• 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

    Upper crustal structure of southern Alaska: An interpretation of seismic refraction data from the Trans-Alaska Crustal Transect

    • CSV
    • RefMan
    • EndNote
    • BibTex
    • RefWorks
    Thumbnail
    Name:
    Wolf_L_1989.pdf
    Size:
    2.739Mb
    Format:
    PDF
    Download
    Author
    Wolf, Lorraine W.
    Chair
    Stone, David B.
    Davies, John N.
    Committee
    Harrison, William D.
    Pulpan, Hans
    Shapiro, Lewis H.
    Wallace, Wesley K.
    Keyword
    Geophysics
    Geology
    Metadata
    Show full item record
    URI
    http://hdl.handle.net/11122/9357
    Abstract
    Seismic refraction and wide-angle reflection data from the U.S. Geological Survey's Trans-Alaska Crustal Transect is used to investigate the upper crustal structure of southcentral Alaska. The data consist of two intersecting refraction lines: the 135-km Chugach profile which follows the E-W strike of the Chugach Mountains and the 126-km Cordova Peak profile which follows the N-S regional dip. The four shots of the Chugach profile and the five shots of the Cordova Peak profile were recorded on 120 portable seismic instruments spaced at 1-km intervals. Interpretation of data from the Chugach terrane indicates that near-surface unconsolidated sediment and glacial ice overlie rocks of unusually high average compressional velocities (5.4-6.9 km/s) in the upper 10 km of crust. A thick unit correlated with a metasedimentary and metavolcanic flysch sequence has velocities of 5.4-5.9 km/s. It is underlain by mafic to ultramafic metavolcanic rocks (6.0-6.4 km/s) correlated with the terrane basement. Mid-crustal layers beneath the Chugach terrane contain two velocity reversals (6.5 and 6.7 km/s) attributed to off-scraped oceanic sedimentary rocks which are underlain by mafic to ultramafic oceanic volcanic crust (7.0-7.2 km/s). Interpretation of data from the Prince William terrane indicates systematically lower velocities in Prince William terrane rocks as compared to Chugach terrane rocks at comparable depths. The upper 10 km of crust, having average compressional velocities of 3.0-6.2 km/s, is correlated with clastic sedimentary and volcanic rocks which are overlain by younger terrigenous sedimentary rocks. A 2-km thick layer at 10-12 km depth is correlated with mafic to ultramafic Prince William terrane basement rocks. The difference in velocity structure between the Chugach and Prince William terranes suggests that the Contact fault zone is a terrane boundary which extends to a depth of at least 10-12 km. Deep structure beneath the two terranes is not well constrained by the seismic refraction data. Potential field data support the interpretation that a thick low-velocity zone occurs at a 12-15 km depth and may contain subducted continental rocks of the Yakutat terrane, which is currently accreting to and being thrust beneath the North American continent along the Gulf of Alaska margin.
    Description
    Dissertation (Ph.D.) University of Alaska Fairbanks, 1989
    Date
    1989
    Type
    Dissertation
    Collections
    Geosciences

    entitlement

     
    ABOUT US|HELP|BROWSE|ADVANCED SEARCH

    The University of Alaska Fairbanks is an affirmative action/equal opportunity employer and educational institution and is a part of the University of Alaska system.

    ©UAF 2013 - 2023 | Questions? ua-scholarworks@alaska.edu | Last modified: September 25, 2019

    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.