Shatter Cones, Upheaval Dome's Outer Rim

J.D. Byous, Chief Research Assoc., A.T. Dowd Research, D.G. Marston, site consultant, 2016 Abstract Here we describe shatter cones and shatter features in Kayenta formation sandstone found on the southern rim lip of Upheaval Dome in Canyonlands National Park, Utah. These samples are located a few feet off of the southern section of the lower syncline loop trail as it drops into the canyon northwest of Holman Springs and are ~220 degrees and ~0.8 miles (~1.28km) from those described by Kriens, Shoemaker and Herkenhoff in 1998. 1 of 7, Upheaval Dome Shatter Cones, A.T. Dowd Research, 2016 Introduction Over the years Upheaval Dome in Canyonlands National Park, Utah has been the center of a geological controversy. Originally B.H. Parker (Harrison 1927) hypothesized that the structure was a salt diapir created by rising salt from the Paradox formation buried deep below. The Parker hypothesis suggests that salt pushed up to create a dome and thereafter eroding away into the onemile-wide crater that we see today. Later studies, 1998, Kriens, Shoemaker and Herkenhoff reported evidence of planar deformation of quartz grains well as samples of shatter cones in the crater center indicating a bolide impact genesis. Then in 2008 investigation by Buchner and Kenkmann found, “multiple sets of thin planar lamellae…”1 to support that impact claim. As late as 2015 a report by Geesaman, et al, holds to the salt diapir derivation claiming the evidence from earlier studies were incomplete and non-convincing of an impact origin.2 Based on the existence of shatter cones on the southern outside rim of the structure, we present this paper in evidence of the impact origin hypothesis. Text and photos © 2016 J. Byous Company/A.T. Dowd Research, all rights reserved UPHEAVAL DOME, UTAH, USA: IMPACT ORIGIN CONFIRMED, E. Buchner and T. Kenkmann Institut für Planetologie, Universität, Stuttgart, Germany, 2008. 2 New Evidence for Long-Term, Salt-Related Deformation at Upheaval Dome, SE Utah, P.J. Geesaman, B.D. Trudgill, T.E. Hearon, M. Rowan, Search and Discovery Article #10756. 2015. 1 2 of 7, Upheaval Dome Shatter Cones, A.T. Dowd Research, 2016 Description Several small clusters of shatter cones and shatter features can be found in Jurassic period, Kayenta formation sandstone3 along the Syncline Loop Trail on the rim edge above the south slope of Upheaval Dome in Canyonlands, National Park, Utah. These samples are located a few feet off of the southern segment of the lower syncline loop trail northwest of Holman Springs and ~220 degrees southeast of the crater center.4 Located within twenty feet of the trail their size and the typical front-lighted sun angle makes observation of the features difficult from the route. Several clusters of the ~0.5” to ~2” (~8mm to ~50mm) inverted “V” cones and linear profiles can be found around a small pinyon pine next to a rock face to the north of the trail where it first drops over the lip of the slope. The apices are aligned with the center of the crater and are formed in and around joints and cracks along the face with a relief of ~1/8” to 3/16” (~3mm to ~5mm). Sand grains from ~250µ to ~500µ make up the Kayenta sandstone and are obvious in the cones and striations. It is probable that other examples will be found nearby in future surveys. In 1998 similar shatter cones and features were described by Kriens, Shoemaker and Herkenhoff.5 They were found near the center of the crater in beds of Moenkopi sandstone some distance away, ~0.8 miles (~1.28km) at ~140 degrees to the northeast. However, samples shown here have a surface texture that is coarser and sharper than those noted in the report. The earlier samples appear to have a somewhat smoother surface textures than the current examples.6 Shatter cones are known to form only in bolide impacts and nuclear detonations. In light of evidence that in human history no know nuclear blasts have occurred at that location, we submit that the bolide impact origin of Upheaval Dome has been established as correct. Following are photographic samples of the shatter cones, shatter features and their locations. Kayenta formation as described in the paper, Structure and evolution of Upheaval Dome: A pinched-off salt diaper, Jackson, et. al. 1998. 4 GPS 38.428650° -109.939640°; UTM zone 12 S 592553.49 m E 4253908.71 m N 5 GEOLOGY OF THE UPHEAVAL DOME IMPACT STRUCTURE, SOUTHEAST UTAH, B.J. Kriens, E.M. Shoemaker, K.E. Herkenhoff, 1998. 6 Correspondence with K.E. Herkenhoff, June, 2016. (Note: We appreciate his input and opinion on these findings.) 3 3 of 7, Upheaval Dome Shatter Cones, A.T. Dowd Research, 2016 4 of 7, Upheaval Dome Shatter Cones, A.T. Dowd Research, 2016 5 of 7, Upheaval Dome Shatter Cones, A.T. Dowd Research, 2016 6 of 7, Upheaval Dome Shatter Cones, A.T. Dowd Research, 2016 7 of 7, Upheaval Dome Shatter Cones, A.T. Dowd Research, 2016