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At least 955 records · Page 53Linked to original sources
USGS1985

ORTHOPHOTOQUAD MAPPING PROGRAM FOR ALASKA.

The U. S. Geological Survey (USGS) is the lead civilian mapping agency in the United States and is responsible for creating and maintaining numerous map series. In Alaska the standard topographic map series is at a scale of 1:63,360, and maps at that scale have been available from the USGS since the late 1940's. In 1981 USGS initiated production of orthophotoquads of Alaska, also at a scale of 1:63,360 to be compatible with the topographic map series. An orthophotoquad (OQ) is prepared from a rectified or differentially rectified and scaled black-and-white photographic image published in quadrangle format. The current status of the Alaska OQ program is summarized and sample OQ's are illustrated. Engineering applications of orthophotoquads are discussed, with an emphasis on their use in the on-shore and near-shore areas. A combination of orthophoto imagery and topographic line maps is described as a planning and engineering tool. Sources of map separates and orthophotoquads are provided.

Conference Paper↗
USGS1991

Aerial videotape mapping of coastal geomorphic changes

An aerial geomorphic mapping system was developed to examine the spatial and temporal variability in the coastal geomorphology of Louisiana. Between 1984 and 1990 eleven sequential annual and post-hurricane aerial videotape surveys were flown covering periods of prolonged fair weather, hurricane impacts and subsequent post-storm recoveries. A coastal geomorphic classification system was developed to map the spatial and temporal geomorphic changes between these surveys. The classification system is based on 10 years of shoreline monitoring, analysis of aerial photography for 1940-1989, and numerous field surveys. The classification system divides shorelines into two broad classes: natural and altered. Each class consists of several genetically linked categories of shorelines. Each category is further subdivided into morphologic types on the basis of landform relief, elevation, habitat type, vegetation density and type, and sediment characteristics. The classification is used with imagery from the low-altitude, high-resolution aerial videotape surveys to describe and quantify the longshore and cross-shore geomorphic, sedimentologic, and vegetative character of Louisiana's shoreline systems. The mapping system makes it possible to delineate and map detailed geomorphic habitat changes at a resolution higher than that of conventional vertical aerial photography. Morphologic units are mapped parallel to the regional shoreline from the aerial videotape imagery onto the base maps at a scale of 1:24,000. The base maps were constructed from vertical aerial photography concurrent with the data of the video imagery.

Conference Paper↗
USGS2000

Mapping the petroleum system - An investigative technique to explore the hydrocarbon fluid system

Creating a petroleum system map includes a series of logical steps that require specific information to explain the origin in time and space of discovered hydrocarbon occurrences. If used creatively, this map provides a basis on which to develop complementary plays and prospects. The logical steps include the characterization of a petroleum system (that is, to identify, map, and name the hydrocarbon fluid system) and the summary of these results on a folio sheet. A petroleum system map is based on the understanding that there are several levels of certainty from "guessing" to "knowing" that specific oil and gas accumulations emanated from a particular pod of active source rock. Levels of certainty start with the close geographic proximity of two or more accumulations, continues with the close stratigraphic proximity, followed by the similarities in bulk properties, and then detailed geochemical properties. The highest level of certainty includes the positive geochemical correlation of the hydrocarbon fluid in the accumulations to the extract of the active source rock. A petroleum system map is created when the following logic is implemented. Implementation starts when the oil and gas accumulations of a petroleum province are grouped stratigraphically and geographically. Bulk and geochemical properties are used to further refine the groups through the determination of genetically related oil and gas types. To this basic map, surface seeps and well shows are added. Similarly, the active source rock responsible for these hydrocarbon occurrences are mapped to further define the extent of the system. A folio sheet constructed for a hypothetical case study of the Deer-Boar(.) petroleum system illustrates this methodology.

AAPG Memoir↗
USGS2001

Mapping crustal heterogeneity using Lg propagation efficiency throughout the Middle East, Mediterranean, Southern Europe and Northern Africa

In this paper we describe a technique for mapping the lateral variation of Lg characteristics such as Lg blockage, efficient Lg propagation, and regions of very high attenuation in the Middle East, North Africa, Europe and the Mediterranean regions. Lg is used in a variety of seismological applications from magnitude estimation to identification of nuclear explosions for monitoring compliance with the Comprehensive Nuclear-Test-Ban Treaty (CTBT). These applications can give significantly biased results if the Lg phase is reduced or blocked by discontinuous structure or thin crust. Mapping these structures using quantitative techniques for determining Lg amplitude attenuation can break down when the phase is below background noise. In such cases Lg blockage and inefficient propagation zones are often mapped out by hand. With our approach, we attempt to visually simplify this information by imaging crustal structure anomalies that significantly diminish the amplitude of Lg. The visualization of such anomalies is achieved by defining a grid of cells that covers the entire region of interest. We trace Lg rays for each event/ station pair, which is simply the great circle path, and attribute to each cell a value equal to the maximum value of the Lg/P-coda amplitude ratio for all paths traversing that particular cell. The resulting map, from this empirical approach, is easily interpreted in terms of crustal structure and can successfully image small blockage features often missed by analysis of raypaths alone. This map can then be used to screen out events with blocked Lg prior to performing Q tomography, and to avoid using Lg-based methods of event identification for the CTBT in regions where they cannot work. For this study we applied our technique to one of the most tectonically complex regions on the earth. Nearly 9000 earthquake/station raypaths, traversing the vast region comprised of the Middle East, Mediterranean, Southern Europe and Northern Africa, have been analyzed. We measured the amplitude of Lg relative to the P-coda and mapped the lateral variation of Lg propagation efficiency. With the relatively dense coverage provided by the numerous crossing paths we are able to map out the pattern of crustal heterogeneity that gives rise to the observed character of Lg propagation. We observe that the propagation characteristics of Lg within the region of interest are very complicated but are readily correlated with the different tectonic environments within the region. For example, clear strong Lg arrivals are observed for paths crossing the stable continental interiors of Northern Africa and the Arabian Shield. In contrast, weakened to absent Lg is observed for paths crossing much of the Middle East, and Lg is absent for paths traversing the Mediterranean. Regions that block Lg transmission within the Middle East are very localized and include the Caspian Sea, the Iranian Plateau and the Red Sea. Resolution is variable throughout the region and strongly depends on the distribution of seismicity and recording stations. Lg propagation is best resolved within the Middle East where regions of crustal heterogeneity on the order of 100 km are imaged (e.g., South Caspian Sea and Red Sea). Crustal heterogeneity is resolvable but is poorest in seismically quiescent Northern Africa.

Pure and Applied Geophysics↗
USGS2013

A new map of standardized terrestrial ecosystems of Africa

Terrestrial ecosystems and vegetation of Africa were classified and mapped as part of a larger effort and global protocol (GEOSS – the Global Earth Observation System of Systems), which includes an activity to map terrestrial ecosystems of the earth in a standardized, robust, and practical manner, and at the finest possible spatial resolution. To model the potential distribution of ecosystems, new continental datasets for several key physical environment datalayers (including coastline, landforms, surficial lithology, and bioclimates) were developed at spatial and classification resolutions finer than existing similar datalayers. A hierarchical vegetation classification was developed by African ecosystem scientists and vegetation geographers, who also provided sample locations of the newly classified vegetation units. The vegetation types and ecosystems were then mapped across the continent using a classification and regression tree (CART) inductive model, which predicted the potential distribution of vegetation types from a suite of biophysical environmental attributes including bioclimate region, biogeographic region, surficial lithology, landform, elevation and land cover. Multi-scale ecosystems were classified and mapped in an increasingly detailed hierarchical framework using vegetation-based concepts of class, subclass, formation, division, and macrogroup levels. The finest vegetation units (macrogroups) classified and mapped in this effort are defined using diagnostic plant species and diagnostic growth forms that reflect biogeographic differences in composition and sub-continental to regional differences in mesoclimate, geology, substrates, hydrology, and disturbance regimes (FGDC, 2008). The macrogroups are regarded as meso-scale (100s to 10,000s of hectares) ecosystems. A total of 126 macrogroup types were mapped, each with multiple, repeating occurrences on the landscape. The modeling effort was implemented at a base spatial resolution of 90 m. In addition to creating several rich, new continent-wide biophysical datalayers describing African vegetation and ecosystems, our intention was to explore feasible approaches to rapidly moving this type of standardized, continent-wide, ecosystem classification and mapping effort forward.

African Geographical Review↗
USGS1962

Generalized structure contour maps of the New Jersey coastal plain

Twelve generalized structural contour maps were prepared from a study of 169 well logs or sample logs of drill cuttings from the Coastal Plain of New Jersey, Delaware, and the E astern Shore of Maryland. The configuration of the tops of the nonmarine Cretaceous deposits (Patuxent , Patapsco, Raritan, and Magothy formations) and the Piney Point Formation (Eocene) show the known subsurface extent of these formations in both New Jersey and Delaware. The structural contour maps show the tops of the Merchantville Formation and Woodbury Clay, the Englishtown Formation, the Marshalltown Formation, the Wenonah Formation and Mount Laurel Sand, the Navesink Forma ti on, and the Red Bank Sand which are a ll of Late Cretaceous age. The maps of the Hornerstown Sand, the Vincentown Formation, and the Manasquan Formation and Shark River Marl of early Tertiary age show the subsurface extent of these formations only in New Jersey. Also included is an outline map showing the locations of wells and seismic station s and a structural contour map showing the configuration of the bedrock surface of the report area. Structural contours on top of the Magothy Formation, or on the top of the Raritan Formation where the Magothy formation is absent, show the configuration of the nonmarine deposits of Cretaceous age. Isopachs of the nonmarine deposits are derived by interpolation between contours on top of the bedrock and the top of either the Magothy Formation or the Raritan Formation where the Magothy is absent. The Merchantville Formation and Woodbury Clay are difficult to separate in the subsurface, and therefore the contour a re drawn on top of the Woodbury Clay. In New Jersey, the thickness of the combined Merchantville Form a ti on and Woodbury Clay ranges from ab out 100 to 140 feet near the outcrop, but exceeds 250 feet in the subsurface along the coast in Ocean County. The top of the Englishtown Formation is easy to recognize because it generally consists of a micaceous white and yellow sand, although locally it is a silty clay . The formation thins toward the southwest from about 160 feet in central Ocean County to less than 20 feet in Salem County . It has not been recognized in Delaware. The Marshalltown Formation varies from black clay to a glauconitic sand. It usually ranges in thickness from 20 to 60 feet . It is very thin or absent in Delaware. The Wenonah Formation and Mount Laurel and arc difficult to separate in New Jersey, and therefore are shown as a unit. The combined thickness range from 60 to 100) feet. In Delaware the two formations are easily separated. The Navesink Formation is generally highly glauconitc and it is difficult to determine the upper limit where overlain by the Hornerstown Sand which is also glauconitic. The contour map on the top of the Navesink is based upon relatively little control. The Red Bank Sand reaches a thickness of about 160 feet in Monmouth County. It thins southwestward and is absent in outcrop in the southern part of the Coastal Plain of New Jersey. A probable equivalent of the Reel Bank has be recognized in Delaware. The Tinton Sand Member is the topmost unit of the Red Bank and in Monmouth County. The Hornerstown Sand is most glauconitic and is about 30 feet thick in outcrop. This is overlain by the Vincentown Formation which consists of two facies (1) calcareous sand facies and (2) quartz sand facies. These a re overlain by the Manasquan Formation and Shark River Marl which are here treated as a unit . In outcrop the combined thickness of the Manasquan Formation and Shark River Marl is about 40 feet, but in the subsurface they thicken to about 200 feet. The Piney Point Formation of Jackson age occur in the subsurface in Cape May and Atlantic Counties, N.J. and in southern Delaware but is not exposed in these States. Brief notes are given on formation of later Tertiary and Pleistocene age , but no contour maps were constructed.

Delaware;New Jersey↗
USGS2005

The manly map: the English construction of gender in early modern cartography

Questions of gender in cartography most often focus on the sex of people involved in the cartographic process. These areas of research include the history of women cartographers (Tyner 1997: 46; Ritzlin 1989: 5; Hudson 1989: 29), the cartography of issues centered on women (Seager and Olson 1986; Seager et al. 1997; Rocheleau et al. 1995: 62), and women in the cartographic labor force (McHaffie 1996). Such studies examine the experiences of men and women in map-making, but not the map itself. When studies have addressed gender and contemporary map design qualities, the focus has been on cognitive aspects of and potential differences between the sexes in the cartographic process of making, analyzing, or reading maps (Golledge and Gilmartin 1986; Gilmartin and Patton 1984). Such studies tend to polarize the experience of gender in cartography as either male or female, when in fact people display properties of both genders. This paper examines facets of the historical basis of contemporary cartographic design principles, especially where these principles are gendered. By examining gender as social constructions of femininity and masculinity and how they have been incorporated into mapping, instead of as the interaction of individuals with maps (although sexual stereotypes act predominantly on individuals on the basis of their sex), we more closely approach the complex array of skills and relationships within which people live, while gaining insight into the stereotypical experiences of individuals. The premise is that early modern map design was not gender neutral in terms of broader social forces shaping gender identity. Historical evidence suggests that modern cartographic design principles originated along the lines of ideals of masculinity.

Book chapter↗
USGS2018

2D and 3D potential field mapping and modelling at the Fallon FORGE site, Nevada, USA

Accurate geological characterization of Fallon FORGE is important for preparing the site as an EGS laboratory. As part of this effort, a 3D geologic map was constructed previously from well logs, surface geologic mapping, 2D seismic profiles, interpreted gravity & magnetic maps, and a gravity-inferred basement surface. In this study, we have conducted both 2D and 3D modelling of high-resolution gravity and magnetic data (pre-existing and new) in an effort to further refine and test this 3D geologic map at Fallon. This effort enabled a direct comparison of the 2D and 3D model results. Potential field modelling was guided by rock-property measurements of samples from drill-core and outcrop from the Fallon area. In total, five 2D potential field model profiles, up to 30 km in length, were constructed that extend across the Fallon area. The 3D gravity model volume was 8 km (N-S) x 8 km (E-W) x 4 km (thick). The majority of the 3D gravity model volume had 100 m cubic cells; but cells near the land surface were 1 m thick to adequately capture topography. Overall, the 2D & 3D geophysical modelling largely confirmed the previously constructed 3D geologic map at Fallon for three reasons: 1) lithologic boundaries in the 2D & 3D density models mostly agree with those in the 3D geologic map, 2) the rock properties used in the models lie within the range of independent measurements made on representative rock samples from the region, and 3) the match between the observed and calculated anomalies are largely within the measurement error of the observed fields. In places where the geophysical and geologic models differ, geophysical model results have revealed subsurface structural features that have helped refine geologic interpretations which, in turn, lead to adjustments to the 3D geologic map. In this paper, we present the 2D & 3D geophysical model results and discuss how they were utilized to confirm and refine our 3D geologic understanding of the Fallon FORGE site.

Geothermal Resources Council Transactions↗
USGS2017

Development of the next generation of seismic design value maps for the 2020 NEHRP Provisions

During the period January 2015 through August 2018, a joint committee of U.S. Geological Survey (USGS) representatives and National Institute of Building Sciences Building Seismic Safety Council (BSSC) volunteers and staff formed a committee to conduct Project 17. The purpose of Project 17 was to formulate recommendations for the rules by which next-generation seismic design value maps, derived from USGS national seismic hazard models, will be developed for adoption by the 2020 National Earthquake Hazard Reduction Program Recommended Provisions for Seismic Regulations of New Buildings and Other Structures (NEHRP Provisions), ASCE 7-22 and the 2024 International Building Code. Two similar projects, Project 97 and Project 07, had been conducted in the past. Each of these projects established, for a period of approximately ten years, the rules by which design ground motion values referenced by the building codes would be developed both by USGS and by private consultants engaged in site-specific studies. Project 17 was originally commissioned in response to issues identified in adopting the 2014 edition of the USGS national seismic hazard model and the design procedures that reference them for use, including the NEHRP Provisions, building codes and referenced standards. Specific issues included: the engineering profession’s discontent with the fluctuating design values portrayed by successive map editions; discovery that the standard spectral shape referenced by the design provisions did not adequately represent ground motion amplitude and spectral character on some sites; and a change in seismologic characterization of the possible size of earthquakes originating on various faults and source zones. Project 17 was funded by the Federal Emergency Management Agency (FEMA), and supported by the USGS with some collaborating experts. An initial planning committee met throughout calendar year 2015 to identify key issues to be considered and to develop a work plan for addressing these as part of the 2020 NEHRP Provisions update cycle. The planning committee recommended an effort of approximately 30-months duration during which the USGS would develop draft design maps based on the rules proposed, to allow evaluation and refinement of the recommendations. A Project 17 Committee (P17C) was empaneled and four task subcommittees were formed, each charged with evaluating one of the key issues identified in the planning effort: Stabilizing mapped values; Definition of Acceptable Risk; Development of multi-period spectral parameter data; and, Definition of procedures for computing deterministic caps, should it be necessary to continue use of such caps in development of the maps. A fifth task subcommittee was formed in 2017 to look at ways to stabilize the seismic design category as an extended effort to stabilize mapped values. The P17C met three times per year throughout 2016, 2017 and 2018 to resolve these issues and develop recommendations for an updated technical basis and procedures to be followed in preparing next-generation seismic design value maps for inclusion in the NEHRP Provisions. The P17C documented these in the form of draft proposals for revision of the NEHRP Provisions. In August 2018, the P17C passed these recommendations to the Provisions Update Committee (PUC) for completion, development of consensus and adoption as appropriate.

Report↗
USGS1993

GIS mapping of earthquake ground shaking in San Francisco, California

Severe earthquakes of the last decade in Mexico, Armenia, and the United States have reemphasized the importance of local geologic site conditions in estimating damage and consequent losses. Recent advances in geographic information system (GIS) technology have created new opportunities for maintaining and integrating extensive spatial databases for applications in seismic hazard analysis. Ground motion data and damage distributions from past earthquakes are combined with GIS databases of geologic information to prepare preliminary maps for inferring input ground motion levels for earthquake resistant design. Maps of bedrock elevation, surface topography, and surface geology are used to develop maps of soil thickness and predominant period. Ground motion attenuation relationships are used to create maps estimating ground shaking intensity for a uniform ground condition. Relationships between geologic characteristics, ground motion amplification, and earthquake intensity are used to produce amplification capability maps. Estimated ground shaking for the uniform ground condition is combined with amplification capability to develop maps predicting regional ground shaking intensity. The methods of predictive GIS mapping described here are useful for estimating characteristics of input ground motion in many urbanized seismic regions of the world.

California↗
USGS2013

Multi-temporal maps of the Montaguto earth flow in southern Italy from 1954 to 2010

Historical movement of the Montaguto earth flow in southern Italy has periodically destroyed residences and farmland, and damaged the Italian National Road SS90 and the Benevento-Foggia National Railway. This paper provides maps from an investigation into the evolution of the Montaguto earth flow from 1954 to 2010. We used aerial photos, topographic maps, LiDAR data, satellite images, and field observations to produce multi-temporal maps. The maps show the spatial and temporal distribution of back-tilted surfaces, flank ridges, and normal, thrust, and strike-slip faults. Springs, creeks, and ponds are also shown on the maps. The maps provide a basis for interpreting how basal and lateral boundary geometries influence earth-flow behavior and surface-water hydrology.

Montaguto Earth Flow↗
USGS1991

Seismicity map of the state of Georgia

This map is one of a series of seismicity maps produced by the U.S. Geological Survey that show earthquake data of individual states or groups of states at the scale of 1:1,000,000. This maps shows only those earthquakes with epicenters located within the boundaries of Georgia, even though earthquakes in nearby states or countries may have been felt or may have cause damage in Georgia. The data in table 1 were used to compile the seismicity map; these data are a corrected, expanded, and updated (through 1987) version of the data used by Algermissen (1969) for a study of seismic risk in the United States. The locations and intensities of some earthquakes were revised and intensities were assigned where none had been before. Many earthquakes were added to the original list from new data sources as well as from some old data sources that has not been previously used. The data in table 1 represent best estimates of the location of the epicenter, magnitude, and intensity of each earthquake on the basis of historical and current information. Some of the aftershocks from large earthquakes are listed, but not all, especially for earthquakes that occurred before seismic instruments were universally used. The latitude and longitude coordinates of each epicenter were rounded to the nearest tenth of a degree and sorted so that all identical locations were grouped and counted. These locations are represented on the map by a triangle. The number of earthquakes at each location is shown on the map by the Arabic number to the right of the triangle. A Roman numeral to the left of a triangle is the maximum Modified Mercoili intensity (Wood and Neumann, 1931) of all earthquakes at that geographic location, The absence of an intensity value indicates that no intensities have been assigned to earthquakes at that location. The year shown below each triangle is the latest year for which the maximum intensity was recorded.

Georgia↗
USGS1979

Seismicity map of the State of Louisiana

This map is one of a series of seismicity maps produced by the U. S. Geological Survey that show earthquake data of individual states or groups of states at the scale of 1:1,000,000. This map shows only those earthquakes with epicenters located within the boundaries of Louisiana, even though earthquakes in nearby states or countries may have been felt or may have caused damage in Louisiana. The data in table 1 were used to compile the seismicity map; these data are a corrected, expanded, and updated (through 1983) version of the data used by Algermissen (1969) for a study of seismic risk in the United States. The locations and intensities of some earthquakes were revised and intensities were assigned where none had been before. Many earthquakes were added to the original list from new data sources as well as from some old data sources that had not been previously used. The data in table 1 represent best estimates of the location of the epicenter, magnitude, and intensity of each earthquake on the basis of historical and current information. Some of the aftershocks from large earthquakes are listed, but not all, especially for earthquakes that occurred before seismic instruments were universally used. The latitude and longitude coordinates of each epicenter were rounded to the nearest tenth of a degree and sorted so that all identical locations were grouped and counted. These locations are represented on the map by a triangle. The number of earthquakes at each location is shown on the map by the arabic number to the right of the triangle. A Roman numeral to the 1eft of a triangle is the maximum Modified Mercalli intensity (Wood and Neumann, 1931) of all earthquakes at that geographic location. The absence of an intensity value indicates that no intensities have been assigned to earthquakes at that location. The year shown below each triangle is the latest year for which the maximum intensity was recorded.

Louisiana↗
USGS1987

Seismicity map of the state of Pennsylvania

This map is one of a series of seismicity maps produced by the U. S. Geological Survey that show earthquake data of individual states or groups of states at the scale of 1:1,000,000. This map shows only those earthquakes with epicenters located within the boundaries of Pennsylvania, even though earthquakes in nearby states may have been felt or may have caused damage in Pennsylvania. The data in table 1 were used to compile the seismicity map; these data are a corrected, expanded, and updated (through 1983) version of the data used by Algermissen (1969) for a study of seismic risk in the United States. The locations and intensities of some earthquakes were revised and intensities were assigned where none had been before. Many earthquakes were added to the original list from new data sources as well as from some old data sources that had not been previously used. The data in table 1 represent best estimates of the location of the epicenter, magnitude, and intensity of each earthquake on the basis of historical and current information. Some of the aftershocks from large earthquakes are listed, but not all, especially for earthquakes that occurred before seismic instruments were universally used. The latitude and longitude coordinates of each epicenter were rounded to the nearest tenth of a degree and sorted so that all identical locations were grouped and counted. These locations are represented on the map by a triangle. The number of earthquakes at each location is shown on the map by the arabic number to the right of the triangle. A Roman numeral to the left of a triangle is the maximum Modified Mercalli intensity (Wood and Neumann, 1931) of a11 earthquakes at that geographic location. The absence of an intensity value indicates that no intensities have been assigned to earthquakes at that location. The year shown below each triangle is the latest year for which the maximum intensity was recorded.

Pennsylvania↗
USGS1988

Maps showing distribution of copper, lead, zinc, cadmium, and silver in samples of minus-60-mesh (0.25-MM) stream sediment and nonmagnetic heavy-mineral concentrate, Walker Lake 1 degree by 2 degrees Quadrangle, California and Nevada

This report is part of a folio of maps of the Walker Lake 1 o x 2 o quadrangle, California and Nevada, prepared under the Conterminous United States Mineral Assessment Program. The folio includes geological, geochemical, and geophysical maps, as well as mineral resources assessment maps, which identify selected known or possible mineral-deposit environments in the quadrangle. The geochemical maps show the distributions of selected individual elements (Chaffee and others, 1988 a, b, c) and the distributions of selected groups of elements (Chaffee, 1988a, b, c). Discussions accompanying the individual element maps are restricted to mineral residences of the individual elements as well as to what types of mineral deposits and environments may be represented by anomalies of a particular element. Discussions accompanying the multielemental maps describe the types of mineral deposits that may be related to each element group and indicate the most favorable localities for these deposits.

California, Nevada↗
USGS1988

Maps showing distribution of iron, cobalt, barium, strontium, arsenic, antimony, and bismuth in samples of minus-60-mesh (0.25-MM) stream sediment and (or) nonmagnetic heavy-mineral concentrate, Walker Lake 1 degree by 2 degrees Quadrangle, California and Nevada

This report is part of a folio of maps of the Walker Lake 1 o x 2 o quadrangle, California and Nevada, prepared under the Conterminous United States Mineral Assessment Program. The folio includes geological, geochemical, and geophysical maps, as well as mineral resources assessment maps, which identify selected known or possible mineral-deposit environments in the quadrangle. The geochemical maps show the distributions of selected individual elements (Chaffee and others, 1988 a, b, c) and the distributions of selected groups of elements (Chaffee, 1988a, b, c). Discussions accompanying the individual element maps are restricted to mineral residences of the individual elements as well as to what types of mineral deposits and environments may be represented by anomalies of a particular element. Discussions accompanying the multielemental maps describe the types of mineral deposits that may be related to each element group and indicate the most favorable localities for these deposits.

California, Nevada↗
USGS1988

Maps showing distribution of 12 selected elements in sample of rock, Walker Lake 1 degree by 2 degrees Quadrangle, California and Nevada

This report is part of a folio of maps of the Walker Lake 1 o x 2 o quadrangle, California and Nevada, prepared under the Conterminous United States Mineral Assessment Program. The folio includes geological, geochemical, and geophysical maps, as well as mineral resources assessment maps, which identify selected known or possible mineral-deposit environments in the quadrangle. The geochemical maps show the distributions of selected individual elements (Chaffee and others, 1988 a, b, c) and the distributions of selected groups of elements (Chaffee, 1988a, b, c). Discussions accompanying the individual element maps are restricted to mineral residences of the individual elements as well as to what types of mineral deposits and environments may be represented by anomalies of a particular element. Discussions accompanying the multielemental maps describe the types of mineral deposits that may be related to each element group and indicate the most favorable localities for these deposits.

California, Nevada↗
USGS1988

Maps showing distribution of anomalies based on the use of R-mode factor analysis for selected groupings of elements in samples of minus-60-mesh (0.25-MM) stream sediment and nonmagnetic heavy-mineral concentrate, Walker Lake 1 degree by 2 degrees Quadrangle, California and Nevada

This report is part of a folio of maps of the Walker Lake 1 o x 2 o quadrangle, California and Nevada, prepared under the Conterminous United States Mineral Assessment Program. The folio includes geological, geochemical, and geophysical maps, as well as mineral resources assessment maps, which identify selected known or possible mineral-deposit environments in the quadrangle. The geochemical maps show the distributions of selected individual elements (Chaffee and others, 1988 a, b, c) and the distributions of selected groups of elements (Chaffee, 1988a, b, c). Discussions accompanying the individual element maps are restricted to mineral residences of the individual elements as well as to what types of mineral deposits and environments may be represented by anomalies of a particular element. Discussions accompanying the multielemental maps describe the types of mineral deposits that may be related to each element group and indicate the most favorable localities for these deposits.

California, Nevada↗