Usage
  • 15 views
  • 196 downloads

USING PHOTOGRAMMETRY TO ANALYZE THE MORPHOLOGY, TAPHONOMY, AND SEDIMENT DEFORMATION OF BRASILICHNIUM TRACKWAYS ON A SLOPING SAND DUNE FROM THE NAVAJO FORMATION

  • Author / Creator
    Rodriguez, Maria de Jesus
  • The ichnogenus Brasilichnium is widely distributed locally and is found stratigraphically on
    eolian sediments of the same western erg system of the Early Jurassic period. Exceptionally wellpreserved
    synapsid trackways of Brasilichnium were discovered by researchers from the National Park
    Service in 2014. The sandstone slab (locality GLCA #357), located within Glen Canyon National
    Recreation Area (GLCA), is found in the Early Jurassic formation known as the Navajo Sandstone. This
    study investigates the morphology of the trackways fossilized on the lee side of a sloping dune face,
    provides interpretations of the sedimentary structures associated with locomotion, and their taphonomy in
    an eolian environment. The track-bearing surface is composed of eleven trackways including
    Brasilichnium, one Grallator-like trace, and a few unknown traces that are seen moving in different
    orientations relative to each other. This site, named Santucci’s Site after the discoverer, was examined
    using structure-from-motion (SfM) photogrammetry to create 3D images of these tracks. These tetrapod
    tracks show the trackmakers walking on a dune slip face in an eolian environment and changing direction
    while doing so. Sedimentary features include grain flows, or “avalanches”, located below the
    Brasilichnium tracks and two sets of wind ripples on the same track-bearing surface. These pes
    depressions show an imbalance of weight distribution while the animal was walking on the seemingly
    hyper-arid substrate. These trackways show bipedal and quadrupedal locomotion and a change of forward
    motion as the trackmakers strolled upslope, downslope, and diagonally across the face of a sloping dune.
    In addition to morphological variation, SfM photogrammetry shows how this site has been
    impacted in modern times by the fluctuating water level elevations due to a recent megadrought over the
    western United States. Photogrammetry performed in 2014 and 2022 show large-grade weathering of
    these trackways over the span of eight years. This level of weathering largely affected the preservation of
    the trackways, but in a few ways helped expose a few new features.

  • Subjects / Keywords
  • Graduation date
    Fall 2023
  • Type of Item
    Thesis
  • Degree
    Master of Science
  • DOI
    https://doi.org/10.7939/r3-20tr-da34
  • License
    This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.