Published in 2000 in Journal of Geophysical Research - Planets, vol. 105
(no. E4, April 25), pages 9489-9505.
Submitted June 22, 1999, revised November 19, 1999, accepted December 7, 1999.
Abstract
The origin of Upheaval Dome, in Canyonlands National Park of southeastern Utah,
has been a topic of controversy among geologists and planetary scientists.
The structure has long been thought
to have been created by salt diapirism from the underlying Paradox Formation.
Recent studies have suggested that impact could have formed
the dome. To test the various hypotheses,
we acquired, processed, and interpreted seismic reflection data within
and adjacent to the structure. Both conventionally
stacked and prestack-migrated images show <100 m relief in
the Paradox
Formation, contrary to salt diapirism hypotheses. Further, we have
identified features within the images typical of impact structures, such as
listric normal faults having displacements toward the center of the dome.
Deformation occurs in two depth ranges, with the faulting that created the
central uplift appearing only above the Hermosa Formation, in the upper 800
m of the structure.
The images also suggest limited fracturing of the Hermosa and salt flow in the
Paradox Formation, perhaps due to gravitational relaxation of the crater form.
Our image of a nearly flat top of the Paradox salt
strongly favors an impact origin for Upheaval Dome.
