Access

You are not currently logged in.

Access your personal account or get JSTOR access through your library or other institution:

login

Log in to your personal account or through your institution.

If you need an accessible version of this item please contact JSTOR User Support

Geology and Taphonomy of the Coelophysis Quarry, Upper Triassic Chinle Formation, Ghost Ranch, New Mexico

Hilde L. Schwartz and David D. Gillette
Journal of Paleontology
Vol. 68, No. 5 (Sep., 1994), pp. 1118-1130
Published by: Paleontological Society
Stable URL: http://www.jstor.org/stable/1306181
Page Count: 13
  • Read Online (Free)
  • Download ($12.00)
  • Cite this Item
If you need an accessible version of this item please contact JSTOR User Support
Geology and Taphonomy of the Coelophysis Quarry, Upper Triassic Chinle Formation, Ghost Ranch, New Mexico
Preview not available

Abstract

The Coelophysis dinosaur quarry at Ghost Ranch, near Abiquiu, New Mexico, is unique among Triassic fossil sites for its yield of numerous complete and partial skeletons of a single species of theropod dinosaur (Coelophysis bauri). Since its discovery in 1947 by E. H. Colbert in the red siltstone beds of the Upper Triassic Chinle Formation, the quarry has yielded the remains of at least 1,000 individuals from approximately 30 cubic meters of excavated material. The main bone-bearing strata are abandoned channel deposits that are part of a siltstone overbank sequence. The Coelophysis remains found at the quarry are remarkably whole and well preserved, though they range in degree of articulation from complete skeletons to isolated limbs and bones. Skeletons, partial skeletons, and bones are crudely aligned and show little evidence of predator or scavenger disturbance or surface weathering. Geologic and taphonomic evidence suggests that the dinosaurs preserved in the Ghost Ranch quarry were transported to the site as carcasses by fluvial currents. The carcasses blocked a small channel and were subsequently buried by silts. Petrographic study and neutron activation analysis reveal no evidence of volcanic ash, paleopathologic osteology, or unusual chemistry in the quarry bone and sediments. The virtual monospecificity, taphonomy, and ecology of the assemblage suggest that the dinosaurs perished due to a regional environmental crisis, such as drought.

Page Thumbnails

  • Thumbnail: Page 
1118
    1118
  • Thumbnail: Page 
1119
    1119
  • Thumbnail: Page 
1120
    1120
  • Thumbnail: Page 
1121
    1121
  • Thumbnail: Page 
1122
    1122
  • Thumbnail: Page 
1123
    1123
  • Thumbnail: Page 
1124
    1124
  • Thumbnail: Page 
1125
    1125
  • Thumbnail: Page 
1126
    1126
  • Thumbnail: Page 
1127
    1127
  • Thumbnail: Page 
1128
    1128
  • Thumbnail: Page 
1129
    1129
  • Thumbnail: Page 
1130
    1130