The Stratigraphic Position of a Dinosaur Quarry at Black Mesa, Kenton, OK

Madison Rice, Lauren Hall, Anne Weil

Research output: Contribution to conferencePosterpeer-review

Abstract

Background: The Homestead Quarry is a paleontological quarry located at Black Mesa where fossils of Jurassic invertebrates and vertebrates, including dinosaurs, have been unearthed. Present-day, the quarry is located below the mesa, where a landslide occurred within the past 2ky. Its location suggested two hypotheses of original location: firstly, the quarry may be in its original position. Alternatively, it may have been displaced less than ten meters during the landslide. This project sought to determine the position of the quarry block relative to the adjacent mesa by attempting to correlate geologic beds from one site to the other.

Methods: Two trenches were excavated during a 2-week period to reach fresh exposures of Jurassic rock. The first trench was located below the Homestead Quarry; the other trench was located to the north on the mesa. 0.3-1.5 m of soil was removed to reach in-situ beds. The mesa trench was discontinuous due to rock fall. GPS coordinates were recorded at the top and bottom of the trench. Stratigraphic sections were recorded; the thickness of each bed was surveyed using a Jacob’s staff and pocket transit. Description of beds included color, grain size, hardness, and documentation of fossils or sedimentary structures. Comparisons of the two described sections were made.

Results: The presence of kaolinite below the quarry indicates the quarry is within the Cimarron or Boise Member of the Morrison Formation. The lack of chert means that the quarry cannot be in the Cimarron Member. The lack of kaolinite or lake sediments in the mesa trench is unexpected, as the elevation indicated by a GPS reading and surveying suggested that the trench was being dug at and above the same elevation as that of the quarry. We could not locate sediments correlating those in the Homestead quarry to those on the mesa.

Conclusions: The geologic beds of the Homestead Quarry could not be correlated to those of the mesa. This was surprising and contradicted the previous ideas of the quarry’s stratigraphic position. We now have two new hypotheses: the quarry was likely either greatly displaced vertically in a landslide, much more than previously thought; or a fault between the mesa and the quarry has displaced it in space. Faulting is very common in this area due to tectonic uplift and volcanic activity. More work needs to be done to determine the reason for the differences observed between the Homestead quarry sediments and those of the adjacent mesa.
Original languageAmerican English
Pages85
StatePublished - 16 Feb 2024
Event
Oklahoma State University Center for Health Sciences Research Week 2024
- Oklahoma State University Center for Health Sciences, Tulsa, United States
Duration: 13 Feb 202417 Feb 2024
https://medicine.okstate.edu/research/research_days.html

Conference

Conference
Oklahoma State University Center for Health Sciences Research Week 2024
Country/TerritoryUnited States
CityTulsa
Period13/02/2417/02/24
Internet address

Keywords

  • Morrison Formation
  • sedimentology
  • Lake Stovall

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