Cedarville University DigitalCommons@Cedarville Science and Mathematics Faculty Publications Department of Science and Mathematics 1-21-2015 Intraformational Parabolic Recumbent Folds in the Coconino Sandstone (Permian) and Two Other Formations in Sedona, Arizona (USA) John Whitmore Cedarville University, [email protected] Guy Forsythe Paul A. Garner Follow this and additional works at: http://digitalcommons.cedarville.edu/ science_and_mathematics_publications Part of the Geology Commons Recommended Citation Whitmore, John; Forsythe, Guy; and Garner, Paul A., "Intraformational Parabolic Recumbent Folds in the Coconino Sandstone (Permian) and Two Other Formations in Sedona, Arizona (USA)" (2015). Science and Mathematics Faculty Publications. 308. http://digitalcommons.cedarville.edu/science_and_mathematics_publications/308 This Article is brought to you for free and open access by DigitalCommons@Cedarville, a service of the Centennial Library. It has been accepted for inclusion in Science and Mathematics Faculty Publications by an authorized administrator of DigitalCommons@Cedarville. For more information, please contact [email protected]. Answers Research Journal 8 (2015):21–40. www.answersingenesis.org/arj/v8/parabolic_recumbent_folds_Sedona_Arizona.pdf Intraformational Parabolic Recumbent Folds in the Coconino Sandstone (Permian) and Two Other Formations in Sedona, Arizona (USA) John H. Whitmore, Cedarville University, 251 N. Main St., Cedarville, OH 45314 USA [email protected] Guy Forsythe, PO Box 2526, Sedona, AZ 86339 USA [email protected] Paul A. Garner, 75 West Drive Gardens, Soham, Ely, Cambridgeshire CB7 5EZ United Kingdom [email protected] Abstract We report sedimentary structures that in all ways resemble parabolic recumbent folds (PRFs) in the cross-bedded portions of the Schnebly Hill Formation, the Coconino Sandstone and the Toroweap Formation (Arizona, USA). Field evidence suggests they are penecontemporaneous and intraformational. Intraformational refers to deformation that occurs between undeformed beds. Recumbent cross-bed sets occur over a wide area (>375 km2 [144 mi2]) at many different locations and horizons in the Sedona area, especially within the Coconino Sandstone. Deformation resulting from slumping dunes (dry or damp) is ruled out because of the nature of the deformation along cross-bed dip, the size and length of the deformation along horizontal bedding planes (sometimes up to 170 m [557 ft] along dip) and the lack of small faults usually concurrent with such slumping known from modern dunes. Neither do the folds resemble deformation that has been caused by post-depositional groundwater movement or seismic activity which often produces convolute bedding. We do report some seismic features in the Schnebly Hill Formation, but these features have distinct characteristics that distinguish them from PRFs. Although the exact mechanism of PRF formation is still debated, it is generally agreed that strong water currents combined with liquefaction play major roles in overturning the top of a cross-bed set during the deposition of the cross-bed. Rare planar-beds, directly associated with the PRFs in the Coconino, suggest that the needed liquefaction may have occurred from changes in flow regime. Some workers have already suggested that parts of the Schnebly Hill and Coconino were deposited by marine sand waves on a shallow continental shelf; a hypothesis that is considerably strengthened in light of these new data along with additional petrographic data that we have collected. Keywords: Coconino Sandstone, Schnebly Hill Formation, Toroweap Formation, parabolic recumbent folds, cross-bedded sandstones, soft-sediment deformation, liquefaction, primary current lineation, cross-bed dips Introduction and Background a meter), the wedge-planar cross-bedding style The Coconino Sandstone is a prominent Permian is dominant and persistent. In central Arizona cross-bedded sandstone that outcrops over much of the cross-bedded portions of the Schnebly Hill northern and central Arizona, including the Grand Formation are transitional with the overlying Canyon. It is characterized by fine-grained sand Coconino. For the most part, the contact between which outcrops in large cross-beds. The Coconino the two formations is defined by color; changing was first described in detail by the eminent Grand from red in the Schnebly Hill to tan in the Coconino. Canyon geologist Edwin McKee (1934) who later The Toroweap Formation lies above the Coconino, used it as a type example of an ancient eolian but in places it intertongues laterally and vertically sandstone (McKee 1979). The bedding style of the with the Coconino (Blakey and Knepp 1989). The Coconino is dominated by wedge-planar cross-beds; Toroweap primarily consists of planar-bedded it has not been until recently, when Whitmore et al. limestones, dolomite, sandstone, and gypsum which (2011) reported scattered planar-beds throughout were deposited in a shallow ocean (Rawson and the formation, that any other bedding styles were Turner-Peterson 1980). The Toroweap occasionally widely reported in the Coconino. Whether the has a cross-bedded sandstone facies which is similar Coconino is observed at its southern margin near to that found in the Schnebly Hill and Coconino. In Pine (where it is about 300 m [984 ft] thick), or at the the Toroweap, the cross-beds are often interpreted northern edge of the formation near the Arizona- as the product of coastal sand dunes (Rawson and Utah border (where it thins to only a fraction of Turner-Peterson 1980). ISSN: 1937-9056 Copyright © 2015 Answers in Genesis. All rights reserved. Consent is given to unlimited copying, downloading, quoting from, and distribution of this article for non-commercial, non-sale purposes only, provided the following conditions are met: the author of the article is clearly identified; Answers in Genesis is acknowledged as the copyright owner; Answers Research Journal and its website, www.answersresearchjournal.org, are acknowledged as the publication source; and the integrity of the work is not compromised in any way. For more information write to: Answers in Genesis, PO Box 510, Hebron, KY 41048, Attn: Editor, Answers Research Journal. The views expressed are those of the writer(s) and not necessarily those of the Answers Research Journal Editor or of Answers in Genesis. 22 J. H. Whitmore, G. Forsythe, and P. A. Garner Here we report meters-thick, many tens of meters- one from the Coconino in the Wupatki National long and extensive (>375 km2 [144.7 mi2]) occurrence Monument area (McKee 1979) and several from the of folds, many of which resemble parabolic recumbent Toroweap in the Oak Creek Canyon area (Rawson folds (PRFs), in parts of the Schnebly Hill, Coconino and Turner-Peterson 1980). The deformation we Sandstone and Toroweap Formation cross-beds in are describing in these formations is not vertically the Sedona, Arizona area (Fig. 1). We will focus on developed, but confined laterally to long individual deformation found in the Coconino Sandstone. Only cross-bed sets; it is quite different from the soft- two folded areas have previously been reported in sediment deformation features and convolute these formations, both interpreted as eolian slumps: bedding commonly found in the Navajo Sandstone PW 111°50’ W 19 km from MP Sedona LC DC BC CS 15 km from Sedona BM 2/3 BM 4 BM 1 MM 34°54’ N BR N CB CC 1 km Sedona OCC Sedona to 19 km north on 89A Canyons and Ridges Rt. 89A BC - Boynton Canyon BM - Bear Mountain BR - Brins Ridge CB - Capitol Butte CS - Cave Springs CC - Cockscomb CR - Castle Rock DC - Dry Creek Rt. 179 LC - Loy Canyon MM - Mescal Mountain MP - Dave Miller Pass OCC - Oak Creek Canyon PW - Pumphouse Wash CR 1 CR 2 Fig. 1. Map of Sedona, Arizona area showing locations where we have found Type I and II deformation of cross-beds in the Coconino Sandstone, Schnebly Hill, and Toroweap Formations (deformation types illustrated in Fig. 2 and defined in the text). Intraformational Parabolic Recumbent Folds in the Coconino Sandstone (Permian) Sedona, Arizona (USA) 23 Type I commonly occur in beds from 0.1 m (0.32 ft) to about 2 m (6.56 ft) in thickness, with some even thicker. Small examples have been produced experimentally 10 cm but only in subaqueous settings. All previously to 5 m known field examples occur in subaqueous cross- bedded sandstones (see table in Wells et al. 1993). Sometimes sheath folds are associated with the recumbent folds (Foos 2003, Plate 3-B). Type II Type II ( or contorted) folds are numerous folds that differ in the size, shape, and attitudes of the axial planes. The largest and most complex folding 10 cm to (some of which may be disharmonic) occurs near the 5 m top of the cross-bed set. Near the bottom of the cross- bed set, less folding and deformation occurs. As in Type I folds, stratification in the upper part of the cross-bed set may be blurred or absent. Faulting is Type III absent. Type I and Type II folds can occur together in the same cross-bed set showing a genetic relationship between the two types of folding. The deformation can 10 cm be mild or rather complex. Beds occur in thicknesses to from 0.1 to 5 m (0.32 to 16.4 ft). 25 cm Type III (or brecciated and faulted) folds include deformation structures that contain a mixture of overturned folds, thrust faults, “crinkly” bedding Fig. 2. The three primary types of deformation that occur and structureless sand. This type of deformation in cross-bedded sandstone units