Research Paper GEOSPHERE Sheeting joints and polygonal patterns in the Navajo Sandstone, southern Utah: Controlled by rock fabric, tectonic joints, buckling, GEOSPHERE, v. 14, no. 4 and gullying https://doi.org/10.1130/GES01614.1 David B. Loope and Caroline M. Burberry 14 figures; 1 table Department of Earth and Atmospheric Sciences, University of Nebraska, Lincoln, Nebraska 68588, USA CORRESPONDENCE:
[email protected] ABSTRACT overburden, sheeting joints (like “A-tents” and “pop-ups”; Jahns, 1943; Ro- CITATION: Loope, D.B., and Burberry, C.M., 2018, Sheet‑ mani and Twidale, 1999; Twidale and Bourne, 2003) have more recently been ing joints and polygonal patterns in the Navajo Sand‑ stone, southern Utah: Controlled by rock fabric, tec‑ Sheeting joints are ubiquitous in outcrops of the Navajo Sandstone on the interpreted as products of compressive stresses parallel to exposed rock sur- tonic joints, buckling, and gullying: Geosphere, v. 14, west-central Colorado Plateau, USA. As in granitic terrains, these are open- faces (Holzhausen, 1989; Bahat et al., 1999; Martel, 2011, 2017). These stresses no. 4, p. 1–19, https://doi.org/10.1130/GES01614.1. ing-mode fractures and form parallel to land surfaces. In our study areas in can be perturbed by local topography, so landscapes have strong influences south-central Utah, liquefaction during Jurassic seismic events destroyed on the distribution and abundance of fresh, fractured rock (Miller and Dunne, Science Editor: Raymond M. Russo stratification in large volumes of eolian sediment, and first-order sheeting 1996; St. Clair et al., 2015; Slim et al., 2015). At shallow depth, compressive joints are now preferentially forming in these structureless (isotropic) sand- stress parallel to convex land surfaces induces tension perpendicular to the Received 13 September 2017 stones.