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Late Cenozoic Offshore Record of Exhumation and Sediment Routing in Southeast Alaska from Detrital Zircon U/Pb and FT double-dating

Bootes, Nathaniel R
http://rave.ohiolink.edu/etdc/view?acc_num=ucin1592169111121451

Abstract Details

2020, MS, University of Cincinnati, Arts and Sciences: Geology.
In this study, we investigate the late Miocene–Pleistocene offshore sedimentary record of the Yakutat microplate to evaluate the spatial and temporal variations in exhumation and sediment routing patterns at the heavily glaciated, actively converging plate boundary in southeast Alaska. We present new detrital zircon fission track and U-Pb double-dating age data from fourteen samples from 4 offshore boreholes on the Yakutat shelf. We compare our results with published thermochronology and geochronology data from on-land and offshore in order to constrain grain provenance. We find that offshore strata east of the Pamplona Zone deformation front are sourced from the rapidly exhuming areas along the Fairweather Fault as well as the slowly exhuming Insular superterrane. In contrast, Pliocene–Pleistocene strata west of the Pamplona Zone reveal limited offshore lateral sediment transport from the rapidly exhuming plate corner across the shelf. Instead, the western strata are sourced from the St. Elias fold and thrust belt and the Chugach Metamorphic Complex. In general, successive samples from most wells show a small percentage of young grains with decreasing ZFT lag times as short as 1-3 Myr, indicating localized, rapid exhumation >2 km/Myr. Based on changes in sediment provenance, we suggest that the proto-Bering Glacier captured the Bagley Ice Valley catchment north of the Yakutat plate boundary around 3.5 Ma, leading to development of the modern Bagley-Bering Glacier System. In addition, data from strata deposited at ~8.6 Ma suggest that rapid exhumation was ongoing in the late Miocene. Overall, the data help discern several stages in the evolution of sediment routing patterns in response to dynamic tectonic and surficial processes along this active convergent margin.
Craig Dietsch, Ph.D. (Committee Chair)
Eva Enkelmann, Ph.D. (Committee Member)
Richard Lease, Ph.D. (Committee Member)
99 p.
Geology
Zircon fission track; UPb; St Elias; Yakutat; thermochronology; detrital zircon

Recommended Citations

Citations

  • Bootes, N. R. (2020). Late Cenozoic Offshore Record of Exhumation and Sediment Routing in Southeast Alaska from Detrital Zircon U/Pb and FT double-dating [Master's thesis, University of Cincinnati]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1592169111121451

    APA Style (7th edition)

  • Bootes, Nathaniel. Late Cenozoic Offshore Record of Exhumation and Sediment Routing in Southeast Alaska from Detrital Zircon U/Pb and FT double-dating. 2020. University of Cincinnati, Master's thesis. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=ucin1592169111121451.

    MLA Style (8th edition)

  • Bootes, Nathaniel. "Late Cenozoic Offshore Record of Exhumation and Sediment Routing in Southeast Alaska from Detrital Zircon U/Pb and FT double-dating." Master's thesis, University of Cincinnati, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1592169111121451

    Chicago Manual of Style (17th edition)

ucin1592169111121451
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