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Wiley InterScience | ||||
  Ground WaterVolume 33 Issue 4, Pages 561 - 569 Published Online: 4 Aug 2005 Journal compilation © 2010 National Ground Water Association
Abstract | References | Full Text: PDF (Size: 1726K) | Related Articles | Citation Tracking  Roberts Rift, Canyonlands, Utah, A Natural Hydraulic Fracture Caused by Comet or Asteroid Impact Copyright 1995 National Ground Water Association ABSTRACT
The impact that created Upheaval crater in Canyonlands National Park, Utah, is invoked here as the source for energy that simultaneously caused Roberts rift. However, no temporal linkage has been proven between the impact and rifting events. Roberts rift lies between 22 and 32 km northeast of the Upheaval impact crater on a subradial trend. The fissure contains clasts that were carried as much as 1,000 m upward from Paleozoic sources into the Mesozoic section. A plausible model for both the rifting and clast movement involves incremental loading of overpressured fluid compartments in the Pennsylvanian Paradox section and attendant hydraulic fracturing of the overlying confining strata during the impact event. The clasts were proppants entrained in upward moving fluids that originated from overpressured aquifers in the Pennsylvanian section or materials eroded from the fissure walls. Alteration halos and mineralization along the fissure reveal that there was upward leakage of reducing fluids from the overpressured zones following opening of the fissure. The fissure infillings became cemented with time, thus reducing fissure permeabilities to negligible. Received March 1994, revised August 1994 and November 1994, accepted October 1994. |
