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

  • ichonology
  • brasilichnium
  • Navajo Formation
  • trackway
  • Grallator
  • Glen Canyon National Recreation Area

• 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.