KUKU

KU ScholarWorks

  • myKU
  • Email
  • Enroll & Pay
  • KU Directory
    • Login
    View Item 
    •   KU ScholarWorks
    • Dissertations and Theses
    • Dissertations
    • View Item
    •   KU ScholarWorks
    • Dissertations and Theses
    • Dissertations
    • View Item
    JavaScript is disabled for your browser. Some features of this site may not work without it.

    Construction and Exhumation of the Sierra Nevada Range: an investigation of geochronology, thermochronology and trace element mineral chemistry

    Thumbnail
    View/Open
    Lee_ku_0099D_16282_DATA_1.pdf (51.29Mb)
    Issue Date
    2018-12-31
    Author
    Lee, John Patrick
    Publisher
    University of Kansas
    Format
    179 pages
    Type
    Dissertation
    Degree Level
    Ph.D.
    Discipline
    Geology
    Rights
    Copyright held by the author.
    Metadata
    Show full item record
    Abstract
    This dissertation describes the development of the Sierra Nevada range from its construction as a magmatic arc to its current configuration as a significant tectonic block or microplate in the western North American Cordillera. The Sierra Nevada range is a large coherent physiographic and tectonic block built upon a Mesozoic age batholith that is one of the most well studied extinct continental arc systems in the world. Models of batholith construction, magmatic evolution and subduction mechanics have all been refined as a result of the geologic relationships observed in the Sierra Nevada. However, several important questions related to processes of continental arc systems are still unresolved. Specifically, the complex interplay between orogenesis and erosion in the Sierra Nevada is debated, as is the ‘longevity’ of the range created during Mesozoic and early Cenozoic subduction. The cause and source of voluminous magmas emplaced during magmatic flare-up events (e.g. late-Cretaceous flare-up of the Sierra Nevada) is not yet resolved. It is speculated that crustal thickening results in anatexis of the lower crust, but robust validation of this model in the chemistry of flare-up magmas is needed. This dissertation applies multiple geochronologic, thermochronometric and geochemical techniques to examine these questions. In Chapter 1, we investigate the timing and magnitude of erosion in the central Sierra Nevada range. Interpretation of the data presented here supports previous investigations in the southern and northern Sierra Nevada, which posit high rates of erosion in the late Cretaceous and early Cenozoic. The data presented in Chapter 1 also indicates that the paleotopography of the late Cretaceous range was of significant topographic relief and that the distribution of major paleotopographic features (e.g. river canyons, major interfleuve divides) in the late Cretaceous were similar to those of the modern range. Chapter 2 investigates the cooling trends observed in batholithic rocks from temperatures of 800°C <T<60°C. We interpret these results to indicate a characteristic pattern of post-emplacement cooling that reflects two dominating mechanisms: (1) post-emplacement conductive equilibration of temperatures followed by (2) cooling as a result of exhumation. Chapter 3 investigates the long-term fractionation of magmas during the late-Cretaceous flare-up event by analyzing trace element concentrations in magmatic zircons. We find evidence for increasingly fractionated melts throughout the flare-up event; an observation that supports models of anatexis as a result of crustal thickening. We also find that the late- Cretaceous flare-up may have started earlier in the northern portions of the range and migrated south over a period of 10-15 Ma, thus indicating a temporal and spatial progression not yet recognized.
    URI
    http://hdl.handle.net/1808/28045
    Collections
    • Dissertations [4625]
    • Geology Dissertations and Theses [232]

    Items in KU ScholarWorks are protected by copyright, with all rights reserved, unless otherwise indicated.


    We want to hear from you! Please share your stories about how Open Access to this item benefits YOU.


    Contact KU ScholarWorks
    785-864-8983
    KU Libraries
    1425 Jayhawk Blvd
    Lawrence, KS 66045
    785-864-8983

    KU Libraries
    1425 Jayhawk Blvd
    Lawrence, KS 66045
    Image Credits
     

     

    Browse

    All of KU ScholarWorksCommunities & CollectionsThis Collection

    My Account

    Login

    Statistics

    View Usage Statistics

    Contact KU ScholarWorks
    785-864-8983
    KU Libraries
    1425 Jayhawk Blvd
    Lawrence, KS 66045
    785-864-8983

    KU Libraries
    1425 Jayhawk Blvd
    Lawrence, KS 66045
    Image Credits
     

     

    The University of Kansas
      Contact KU ScholarWorks
    Lawrence, KS | Maps
     
    • Academics
    • Admission
    • Alumni
    • Athletics
    • Campuses
    • Giving
    • Jobs

    The University of Kansas prohibits discrimination on the basis of race, color, ethnicity, religion, sex, national origin, age, ancestry, disability, status as a veteran, sexual orientation, marital status, parental status, gender identity, gender expression and genetic information in the University’s programs and activities. The following person has been designated to handle inquiries regarding the non-discrimination policies: Director of the Office of Institutional Opportunity and Access, IOA@ku.edu, 1246 W. Campus Road, Room 153A, Lawrence, KS, 66045, (785)864-6414, 711 TTY.

     Contact KU
    Lawrence, KS | Maps