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HarwoodDavidMichael1986 2vol ljc.pdf (20.95 MB)

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Diatom Biostratigraphy and Paleoecology with a Cenozoic History of Antarctic Ice Sheets

Harwood, David Michael
http://rave.ohiolink.edu/etdc/view?acc_num=osu1394723672

Abstract Details

1986, Doctor of Philosophy, Ohio State University, Geological Sciences.
The history of Cenozoic ice sheets in Antarctica has been interpreted largely from deep-sea data. A new approach, which provides a more direct evaluation of Antarctic ice history, involves the examination of reworked diatom assemblages in the Sirius Formation tillites. These diatoms originate from subglacial sedimentary basins in East Antarctica and indicate periods of relative warmth, ice sheet retreat and the repeated presence of marine seaways/embayments in the continental interior during the Cenozoic. Antarctic ice-minima conditions are indicated by marine diatoms and other microfossils recovered from Sirius Formation localities spread over 1300 km in the Transantarctic Mountains. The modern distribution and temperature limits of several Pliocene diatoms recovered from the Sirius Formation indicate marine water as warm as ~2°-5°C in the antarctic interior to at least 85°S latitude. Geologic time intervals not represented by microfossils in the Sirius Formation may indicate times of extensive ice development. The glacial history these microfossils suggest is substantiated by comparison to global sea-level and benthic foraminiferal oxygen isotope data. A detailed analysis of isotopic and eustatic records, together with Sirius Formation data, indicate ice-minima conditions and relative warmth, with marine seaways across Antarctica, during the Pliocene (~5 to 2.5 Ma), middle Miocene (~17 to 14 Ma), late Oligocene/early Miocene (~27 to 23 Ma) and during much of the early Oligocene and remaining Paleogene. Glaciations are indicated during the late Oligocene (~31 to 27 Ma), late Miocene (~10 to 5 Ma) and Pleistocene (~2.5 Ma to present). Bottom-water/ice-shelf events, recognized in a detailed comparison of eustatic and benthic oxygen isotopic data, preceed late Oligocene and late Miocene ice-sheet growth by ~5 million years. Analysis of diatom biostratigraphy and paleoecology from numerous in situ Oligocene through Pliocene sedimentary outcrops and drill-holes around the Antarctic periphery have aided dating of the above reworked microfossils and have documented glacial and marine fluctuations in more uniform environments. Of particular significance is the recovery of upper Oligocene glacial-marine sediments in the MSSTS-1 drill-hole, the oldest known from Antarctica.
Peter-N. Webb (Advisor)
John H. Mercer (Committee Member)
Larry A. Krissek (Committee Member)
Stig M. Bergstrom (Committee Member)
592 p.
Geology; Mineralogy

Recommended Citations

Citations

  • Harwood, D. M. (1986). Diatom Biostratigraphy and Paleoecology with a Cenozoic History of Antarctic Ice Sheets [Doctoral dissertation, Ohio State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=osu1394723672

    APA Style (7th edition)

  • Harwood, David. Diatom Biostratigraphy and Paleoecology with a Cenozoic History of Antarctic Ice Sheets . 1986. Ohio State University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=osu1394723672.

    MLA Style (8th edition)

  • Harwood, David. "Diatom Biostratigraphy and Paleoecology with a Cenozoic History of Antarctic Ice Sheets ." Doctoral dissertation, Ohio State University, 1986. http://rave.ohiolink.edu/etdc/view?acc_num=osu1394723672

    Chicago Manual of Style (17th edition)

osu1394723672
313
© 1986, all rights reserved.
This open access ETD is published by The Ohio State University and OhioLINK.