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At least 199 records · Page 11Linked to original sources
USGS2006

A database of lotic invertebrate traits for North America

The assessment and study of stream communities may be enhanced if functional characteristics such as life-history, habitat preference, and reproductive strategy were more widely available for specific taxa. Species traits can be used to develop these functional indicators because many traits directly link functional roles of organisms with controlling environmental factors (for example, flow, substratum, temperature). In addition, some functional traits may not be constrained by taxonomy and are thus applicable at multiple spatial scales. Unfortunately, a comprehensive summary of traits for North American invertebrate taxa does not exist. Consequently, the U.S. Geological Survey's National Water-Quality Assessment Program in cooperation with Colorado State University compiled a database of traits for North American invertebrates. A total of 14,127 records for over 2,200 species, 1,165 genera, and 249 families have been entered into the database from 967 publications, texts and reports. Quality-assurance procedures indicated error rates of less than 3 percent in the data entry process. Species trait information was most complete for insect taxa. Traits describing resource acquisition and habitat preferences were most frequently reported, whereas those describing physiological tolerances and reproductive biology were the least frequently reported in the literature. The database is not exhaustive of the literature for North American invertebrates and is biased towards aquatic insects, but it represents a first attempt to compile traits in a web-accessible database. This report describes the database and discusses important decisions necessary for identifying ecologically relevant, environmentally sensitive, non-redundant, and statistically tractable traits for use in bioassessment programs.

Data Series↗
USGS2018

James Dwight Dana and John Strong Newberry in the US Pacific Northwest: The roots of American fluvialism

Recognition of the power of rivers to carve landscapes transformed geology and geomorphology in the late nineteenth century. Wide acceptance of this concept—then known as “fluvialism”—owes to many factors and people, several associated with exploration of western North America. Especially famous are the federal geographic and geologic surveys of the US Southwest with John Wesley Powell and Grove Karl Gilbert, which produced key insights regarding river processes. Yet earlier and less-known surveys also engaged young geologists embarking on tremendously influential careers, particularly the 1838–1842 US Exploring Expedition with James Dwight Dana and the 1853–1855 railroad surveys including John Strong Newberry. Informed but little constrained by European and British perspectives on landscape formation, Dana and Newberry built compelling cases for the erosive power of rivers, largely from observations in the US Pacific Northwest. They seeded the insights of the later southwestern surveys, Dana by his writings and station at Yale and his hugely influential Manual of Geology , published in 1863, and Newberry by becoming the first geologist to explore the dramatic river-carved canyons of the Southwest and then a forceful proponent of the federal surveys spotlighting the erosional landscapes. Newberry also gave Gilbert his start as a geologist. Although Dana and Newberry are renowned early American geologists, their geomorphic contributions were overshadowed by the works of Powell, Gilbert, and William Morris Davis. Yet Dana and Newberry were the first ardent American proponents of fluvialism, providing strong roots that in just a few decades transformed western geology, roots nourished in large measure by the geologically fertile landscapes of the US Pacific Northwest.

Journal of Geology↗
USGS2019

The US Geological Survey’s Earth Mapping Resources Initiative (Earth MRI)—Providing framework geologic, geophysical, and elevation data to the nation’s critical mineral-bearing regions

New detailed mapping of the geologic resources of the Nation has the potential to significantly close the gap in the essential data needed to fuel a modern era of economic development and technological innovation, while at the same time dramatically enhancing our understanding of the fundamental way geology impacts everyday life, from the domestic critical mineral resources that are necessary for modern technology and the economy, to domestic energy and water resources, geologic hazards, agriculture, and other pressing needs. The U.S. Geological Survey established the Earth Resources Mapping Initiative (Earth MRI) to address the shortfall in geologic, geophysical, and elevation data with sufficient detail to support evaluation of regions in the United States that have potential to host critical mineral resources. The new effort is a collaboration with the Association of American State Geologists, who are providing new detailed geologic maps and making available online archived data and information related to critical mineral resources. The geophysical and lidar surveys are being contracted through industry specialists to assure that high-quality data are available to the public. This article provides an overview of the Earth MRI effort with discussions on the initial geophysical surveys funded for areas that have known potential for rare earth element resources. Subsequent projects are being designed to address areas that may host other critical mineral resources.

Fast Times↗
USGS2002

Digital mapping techniques '02, workshop proceedings : May 19-22, 2002, Salt Lake City, Utah

The Digital Mapping Techniques '02 (DMT'02) workshop was attended by 101 technical experts from 43 agencies, universities, and private companies, including representatives from 25 state geological surveys (see Appendix A). This workshop was similar in nature to the previous five meetings, held in Lawrence, Kansas (Soller, 1997), in Champaign, Illinois (Soller, 1998a), in Madison, Wisconsin (Soller, 1999), in Lexington, Kentucky (Soller, 2000), and in Tuscaloosa, Alabama (Soller, 2001). This year's meeting was hosted by the Utah Geological Survey, from May 19 to 22, 2002, on the University of Utah campus in Salt Lake City. As in the previous meetings, the objective was to foster informal discussion and exchange of technical information. When an attendee adopts or modifies a newly learned technique on the basis of discussions at the workshop, the workshop clearly has met that objective. Evidence of learning and cooperation among participating agencies continued to be a highlight of the DMT workshops (see example in Soller, 1998b, and various papers in this volume). All the DMT workshops have been coordinated by the Association of American State Geologists (AASG) and the U.S. Geological Survey (USGS) Data Capture Working Group, which was formed in August 1996 to support the AASG and the USGS in their effort to build a National Geologic Map Database (see Soller and Berg, this volume, and http://ncgmp.usgs.gov/ngmdbproject/standards/datacapt/ ). The Working Group was formed because increased production efficiencies, standardization, and quality of digital map products were needed for the database--and the State and Federal geological surveys--to provide more high-quality digital maps to the public. At the 2002 meeting, oral and poster presentations and special discussion sessions emphasized (1) methods for creating and publishing map products (here, "publishing" includes Web-based release); (2) techniques for scanning already published maps and managing and delivering them on the Web; (3) continued development of the National Geologic Map Database; and (4) progress toward building a standard geologic map data model. In addition, special presentations were provided on building a statewide GIS council, incorporating geology as a NSDI Framework layer, and resolving the roles of surveyors and GIS professionals.

Open-File Report↗
USGS2024

North American bird banding program longevity records

Longevity in wild birds refers to the longest-lived individual of any particular species. This measure of age can reflect important life history traits and identifying differences in longevity patterns between species can reveal unique threats or conservation needs. Because it requires the identification of individual birds, longevity can usually only be measured through banding or marking of individuals. A bird’s age can generally be determined at the time of banding and then recalculated whenever the bird is subsequently recovered, recaptured, or resighted. The North American Bird Banding Program (NABBP), comprised of the U.S. Geological Survey Eastern Ecological Science Center Bird Banding Laboratory (BBL) and Canada’s Bird Banding Office (BBO), curates a vast dataset of all North American bird banding records, as well as subsequent encounters of banded birds reported by banders and members of the public. Although not all bird populations are banded equally and band encounters are only reported voluntarily, the NABBP is thus uniquely situated to catalogue and report longevity records for bird species under our purview.

North American Bird Bander↗
USGS2011

Development of a bioenergetics model for age-0 American shad

Bioenergetics modeling can be used as a tool to investigate the impact of non-native age-0 American shad ( Alosa sapidissima ) on reservoir and estuary food webs. The model can increase our understanding of how these fish influence lower trophic levels as well as predatory fish populations that feed on juvenile salmonids. Bioenergetics modeling can be used to investigate ecological processes, evaluate alternative research hypotheses, provide decision support, and quantitative prediction. Bioenergetics modeling has proven to be extremely useful in fisheries research (Ney et al. 1993,Chips and Wahl 2008, Petersen et al. 2008). If growth and diet parameters are known, the bioenergetics model can be used to quantify the relative amount of zooplankton or insects consumed by age-0 American shad. When linked with spatial and temporal information on fish abundance, model output can guide inferential hypothesis development to demonstrate where the greatest impacts of age-0 American shad might occur. Bioenergetics modeling is particularly useful when research questions involve multiple species and trophic levels (e.g. plankton communities). Bioenergetics models are mass-balance equations where the energy acquired from food is partitioned between maintenance costs, waste products, and growth (Winberg 1956). Specifically, the Wisconsin bioenergetics model (Hanson et al. 1997) is widely used in fisheries science. Researchers have extensively tested, reviewed, and improved on this modeling approach for over 30 years (Petersen et al. 2008). Development of a bioenergetics model for any species requires three key components: 1) determine physiological parameters for the model through laboratory experiments or incorporate data from a closely related species, 2) corroboration of the model with growth and consumption estimates from independent research, and 3) error analysis of model parameters. Wisconsin bioenergetics models have been parameterized for many of the salmonids and predatory fishes encountered in the lower Columbia River (Petersen and Ward 1999). The Wisconsin bioenergetics model has not been developed for American shad, however Limburg (1996) parameterized a simplified bioenergetics growth model for this species. A common application for the Wisconsin bioenergetics model is to estimate the consumption or growth of a fish population under different temperature and feeding scenarios (Ney 1993). One advantage of the bioenergetics approach is that consumption can be estimated without direct field measurements of predation rate (prey·predator -1 · day -1 ; Petersen and Ward 1999). Field estimates of fish consumption are time consuming and costly to determine, and estimates may show wide variance due to environmental and sampling variability. However, the consumption parameters used in a newly developed bioenergetics model must be verified with field and laboratory estimates of consumption (Ney 1993). The objective of this research was to parameterize a Wisconsin bioenergetics model for age-0 American shad using published physiological data on American shad and closely related alosine species. The American shad bioenergetics model will be used as a tool to explore various hypotheses about how age-0 American shad directly and indirectly affect Columbia River salmon through ecological interactions in lower Columbia River food webs. One over-arching focus of the larger research project was to identify potential interactions between age-0 American shad and juvenile salmonids, addressing potential outcomes through bioenergetics modeling scenarios. This report contains two bioenergetics modeling applications to demonstrate how these models can be used to address management questions and direct research effort. The first modeling application uses the American shad bioenergetics model described in this report to explore prey consumption by age-0 American shad (Chapter 1, this report). Dietary data on age-0 American shad and previously published reports on the diet of juvenile fall Chinook salmon (Rondorf et al. 1990, USGS unpublished data) suggested there might be considerable dietary overlap between these species in the lower Columbia River. The U.S. Geological Survey (USGS) was interested in using the American shad bioenergetics model to explore hypotheses concerning dietary overlap between age-0 American shad and emigrating fall Chinook salmon. The second modeling application uses the fall Chinook salmon bioenergetics model (Koehler et al. 2006) to explore the growth potential of juvenile fall Chinook salmon predating on age-0 American shad in the lower Columbia River. This modeling was based dietary information on a small number of age-0 fall Chinook salmon (n = 13) collected in John Day Reservoir in 1994 - 1996 (unpublished USGS data). Analysis of this dietary data found that these salmonids were feeding primarily on age-0 American shad (> 75% by weight).

Oregon↗
USGS2014

The value of geophysical methods in ground‐water studies

Two meanings are unfortunately given to the term geophysics. In the broad sense, based on the etymology of the term, geophysics means the physics of the Earth. This is its significance in the names “Geophysical Laboratory of the Carnegie Institution of Washington,” “International Union of Geodesy and Geophysics,” and “American Geophysical Union.” In this sense the sciences of geology and hydrology are largely geophysics, although in part they are geochemistry or biology. Geologists and hydraulic engineers who are elected to membership in the American Geophysical Union are, however, often surprised to find that they are regarded as “geophysicists.” I hope that when the Union establisnes a journal, its name will include the expression “Earth physics” or “Physics of the Earth,” in order that there will be no misunderstanding as to its scope.

Eos, Transactions, American Geophysical Union↗
USGS2014

Characterization of subsurface stratigraphy along the lower American River floodplain using electrical resistivity, Sacramento, California, 2011

In July 2011, the U.S. Geological Survey, in cooperation with the U.S. Army Corps of Engineers, completed a geophysical survey using electrical resistivity along an approximately 6-mile reach of the lower American River in Sacramento, California, to map near-surface lithological variations. This survey is a part of a manifold and comprehensive study of river-flow dynamics and geologic boundary-property knowledge necessary to estimate scour potential and levee erosion risk. Data were acquired on the left (south or west) bank between river mile 5 and 10.7 as well as a short section on the right bank from river mile 5.4 to 6. Thirteen direct-current resistivity profiles and approximately 8.3 miles of capacitively coupled resisistivity data were acquired along accessible areas of the floodplain between the levee and river bank. Capacitively coupled resistivity was used as a reconnaissance tool, because it allowed for greater spatial coverage of data but with lower resolution and depth of investigation than the DC resistivity method. The study area contains Pleistocene-age alluvial deposits, dominated by gravels, sands, silts, and clays, that vary in both lateral extent and depth. Several generations of lithologic logs were used to help interpret resistivity variations observed in the resistivity models.

California↗
USGS2011

Lithosphere-asthenosphere interaction beneath the western United States from the joint inversion of body-wave traveltimes and surface-wave phase velocities

The relation between the complex geological history of the western margin of the North American plate and the processes in the mantle is still not fully documented and understood. Several pre-USArray local seismic studies showed how the characteristics of key geological features such as the Colorado Plateau and the Yellowstone Snake River Plains are linked to their deep mantle structure. Recent body-wave models based on the deployment of the high density, large aperture USArray have provided far more details on the mantle structure while surface-wave tomography (ballistic waves and noise correlations) informs us on the shallow structure. Here we combine constraints from these two data sets to image and study the link between the geology of the western United States, the shallow structure of the Earth and the convective processes in mantle. Our multiphase DNA10-S model provides new constraints on the extent of the Archean lithosphere imaged as a large, deeply rooted fast body that encompasses the stable Great Plains and a large portion of the Northern and Central Rocky Mountains. Widespread slow anomalies are found in the lower crust and upper mantle, suggesting that low-density rocks isostatically sustain part of the high topography of the western United States. The Yellowstone anomaly is imaged as a large slow body rising from the lower mantle, intruding the overlying lithosphere and controlling locally the seismicity and the topography. The large E-W extent of the USArray used in this study allows imaging the 'slab graveyard', a sequence of Farallon fragments aligned with the currently subducting Juan de Fuca Slab, north of the Mendocino Triple Junction. The lithospheric root of the Colorado Plateau has apparently been weakened and partly removed through dripping. The distribution of the slower regions around the Colorado Plateau and other rigid blocks follows closely the trend of Cenozoic volcanic fields and ancient lithospheric sutures, suggesting that the later exert a control on the locus of magmato-tectonic activity today. The DNA velocity models are available for download and slicing at http://dna.berkeley.edu. ?? 2011 The Authors Geophysical Journal International ?? 2011 RAS.

Geophysical Journal International↗
USGS2023

National map of focus areas for potential critical mineral resources in the United States

Introduction The U.S. Geological Survey (USGS) launched the Earth Mapping Resources Initiative (Earth MRI) to modernize the surface and subsurface geologic mapping of the United States, with a focus on identifying areas that may have the potential to contain critical mineral resources. EarthMRI can inform strategies to ensure secure and reliable domestic critical mineral supplies for the United States as mandated by Executive Order 13817 and the Infrastructure and Jobs Act of 2021 (Public Law 117–58, 135 Stat. 529). Earth MRI is a collaborative effort between the USGS and the State geological surveys as represented by the Association of American State Geologists to identify, prioritize, and acquire new geoscience data for geographic areas, or focus areas, across the Nation that have potential to host critical mineral resources. Mapping of focus areas was based on a framework of mineral systems and their associated mineral deposit types that could possibly host critical minerals. Using readily available geologic, geophysical, geochemical, and mineral deposit data, teams of USGS scientists worked with representatives of State geological surveys in a series of workshops to outline focus areas that contain evidence of key features for one or more mineral systems. These areas can be used to guide future efforts to collect new geologic, geophysical, geochemical, and topographic data that focus on critical minerals through Earth MRI.

Fact Sheet↗
USGS2002

Magnetic anomaly map of North America

This digital Magnetic Anomaly database and map for the North American continent is the result of a joint effort by the Geological Survey of Canada (GSC), U.S. Geological Survey (USGS), and Consejo de Recursos Minerales of Mexico (CRM). The database and map represent a substantial upgrade from the previous compilation of Magnetic Anomaly data for North America, now over a decade old (Committee for the Magnetic Anomaly Map of North America, 1987). This integrated, readily accessible, modern digital database of magnetic anomaly data will be a powerful tool for further evaluation of the structure, geologic processes, and tectonic evolution of the continent and may also be used to help resolve societal and scientific issues that span national boundaries. The North American magnetic anomaly map derived from the digital database provides a comprehensive magnetic view of continental-scale trends not available in individual data sets, helps link widely separated areas of outcrop, and unifies disparate geologic studies. This booklet outlines the data processing and compilation procedures used to produce the magnetic anomaly database and map that accompany this booklet.

Special Map↗
USGS1997

Introduction to special section: The Trans-Alaska Crustal Transect (TACT) across Arctic Alaska

This special section of the Journal of Geophysical Research addresses the composition and structural evolution of the lithosphere in northern Alaska. Investigations reported in this section were mainly undertaken as part of the Trans‐Alaska Crustal Transect (TACT), an integrated geological and geophysical transect of the entire Alaskan lithosphere along a north‐south corridor undertaken from 1984 to 1992 (Figure 1). The onshore segment of the transect approximately follows along the route of the trans‐Alaskan pipeline; the offshore segment extends across the continental margin in the Gulf of Alaska to the Pacific plate. The TACT line is unique in that it provides a coordinated onshore/offshore geological and geophysical traverse of the North American plate in Alaska from the active convergent Pacific margin to the passive Arctic margin of the continent.

Alaska↗
USGS2025

The Mammoth magnetic anomaly, Pinal County, Arizona

A high-resolution Earth Mapping Resources Initiative airborne geophysical survey was flown in the southwest North American porphyry copper province to improve bedrock geologic maps and to identify areas that have unrecognized critical mineral resource potential. During the review of the aeromagnetic data, a distinctly monopolar-shaped, negative magnetic anomaly was observed at a flight elevation of 200 m above the ground with a maximum amplitude of –9500 nT. We have named this the Mammoth magnetic anomaly (MMA) because it is centered 12 km northeast of the town of Mammoth, Arizona, USA. The total field anomaly (TFA) contour of –500 nT enclosing the MMA defines an elongate shape measuring 2.5 km long by 1 km wide that trends northwest–southeast. Given the striking nature of this negative, monopolar-shaped magnetic anomaly, we conducted a ground campaign in May 2025 to determine its authenticity and potential relationship to critical mineral endowment. The MMA was confirmed on the ground with a TFA approaching –46,000 nT. Total magnetic intensity (TMI) observations routinely fell below the 18,000 nT operating floor of an industry-standard cesium-vapor total field magnetometer, and extremely low TMI measurements were corroborated along coincident traverse lines using two high dynamic range, but lower sensitivity, smartphone vector magnetometers. The lowest TMI values recorded by both smartphone magnetometers were 1000 nT and confirmed with multiple adjacent and crossing lines. Field observations suggest that this magnetic feature is caused by strong remanent magnetization within fine-grained magnetite hosted within locally altered Pinal Schist.

Arizona↗
USGS2026

Cruise summary—Samoa Basin abyssal mapping—Box coring leg, Pago Pago, Territory of American Samoa to Pago Pago, American Samoa, April 11– May 1, 2026

Expedition Summary U.S. Geological Survey scientists led a box coring effort to the Samoa Basin to characterize minerals and the surrounding abyssal sediments and fauna. Thirty-eight box cores were deployed between April 13, 2026, and April 28, 2026. Thirty-six box cores recovered sufficient material to determine nodule density, and 35 recovered sufficient material for subcores to be collected. The purpose of this Data Report is to provide a summary of samples collected, initial results that were obtained shipboard, and briefly mention planned future analyses from this expedition.

Data Report↗
USGS2007

Report of the First National Lidar Initiative Meeting, February 14-16, Reston, Va.

The first National Lidar Initiative meeting was held on February 14-16, 2007 at the USGS National Center in Reston, Virginia. This meeting was a successor to a meeting held September 12, 2006 of several agencies, including the National Aeronautics and Space Administration (NASA), the Association of American State Geologists (AASG), and the U.S. Geological Survey (USGS). During the 2006 discussion, the USGS presented a plan to organize a meeting to discuss the feasibility and strategy of a National Lidar Initiative. Originally scheduled as a workshop to be held in June, 2007, the meeting was moved up to February to accommodate the desire of AASG to have talking points available at their Annual Meeting in March, 2007. The original workshop was recast as a meeting of representatives from Federal, State, and local government, and from private industry, to formulate a national initiative with the goal of collecting high resolution, high accuracy light detection and ranging (lidar) data for all 50 states. The goals of the National Lidar Initiative meeting were to: 1) Identify government staff with all scales of applications who are willing to help devise a potential national strategy and communicate the initiative throughout the lidar community. 2) Identify points of contact for future meetings, information exchanges, and design teams. 3) Compose a document explaining the need of a consistent national lidar dataset. 4) Identify champions of this idea who would be willing to work toward funding this effort. This report is intended to summarize the views expressed by the invited speakers and the participant's discussions on a National Lidar Initiative. It is not intended to be a comprehensive document on the technical aspects of lidar, what lidar can be used for, or the state of the art in lidar technology, although many of these aspects do come through in the views of the presenters.

Open-File Report↗
USGS1966

Geology of the Arabian Peninsula: Sedimentary geology of Saudi Arabia

Systematic mapping of the sedimentary geology of Saudi Arabia by Arabian-American Oil Co. (Aramco) began in 1933. By 1959, exploration parties of one type or another had surveyed more than 1,300,000 square kilometers (500,000 square miles) of sedimentary outcrop. The foundation for sedimentary deposition is the Arabian Shield a vast Precambrian complex of igneous and metamorphic rocks that occupies roughly one-third of the Arabian Peninsula in the west and crops out sporadically along the southern coast. Since the outset of the Paleozoic Era the shield has been amazingly stable, subject only to gentle, epeirogenic movement. On this rigid land mass was deposited an aggregate total of nearly 5,500 meters (18,000 feet) of sedimentary rocks ranging in age from presumed Cambrian to Pliocene(?). Paleozoic, Mesozoic, and lower Tertiary strata are magnificently exposed in central Arabia where they crop out in a great curved belt bordering the shield. Here the landscape is dominated by a series of essentially parallel west-facing escarpments, each supported by a resistant limestone cap. Exposures are unusually good, and many rock units can be traced without significant interruption for 500 to nearly 1,000 km. Beds reflecting buried basement configuration dip gently and uniformly away from the escarpment region into the Persian Gulf and Rub' al Khali basins. East of the escarpment belt is a broad expanse of relatively low-relief terrain in which Tertiary and younger deposits effectively mask older units. Clues to the character of pre-Tertiary rocks in this large area, which includes the Rub' al Khali desert and most of northeastern Arabia, are afforded only by widely scattered bore holes and oil wells. In extreme northwestern Arabia, largely lower Paleozoic sedimentary rocks are exposed, although a basinal area bordering the Paleozoic rocks on the north is characterized by thick Upper Cretaceous to Tertiary strata. Tertiary to Recent volcanic rocks cover substantial parts of the area. In general the older sedimentary rocks are exposed in north-central and northwestern Arabia near the Precambrian basement where as much as 2,000 m of lower Paleozoic rocks are present. Although unfossiliferous, the lower 600 m can be equated, at least in part, to rocks of certain Cambrian age in Jordan. Higher beds contain intervals confidently dated as Lower Ordovician, Silurian, and Lower Devonian. Lower Paleozoic rocks are chiefly coarse-grained sandstone of terrestrial origin, although marine shale occurs at several levels and the upper 300 m is mainly shale with thin beds of limestone. Lower Paleozoic strata are succeeded in the central escarpment region by a thick sequence (about 1,000 m) of Upper Permian and Triassic sedimentary rocks. The initial deposit, the Khuff Formation, is mostly shallow-water limestone; overlying beds are nonmarine elastics except for thick carbonate units in the middle part of the section. Above the Triassic System is some 200 to 500 m of Lower and Middle Jurassic rocks which, near the middle of the escarpment region, are interbedded marine shale and shelf limestone. These grade to sandstone, in part continental, in the northern and southern areas of outcrop. The Middle Jurassic is overlain by a great sequence-of nearly pure carbonate rocks, highly fossiliferous and accurately dated as Upper Jurassic and early Lower Cretaceous. The Jurassic System is spectacularly displayed in central Arabia where it forms the backbone of the escarpment region the Tuwayq Mountains. Carbonate sedimentation was interrupted several times in the closing stages of the Jurassic b^ the onset of evaporite conditions which gave rise to cyclic deposits of anhydrite and calcarenite. The resulting sequence the Arab Formation is of prime importance for its porous carbonate members contain billions of barrels of proved oil reserves The carbonate sequence is succeeded by a thick body of late Lower and Middle Cretaceous sandstone. (The Middle Cretaceous Series and Epoch, as defined by European geologist-, are used in this report.) Late Lower Cretaceous rocks are nonmarine and appear only in the middle and southern parts of the escarpment region. Middle Cretaceous rocks, nonmarine in the south, become progressively more marine in the north where they follow a transgressive path northwest across older beds as far as Jordan. Upper Cretaceous and Eocene rocks, almost exclusively in limestone and dolomite facies, are extensively exposed alorc the eastern edge of the escarpment belt and continue northwest into Iraq. The sequence, with an average thickness of about 5^0 m, includes rocks of Upper Cretaceous, Paleocene, lower Eocene, and middle Eocene ages. The stratigraphic sequence above the Eocene consists of 200 to 600 m of Miocene and Pliocene rocks, mostly of nonmarine origin. These deposits a heterogeneous assemblage of marly sandstone, sandy marl, and sandy limestone blanket the Rub' al Khali and northeastern Arabia. Above the Miocene and Pliocene rocks are unconsolidated Quaternary deposits which comprise great sand deserts and widespread gravel sheets. Sand of the Rub' al Khali Desert alone covers about 600,000 sq km (230,000 sq mi) or most of southern Arabia. Two major structural provinces are recognized within the Arabian Peninsula and adjacent areas. One is the comparatively stable interior region whose rigidity is controlled by the Precambrian basement. The other is the great mobile belt of Taurus, Zagros, and Oman Mountains, bordering the stable region on the north and east. Saudi Arabia falls entirely within the stable region. The interior stable region contains the Arabian shield as well as the Arabian Shelf an extension of the basement thinly veneered with little-disturbed sedimentary rocks. Widespread structural events, presumably related to epeirogenic movement within the basement, have divided the Arabian Shelf into several distinct and significant structural elements the Interior Homocline, the Interior Platform, and several basinal areas. Bordering the shield is a great belt of sedimentary rocks whose dip basinward is so slight and uniform as to be impreceptible to the eye. This Interior Homocline has an average width of about 400 km and a persistent dip varying from slightly more than 1°00' in older units to less than 0°30' in the youngest. One structural feature of the homocline the central Arabian arch has greatly influenced the present surface distribution of sedimentary rocks in the interior escarpment region. The arch, which affects all rocks from the basement up, marks the area of maximum curvature of the homocline in central Arabia. Although the arch has a varied history, it is apparently a residual high between the periodically sinking Persian Gulf and Rub' al Khali basins rather than a true independent positive feature. Support for this concept conies from the presence of a great arc of tensional structures the central Arabian graben and trough system near the crest of the arch and along the hinge line between the Persian Gulf basin and the stable western block. Bordering the homocline is the Interior Platform, a remarkably flat area of varying width in which systematic dip off the crystalline core no longer prevails. Superimposed on the platform are several major north-south anticlinal trends which include the great oil fields of Arabia Adjacent to the platform are several basinal areas that have from time to time received thick sedimentary deposits. Such basinal sags have developed on the shelf in the northeastern Rub' al Khali, northern Persian Gulf, Dibdibah and Sirhan-Turayf areas.

Professional Paper↗
USGS1980

Chemical, physical, and radiological quality of selected public water supplies in Florida : January-May 1979

Verde Valley--an area of complex geology where the crust of the North American plate changes from unstable to stable--is in central Arizona in the transition zone between the Basin and Range and the Colorado Plateaus tectonic provinces. Volcanism and tectonism have been progressing northeastward along the transition zone for about 20 million years. The Verde Hot Springs area is the focal point of the intersection of three major lineaments. More than 100 water samples were collected from wells and springs in the valley, and temperatures of the potential geothermal resources were calculated using two geochemical methods or geothermometers--silica and Na-K-Ca geothermometers. Because of the high concentration of dissolved magnesium in the ground water, the silica geotemperatures are considered to be more reliable than the Na-K-Ca geotemperatures. The Camp Verde and Verde Hot Springs areas contain ground water that has quartz-silica geotemperatures of between 99 and 135C and chalcedony-silica geotemperatures of between 73 and 111C. The geochemical evidence to substantiate a geothermal resource in Verde Valley is not conclusive, and further work including test drilling, should be done to verify the silica geotemperatures given in the map. (Kosco-USGS)

Water-Resources Investigations Report↗
USGS2014

Nonlethal screening of bat-wing skin with the use of ultraviolet fluorescence to detect lesions indicative of white-nose syndrome

Definitive diagnosis of the bat disease white-nose syndrome (WNS) requires histologic analysis to identify the cutaneous erosions caused by the fungal pathogen Pseudogymnoascus [formerly Geomyces] destructans (Pd). Gross visual inspection does not distinguish bats with or without WNS, and no nonlethal, on-site, preliminary screening methods are available for WNS in bats. We demonstrate that long-wave ultraviolet (UV) light (wavelength 368–385 nm) elicits a distinct orange–yellow fluorescence in bat-wing membranes (skin) that corresponds directly with the fungal cupping erosions in histologic sections of skin that are the current gold standard for diagnosis of WNS. Between March 2009 and April 2012, wing membranes from 168 North American bat carcasses submitted to the U.S. Geological Survey National Wildlife Health Center were examined with the use of both UV light and histology. Comparison of these techniques showed that 98.8% of the bats with foci of orange–yellow wing fluorescence (n = 80) were WNS-positive based on histologic diagnosis; bat wings that did not fluoresce under UV light (n = 88) were all histologically negative for WNS lesions. Punch biopsy samples as small as 3 mm taken from areas of wing with UV fluorescence were effective for identifying lesions diagnostic for WNS by histopathology. In a nonlethal biopsy-based study of 62 bats sampled (4-mm diameter) in hibernacula of the Czech Republic during 2012, 95.5% of fluorescent (n = 22) and 100% of nonfluorescent (n = 40) wing samples were confirmed by histopathology to be WNS positive and negative, respectively. This evidence supports use of long-wave UV light as a nonlethal and field-applicable method to screen bats for lesions indicative of WNS. Further, UV fluorescence can be used to guide targeted, nonlethal biopsy sampling for follow-up molecular testing, fungal culture analysis, and histologic confirmation of WNS.

Journal of Wildlife Diseases↗