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Bighorn Basin GeoScience Center Gypsum Spring Dinosaur Tracksite CLINK ON LINKS BELOW FOR
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CONTACT Cliff
Manuel, Chairman Bighorn
Basin Geoscience Center, Inc. 537
Greybull Avenue Greybull,
Wyoming 82426 Phone: 307.765.2286 Cell:
406.672.1462 e-mail: cliff@bbgeoscience.org |
New rare dinosaur tracksite found in northern Wyoming Nov. 16, 2000 BLOOMINGTON, Ind. -- The dinosaur record of the
Middle Jurassic period (159-187 million years ago) is considered sparse
worldwide, with relatively little known about dinosaurs from this period.
However, recent discoveries of the most extensive Middle Jurassic dinosaur
tracksites in North America are changing that. In 1997, near the town of Shell in the Bighorn
Basin of northern Wyoming, Indiana University geologist Erik Kvale found extensive dinosaur track-bearing deposits in 167
million-year-old rock in the Sundance Formation that was previously thought
to have been totally underwater during the time when dinosaurs lived. Now Kvale and collaborators report the
presence of an even older, more extensive dinosaur track-bearing deposit in
the Bighorn Basin. The scientists presented their results today (Nov. 16) at
the annual convention of the Geological Society of America in Reno, Nev. The new discovery is in a meter-thick layer of
rock in the Gypsum Spring Formation. Estimated to be 170 million years old, this newly discovered layer preserves
evidence that dinosaurs that inhabited this part of Wyoming may have been
swimmers. The
Gypsum Spring Dinosaur Tracksite
was first discovered in 1999 by Walter Parrs Jr., a New York City resident
visiting a local ranch (The Hideout).
It includes impressions made by land-dwelling two-legged dinosaurs that were
small- to medium-sized, comparable to those found in the younger Sundance
Formation. Some of the tracks were made by carnivorous dinosaurs called
theropods.
Walter Parrs at
Gypsum Spring Dinosaur Tracksite discovery site Outcrops containing Gypsum Spring tracks occur
sporadically over a 2000-square-kilometer area. In some areas the
track-bearing surface consists entirely of grooves that appear to be the
remains of scratch marks made by dinosaurs whose feet briefly touched a muddy
bottom while they were swimming. The groove marks have a size and spacing
consistent with terrestrial dinosaur tracks found elsewhere in the Gypsum
Spring Formation. Unlike the Sundance tracks that preserve only
the three toes and rarely the heel of the dinosaur's foot, many examples of
toe and heel impressions have been found in the Gypsum Spring trackways. As a
result, estimates of a dinosaur's speed based on foot size and stride can be
made for these dinosaurs. Estimates of dinosaur speeds up to 9.2 kilometers
per hour have been calculated. Interestingly, the researchers believe that
algal and bacterial mats that once covered the tidal flats inhabited by these
animals may have helped in preserving their tracks over millions of years.
Such microbial mats are present on many of today's beaches and tidal flats.
Within minutes to hours after the dinosaurs walked across a tidal flat, a
thin microbial mat covered their tracks. This stabilized the tracks and
prevented erosion of the track-bearing surface by wind or waves until it was
buried by other sediments and eventually hardened into rock. For the Middle Jurassic period in the United States,
reptilian discoveries had been limited to Utah. These include: (1) the
skeleton of one land-dwelling primitive crocodile-like reptile; (2) dinosaur
tracks in the formation called the Entrada, which is several million years
younger; and (3) a few small dinosaur tracks from the Sundance equivalent
called the Carmel Formation. Therefore, the existence of abundant dinosaur
tracks within the older Gypsum Spring Formation and Sundance Formation
contributes significantly to knowledge of the geographic distribution of
dinosaurs in North America during this time. The original 1997 discovery in the Sundance
Formation resulted in the establishment of the Red Gulch Dinosaur Tracksite
on public lands administered by the Department of the Interior's Bureau of
Land Management. The Red Gulch site is a 40-acre area currently being
developed by BLM as a dinosaur educational site accessible to the public. The above is
modified from an Copyright © 2010, 2011, 2012 Bighorn Basin Geoscience Center. All rights
reserved
(except for images and text as noted) Last updated: December 10, 2011 Bighorn
Basin GeoScience Center ~ 537 Greybull Avenue ~
Greybull, Wyoming 82426 Web
site maintenance by: Cliff Manuel
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