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RE: Cleveland-Lloyd, Dry Mesa, Bakker (was RE: Tarbosaurus?)



Actually, Sue Ann Bilbey did her disseration (at Univ. Utah) on the geology
and taphonomy of the Cleveland-Lloyd.  These results were summarized in the
Morrison double volume of Modern Geology:
Bilbey, S.A.  1998.  Cleveland-Lloyd dinosaur quarry - age, stratigraphy and
depositional environments.  Modern Geology 222: 87-120.

Her conclusion as to the dinosaur-bearing part of the quarry: The layer is a
lake deposit, and there is strong indication of volcaniclastic sediment.
There is no single clear explanation for the death assemblage, however.
Dodson et al.'s idea of it being an oxbow lake is not supported by the
sedimentological evidence: the layers immediately below the lake are
paleosols.  Periodic minor flooding was not large enough to have been
catastrophic. Possibly an influx of the volcaniclastic debries might have
temporarily absorbed the water of the lake, leaving a restricted body.
There is evidence of scavenging and trampling of the carcasses.

She apparently changed her mind because she said seep in recent article...
Bilbey, Sue Ann, 1999. Taphonomy of the Cleveland-Lloyd Dinosaur Quarry in
the Morrison Formation, Central Utah - a lethal spring-fed pond. In:
Vertebrate Paleontology in Utah. Edited by David D. Gillette. Miscellaneous
Publication 99-1, Utah Geological Survey: 121-133.

Another article is...

Richmond, Dean R., and Thomas H. Morris, 1996. The Dinosaur Death-Trap of
the Cleveland-Lloyd Quarry, Emery County, Utah. In: The Continental
Jurassic, Michael Morales, Ed., 1996, Museum of Northern Arizona Bulletin,
60: 533-545.

And a newer one.

Richmond, Dean R., and Thomas H. Morris, 1998. Stratigraphy and cataclysmic
deposition of the Dry Mesa Dinosaur Quarry, Mesa County, Colorado. In: The
Upper Jurassic Morrison Formation: An Interdisciplinary Study, Denver Museum
of Natural History, Denver USA, May 26-28, 1994. Edited by Kenneth
Carpenter, Daniel J. Chure and James I. Kirkland. Modern Geology, Volume 22,
Part 1: 121-143.
Tracy