The Geology of the N.A.S.A. Arizona Sedimentary Test Site Mohave Co. Arizona A thesis submitted in partial fulfillment of the requirements for the degree of Master of Science in Geology by Peter Anderson Brennan University of Nevada Reno. Nevada June 1968 The thesis of Peter Anderson Brennan is Approved Dept. Chairman Dean, Graduate School University of Nevada Reno June 1968 a b s t r a c t The NASA Fundamental Sedimentary Test Site in northern Mohave County, Arizona contains exposures of limestone, sandstone, conglomerate and thin layers of basalt. Structurally, the area consists of southeasterly dipping rock units transversed by a series of minor high angle faults, and a major low angle normal fault. The structure is complicated by drag folding along some of the faults, and minor changes in the direction and amount of the regional dip. The Tertiary and Quarternary units are superimposed unconformably over the faulted and tilted upper Paleozoic rocks. The topography is moderate, much of the site being in a broad flat valley. Because of the arid weathering conditions large detrital fans have been developed in the valleys. These fans support typical high desert vegetation. Remote sensing aircraft flights have yielded photographs, imagery and sensor data which, with detailed ground information provides an almost unique area in which to study the possible contributions of remote sensing to geology. Radar ultraviolet, photographic infrared, thermal infrared, microwave radiometry and scatterometry are available for the site. A comparative analysis between each of the sensing systems and the classical geologic study shows subtle peculiarities of each system giving data not otherwise available, except by careful field and laboratory studies. By integrating the various systems, details have been added and corrections made to the existing geologic interpretations. Two systems, the radar and the thermal infrared have been completely evaluated and are in- cluded. The degree of development of remote sensing instruments is not such that geologic mapping can be done from airborne data alone. In this study the remote sensors have provided valuable supplementary information and confirmed much of the geologic mapping. This study should enable future geology in similar areas to be done using remotely sensed data as a back­ bone, reducing field time by as much as 50 percent. TABLE OF CONTENTS A B S T R A C T ........................................ .. INTRODUCTION ............ ................... 1 Previous W o r k ........ ............ _ 4 Geologic S e tt in g......................... .. 5 Remote Sensor Data ......................... 7 STRATIGRAPHY ................................. g Pennsylvanian System ............. 9 Callvilie Limestone ........... 9 Permian System ................ 12 Hermit Formation ........................ 12 Coconino Sandstone ............ .... 19 Pre-Kaibab Unconformity ................. 26 Kaibab Limestone ....................... 27 Post-Kaibab Unconformity ............... 32 Cottonwood Wash Formation ............... 34 Triassic Jurassic, and Cretaceous Systems . 44 Tertiary System............................ 46 Muddy Creek Formation................... 47 Clastic M e m b e r ..................... 47 Fortification Basalt ................. 50 Quaternary Alluvium ....................... 58 STRUCTURE............................................ 60 General Structure ............................. 60 Western Boundary Fault ......................... 60 Strike Slip Faults v Jointing.................. 53 GEOLOGIC HISTORY ............................... 65 APPENDIX I — RADAR IMAGERY..................... 70 APPENDIX II - INFRARED IMAGERY .................. 80 R E F E R E N C E S ....................... 91 vi TABLE OF FIGURES Figure Page 1 Index m a p ........................ 2 2 Index m a p ........................ 3 3 Flight lines ............................ 6 4 Formation names ......................... 8 5 Callville Limestone ..................... 10 6 Hermit Formation ........................ 14 7 Hermit grain size distribution ......... 16 8 Coconino Sandstone ...................... 22 9 Coconino Sandstone ..................... 22 10 Coconino grain size distribution .... 24 11 Kaibab Limestone.................. 29 12 Basal "Cottonwood Wash" unconformity . 33 13 Air view of "Cottonwood W a s h " .... 35 14 "Cottonwood W a s h " .......... 35 15 "Cottonwood Wash" conglomerate ........ 37 16 "Cottonwood Wash" limestone ............. 41 17 Muddy Creek conglomerate ............... 48 18 Muddy Creek metamorphic boulders .... 48 19 Muddy Creek grain size distribution . 49 20 Air view of basalt f l o w s ........ 51 21 Basalt flows ..................... 51 22 Basalt flows ..................... 54 23 Surface of basalt f l o w .......... 54 24 Or-An-Ab triangular diagram ....... 57 vii 25 Structure contour m a p ......... 62 26 Rose diagrams and strain relationships. 64 27 Paleozoic carbonate sequence ........ 66 28 Horizontal radar returns ............. 78 29 Vertical radar returns ............... 79 30 Infrared temperature correlation chart. 87 31 Infrared imagery. ..................... 89 32 Infrared imagery. ................. 90 viii TABLE OF TABLES TABLE 1 Section of Hermit Formation.......... 17 TABLE 2 Hermit grain s i z e .................; 19 TABLE 3 Section of Coconino Sandstone......... 23 TABLE 4 Section of Kaibab Limestone........... 30 TABLE 5 Chemical analyses of lithic sands . 39 TABLE 6 Section of "Cottonwood Wash" limestone. 40 TABLE 7 Mineral composition of b a s a l t ......... 52 TABLE 8 Chemical variation of basalt........... 55 TABLE 9 Experimental iron ratios of basalts . 55 TABLE 10 Radar returns ..... ............... 73 TABLE 11 Infrared temperatures................. 86 IX 1 INTRODUCTION The purpose of the geologic study is to provide calibration for instruments with potential value in the locating and mapping of earth resources. The geology required for the interpretation of the output of airborne and potential satellite instruments goes beyond standard geologic mapping. Because of the pecularities of the sensors, aspects of soil, vegetation, weathering characteristics, surface texture and any other parameters which differentiate rock units must be studied. The NASA Fundamental Test Site for sedimentary rocks is located in extreme northwestern (Mohave County) Arizona, centered approxi­ mately 30° 37' N, 113° 571 W, and is oriented N-S. The 1 x 10 mile site is most easily accessible from Mesquite, Nevada, a distance of 17 miles over unsurfaced roads. This area was chosen for the variety of sedimentary lithologies which are readily distinguished from the air by both color and topographic expression. The terrain has moder­ ately low relief with only one escarpment exceeding 430 feet; the average elevation is approximately 3900 feet. Major adjacent topo­ graphic features should facilitate identification of the area from extreme altitudes. In this arid region where rainfall amounts to only a few inches per year, no bodies of water exist on the site. Lake Mead, 40 miles south, provides a large stable body of water which may be used for sensor calibration. 0 25 40 Kilometers SCALE Figure 1 . Index Map of Cane Springs area, Arizona. 2 PREVIOUS WORK Topographic coverage is supplied by the 15' Cane Springs (Arizona) quadrangle map. The southern half of the area is covered in more detail by the Ik' Littlefield SW quadrangle. The AMS 1:250,000 sheet for the Grand Canyon provides a large scale map of most of Mohave County. Two geologic maps have been published. The first is a reconnaissance map by Darton (1924), at a scale of 1:500,000, the second is a county map by the Arizona Bureau of Mines (1959) at a scale of 1:375,000. Both maps have their limitations; Darton concerned himself with bedrock and does not give adequately detailed information regarding the alluvial cover. The 1959 map is difficult to reconcile with the bedrock configuration. A revision of the Arizona Bureau of Mines map of Mohave county is now being compiled. 4 GEOLOGIC SETTING The Virgin and Beaver Dam Mountains form a transition zone between the Colorado Plateau and the Basin and Range Provinces. To the west, the typical Basin and Range topography of North-trending faulted mountains and alluvium-filled valleys extend across southern Nevada and into California. To the east, a series of north-south trending stop faults and long low mesas slowly bring the land up to the level of the Colorado Plateau. To the east the Grand Wash Fault, Hurricane Fault, and a series of smaller faults expose Mesozoic rocks and increase the general elevation to more than 5000 feet. These flat-lying Mesozoic sediments are best seen in Zion National Park. Immediately to the east of the sedimentary test site, a series of thin, dissected basalt flows top flat mesas extending to the Hurricane Cliffs on the east and Lake Mead on the south. These flows are uniform sheets that issued passively from fissures. On the east flank of the Virgin Mountains the rocks dip southeast away from the mountain core. At the north end of the site, beds dip 40° SE; at the center of the site they dip 20° ESE; further south they dip 15° ESE, and at the south end, flat-lying lavas cover the older sedimentary units. The faulting in the area, though complex, does not greatly disturb the normal sequence of beds except at the north end of the site where the upper Permian lies between the Pennsylvanian and lower Permian section, as a result of two faults of large displacement. 5 r i y u r u o FLIGHT LINES