Show simple item record

dc.contributor.advisorBaldauf, Jack
dc.creatorBrookshire, Brian Neville, Jr.
dc.date.accessioned2005-02-17T21:08:19Z
dc.date.available2005-02-17T21:08:19Z
dc.date.created2003-12
dc.date.issued2005-02-17
dc.identifier.urihttp://hdl.handle.net/1969.1/1626
dc.description.abstractApproximately 6.6 million years ago in the Eastern Equatorial Pacific a large increase in biogenic mass accumulation rates (MAR’s) occurred. This increased level of biogenic mass accumulation persisted until about 4.4 Ma at which time levels returned to those similar to before the transition at 6.6 Ma. The exact nature of the change that facilitated this transition in biogenic MAR’s, however, was not understood. Here we present the results of a study which characterizes the diatom assemblage spanning the depositional transition at 6.6 Ma from sediments taken from ODP Hole 850B. A close inspection of lithology reveals a clear change in lithology from a diatom nannofossil ooze to a nannofossil diatom ooze at 6.6 Ma. This transition is immediately followed by the occurrence of laminated diatom ooze (LDO). Diatom absolute abundance data reveals three levels of productivity associated with pre-transitional, post-transitional, and LDO formational sediments. An increase in the absolute abundance of Thalassionema nitzschioides was the major contributor to the formation of post-transitional, and LDO sediments. The known ecological preferences of this species indicate an overall increase in nutrient availability followed by sporadic changes in nutrient availability. These changes in nutrient availability could be associated with the establishment, or increase in strength, of an upwelling cell and/or the increase in nutrients made available via upwelling due to a shoaling of the thermocline.en
dc.format.extent2449768 bytesen
dc.format.extent44736 bytesen
dc.format.mediumelectronicen
dc.format.mimetypeapplication/pdf
dc.format.mimetypeapplication/octet-stream
dc.language.isoen_US
dc.publisherTexas A&M University
dc.subjectpaleoceanographyen
dc.subjectpaleoproductivityen
dc.subjectdiatomen
dc.subjecteastern equatorial pacificen
dc.titleCharacter of the diatom assemblage spanning a depositional transition in the Eastern Equatorial Pacific Ocean at 6.6 Maen
dc.typeBooken
dc.typeThesisen
thesis.degree.departmentOceanographyen
thesis.degree.disciplineOceanographyen
thesis.degree.grantorTexas A&M Universityen
thesis.degree.nameMaster of Scienceen
thesis.degree.levelMastersen
dc.contributor.committeeMemberRaymond, Anne
dc.contributor.committeeMemberFirth, John
dc.contributor.committeeMemberSlowey, Niall
dc.type.genreElectronic Thesisen
dc.type.materialtexten
dc.format.digitalOriginborn digitalen


Files in this item

Thumbnail
Thumbnail

This item appears in the following Collection(s)

Show simple item record