University, 2007. / "Graduate Program in Geological Sciences." Includes bibliographical references (p. 219-232).

Page generated in 0.0355 seconds