Virginia Tech
    • Log in
    View Item 
    •   VTechWorks Home
    • ETDs: Virginia Tech Electronic Theses and Dissertations
    • Doctoral Dissertations
    • View Item
    •   VTechWorks Home
    • ETDs: Virginia Tech Electronic Theses and Dissertations
    • Doctoral Dissertations
    • View Item
    JavaScript is disabled for your browser. Some features of this site may not work without it.

    Exceptional Preservation and Bias in the Fossil Record

    Thumbnail
    View/Open
    Hawkins_AD_D_2017.pdf (6.655Mb)
    Downloads: 104
    Date
    2017-12-11
    Author
    Hawkins, Andrew Donald
    Metadata
    Show full item record
    Abstract
    The three projects described herein focus on two instances of exceptional preservation and on potential source of bias in the fossil record. The occurrence of exceptionally preserved fossil assemblages and the existence of systematic bias in the fossil record from a variety of sources represent opposing forces acting on the information quality of the fossil record. Exceptionally preserved assemblages capture features of anatomy and components of assemblages not normally recorded in the fossil record. Systematic biases affecting the fossil record do the opposite, skewing our perception of patterns of diversity, the relative dominance of clades and changes in ecosystems through time. Chapter one presents the results of an analog modeling analysis to assess whether and how a newly proposed potential mechanism, the preferential sampling of larger specimens during fossil sampling due to the greater likelihood of larger specimens being intersected by a fracture surface, contributes to the lithification bias. Chapters two and three focus on the exceptionally preserved vermiform fossils from the Winneshiek Lagerstätte in northeastern Iowa and microfossils from the Doushantuo Formation of South China, respectively. Chapter two aims at resolving the identity of the Winneshiek vermiform fossils and presents evidence that these structures represent phosphatized bromalites, an ichnologic category that includes coprolites and cololites. Chapter three presents a biostratigraphy study of exceptionally preserved microfossils at three sections of the Doushantuo Formation in South China. Acanthomorphic acritarchs represent a promising tool for subdivision and correlation of the Doushantuo Formation of South China and Ediacaran strata around the world. However, the occurrence of acanthomorphic acritarchs within the Doushantuo Formation is controlled by the availability of early diagenetic chert nodules that host microfossils such as acanthomorphic acritarchs. One of these sections contains the rare occurrence of early diagenetic cherts in an upper slope section. This new biostratigraphic data adds to the growing body of integrated chemostratigraphic and biostratigraphic data from the Doushantuo Formation. By understanding both exceptional preservation and sources of bias in the fossil record it is possible to separate artifact and noise from the true signal of the history of life.
    URI
    http://hdl.handle.net/10919/89751
    Collections
    • Doctoral Dissertations [14916]

    If you believe that any material in VTechWorks should be removed, please see our policy and procedure for Requesting that Material be Amended or Removed. All takedown requests will be promptly acknowledged and investigated.

    Virginia Tech | University Libraries | Contact Us
     

     

    VTechWorks

    AboutPoliciesHelp

    Browse

    All of VTechWorksCommunities & CollectionsBy Issue DateAuthorsTitlesSubjectsThis CollectionBy Issue DateAuthorsTitlesSubjects

    My Account

    Log inRegister

    Statistics

    View Usage Statistics

    If you believe that any material in VTechWorks should be removed, please see our policy and procedure for Requesting that Material be Amended or Removed. All takedown requests will be promptly acknowledged and investigated.

    Virginia Tech | University Libraries | Contact Us