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At least 1,207 records · Page 67Linked to original sources

Map Showing Seacliff Response to Climatic and Seismic Events, Seabright Beach, Santa Cruz County, California

Introduction The coastal cliffs along much of the central California coast are actively retreating. Large storms and periodic earthquakes are responsible for most of the documented sea cliff slope failures. Long-term average erosion rates calculated for this section of coast do not provide the spatial or temporal data resolution necessary to identify the processes responsible for retreat of the sea cliffs where episodic retreat threatens homes and community infrastructure. Research suggests that more erosion occurs along the California coast over a short time scale, during periods of severe storms or seismic activity, than occurs during decades of normal weather or seismic quiescence. This is the third map in a series of maps prepared to document the processes of short-term sea cliff retreat through the identification of slope failure styles, spatial variability of failures, and temporal variation in retreat amounts in an area that has been identified as an erosion hotspot. This map presents sea cliff failure and retreat data from the Seabright Beach section, California, which is located on the east side of Santa Cruz along the northern Monterey Bay coast. The data presented in this map series provide high-resolution spatial and temporal information on the location, amount, and processes of sea cliff retreat in Santa Cruz, California. These data show the response of the sea cliffs to both large magnitude earthquakes and severe climatic events such as El Ni?os; this information may prove useful in predicting the future response of the cliffs to events of similar magnitude. The map data can also be incorporated into Global Information System (GIS) for use by researchers and community planners. During this study we developed a method for investigating short-term processes of sea cliff evolution using rectified photographic stereo models. This method allows us to document the linear extent of cliff failures, the spatial and temporal relationship between failures, and the type or style of slope failure. Seabright Beach extends 0.9 km from San Lorenzo Point on the west to the Santa Cruz Yacht Harbor on the east. The cliffs at Seabright Beach are completely protected from wave attack by a wide beach. The protective beach is a relatively recent feature that formed after the emplacement of the Santa Cruz Yacht Harbor jetty in 1963-1964. Prior to the completion of the jetty, the cliffs at Seabright Beach were subject to daily wave attack. The data in this study are post-jetty construction; therefore, the sea cliff failures and cliff retreat are the result of nonmarine processes (rainfall, groundwater and seismic shaking). The 8 to 15 m high cliffs at Seabright Beach are composed of the Miocene to Pliocene Purisima Formation, which is overlain by unconsolidated Pleistocene terrace deposits. The relative thickness of these units varies along the length of the cliff. At the west end of Seabright Beach, including San Lorenzo Point, nearly the entire cliff section is composed of Purisima Formation and is capped by less than 2 m of terrace deposits. In this exposure, the Purisima Formation is a moderately weathered, moderately indurated massive sandstone. The height of the cliffs and the thickness of the Purisima Formation decrease to the east. In the cliffs immediately adjacent to the harbor, the entire exposure is composed of terrace deposits. Toe-slope debris and wind-blown sand form a nearly continuous fan along the cliff base that obscure the lower portion of the cliff. This study documents the impacts of earthquakes and large storms to the sea cliffs in the Seabright Beach section. The first event is the 1989 Loma Prieta earthquake, a M7.1 earthquake that caused widespread damage to the area stretching from Santa Cruz to the San Francisco Bay. The epicenter of the earthquake was located in the Santa Cruz Mountains, approximately 9 km inland from the coast. Extensive block and debris falls, induced by the seismic shaking, occ

Miscellaneous Field Studies Map↗

Geologic map of the Upper Hurricane Wash and vicinity, Mohave County, northwestern Arizona

This digital map database is compiled from unpublished open file reports by the author and represents the general distribution of surficial and bedrock geology in the mapped area. The map area lies within the Shivwits and Uikaret Plateaus, together with the accompanying pamphlet, it provides current information on the geologic structure, stratigraph, and Cenozoic geology of the area. The database delineates map units that are identified by age and lithology following the stratigraphic nomenclature of the U.S. Geological Survey. The scale of the source maps limits the spatial resolution of the database to 1:31,680 or smaller.

Miscellaneous Field Studies Map↗

Geologic map of the Ponca quadrangle, Newton, Boone, and Carroll Counties, Arkansas

This digital geologic map compilation presents new polygon (i.e., geologic map unit contacts), line (i.e., fault, fold axis, and structure contour), and point (i.e., structural attitude, contact elevations) vector data for the Ponca 7 1/2' quadrangle in northern Arkansas. The map database, which is at 1:24,000-scale resolution, provides geologic coverage of an area of current hydrogeologic, tectonic, and stratigraphic interest. The Ponca quadrangle is located in Newton, Boone, and Carroll Counties about 20 km southwest of the town of Harrison. The map area is underlain by sedimentary rocks of Ordovician, Mississippian, and Pennsylvanian age that were mildly deformed by a series of normal and strike-slip faults and folds. The area is representative of the stratigraphic and structural setting of the southern Ozark Dome. The Ponca quadrangle map provides new geologic information for better understanding groundwater flow paths and development of karst features in and adjacent to the Buffalo River watershed.

Miscellaneous Field Studies Map↗

Geologic map of upper Clayhole Valley and vicinity, Mohave County, northwestern Arizona

This digital map database is compiled from unpublished data and new mapping by the authors and represents the general distribution of surficial and bedrock geology in the mapped area. Together with the accompanying pamphlet, it provides current information on the geologic structure and stratigraphy of the area. The database delineates map units that are identified by age and lithology following the stratigraphic nomenclature of the U.S. Geological Survey. The scale of the source maps limits the spatial resolution of the database to 1:31,680 or smaller.

Miscellaneous Field Studies Map↗

Geologic map of the Lower Grand Wash cliffs and vicinity, Mohave County, Northwestern Arizona

This digital map database is compiled from unpublished data and new mapping by the authors and represents the general distribution of surficial and bedrock geology in the mapped area. Together with the accompanying pamphlet, it provides current information on the geologic structure and stratigraphy of the area. The database dilineates map units that are identified by age and lithology following the stratigraphic nomenclature of the U.S. Geological Survey. The scale of the source maps limits the spatial resolution of the database to 1:31,680 or smaller.

Miscellaneous Field Studies Map↗

Reconnaissance geologic map and geochemical analyses of stream-sediment and rock samples of the Anchorage A-6 quadrangle, Alaska

A reconnaissance geologic map and analytical data for 70 stream-sediment samples and 34 rock samples for the Anchorage A-6 1:63,360 scale quadrangle are presented in this report, together with a statistical treatment of the geochemical data. The bedrock was mapped and samples collected during the summers of 1969, 1970, and 1971 as part of a continuing U.S. Geological Survey project to map basement rocks in the western Chugach Mountains. Most of the early work on the bedrock geology of the Anchorage A-6 quadrangle was done by Capps (1916 and 1940), who studied the geology of the Turnagain-Knik region, and by Park (1933), who studied the Girdwood gold mining district, most of which is in the Anchorage A-6 quadrangle. Recent studies of bedrock in the quadrangle and nearby areas are described in papers by Clark and Bartsch (1971a, b) and Clark (in press, a, b). Grateful acknowledgement is given to several persons who made valuable contributions to this report. They include Henry R. Schmoll and Ernest Dobrovolny who mapped the contacts between bedrock and surficial deposits shown in figure 1, David L. Jones who did the paleontological studies, and Susan R. Bartsch and Pamela S. Morse who participated in the geologic mapping and geochemical sampling.

Alaska↗

Maps showing distribution of anomalous amounts of selected elements in stream-sediment and rock samples, Eagle quadrangle, Alaska

Maps showing the distribution of anomalous amounts of selected elements found in more than 1,600 stream-sediment and more than 1,500 rock samples have been prepared form results of semiquantitative spectrographic analyses. The samples were collected in the Eagle quadrangle, east-central Alaska, in the summers of 1968, 1969, 1970, and 1971. Figure 1 is a map showing localities for all stream-sediment samples analyzed and indicates by symbols those containing anomalous amounts of one or more of the following elements: gold (Au), silver (Ag), arsenic (As), bismuth (Bi), copper (Cu), chromium (Cr), molybdenum (Mo), nickel (Ni), lead (Pb), antimony (Sb), tin (Sn), tungsten (W), and zinc (Zn). Figure 2 shows the localities for analyzed rock samples and indicates those containing specified amounts of the same elements as selected from the stream-sediment samples. Maps similar to these which showed the distribution of anomalous amounts of selected elements in stream-sediment and rock samples from the Eagle quadrangle were compiled in 1971 and issued as a U.S. Geological Survey open-file report (Foster and Yount, 1971). The maps of this report are revised from the open-file maps to include the sampling in the summer of 1971.

Alaska↗

Map showing unconsolidated materials, Southwick quadrangle, Massachusetts-Connecticut

This map is intended to serve as an aid in reconnaissance evaluation of unconsolidated materials and can be used to identify areas of potential interest. The units on this map indicate the first material of substantial thickness (generally greater than 3 feet (1 m) encountered beneath the soil layer. The soil layer (commonly a foot or two (about 0.5 m) thick) is not mapped. Other materials, different in composition, may underlie each map unit (see block diagram) or may occur as minor lenses within each map unit.

Connecticut, Massachusetts↗

Geochemical maps showing the distribution and abundance of beryllium in the Tanacross Quadrangle, Alaska

This series of geochemical maps shows the distribution of beryllium in three sample media: (A) the oxide residue (the oxalic-acid-leachable fraction) of the stream sediment, (B) the minus-80-mesh stream sediment, and (C) the ash of aquatic bryophytes (mosses). The geochemical data are plotted on a base map that shows generalized geology and the drainage pattern. The map symbols show the sample sites and ranges of values in the following manner: (1) open symbols denote background, (2) small black symbols represent weakly anomalous values, and (3) large black symbols denotes strongly anomalous values. Because the small black symbols represent weakly anomalous values, they are considered to be significant only where they correlate with strongly anomalous metal values either in the same or in other sample media. The ranges of values represented by the map symbols are shown on the histograms that accompany the geochemical maps. An explanation of sampling, preparation, and analytical procedures is given in Circular 734, which accompanies this folio. Complete analytical data for geochemical samples collected by the U.S. Geological Survey in the Tanacross quadrangle are available in a U.S. Geological Survey open-file report (O'Leary and others, 1976).

Alaska↗

Maps showing mineralogical and geochemical data for heavy-mineral concentrates in the Tanacross quadrangle, Alaska

This series of maps showing the following data for heavy mineral concentrates: distribution and abundance of selected ore-related minerals, distribution and abundance of copper in the magnetic fraction, and distribution and abundance of lead, copper, tin, beryllium, tungsten and bismuth in the nonmagnetic fraction. The data are plotted on base maps showing generalized geology, base metal prospects in the Yukon-Tanana Upland, and the drainage pattern. The distribution and abundance of ore-related minerals (fig. A) were obtained by microscopic examination of the heavy-mineral concentrates. The number of mineral grains observed is shown in the map explanation. Figures B through H are geochemical maps showing the distribution and abundance of metals as determined by six-step semi-quantitative emission spectrography. The geochemical map symbols show sample sites and the actual values for the element in the sample as determined by spectrography. An explanation of sampling, preparation, and analytical procedure is given in Circular 734 which accompanies this folio. Complete analytical data for geochemical samples collected by the U.S. Geological Survey in the Tanacross quadrangle are available in an open-file report (O'Leary and others, 1976).

Alaska↗

Mineral resources map of the McCarthy Quadrangle, Alaska

The mineral resources map is an assessment of the occurrence of mineral deposits in the McCarthy quadrangle by area and type of deposit. Descriptions of known mineral deposits and occurrences in the quadrangle provided by MacKevett (1976b) should be used in conjunction with this map. Areas enclosing both known deposits and areas favorable for unfound deposits are delineated in the mineral resources map. Types of deposits known to be widely scattered throughout the quadrangle, such as placer gold, and types with only a slight chance of being in the quadrangle are not delineated. Selection of favorable areas was based on occurrences of known deposits and geologic, geophysical, geochemical, and earth satellite data presented in the McCarthy folio (U.S. Geol. Survey MF maps 773A, B, D-N and Circular 739) and some additional geochemical data published in open-file form (O'Leary and others, 1976). Delineation of boundaries was made by the informed judgment of the team members, but final responsibility rests with the authors of this map.

Alaska↗

Geochemical and generalized geologic map showing distribution and abundance of molybdenum, copper, and lead in stream sediments in the Chandalar Quadrangle, Alaska

This geochemical map shows the distribution and abundance of molybdenum (Mo), copper (Cu), and lead (Pb) of -80 mesh (177 micrometers) stream sediment samples in the Chandalar quadrangle, Alaska. The map is a part of a series of geochemical maps that together with the background information circular (Reiser and others, 1978) comprise the folio on the Chandalar quadrangle, Alaska. The data are plotted on a subdued base map showing the generalized geology, topography, and sample localities. Map symbols showing the ranges of metal values are indicated on the accompanying histograms and all values shown are considered anomalous. An explanation of sampling, preparation, analytical procedures and geochemical raw data for all samples are discussed by O'Leary and others (1976). The -80 mesh (177 micrometers) stream sediment medium was used in this study because of the regional setting in the north-central Brooks Range. Given the rather restrictive time and manpower constraints the -80 mesh (177 micrometers) stream sediment combined with panned concentrates was determined to be the most economical and adequate medium in this case where clastic sediments are being derived from local bedrock. The study area is generally one of high relief with short fast-moving streams and broad glacial valleys. All samples were taken from active streams, as close to the center channel as possible. All sediments were considered to be locally derived. Care was taken, when sampling an obviously glaciated terrane, to sample above or upstream from morainal material, wherever possible. Most samples were taken in areas where bedrock was within 30 m of the sample site.

Alaska↗

Geochemical and generalized geologic map showing distribution and abundance of zinc in stream sediments in the Chandalar Quadrangle, Alaska

This geochemical map shows the distribution and abundance of zinc in -80 mesh (177 micrometers) stream sediment samples in the Chandalar quadrangle, Alaska. The map is a part of a series of geochemical maps that together with the background information circular (Reiser and others, 1978) comprise the folio on the Chandalar quadrangle, Alaska. The data are plotted on a subdued base map showing the generalized geology, topography, and sample localities. Map symbols show the metal values that are considered anomalous; these symbols are defined on the accompanying histograms. An explanation of sampling, preparation, analytical procedures and the geochemical raw data for all samples are presented by O'Leary and others (1976). The -80 mesh (177 micrometers) stream sediment medium was used in this study because of the regional setting in the north-central Brooks Range. Given the rather restrictive time and manpower constraints the -80 mesh (177 micrometers) stream sediment combined with panned concentrates was determined to be the most economical and adequate medium in this case where clastic sediments are being derived from local bedrock. The study area is generally one of high relief with short fast-moving streams and broad glacial valleys. All samples were taken from active streams, as close to the center channel as possible. All sediments were considered to be locally derived. Care was taken, when sampling an obviously glaciated terrane, to sample above or upstream from morainal material, wherever possible. Most samples were taken in areas where bedrock was within 30 m of the sample site. Due to poor sensitivity for zinc by spectrographic analysis (200 ppm) all zinc analyses were done by atomic absorption.

Alaska↗

Geochemical and generalized geologic map showing distribution and abundance of nickel, cobalt, lanthanum and yttrium in stream sediments, Chandalar 1° by 3° quadrangle, Alaska

This geochemical map shows the distribution and abundance of nickel (Ni), cobalt (Co), lanthanum (La), and yttrium (Y) in -80 mesh (177 micrometers) stream sediment samples in the Chandalar quadrangle, Alaska. The map is a part of a series of geochemical maps that together with the background information circular (Reiser and others, 1978) comprise the folio on the Chandalar quadrangle, Alaska. The data are plotted on a subdued base map showing the generalized geology, topography, and sample localities. Map symbols showing the ranges of metal values are indicated on the accompanying histograms and all values shown are considered anomalous. An explanation of sampling, preparation, and analytical procedures, and geochemical raw data for all samples are discussed by O'Leary and others (1976). The -80 mesh (177 micrometers) stream-sediment medium was used in this study because, given the rather restrictive time and manpower constraints, this medium combined with panned concentrates was determined to be the most economical and adequate medium in this area of the north-central Brooks Range where clastic sediments are derived from local bedrock. The study area is generally one of high relief with short fast moving streams and broad glacial valleys. All samples were taken from active streams, as close to the center channel as possible. All sediments were considered to be locally derived. Care was taken, when sampling an obviously glaciated terrane, to sample above or upstream from morainal material, wherever possible. Most samples were taken in areas where bedrock was within 30 m of the sample site.

Alaska↗

Geochemical and generalized geologic map showing distribution and abundance of barium, arsenic, boron, and vanadium in stream sediments in the Chandalar Quadrangle, Alaska

This geochemical map shows the distribution and abundance of barium (Ba), arsenic (As), boron (B), and vanadium (V) in -80 mesh (177 micrometers) stream sediment samples in the Chandalar quadrangle, Alaska. The map is a part of a series of geochemical maps that together with the background information circular (Reiser and others, 1978) comprise the folio on the Chandalar quadrangle, Alaska. The data are plotted on a subdued base map showing the generalized geology, topography, and sample localities. Map symbols showing the ranges of metal values are indicated on the accompanying histograms and all values shown are considered anomalous. An explanation of sampling, preparation, analytical procedures, and geochemical raw data for all samples are discussed by O'Leary and others (1976). The -80 mesh (177 micrometers) stream sediment medium was used in this study because of the regional setting in the north-central Brooks Range. Given the rather restrictive time and manpower constraints the -80 mesh (177 micrometers) stream sediment combined with panned concentrates was determined to be the most economical and adequate medium in this case where clastic sediments are being derived from local bedrock. The study area is generally one of high relief with short fast-moving streams and broad glacial valleys. All samples were taken from active streams, as close to the center channel as possible. All sediments were considered to be locally derived. Care was taken, when sampling an obviously glaciated terrane, to sample above or upstream from morainal material, wherever possible. Most samples were taken in areas where bedrock was within 30 m of the sample site. Due to the poor sensitivity by spectrographic analysis for arsenic, 200 ppm (parts per million), all arsenic analyses were done by colorimetry.

Alaska↗

Geochemical and generalized geologic map showing distribution and abundance of antimony and niobium in stream sediments, Chandalar 1° by 3° quadrangle, Alaska

This geochemical map shows the distribution and abundance of antimony (Sb) and niobium (Nb) in -80 mesh (177 micrometers) stream sediment samples in the Chandalar quadrangle, Alaska. The map is one of a series of geochemical maps that together with the background information circular (Reiser and others, 1978) comprise the folio on the Chandalar quadrangle, Alaska. The data are plotted on a subdued base map showing the generalized geology, topography, and sample localities. Map symbols showing the ranges of metal values are indicated on the accompanying histograms and all values shown are considered anomalous. An explanation of sampling, preparation, analytical procedures, and geochemical raw data for all samples are discussed by O'Leary and others (1976). The -80 mesh (177 micrometers) stream sediment medium was used in this study because, given the rather restrictive time and manpower constraints, this sample medium combined with panned concentrates were determined to be the most economical and adequate media in this area of the north-central Brooks Range where clastic sediments are derived from local bedrock. The study area is generally one of high relief with short fast moving streams and broad glacial valleys. All samples were taken from active streams, as close to the center channel as possible. All sediments were considered to be locally derived. Care was taken, when sampling an obviously glaciated terrane, to sample above or upstream from morainal material, wherever possible. Most samples were taken in areas where bedrock was within 30 m of the sample site. Due to the high limit of determination for antimony by spectrographic analysis (100 parts per million), all samples collected in 1975 for this study were analyzed for antimony by the atomic absorption method. Spectrographic antimony values for samples collected prior to this study were not used. Most of these previously collected samples are from the area between the North Fork and the Middle Fork of the Chandalar River and south of the Squaw Lake-Grove Creek Valley in the central part of the quadrangle and are discussed by Brosge and Reiser, 1970, 1972.

Alaska↗

Geologic map of Gunnison Gorge National Conservation Area, Delta and Montrose Counties, Colorado

This publication consists of a geologic map database and printed map sheet. The map sheet has a geologic map as the center piece, and accompanying text describes (1) the various geological units, (2) the uplift history of the region and how it relates to canyon downcutting, (3) the ecology of the gorge, and (4) human history. The map is intended to be used by the general public as well as scientists and goes hand-in-hand with a separate geological guide to Gunnison Gorge.

Colorado↗

Geologic map of the Hasty Quadrangle, Boone and Newton Counties, Arkansas

This digital geologic map compilation presents new polygon (for example, geologic map unit contacts), line (for example, fault, fold axis, and structure contour), and point (for example, structural attitude, contact elevations) vector data for the Hasty 7.5-minute quadrangle in northern Arkansas. The map database, which is at 1:24,000-scale resolution, provides geologic coverage of an area of current hydrogeologic, tectonic, and stratigraphic interest. The Hasty quadrangle is located in northern Newton and southern Boone Counties about 20 km south of the town of Harrison. The map area is underlain by sedimentary rocks of Ordovician, Mississippian, and Pennsylvanian age that were mildly deformed by a series of normal and strike-slip faults and folds. The area is representative of the stratigraphic and structural setting of the southern Ozark Dome. The Hasty quadrangle map provides new geologic information for better understanding groundwater flow paths in and adjacent to the Buffalo River watershed.

Scientific Investigations Map↗