Geology topics
Tracey J. Felger
Publications and source records attributed to Tracey J. Felger.
Post-Early Miocene silicic volcanism in the northern Mojave Desert, California
Silicic volcanism that postdates widespread early Miocene volcanism in the Mojave Desert is underappreciated. We compiled age, petrographic, and geochemical data for volcanic rocks in a wide swath of the desert south of the Garlock fault using an age threshold of post-18.8 Ma, approximately the limit of the earlier Miocene volcanism as marked by the eruption of the widespread Peach Spring Tuff. In addition to the well-known young basaltic volcanic centers not considered in this paper, several dozen silicic volcanic edifices are known or likely to be younger than 18.8 Ma. Several examples of rhyolite tuffs and basalt lava in middle Miocene basin occur in sequences of the Barstow Formation and its correlatives. Dacite domes are common in the Calico Mountains, dated at ~17 Ma, and similar, but mostly undated, domes are scattered nearby in the Barstow area and east of the Calico Mountains. North of Barstow, chains of rhyolite domes and scattered dacite domes are known. A few of these domes and flows are dated in the range of 13-7 Ma. Farther north, the Lava Mountains have several volcanic sequences from 12 to 7 Ma and ranging in composition from basalt to rhyolite. Farther east and west are more rhyolite and dacite domes, in general undated, as well as the extensive ~17.8 Ma Woods Mountains rhyolite center. Sparse geochemical data for the silicic rocks indicate distinct rhyolite and dacite groups, and rare andesite. Understanding of these potentially young silicic volcanic rocks is hampered by poor age control and geochemical data, but more study holds promise for better understanding the origins of volcanism in the Mojave Desert.
Geologic and geophysical maps of the Newfoundland Mountains and part of the adjacent Wells 30' x 60' quadrangles, Box Elder County, Utah
The Newfoundland Mountains map area (Newfoundland Mountains and adjacent part of Wells 30' x 60' quadrangles) is located in Box Elder County, northwestern Utah. The map encompasses broad expanses of the Great Salt Lake Desert as well as several picturesque mountain ranges (figures 1, 2, and 3). The geology of the area was last mapped and summarized by Doelling (1980). Since that landmark study, much of the area has been mapped in greater detail and new paleontologic, geochronologic, and structural data provide for an updated view of the geology. In addition, new geophysical studies (Langenheim and others, 2013; Langenheim, 2016) provide key data for improved interpretation of subsurface geology. The geologic map (plate 1) was compiled from fifteen 7.5' quadrangles mapped at a scale of 1:24,000 (mostly in the western part of the area), one map covering the Newfoundland Mountains at a scale of 1:31,680 (Allmendinger and Jordan, 1989), unpublished geologic mapping at scales from 1:24,000 to 1:50,000 (most by Miller; Bovine Mountain by T.E. Jordan), and reconnaissance mapping and aerial photo interpretation in intervening areas by Miller. Some published maps were remapped or reinterpreted by the authors in light of more recent studies north of the map area. Geologic mapping conducted as part of several theses/dissertations and a few published papers also were used (plate 2, index to geologic mapping). Concealed faults under valley bottoms were interpreted from gravity and aeromagnetic data. Our approach for this map was to integrate across the main themes of the mapped geology by generalizing units, structures, and polygons. This has the aim of illustrating the principal tectonic and stratigraphic packages, as well as illustrating the patterns of surficial units and geomorphology. Cross sections (plate 2) were constructed to coincide with representative cross sections for several detailed geologic maps. This approach required large bends across valleys. Basin geometry shown in the cross sections was constrained by gravity data and a seismic line since few deep drill holes are available.
Attribute rules and dictionary symbology in ArcGIS Pro help streamline geologic map compilation in GeMS
Attribute rules and dictionary symbology are functionality available in ArcGIS Pro that can dramatically streamline the compilation of geologic maps in GeMS - the Geologic Map Schema that is the standard delivery schema mandated for projects funded by the Cooperative Geologic Mapping Program. Testing of the functionality produced attribute rules and a symbol dictionary that support two compilation workflows, one for digitizing an existing analog map, the other for compiling new field mapping.
Insights into post-Miocene uplift of the western margin of the Colorado Plateau from the stratigraphic record of the lower Colorado River
The spatial and temporal distribution of Pliocene to Holocene Colorado River deposits (southwestern USA and northwestern Mexico) form a primary data set that records the evolution of a continental-scale river system and helps to delineate and quantify the magnitude of regional deformation. We focus in particular on the age and distribution of ancestral Colorado River deposits from field observations, geologic mapping, and subsurface studies in the area downstream from Grand Canyon (Arizona, USA). A new 4.73 ± 0.17 Ma age is reported for a basalt that flowed down Grand Wash to near its confluence with the Colorado River at the eastern end of what is now Lake Mead (Arizona and Nevada). That basalt flow, which caps tributary gravels, another previously dated 4.49 ± 0.46 Ma basalt flow that caps Colorado River gravel nearby, and previously dated speleothems (2.17 ± 0.34 and 3.87 ± 0.1 Ma) in western Grand Canyon allow for the calculation of long-term incision rates. Those rates are ~90 m/Ma in western Grand Canyon and ~18–64 m/Ma in the eastern Lake Mead area. In western Lake Mead and downstream, the base of 4.5–3.5 Ma ancestral Colorado River deposits, called the Bullhead Alluvium, is generally preserved below river level, suggesting little if any bedrock incision since deposition. Paleoprofiles reconstructed using ancestral river deposits indicate that the lower Colorado River established a smooth profile that has been graded to near sea level since ca. 4.5 Ma. Steady incision rates in western Grand Canyon over the past 0.6–4 Ma also suggest that the lower Colorado River has remained in a quasi–steady state for millions of years with respect to bedrock incision. Differential incision between the lower Colorado River corridor and western Grand Canyon is best explained by differential uplift across the Lake Mead region, as the overall 4.5 Ma profile of the Colorado River remains graded to Pliocene sea level, suggesting little regional subsidence or uplift. Cumulative estimates of ca. 4 Ma offsets across faults in the Lake Mead region are similar in magnitude to the differential incision across the area during the same approximate time frame. This suggests that in the past ~4 Ma, vertical deformation in the Lake Mead area has been localized along faults, which may be a surficial response to more deep-seated processes. Together these data sets suggest ~140–370m of uplift in the past 2–4 Ma across the Lake Mead region.
Geologic map of the Castle Rock 7.5' quadrangle, Arizona and California
The Castle Rock quadrangle is in the northeast corner of Chemehuevi Valley, California and Arizona. It includes the Colorado River’s entrance to the valley at the mouth of Topock Gorge and the northern outskirts of Lake Havasu City, Arizona, and the Chemehuevi Indian Tribe community of Havasu Lake, California. The map includes large parts of the Chemehuevi Indian Reservation and the Havasu National Wildlife Refuge. Upon its exit through the mouth of Topock Gorge, the Colorado River enters Chemehuevi Valley where its floodplain (now submerged under Lake Havasu) is flanked by alluvial piedmonts of the Chemehuevi and Mohave Mountains to the west and east, respectively. This abrupt transition offers a useful perspective into the structural evolution of the Colorado River extensional corridor and of the Colorado River itself. It contains key structural and stratigraphic elements recording a complex history of Cretaceous plutonism and deformation, significant tectonic extension, volcanism, and sedimentation in the Miocene, and, ultimately, the evolution of the Colorado River from the latest Miocene to the present. Lake Havasu submerged the axis of Chemehuevi Valley following the completion of Parker Dam in 1938, and the Colorado River now feeds a verdant delta marsh that composes part of the map. Important bedrock units include the Cretaceous Chemehuevi Mountains Plutonic Suite, the 18.78 Ma Peach Spring Tuff, and thick overlying sequences of interlayered Miocene megabreccia and fanglomerate. The exposure of these units is closely linked to extension along the Chemehuevi-Whipple Mountains detachment fault system. The complex bedrock geologic framework serves as the structural and topographic foundation for the key strata chronicling the evolution of the lower Colorado River. Important stratigraphic units that bear on its evolution to the present day include the Bouse Formation, the Bullhead Alluvium, and the Chemehuevi Formation. The map area also contains the river’s modern delta at the head of Lake Havasu.
The Colorado River and its deposits downstream from Grand Canyon in Arizona, California, and Nevada
Understanding the evolution of the Colorado River system has direct implications for (1) the processes and timing of continental-scale river system integration, (2) the formation of iconic landscapes like those in and around Grand Canyon, and (3) the availability of groundwater resources. Spatial patterns in the position and type of Colorado River deposits, only discernible through geologic mapping, can be used to test models related to Colorado River evolution. This is particularly true downstream from Grand Canyon where ancestral Colorado River deposits are well-exposed. We are principally interested in (1) regional patterns in the minimum and maximum elevation of each depositional unit, which are affected by depositional mechanism and postdepositional deformation; and (2) the volume of each unit, which reflects regional changes in erosion, transport efficiency, and accommodation space. The volume of Colorado River deposits below Grand Canyon has implications for groundwater resources, as the primary regional aquifer there is composed of those deposits. To this end, we are presently mapping Colorado River deposits and compiling and updating older mapping. This preliminary data release shows the current status of our mapping and compilation efforts. We plan to update it at regular intervals in conjunction with ongoing mapping.
Geologic and geophysical maps and volcanic history of the Kelton Pass SE and Monument Peak SW Quadrangles, Box Elder County, Utah
The Kelton Pass SE and Monument Peak SW 7.5' quadrangles are located in Box Elder County, northwestern Utah (figure 1; plate 1). The northern boundary of the map area is 8.5 miles (13.7 km) south of the Utah-Idaho border, and the southern boundary reaches the edge of mud flats at the north end of Great Salt Lake. Elevations range from 4218 feet (1286 m) along the mud flats to 5078 feet (1548 m) in the Wildcat Hills. Deep Creek forms a prominent drainage between the Wildcat Hills and Cedar Hill. The closest towns are the ranching communities of Snowville, Utah (10 miles [16 km] to the northeast) (figure 1), and Park Valley, Utah (10 miles [16 km] to the west). The Kelton Pass SE and Monument Peak SW 7.5' quadrangles are located entirely within southern Curlew Valley, which drains south into Great Salt Lake, and extends north of the area shown on figure 1 into Idaho. Curlew Valley is bounded on the west by the Raft River Mountains and on the east by the Hansel Mountains (figure 1). Sedimentary and volcanic bedrock exposures within the quadrangles form the Wildcat Hills, Cedar Hill, and informally named Middle Shield (figure 1). Exposed rocks and deposits are Permian to Holocene in age, and include the Permian quartz sandstone and orthoquartzite of the Oquirrh Formation (Pos), tuffaceous sedimentary rocks of the Miocene Salt Lake Formation (Ts), Pliocene basaltic lava flows (Tb) and dacite (Tdw), Pleistocene rhyolite (Qrw) and basalt (Qb), and Pleistocene and Holocene surficial deposits of alluvial, lacustrine, and eolian origin. Structurally, the map area is situated in the northeastern Basin and Range Province, and is inferred to lie within the hanging wall of the late Miocene detachment faults exposed in the Raft River Mountains to the northwest (e.g., Wells, 1992, 2009; figure 1). This mapping project was undertaken to produce a comprehensive, large-scale geologic map of the Wildcat Hills, as well as to improve understanding of the volcanic and tectonic evolution of southern Curlew Valley. The resultant publication includes a geologic map of the Kelton Pass SE and Monument Peak SW quadrangles (plate 1), two interpretive geologic cross sections (plate 2), new geophysical data and interpretations, and new geochronology data for volcanic units within and near the quadrangles.
Preliminary geologic map of Black Canyon and surrounding region, Nevada and Arizona
Thermal springs in Black Canyon of the Colorado River, downstream of Hoover Dam, are important recreational, ecological, and scenic features of the Lake Mead National Recreation Area. This report presents the results from a U.S. Geological Survey study of the geologic framework of the springs. The study was conducted in cooperation with the National Park Service and funded by both the National Park Service and National Cooperative Geologic Mapping Program of the U.S. Geological Survey. The report has two parts: A, a 1:48,000-scale geologic map created from existing geologic maps and augmented by new geologic mapping and geochronology; and B, an interpretive report that presents results based on a collection of fault kinematic data near springs within Black Canyon and construction of 1:100,000-scale geologic cross sections that extend across the western Lake Mead region. Exposures in Black Canyon are mostly of Miocene volcanic rocks, underlain by crystalline basement composed of Miocene plutonic rocks or Proterozoic metamorphic rocks. The rocks are variably tilted and highly faulted. Faults strike northwest to northeast and include normal and strike-slip faults. Spring discharge occurs along faults intruded by dacite dikes and plugs; weeping walls and seeps extend away from the faults in highly fractured rock or relatively porous volcanic breccias, or both. Results of kinematic analysis of fault data collected along tributaries to the Colorado River indicate two episodes of deformation, consistent with earlier studies. The earlier episode formed during east-northeast-directed extension, and the later during east-southeast-directed extension. At the northern end of the study area, pre-existing fault blocks that formed during the first episode were rotated counterclockwise along the left-lateral Lake Mead Fault System. The resulting fault pattern forms a complex arrangement that provides both barriers and pathways for groundwater movement within and around Black Canyon. Regional cross sections in this report show that thick Paleozoic carbonate aquifer rocks of east-central Nevada do not extend into the Black Canyon area and generally are terminated to the south at a major tectonic boundary defined by the northeast-striking Lake Mead Fault System and the northwest-striking Las Vegas Valley shear zone. Faults to the west of Black Canyon strike dominantly north-south and form a complicated pattern that may inhibit easterly groundwater movement from Eldorado Valley. To the east of Black Canyon, crystalline Proterozoic rocks locally overlain by Tertiary volcanic rocks in the Black Mountains are bounded by steep north-south normal faults. These faults may also inhibit westerly groundwater movement from Detrital Valley toward Black Canyon. Finally, the cross sections show clearly that Proterozoic basement rocks and (or) Tertiary plutonic rocks are shallow in the Black Canyon area (at the surface to a few hundred meters depth) and are cut by several major faults that discharge most of the springs in the Black Canyon. Therefore, the faults most likely provide groundwater pathways to sufficient depths that the groundwater is heated to the observed temperatures of up to 55 °C.
Geologic framework of thermal springs, Black Canyon, Nevada and Arizona
Thermal springs in Black Canyon of the Colorado River, downstream of Hoover Dam, are important recreational, ecological, and scenic features of the Lake Mead National Recreation Area. This report presents the results from a U.S. Geological Survey study of the geologic framework of the springs. The study was conducted in cooperation with the National Park Service and funded by both the National Park Service and National Cooperative Geologic Mapping Program of the U.S. Geological Survey. The report has two parts: A, a 1:48,000-scale geologic map created from existing geologic maps and augmented by new geologic mapping and geochronology; and B, an interpretive report that presents results based on a collection of fault kinematic data near springs within Black Canyon and construction of 1:100,000-scale geologic cross sections that extend across the western Lake Mead region. Exposures in Black Canyon are mostly of Miocene volcanic rocks, underlain by crystalline basement composed of Miocene plutonic rocks or Proterozoic metamorphic rocks. The rocks are variably tilted and highly faulted. Faults strike northwest to northeast and include normal and strike-slip faults. Spring discharge occurs along faults intruded by dacite dikes and plugs; weeping walls and seeps extend away from the faults in highly fractured rock or relatively porous volcanic breccias, or both. Results of kinematic analysis of fault data collected along tributaries to the Colorado River indicate two episodes of deformation, consistent with earlier studies. The earlier episode formed during east-northeast-directed extension, and the later during east-southeast-directed extension. At the northern end of the study area, pre-existing fault blocks that formed during the first episode were rotated counterclockwise along the left-lateral Lake Mead Fault System. The resulting fault pattern forms a complex arrangement that provides both barriers and pathways for groundwater movement within and around Black Canyon. Regional cross sections in this report show that thick Paleozoic carbonate aquifer rocks of east-central Nevada do not extend into the Black Canyon area and generally are terminated to the south at a major tectonic boundary defined by the northeast-striking Lake Mead Fault System and the northwest-striking Las Vegas Valley shear zone. Faults to the west of Black Canyon strike dominantly north-south and form a complicated pattern that may inhibit easterly groundwater movement from Eldorado Valley. To the east of Black Canyon, crystalline Proterozoic rocks locally overlain by Tertiary volcanic rocks in the Black Mountains are bounded by steep north-south normal faults. These faults may also inhibit westerly groundwater movement from Detrital Valley toward Black Canyon. Finally, the cross sections show clearly that Proterozoic basement rocks and (or) Tertiary plutonic rocks are shallow in the Black Canyon area (at the surface to a few hundred meters depth) and are cut by several major faults that discharge most of the springs in the Black Canyon. Therefore, the faults most likely provide groundwater pathways to sufficient depths that the groundwater is heated to the observed temperatures of up to 55 °C.
Geologic map of Lake Mead and surrounding regions, southern Nevada, southwestern Utah, and northwestern Arizona
Regional stratigraphic units and structural features of the Lake Mead region are presented as a 1:250,000 scale map, and as a Geographic Information System database. The map, which was compiled from existing geologic maps of various scales, depicts geologic units, bedding and foliation attitudes, faults and folds. Units and structural features were generalized to highlight the regional stratigraphic and tectonic aspects of the geology of the Lake Mead region. This map was prepared in support of the papers presented in this volume, Special Paper 463, as well as to facilitate future investigations in the region. Stratigraphic units exposed within the area record 1800 million years of geologic history and include Proterozoic crystalline rocks, Paleozoic and Mesozoic sedimentary rocks, Mesozoic plutonic rocks, Cenozoic volcanic and intrusive rocks, sedimentary rocks and surficial deposits. Following passive margin sedimentation in the Paleozoic and Mesozoic, late Mesozoic (Sevier) thrusting and Late Cretaceous and early Tertiary compression produced major folding, reverse faulting, and thrust faulting in the Basin and Range, and resulted in regional uplift and monoclinal folding in the Colorado Plateau. Cenozoic extensional deformation, accompanied by sedimentation and volcanism, resulted in large-magnitude high- and low-angle normal faulting and strike-slip faulting in the Basin and Range; on the Colorado Plateau, extension produced north-trending high-angle normal faults. The latest history includes integration of the Colorado River system, dissection, development of alluvial fans, extensive pediment surfaces, and young faulting. Stratigraphic units exposed within the area record 1800 million years of geologic history and include Proterozoic crystalline rocks, Paleozoic and Mesozoic sedimentary rocks, Mesozoic plutonic rocks, Cenozoic volcanic and intrusive rocks, sedimentary rocks and surfi cial deposits. Following passive margin sedimentation in the Paleozoic and Mesozoic, late Mesozoic (Sevier) thrusting and Late Cretaceous and early Tertiary compression produced major folding, reverse faulting, and thrust faulting in the Basin and Range, and resulted in regional uplift and monoclinal folding in the Colorado Plateau. Cenozoic extensional deformation, accompanied by sedimentation and volcanism, resulted in large-magnitude high- and low-angle normal faulting and strike-slip faulting in the Basin and Range; on the Colorado Plateau, extension produced north-trending high-angle normal faults. The latest history includes integration of the Colorado River system, dissection, development of alluvial fans, extensive pediment surfaces, and young faulting.
Integration of tectonic, sedimentary, and geohydrologic processes leading to a small-scale extension model for the Mormon Mountains area north of Lake Mead, Lincoln County, Nevada
Scattered remnants of highly diverse stratigraphic sections of Tertiary lacustrine limestone, andesite flows, and 23.8–18.2 Ma regional ash-flow tuffs on the north flank of the Mormon Mountains record previously unrecognized deformation, which we interpret as pre–17 Ma uplift and possibly weak extension on the north flank of a growing dome. Directly to the north of the Mormon dome, 17–14 Ma ash-flow tuffs and rhyolite are interstratified with landslides, debris avalanches, debris flows, and alluvial-fan deposits that accumulated to a thickness of more than 2 km in an extension-parallel basin. The source for the landslides and debris avalanche deposits is unknown, but it was probably an adjacent scarp along a transverse fault bounding an early part of the Mormon dome. An average 45° of easterly tilt of the entire Tertiary basin-fill succession represents the major post–14 Ma deformation event in the region. We question the basis for the published estimate of 22 km of westerly displacement on the Mormon Peak detachment fault and, on the basis of landslides in the upper plate having a probable source in the adjacent Mormon dome, constrain the heave to ~4 km. We interpret the dome and basin as coupled strains similar to others in the region and suggest that these strains reflect a waveform pattern of extension-normal lateral midcrustal ductile flow. Previously, doming was interpreted as an isostatic response to tectonic unloading by large-displacement detachment faults or as pseudo-structural highs stranded by removal of middle crust from adjacent areas. Moreover, we argue that the strong thinning of upper-plate rock successions throughout the Mormon Mountains and Tule Springs Hills resulted from a loss of rock volume by protracted fluid flow, dissolution, and collapse, seriously limiting the usefulness of upper-plate strain in evaluating extension magnitude. We present a geohydrologic model that couples uplift driven by ductile inflow with dissolution driven by fluid infiltration, possibly augmented by mantle-derived CO 2 -rich fluids. Karsting in the uplands led to carbonate sedimentation in adjacent lowlands. Whether or not our downward revision of extension in the Mormon Mountains is valid, extension at that latitude is isolated from extension in the Lake Mead area by a low-strain corridor between the two areas. Recognition of the isolated and potentially diminished strain impacts estimates of maximum finite elongation of the Basin and Range Province because one of three vector paths used in those estimates passes through the Mormon Mountains.
Geologic map of the Fredonia 30' x 60' quadrangle, Mohave and Coconino counties, northern Arizona
This geologic map is the result of a cooperative effort of the U.S. Geological Survey, the National Park Service, the U.S. Forest Service, and the Bureau of Land Management (BLM) and the Kaibab-Paiute Tribe to provide a regional geologic database for resource management officials of all government and agencies, city municipalities, private enterprises, and individuals of this part of the Arizona Strip. The Arizona Strip is part of northwestern Arizona north of the Colorado River and bounded by the States of Nevada and Utah. Field work on the Kaibab-Paiute Indian Reservation was conducted from 2002 to 2005 with permission from the Kaibab-Paiute Tribal Government of that administration and permission was granted to publish a geologic map of 4 quadrangles online (Billingsley and others, 2004). The Kaibab-Paiute Tribal government of 2006 to 2008 requested that all geologic information within the Kaibab-Paiute Indian Reservation not be published as part of the Fredonia 30' x 60' quadrangle (this publication). For further information, contact the Kaibab-Paiute Tribal government at HC 65 Box 2, Fredonia, Arizona, 86022, telephone # (928) 643-7245. Visitors to the Kaibab-Paiute Indian Reservation are required to obtain a permit and permission for access from the Tribal Offices at the junction of State Highway 389 and the paved road leading to Pipe Spring National Monument. The Fredonia 30' x 60' quadrangle encompasses approximately 5,018 km2 (1,960 mi2) within Mohave and Coconino Counties, northern Arizona and is bounded by longitude 112 deg to 113 deg W., and latitude 36 deg 30' to 37 deg N. The map area lies within the southern Colorado Plateaus geologic province (herein Colorado Plateau). The map area is locally subdivided into seven physiographic parts: the Grand Canyon (Kanab Canyon and its tributaries), Kanab Plateau, Uinkaret Plateau, Kaibab Plateau, Paria Plateau, House Rock Valley, and Moccasin Mountains as defined by Billingsley and others, 1997, (fig. 1). Elevations range from 2,737 m (8,980 ft) just west of State Highway 67 on the Kaibab Plateau, southeast corner of the map area to about 927 m (3,040 ft) in Kanab Canyon, south-central edge of the map area.
Database for the Geologic Map of the Summit Region of Kilauea Volcano, Hawaii
INTRODUCTION The area covered by this map includes parts of four U.S. Geological Survey (USGS) 7.5' topographic quadrangles (Kilauea Crater, Volcano, Ka`u Desert, and Makaopuhi). It encompasses the summit, upper rift zones, and Koa`e Fault System of Kilauea Volcano and a part of the adjacent, southeast flank of Mauna Loa Volcano. The map is dominated by products of eruptions from Kilauea Volcano, the southernmost of the five volcanoes on the Island of Hawai`i and one of the world's most active volcanoes. At its summit (1,243 m) is Kilauea Crater, a 3 km-by-5 km collapse caldera that formed, possibly over several centuries, between about 200 and 500 years ago. Radiating away from the summit caldera are two linear zones of intrusion and eruption, the east and the southwest rift zones. Repeated subaerial eruptions from the summit and rift zones have built a gently sloping, elongate shield volcano covering approximately 1,500 km2. Much of the volcano lies under water: the east rift zone extends 110 km from the summit to a depth of more than 5,000 m below sea level; whereas, the southwest rift zone has a more limited submarine continuation. South of the summit caldera, mostly north-facing normal faults and open fractures of the Koa`e Fault System extend between the two rift zones. The Koa`e Fault System is interpreted as a tear-away structure that accommodates southward movement of Kilauea's flank in response to distension of the volcano perpendicular to the rift zones. This digital release contains all the information used to produce the geologic map published as USGS Geologic Investigations Series I-2759 (Neal and Lockwood, 2003). The main component of this digital release is a geologic map database prepared using ArcInfo GIS. This release also contains printable files for the geologic map and accompanying descriptive pamphlet from I-2759.
Geologic map of Wupatki National Monument and vicinity, Coconino County, Northern Arizona
Introduction The geologic map of Wupatki National Monument is a cooperative effort between the U.S. Geological Survey, the National Park Service, and the Navajo Nation to provide geologic information for resource management officials of the National Park Service, U.S. Forest Service, Navajo Indian Reservation (herein the Navajo Nation), and visitor information services at Wupatki National Monument, Arizona. Funding for the map was provided in part by the Water Rights Branch of the Water Resources Division of the National Park Service. Field work on the Navajo Nation was conducted under a permit from the Navajo Nation Minerals Department. Any persons wishing to conduct geologic investigations on the Navajo Nation must first apply for, and receive, a permit from the Navajo Nation Minerals Department, P.O. Box 1910, Window Rock, Arizona 86515, telephone (928)-871-6587. Wupatki National Monument lies within the USGS 1:24,000-scale Wupatki NE, Wupatki SE, Wupatki SW, Gray Mountain, East of SP Mountain, and Campbell Francis Wash quadrangles in northern Arizona. The map is bounded approximately by longitudes 111? 16' to 111? 32' 30' W. and latitudes 35? 30' to 35? 37' 40' N. The map area is in Coconino County on the southern part of the Colorado Plateaus geologic province (herein Colorado Plateau). The map area is locally subdivided into three physiographic parts, the Coconino Plateau, the Little Colorado River Valley, and the San Francisco Volcanic Field as defined by Billingsley and others (1997) [fig. 1]. Elevations range from 4,220 ft (1,286 m) at the Little Colorado River near the northeast corner of the map area to about 6,100 ft (1,859 m) at the southwest corner of the map area. The small community of Gray Mountain is about 16 mi (26 km) northwest of Wupatki National Monument Visitor Center, and Flagstaff, Arizona, the nearest metropolitan area, is about 24 mi (38 km) southwest of the Visitor Center (fig. 1). U.S. Highway 89 provides access to the west entrance of Wupatki National Monument. A paved Coconino County road provides a loop from Wupatki National Monument south to Sunset Crater National Monument and back to U.S. Highway 89 about 10 mi (16 km) north of Flagstaff, Arizona. Access to Coconino National Forest is via dirt roads maintained by the National Forest Service. Several unimproved dirt roads on Babbitt Ranch lands provide limited access to remote areas north of Wupatki National Monument. Travel is mostly restricted to paved roads within Wupatki National Monument, and a dirt road that crosses the Little Colorado River provides access to the Navajo Nation area east and northeast of the Little Colorado River. The Little Colorado River crossing is not bridged and can be impassable when the river is flowing. Four-wheel-drive vehicles are recommended but not necessary for travel in remote parts of the Navajo Nation. Extra food and water are highly recommended for travel in this sandy area. Land ownership north of Wupatki National Monument forms a checkerboard pattern between private and State land. Coconino National Forest manages lands south of Wupatki National Monument and the National Park Service manages Wupatki National Monument. The Leupp and Tolani Lake Chapters of the Navajo Nation manage the area northeast and east of the Little Colorado River (see land management boundaries on map). The geologic map of Wupatki National Monument provides updated geologic framework information for this part of the Colorado Plateau. The geologic information supports Federal, State, and private land managers when conducting geologic, biologic, and hydrologic investigations and will support future and ongoing geologic and associated scientific investigations of all disciplines within the Wupatki National Monument area.
Geologic map of the Cameron 30' x 60' quadrangle, Coconino County, northern Arizona
This geologic map is the result of a cooperative effort of the U.S. Geological Survey and the National Park Service in collaboration with the Navajo Nation and the Hopi Tribe to provide regional geologic information for resource management officials of the National Park Service, U.S. Forest Service, Navajo Indian Reservation (herein the Navajo Nation), the Hopi Tribe, and for visitor information services at Grand Canyon National Park, Arizona as well as private enterprises that have lands within the area. The Cameron 30’ x 60’ quadrangle encompasses approximately 5,018 km 2 (1,960 mi 2 ) within Coconino County, northern Arizona and is bounded by longitude 111° to 112° W., and latitude 35°30’ to 36° N. The map area is within the southern Colorado Plateaus geologic province (herein Colorado Plateau). The map area is locally subdivided into six physiographic areas: the Grand Canyon (including the Little Colorado River Gorge), Coconino Plateau, Marble Plateau, Little Colorado River Valley, Moenkopi Plateau, and the San Francisco Volcanic Field as defined by Billingsley and others, 1997 (fig. 1). Elevations range from about 2,274 m (7,460 ft) at the south rim of Grand Canyon along State Highway 64 to about 994 m (3,260 ft) in the Grand Canyon, northeast quarter of the map area. The Cameron quadrangle is one of the few remaining areas near the Grand Canyon where uniform geologic mapping was needed for geologic connectivity of the regional geologic framework that will be useful to federal, state, and private land resource managers who direct environmental and land management programs such as range management, biological studies, flood control, and water resource investigations. The geologic information presented will support future and ongoing local geologic investigations and associated scientific studies of all disciplines within the Cameron quadrangle area.
Geologic map of the Valle 30' x 60' quadrangle, Coconino County, northern Arizona
The geologic map of the Valle 30' x 60' quadrangle is the result of a cooperative effort between the U.S. Geological Survey and the National Park Service to provide geologic information for regional resource management and visitor information services for Grand Canyon National Park, Arizona. The map area encompasses approximately 1,960 sq.mi. within Coconino County, northern Arizona and is bounded by long 112 deg to 113 deg W. and lat 35 deg 30 min to 36 deg N. and lies within the southern Colorado Plateaus geologic province (herein Colorado Plateau). The map area is locally subdivided into four physiographic parts; (1) the Grand Canyon (Cataract Canyon and extreme northeast corner of the map area), (2) the Coconino Plateau, (3) the Mount Floyd Volcanic Field, and (4) the San Francisco Volcanic Field as defined by Billingsley and others, 1997. Elevations range from 7,460 ft (2,274 m) on the Coconino Plateau along State Highway 64 northeast corner of the map area, to about 4,200 ft (1,280 m) at the bottom of Cataract Canyon. Settlements within the map area include Tusayan and Valle, Arizona. State Highway 64 and U.S. Highway 180 provide access to the Tusayan and Valle areas. Indian Route 18 is a paved highway in the northwest corner of the map area that is maintained by the Hualapai and Havasupai Indian Tribes and leads from State Route 66 about 7 mi (11 km) east of Peach Springs, Arizona to Hualapai Hilltop, a parking lot just north of the map area at the rim of Cataract Canyon where visitors begin an 8 mi (13 km) hike into Havasupai, Arizona. Other remote parts of the map are accessed by two dirt roads, which are maintained by Coconino County, and by several unmaintained local ranch roads. Weather conditions restrict travel within the area and visitors must obtain permission to access a few local ranch lands in the south-central edge of the map area. Extra water and food are highly recommended when traveling in this remote region. Access into Cataract Canyon is restricted to horse or foot travel and visitors must obtain permission from the Havasupai Tribe to hike within the Havasupai Indian Reservation. In the central part of the map area, most of the land is privately owned and managed by the Babbitt Ranches Inc. in conjunction with the Nature Conservancy and the Navajo Tribe. In the southern half of the map, land alternates between privately owned land and State land forming a checkerboard pattern. The National Park Service manages land in Grand Canyon National Park (extreme northeast edge of map area), the U.S. Forest Service manages lands in the Kaibab National Forest, the Hualapai Tribe manages lands in the northwest quarter of the map area, and the Havasupai Tribe manages lands within Cataract Canyon and adjacent parts of the Coconino Plateau.