• Login
    View Item 
    •   Home
    • University of Alaska Fairbanks
    • UAF Graduate School
    • Geosciences
    • View Item
    •   Home
    • University of Alaska Fairbanks
    • UAF Graduate School
    • Geosciences
    • View Item
    JavaScript is disabled for your browser. Some features of this site may not work without it.

    Browse

    All of Scholarworks@UACommunitiesPublication DateAuthorsTitlesSubjectsTypeThis CollectionPublication DateAuthorsTitlesSubjectsType

    My Account

    Login

    First Time Submitters, Register Here

    Register

    Statistics

    Display statistics

    History of the Chukchi borderland and the Amerasia basin, Arctic Ocean

    • CSV
    • RefMan
    • EndNote
    • BibTex
    • RefWorks
    Thumbnail
    Name:
    Ilhan_I_2018.pdf
    Size:
    13.83Mb
    Format:
    PDF
    Download
    Author
    Ilhan, Ibrahim
    Chair
    Coakley, Bernard J.
    Committee
    Johnson, Christopher A.
    Houseknecht, David W.
    Whalen, Michael T.
    Keyword
    Geology
    Arctic Ocean
    Chukchi Sea
    Structural geology
    Plate tectonics
    Metadata
    Show full item record
    URI
    http://hdl.handle.net/11122/9688
    Abstract
    Structural and stratigraphic interpretation of 2D multi-channel seismic (MCS) reflection profiles through recognition of the sub-surface reflection patterns and integration of the seismic interpretation with the other geophysical and geological data reveal the history of the Chukchi Borderland. This investigation provides new constraints for the tectonic development of the Amerasia Basin. North-striking normal faults of the Chukchi Borderland dissect the continental basement into the Chukchi Plateau, Northwind Basin and Northwind Ridge from west to east. A well-developed angular unconformity (Au) separates the stratigraphic section into sub and super-Au seismic units. Sub-Au units include: (1) seaward dipping reflections (SDRs) observed in the juncture between the North Chukchi-Toll Basins and Chukchi Plateau; (2) growth and folded strata in the Northwind Basin; (3) thrust faults in the Northwind Basin and over the Northwind Ridge; and (4) a clinoform sequence that downlaps onto the extended continental crust of the Canada Basin, supported by presence of SDRs and diapiric reflections within the crust. Au is inferred to correlate to the Hauterivian (LCu) and the Middle Jurassic (Ju) unconformities of the Alaska North Slope. The SDRs indicate that the southwestern margin of the Chukchi Borderland may be a rifted continental margin. Loosely constrained age control of a super-Au unit (inferred condensed section, perhaps correlative to Hauterivian pebble shale or the Jurassic upper Kingak shale units of Alaska North Slope) implies that the rifted margin subsided no later than the earliest Cretaceous, providing a plausible time constraint for Middle Jurassic-earliest Cretaceous rifting in the North Chukchi Basin. The growth strata and north-striking normal faults of the Northwind Basin are continuous with the extensional structures of the Mississippian Hanna Trough, providing a geologic linkage between the two. The folding and thrust faults reveal a phase of contraction confined to sub-Au units of the south and eastern Northwind Basin and Northwind Ridge. The clinoform sequence of the Northwind Ridge-Canada Basin is inferred to correlate with the Upper Jurassic-Lower Cretaceous Kingak shale unit of Alaska North Slope, implying that the extension of the crust beneath the western Canada Basin occurred no later than the Middle Jurassic. Super-Au strata (~16 km) onlap the condensed section, SDRs, growth and passive margin strata from west to east, tapering down to a few kilometers north and eastward across the seismic grid. These are part of the Aptian through Cenozoic Brookian megasequence, a series of clinothems, deposited across the foreland of the Chukotka and Brooks Range orogens. These strata were deposited by northward-migrating depositional systems that progressively filled the North Chukchi Basin and buried the southern flank of the Chukchi Borderland, and deposited along the Northwind margin of the Canada Basin. Another unit of growth strata is observed in the Northwind Basin, indicating another phase of extension of the Boderland. The Upper Cretaceous section of the Brookian megasequence is displaced by normal faults over the Chukchi Plateau and inferred age-equivalent strata over the Northwind Ridge. These constrain the second phase of extension of the interior Borderland to the Late Cretaceous to Paleocene. The recognition of the sub-Au units and continuity of the super-Au units across the area, north-striking normal faults, and the absence of east-directed thrust faults between the Northwind Ridge and Canada Basin invalidate one model proposed for tectonic development of the Amerasia Basin. Models that require significant relative motion between the Chukchi Shelf and Borderland since the Middle Jurassic are precluded by these observations.
    Description
    Dissertation (Ph.D.) University of Alaska Fairbanks, 2018
    Date
    2018-08
    Type
    Dissertation
    Collections
    Geosciences

    entitlement

     
    ABOUT US|HELP|BROWSE|ADVANCED SEARCH

    The University of Alaska is an affirmative action/equal opportunity employer, educational institution and provider and prohibits illegal discrimination against any individual.

    Learn more about UA’s notice of nondiscrimination.

    Open Repository is a service operated by 
    Atmire NV
     

    Export search results

    The export option will allow you to export the current search results of the entered query to a file. Different formats are available for download. To export the items, click on the button corresponding with the preferred download format.

    By default, clicking on the export buttons will result in a download of the allowed maximum amount of items.

    To select a subset of the search results, click "Selective Export" button and make a selection of the items you want to export. The amount of items that can be exported at once is similarly restricted as the full export.

    After making a selection, click one of the export format buttons. The amount of items that will be exported is indicated in the bubble next to export format.