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At least 469 records · Page 26Linked to original sources
USGS1990

Map showing the distribution of tin in stream-sediment samples, Richfield 1° x 2° quadrangle, Utah

This map of the Richfield 1° x 2° quadrangle, Utah, shows the regional distribution of tin in the less-than-0.180-mm (minus-80-mesh) fraction of stream-sediments. It is part of a folio of maps of the Richfield 1° x 2° quadrangle, Utah, prepared under the Conterminuous United States Mineral Assessment Program. Other published geochemical maps in this folio are listed in the references (this publication). The Richfield quadrangle is located in west-central Utah and includes the eastern part of the Pioche-Marysvale igneous and mineral belt, which extends from the vicinity of Pioche in southeastern Nevada, east-northeastward for 155 miles into central Utah. The western two-thirds of the Richfield quadrangle is part of the Basin and Range province, whereas the eastern third is part of the High Plateaus of Utah, a subprovince of the Colorado Plateau. Bedrock in the northern part of the Richfield quadrangle consists predominantly of Late Proterozoic and Paleozoic sedimentary strata that were thrust eastward during the Sevier orogeny in Cretaceous time onto an autochthon of Mesozoic sedimentary rocks located in the eastern part of the quadrangle. The southern part of the quadrangle is largely underlain by Oligocene and younger volcanic rocks and related intrusions. Extensional tectonism in late Cenozoic time broke the bedrock terrain into a series of north-trending fault blocks; the uplifted mountain areas were eroded to various degrees and the resulting debris was deposited in adjacent basins. Most of the mineral deposits in the Pioche-Marysvale mineral belt were formed as a result of igneous activity in the middle and late Cenozoic time. A more complete description of the geology and a mineral-resource appraisal of the Richfield quadrangle appears in Steven and Morris (1984 and 1987). The regional sampling program was designed to define broad geochemical patterns and trends that can be utilized along with geological and geophysical data to assess the mineral-resource potential for this quadrangle. Reconnaissance geochemical surveys are valuable tools in mineral exploration, especially when used in conjunction with data obtained from other earth science disciplines. Identifying specific exploration targets generally involves additional, more detailed investigations.

Utah↗
USGS1990

Map showing the distribution of uranium in stream-sediment samples, Richfield 1° x 2° quadrangle, Utah

This map of the Richfield 1° x 2° quadrangle, Utah, shows the regional distribution of uranium in the less-than-0.180-mm (minus-80-mesh) fraction of stream-sediments. It is part of a folio of maps of the Richfield 1° x 2° quadrangle, Utah, prepared under the Conterminuous United States Mineral Assessment Program. Other published geochemical maps in this folio are listed in the references (this publication). The Richfield quadrangle is located in west-central Utah and includes the eastern part of the Pioche-Marysvale igneous and mineral belt, which extends from the vicinity of Pioche in southeastern Nevada, east-northeastward for 155 miles into central Utah. The western two-thirds of the Richfield quadrangle is part of the Basin and Range province, whereas the eastern third is part of the High Plateaus of Utah, a subprovince of the Colorado Plateau. Bedrock in the northern part of the Richfield quadrangle consists predominantly of Late Proterozoic and Paleozoic sedimentary strata that were thrust eastward during the Sevier orogeny in Cretaceous time onto an autochthon of Mesozoic sedimentary rocks located in the eastern part of the quadrangle. The southern part of the quadrangle is largely underlain by Oligocene and younger volcanic rocks and related intrusions. Extensional tectonism in late Cenozoic time broke the bedrock terrain into a series of north-trending fault blocks; the uplifted mountain areas were eroded to various degrees and the resulting debris was deposited in adjacent basins. Most of the mineral deposits in the Pioche-Marysvale mineral belt were formed as a result of igneous activity in the middle and late Cenozoic time. A more complete description of the geology and a mineral-resource appraisal of the Richfield quadrangle appears in Steven and Morris (1984 and 1987). The regional sampling program was designed to define broad geochemical patterns and trends that can be utilized along with geological and geophysical data to assess the mineral-resource potential for this quadrangle. Reconnaissance geochemical surveys are valuable tools in mineral exploration, especially when used in conjunction with data obtained from other earth science disciplines. Identifying specific exploration targets generally involves additional, more detailed investigations.

Utah↗
USGS1990

Map showing the distribution of zinc in stream-sediment samples, Richfield 1° x 2° quadrangle, Utah

This map of the Richfield 1° x 2° quadrangle, Utah, shows the regional distribution of zinc in the less-than-0.180-mm (minus-80-mesh) fraction of stream-sediments. It is part of a folio of maps of the Richfield 1° x 2° quadrangle, Utah, prepared under the Conterminuous United States Mineral Assessment Program. Other published geochemical maps in this folio are listed in the references (this publication). The Richfield quadrangle is located in west-central Utah and includes the eastern part of the Pioche-Marysvale igneous and mineral belt, which extends from the vicinity of Pioche in southeastern Nevada, east-northeastward for 155 miles into central Utah. The western two-thirds of the Richfield quadrangle is part of the Basin and Range province, whereas the eastern third is part of the High Plateaus of Utah, a subprovince of the Colorado Plateau. Bedrock in the northern part of the Richfield quadrangle consists predominantly of Late Proterozoic and Paleozoic sedimentary strata that were thrust eastward during the Sevier orogeny in Cretaceous time onto an autochthon of Mesozoic sedimentary rocks located in the eastern part of the quadrangle. The southern part of the quadrangle is largely underlain by Oligocene and younger volcanic rocks and related intrusions. Extensional tectonism in late Cenozoic time broke the bedrock terrain into a series of north-trending fault blocks; the uplifted mountain areas were eroded to various degrees and the resulting debris was deposited in adjacent basins. Most of the mineral deposits in the Pioche-Marysvale mineral belt were formed as a result of igneous activity in the middle and late Cenozoic time. A more complete description of the geology and a mineral-resource appraisal of the Richfield quadrangle appears in Steven and Morris (1984 and 1987). The regional sampling program was designed to define broad geochemical patterns and trends that can be utilized along with geological and geophysical data to assess the mineral-resource potential for this quadrangle. Reconnaissance geochemical surveys are valuable tools in mineral exploration, especially when used in conjunction with data obtained from other earth science disciplines. Identifying specific exploration targets generally involves additional, more detailed investigations.

Utah↗
USGS2003

Geologic map of the Rio Puerco quadrangle, Bernalillo and Valencia Counties, New Mexico

The Rio Puerco quadrangle is located southwest of Albuquerque in central New Mexico and covers part of the western part of the Isleta Reservation. The U.S. Geological Survey, the New Mexico Bureau of Geology and Mineral Resources, and the University of New Mexico have conducted geologic mapping on the Isleta Reservation and vicinity as part of the Middle Rio Grande Basin Project. The map area contains surficial deposits, calcic soils, fluvial deposits of the Rio Puerco, deposits of the Santa Fe Group, and three volcanic fields. The area is characterized by predominantly north-trending normal faults with generally down-to-the-east movement. Post-Santa Fe Group deposits are composed of surficial deposits (Pleistocene-Holocene) and fluvial deposits of the Rio Puerco (Pleistocene-Holocene). The surficial deposits are divided into eolian, alluvial, colluvial, and landslide deposits. The fluvial deposits of the Rio Puerco consist of four terrace and present channel deposits. The Santa Fe Group is divided into lower and upper parts. The lower part of the Santa Fe Group is exposed near the southwestern corner of the study area where deposits consist of reddish-brown mudstone and sandstone correlated to the Popotosa Formation (Unit 1) of Lozinsky and Tedford (1991). They interpreted deposition of the unit in a basin-floor playa setting. The Popotosa Formation is in fault contact to the east with deposits of the upper Santa Fe Group. The upper Santa Fe Group is derived from major tributary fluvial systems (ancestral Rio Puerco Puerco and possibly the Rio San Jose drainages) draining the adjacent Colorado Plateau and Sierra Nacimiento and correlated to parts of Kelley's (1977) Ceja Formation of the Santa Fe Group and equivalent to Machette's (1978) Sierra Ladrones Formation, Connell's Arroyo Ojito Formation (Connell and others, 1999, and Maldonado's lithofacies of the Isleta Reservation (Maldonado and Atencio,1998a, b). The group also locally includes a fine- grained unit (lower Pleistocene) referred to here as the sand, silt, and clay of Chavez Grant (Qsc). The Ceja Formation of the Santa Fe Group as defined here is divided into the following units in descending stratigraphic order: (1) upper sand and gravel unit (upper Pliocene), (2) middle silt, sand, and clay unit (upper Pliocene), and (3) lower sand and gravel unit (Pliocene). The three volcanic fields in the map area are: (1) basalt of Cat Hills, dated at 98-110 ka and composed of seven lava flows and four cinder cones; the flows overlie calcic soils that overlie the upper sand and gravel unit of the Ceja Formation; (2) lava flow of Cat Mesa, dated at about 3 Ma and interfingers with the upper part of the Ceja Formation; (3) diabase of Mohinas Mountain, dated at 8.3 Ma (Baldridge and others, 1987) and intrudes the Popotosa Formation. Numerous high-angle faults cut the area but are mostly buried. The faults generally trend north but deviate to the northwest and northeast. The major normal faults are the Cat Mesa and Mohinas Mountain faults.

Miscellaneous Field Studies Map↗
USGS2006

User's Guide, software for reduction and analysis of daily weather and surface-water data: Tools for time series analysis of precipitation, temperature, and streamflow data

The software described here is used to process and analyze daily weather and surface-water data. The programs are refinements of earlier versions that include minor corrections and routines to calculate frequencies above a threshold on an annual or seasonal basis. Earlier versions of this software were used successfully to analyze historical precipitation patterns of the Mojave Desert and the southern Colorado Plateau regions, ecosystem response to climate variation, and variation of sediment-runoff frequency related to climate (Hereford and others, 2003; 2004; in press; Griffiths and others, 2006). The main program described here (Day_Cli_Ann_v5.3) uses daily data to develop a time series of various statistics for a user specified accounting period such as a year or season. The statistics include averages and totals, but the emphasis is on the frequency of occurrence in days of relatively rare weather or runoff events. These statistics are indices of climate variation; for a discussion of climate indices, see the Climate Research Unit website of the University of East Anglia (http://www.cru.uea.ac.uk/projects/stardex/) and the Climate Change Indices web site (http://cccma.seos.uvic.ca/ETCCDMI/indices.html). Specifically, the indices computed with this software are the frequency of high intensity 24-hour rainfall, unusually warm temperature, and unusually high runoff. These rare, or extreme events, are those greater than the 90th percentile of precipitation, streamflow, or temperature computed for the period of record of weather or gaging stations. If they cluster in time over several decades, extreme events may produce detectable change in the physical landscape and ecosystem of a given region. Although the software has been tested on a variety of data, as with any software, the user should carefully evaluate the results with their data. The programs were designed for the range of precipitation, temperature, and streamflow measurements expected in the semiarid Southwest United States. The user is encouraged to review the examples provided with the software. The software is written in Fortran 90 with Fortran 95 extensions and was compiled with the Digital Visual Fortran compiler version 6.6. The executables run on Windows 2000 and XP, and they operate in a MS-DOS console window that has only very simple graphical options such as font size and color, background color, and size of the window. Error trapping was not written into the programs. Typically, when an error occurs, the console window closes without a message.

Open-File Report↗
USGS2007

Publications of the Western Earth Surfaces Processes Team 2005

Introduction The Western Earth Surface Processes Team (WESPT) of the U.S. Geological Survey (USGS) conducts geologic mapping, earth-surface process investigations, and related topical earth science studies in the western United States. This work is focused on areas where modern geologic maps and associated earth-science data are needed to address key societal and environmental issues such as ground-water quality, landslides and other potential geologic hazards, and land-use decisions. Areas of primary emphasis in 2005 included southern California, the San Francisco Bay region, the Mojave Desert, the Colorado Plateau region of northern Arizona, and the Pacific Northwest. The team has its headquarters in Menlo Park, California, and maintains smaller field offices at several other locations in the western United States. The results of research conducted by the WESPT are released to the public as a variety of databases, maps, text reports, and abstracts, both through the internal publication system of the USGS and in diverse external publications such as scientific journals and books. This report lists publications of the WESPT released in 2005 as well as additional 2002, 2003, and 2004 publications that were not included in the previous lists (USGS Open-File Reports 03-363, 2004- 1267, 2005-1362). Most of the publications listed were authored or coauthored by WESPT staff. The list also includes some publications authored by non-USGS cooperators with the WESPT, as well as some authored by USGS staff outside the WESPT in cooperation with WESPT projects. Several of the publications listed are available on the World Wide Web; for these, URL addresses are provided. Many of these web publications are USGS Open-File reports that contain large digital databases of geologic map and related information. Information on ordering USGS publications can be found on the World Wide Web at http://www.usgs.gov/pubprod/, or by calling 1-888-ASK-USGS. The U.S. Geological Survey's web server for geologic information in the western United States is located at http://geology.wr.usgs.gov/. More information is available about the WESPT is available on-line at http://geology.wr.usgs.gov/wgmt.

Open-File Report↗
USGS2007

Publications of the Western Earth Surface Processes Team 2006

The Western Earth Surface Processes Team (WESPT) of the U.S. Geological Survey (USGS) conducts geologic mapping, earth-surface process investigations, and related topical earth science studies in the western United States. This work is focused on areas where modern geologic maps and associated earth-science data are needed to address key societal and environmental issues such as ground-water quality, landslides and other potential geologic hazards, and land-use decisions. Areas of primary emphasis in 2006 included southern California, the San Francisco Bay region, the Mojave Desert, the Colorado Plateau region of northern Arizona, and the Pacific Northwest. The team has its headquarters in Menlo Park, California, and maintains smaller field offices at several other locations in the western United States. This compilation gives the bibliographical citations for 123 new publications, most of which are available online using the hyperlinks provided.

Open-File Report↗
USGS2009

Physical, Chemical, Ecological, and Age Data and Trench Logs from Surficial Deposits at Hatch Point, Southeastern Utah

This report presents data and describes the methodology for physical, chemical and ecological measurements of sediment, soil, and vegetation, as well as age determinations of surficial deposits at Hatch Point, Canyon Rims area, Colorado Plateau, southeastern Utah. The results presented in this report support a study that examines geomorphic and soil factors that may influence boundaries between shrubland and grassland ecosystems in the study area. Shrubland ecosystems dominated by sagebrush (Artemisia tridentata) and grassland ecosystems dominated by native perennial grasses (for example, Hilaria jamesii and Sporabolis sp.) are high-priority conservation targets for the Federal Bureau of Land Management (BLM) and other resource managers because of their diversity, productivity, and vital importance as wildlife habitat. These ecosystems have been recognized as imperiled on a regional scale since at least the mid-1990s due to habitat loss (type conversions), land-use practices, and invasive exotic plants. In the Intermountain West, the exotic annual cheatgrass (Bromus tectorum) is recognized as one of the most pervasive and serious threats to the health of native sagebrush and grassland ecosystems through effects on fire regimes and resource conditions experienced by native species.

Open-File Report↗
USGS2011

Aggregate resource availability in the conterminous United States, including suggestions for addressing shortages, quality, and environmental concerns

One-third of America's major roads are in poor or mediocre condition, and over one-quarter of the bridges are either structurally deficient or functionally obsolete. A 70-percent increase in annual aggregate production may be required to upgrade the transportation infrastructure. Natural aggregate is widespread throughout the conterminous United States, but the location of aggregate is determined by geology and is non-negotiable. Natural aggregate is in short supply in the Coastal Plain and Mississippi embayment, Colorado Plateau and Wyoming Basin, glaciated Midwest, High Plains, and the non-glaciated Northern Plains. A variety of techniques have been used to overcome local shortages, such as the use of substitute materials, recycling, and importing high-quality aggregates from more distant locations. Although potential sources of aggregate are widespread throughout the United States, many sources may not meet certain physical property requirements, such as soundness, hardness, strength, porosity, and specific gravity, or they may contain contaminants or deleterious materials that render them unusable. Encroachment by conflicting land uses, permitting considerations, environmental issues, and societal pressures can prevent or limit development of otherwise suitable aggregate. The use of sustainable aggregate resource management can help ensure an economically viable supply of aggregate. Sustainable aggregate resource management techniques that have successfully been used include (1) protecting potential resources from encroachment; (2) using marginal-quality local aggregate for applications that do not demand a high-quality resource; (3) using substitute materials such as clinker, scoria, and recycled asphalt and concrete; and (4) using rail and water to transport aggregates from remote sources.

Open-File Report↗
USGS2014

Preliminary bedrock and surficial geologic map of the west half of the Sanders 30' x 60' quadrangle, Navajo and Apache Counties, northern Arizona

The bedrock and surficial geologic map of the west half of the Sanders 30' x 60' quadrangle was completed in a cooperative effort of the U.S. Geological Survey (USGS) and the Navajo Nation to provide regional geologic information for management and planning officials. This report provides baseline geologic information that will be useful in future studies of groundwater and surface water resources, geologic hazards, and the distribution of soils and plants. The west half of the Sanders quadrangle encompasses approximately 2,509 km 2 (980 mi 2 ) within Navajo and Apache Counties of northern Arizona and is bounded by lat 35°30' to 35° N., long 109°30' to 110° W. The majority of the land within the map area lies within the Navajo Nation. South of the Navajo Nation, private and State lands form a checkerboard pattern east and west of Petrified Forest National Park. In the west half of the Sanders quadrangle, Mesozoic bedrock is nearly flat lying except near folds. A shallow Cenozoic erosional basin that developed about 20 Ma in the western part of the map area cut across late Paleozoic and Mesozoic rocks that were subsequently filled with flat-lying Miocene and Pliocene mudstone and argillaceous sandstone and fluvial sediments of the Bidahochi Formation and associated volcanic rocks of the Hopi Buttes volcanic field. The Bidahochi rocks are capped by Pliocene(?) and Pleistocene fluvial sediments and Quaternary eolian and alluvial deposits. Erosion along northeast-southwest-oriented drainages have exposed elongated ridges of Bidahochi Formation and basin-fill deposits that are exposed through shallow eolian cover of similarly oriented longitudinal dunes. Stokes (1964) concluded that the accumulation of longitudinal sand bodies and the development of confined parallel drainages are simultaneous processes resulting in parallel sets of drainages and ridges oriented along the prevailing southwest wind direction on the southern Colorado Plateau.

Arizona↗
USGS2015

Chronostratigraphic cross section of Cretaceous formations in western Montana, western Wyoming, eastern Utah, northeastern Arizona, and northwestern New Mexico, U.S.A.

The chronostratigraphic cross section presented herein is a contribution to the Western Interior Cretaceous (WIK) project of the Global Sedimentary Geology Program. It portrays the Cretaceous formations at 13 localities in a south-trending transect from northwestern Montana through western Wyoming, eastern Utah, and northeastern Arizona, to northwestern New Mexico. The localities are in the Rocky Mountains and on the Colorado Plateau and contain strata that were deposited along the western margin of the Cretaceous Interior Seaway of North America. These strata are marine and nonmarine, mainly siliceous and calcareous, and of Aptian through Maastrichtian ages. They range in thickness from nearly 19,000 feet (ft) in southwestern Montana to about 1,500 ft thick in northeastern Arizona and northwestern New Mexico. Cretaceous formations in western Montana, western Wyoming, and eastern Utah disconformably overlie Jurassic rocks and locally include beds of either Aptian and Albian ages or Albian age. The Aptian beds consist of various lithologies of nonmarine origin. Albian beds consist of various nonmarine and marine lithologies. The Lower Cretaceous strata range in thickness from 4,300 ft in northern Utah to 180 ft in southern Utah and are absent at localities in Arizona and New Mexico. Upper Cretaceous strata at most localities in the transect include beds of Cenomanian through Maastrichtian ages, although at five of the localities in Montana, Wyoming, Utah, Arizona, and New Mexico, younger strata are missing. Beds of Cenomanian, Turonian, Coniacian, Santonian, and Campanian ages in the region are siliceous, calcareous, or bentonitic and were deposited in marine and nonmarine environments. In the following Maastrichtian, siliceous lithologies accumulated in nonmarine environments. Thicknesses of the Upper Cretaceous strata range from more than 17,000 ft in southwestern Montana to nearly 6,000 ft in northwestern New Mexico. In this transect for time-stratigraphic units of the Cretaceous, lateral changes in lithologies, regional differences in thicknesses, and the abundance of associated disconformities possibly reflect local and regional tectonic events. Examples of evidence of those events follow: (1) Disconformities and the absence of strata of lowest Cretaceous age in western Montana, western Wyoming, and northern Utah indicate significant tectonism and erosion probably during the Late Jurassic and earliest Cretaceous; ( 2) stages of Upper Cretaceous deposition in the transect display major lateral changes in thickness, which probably reflect regional and local tectonism.

Arizona, Montana, New Mexico, Utah, Wyoming↗
USGS2021

A geologic field guide to S P Mountain and its lava flow, San Francisco Volcanic Field, Arizona

Introduction We created this guide to introduce the user to the San Francisco Volcanic Field as a terrestrial analog site for planetary volcanic processes. For decades, the San Francisco Volcanic Field has been used to teach scientists to recognize the products of common types of volcanic eruptions and associated volcanic features. The volcanic processes and products observed in this volcanic field are like those observed on lunar and Martian surfaces. As a result, this region has been a favored location for training National Aeronautics and Space Administration astronauts and engineers since the Apollo missions. Though the San Francisco Volcanic Field has more than 600 volcanic vents and flows, this guide will focus on S P Mountain (known locally as S P Crater, located ~30 miles north of Flagstaff, Arizona), one of the best preserved and most accessible of the volcanic cones and lava flows. S P Mountain presents both major types of basaltic eruptions—explosive and effusive—as well as some commonly associated tectonic landforms. We assume that the user has a basic understanding of geologic concepts and terminology. For more specialized terminology, we include tables showing the classification scheme for lava compositions, styles of eruptions, and tephra sizes (tables 1, 2, and 3). If a further introduction or refresher in volcanological terminology is desired, we suggest reviewing such terms on the U.S. Geological Survey Volcano Science Center’s online glossary ( https://volcanoes.usgs.gov/vsc/glossary/ ). One term requires clarification at the start of this guide—the term cinder. The terms cinder and cinder cone are widely used to describe the material and edifice produced by lava fountains. However, the term comes from the mining and construction industries and has no clear or formal definition. The international committees in geology and volcanology have chosen the term tephra to be the general term to describe pyroclasts (material ejected through a volcanic explosion or from a volcanic vent). Therefore, in this guide, we use the term tephra rather than cinder. This guide is outlined as follows: A brief tour of volcanism across the solar system A brief geologic history of the Colorado Plateau and San Francisco Volcanic Field Background on distributed volcanism and S P Mountain Driving directions and field stops Questions for discussion Each field stop includes a brief description, learning goals, tasks, and a summary of key points. At the end of the field guide are discussion points and questions that will ask the user to consider what they have observed and learned and how such knowledge can be used to better our understanding of geologic processes on other planetary bodies. Upon the completion of this field guide, we expect the user to: Have a basic understanding of the volcanic processes relevant to S P Mountain and its lava flow. Be able to identify different volcanic textures that are associated with tephra cones. Be aware of the different observations one can make at different scales (for example, observing lava flow morphology from aerial or satellite imagery versus tephra characteristics in the field).

Arizona↗
USGS1952

Photogeologic maps of the Verdure 1, 2, 4, 6, 7, and 8 quadrangles, Utah and Colorado

Base maps compiled by Soil Conservation Service, U.S. Department of Agriculture. These maps are compilations of photogeology and surface geology, Colorado Plateau area, United States. They are also known as: Trace Elements Memorandum Report 399 (Verdure 1) Trace Elements Memorandum Report 406 (Verdure 2) Trace Elements Memorandum Report 438 (Verdure 4) Trace Elements Memorandum Report 405 (Verdure 6) Trace Elements Memorandum Report 395 (Verdure 7) Trace Elements Memorandum Report 403 (Verdure 8)

Colorado, Utah↗
USGS1960

Geology and ore deposits of the Klondike Ridge area, Colorado

The region described in this report is in the northeastern part of the Colorado Plateau and is transitional between two major structural elements. The western part is typical of the salt anticline region of the Plateau, but the eastern part has features which reflect movements in the nearby San Juan Mountains. There are five major structural elements in the report area: the Gypsum Valley anticline, Dry Creek Basin, the Horse Park fault block, Disappointment Valley, and the Dolores anticline. Three periods of major uplift are recognized In the southeastern end of the Gypsum Valley anticline. Each was followed by collapse of the overlying strata. Erosion after the first two periods removed nearly all topographic relief over the anticline; erosion after the last uplift has not yet had a profound effect on the topography except where evaporite beds are exposed at the surface. The first and greatest period of salt flow and anticlinal uplift began in the late Pennsylvanian and continued intermittently and on an ever decreasing scale into the Early Cretaceous. Most movement was in the Permian and Triassic periods. The second period of uplift and collapse was essentially contemporaneous with widespread tectonic activity on. the northwestern side of the San Juan Mountains and may have Occurred in the Oligocene and Miocene epochs. Granogabbro sills and dikes were intruded during the middle or upper Tertiary in Disappointment Valley and adjoining parts of the Gypsum Valley and Dolores anticlines. The third and mildest period of uplift occurred in the Pleistocene and was essentially contemporaneous with the post-Hinsdale uplift of the San Juan Mountains. This uplift began near the end of the earliest, or Cerro, stage of glaciation. Uranium-vanadium, manganese, and copper ore as well as gravel have been mined in the Klondike district. All deposits are small, and few have yielded more than 100 tons of ore. Most of the latter are carnotite deposits. Carnotite occurs in the lower part of the basal sandstone unit of the Salt Wash member of the Morrison formation. Most deposits are in a narrow, elongate mineral belt' that cuts obliquely across Klondike Ridge. The remaining deposits probably form a second 'mineral belt' lying about ? mile to the north. Manganese and copper deposits show both stratigraphic and structural controls of mineralization. Most manganese deposits are in red beds near Tertiary faults; most copper deposits, on the other hand, are in brown sandstone, limestone, or gray-green shale and, like manganese, are in or near Tertiary faults. The manganese and copper deposits are hydrothermal in origin and were formed in the roots of an ancient hot springs system, now deeply eroded. The ore-bearing solutions probably consisted of dilute, carbonate-sulfate ground water heated by the near-surface intrusion of small bodies of igneous rock. These solutions obtained their metals by leaching the wallrock; little, if any, material was added by the intrusives. The deposits were formed near the surface under conditions of hydrostatic pressure, and temperatures and pressures in the ore-bearing solutions were probably low. The early solutions were weakly alkaline and reducing in character. A convection cell was established as mineralization progressed, and surface water mingled at depth with the solutions. As a result of mixing and oxidation, the pH of the solution decreased in later stages of mineralization and the Eh rose.

Open-File Report↗
USGS1971

An annotated bibliography of fauna and flora described from the Dockum Group of Triassic age in eastern New Mexico and West Texas

This annotated bibliography was prepared by Warren I. Finch from a rough copy compiled by the late James C. Wright in either late 1967 or early 1968 as an aid to his understanding of the stratigraphic distribution of uranium deposits in Triassic rocks of the Southern high Plains. He did not finish it, inasmuch as several references listed are not annotated. Nevertheless, it is fairly complete for North American literature for years prior to 1967, but it does not contain any papers published in Europe, several of which are pertinent. A few papers oil localities in Wyoming, the Colorado Plateau region, and Mexico are annotated for the purposes of generic and stratigraphic comparison. Wright collated many of the data; cross references are abundant. The bibliography is presented as prepared by Wright; editing was held to a minimum. No additional check was made of the source materials for accuracy of the data--for example, spellings of fossil names. The stratigraphic nomenclature is that: used in the reports cited and may or may not conform to that currently accepted by the U.S. Geological Survey. A list of non-annotated references cited in the annotations was added.

New Mexico, Texas↗
USGS1976

Preliminary investigation of the elemental variation and diagenesis of a tabular uranium deposit, La Sal Mine, San Juan County, Utah

Ore in the La Sal mine, San Juan County, Utah, occurs as a typical tabular-type uranium deposit of the-Colorado Plateau. Uranium-vanadium occurs in the Salt Wash Member of the Jurassic Morrison Formation. Chemical and petrographic analyses were used to determine elemental variation and diagenetic aspects across the orebody. Vanadium is concentrated in the dark clay matrix, which constitutes visible ore. Uranium content is greater above the vanadium zone. Calcium, carbonate carbon, and lead show greater than fifty-fold increase across the ore zone, whereas copper and organic carbon show only a several-fold increase. Large molybdenum concentrations are present in and above the tabular layer, and large selenium concentrations occur below the uranium zone within the richest vanadium zone. Iron is enriched in the vanadium horizon. Chromium is depleted from above the ore and strongly enriched below. Elements that vary directly with the vanadium content include magnesium, iron, selenium, zirconium, strontium, titanium, lead, boron, yttrium, and scandium. The diagenetic sequence is as follows: (1) formation of secondary quartz overgrowths as cement; (2) infilling and lining of remaining pores with amber opaline material; (3) formation of vanadium-rich clay matrix, which has replaced overgrowths as well as quartz grains; (4) replacement of overgrowths and detrital grains by calcite; (5) infilling of pores with barite and the introduction of pyrite and marcasite.

Open-File Report↗
USGS1979

Regional geohydrology of the San Juan hydrologic basin of New Mexico, Colorado, Arizona, and Utah

The San Juan Basin in the southeastern part of the Colorado Plateau, southwest of the San Juan Mountains, broadly includes the Acoma and Gallup Sags in its southern part and the small Chama Basin in its northeastern part. Regionally, the water-yielding strata (aquifers) dip inward toward the center of San Juan Basin or toward the axes of the adjoining structural sags. Aquifers exposed or at shallow depths along the margin of the basin are deeply buried in the center of the basin. The occurrence and movement of ground water is strongly influenced by the structural configuration of the basin; fractures along joints and faults, particularly the Puerco fault belt; distribution and lithology of the rock strata, and the relationship of the uplands recharge areas of the aquifers to the lowland areas where the most ground-water discharges. The aggregate thickness of sedimentary rocks is more than 10,000 feet in the deepest part of the basin. In order of decreasing abundance, these rocks consist of mudstone, claystone, siltstone, sandstone, silty sandstone, coal, limestone, conglomerate, and gypsum. The main aquifers consist of sandstone or sandstone containing lenses of conglomerate except for the San Andres Limestone. The principal aquifers, listed in descending stratigraphic order, are the Tertiary Cuba Mesa and Llaves Members of the San Jose Formation and the Ojo Alamo Sandstone; the Pictured Cliffs, Cliff House, Point Lookout, Gallup, and Dakota Sandstones; the Westwater Canyon and Salt Wash Sandstone Members of the Morrison Formation, the Cow Springs Sandstone, the Zuni Sandstone, and the Entrada Sandstone; and the San Andres Limestone, Glorieta Sandstone, and De Chelly Sandstone. These aquifer are separated by formations, that do not readily transmit water between the aquifers. Regional movement of ground water is mainly to the San Juan and Chaco s Rivers, the Puerco River, the Rio Puerco, and their main tributaries. Ground water from aquifers overlying the Dakota Sandstone discharge within the confines of the San Juan hydrologic basin. Part of the ground water in the Dakota Sandstone, Morrison Formation, and underlying formations moves across the interbasin divide into the Black Mesa, the Blanding Basin, or to the Rio Grande Trough.

Arizona, Colorado, New Mexico, Utah↗