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At least 397 records · Page 22Linked to original sources

Geologic resource evaluation of Pu‘uhonua O Hōnaunau National Historical Park, Hawai‘i. Part II: Benthic habitat mapping

In cooperation with the U.S. National Park Service (NPS), the U.S. Geological Survey (USGS) has mapped the underwater environment in and adjacent to three parks along the Kona coast on the island of Hawai‘i. This report is the second of two produced for the NPS on the geologic resource evaluation of of Pu‘uhonua O Hōnaunau National Historical Park (PUHO) and presents the results of benthic habitat mapping of the offshore waters for PUHO. See Part I (Richmond and others, 2006) for an overview of the regional geology, local volcanics, and a detailed description of coastal landforms in the park. Pu‘uhonua O Hōnaunau National Historical Park boundaries extend only to the mean high tide line and do not officially include the marine environment. However, impacts downslope of any development in the park are of concern to management. The area mapped for this report extends from Hōnaunau Bay, around Pu‘uhonua Point, to Ki‘ilae Bay and the south park boundary and from the shoreline to depths of approximately 40 m (130 ft), where the shelf drops off to a sand-covered bottom. Pu‘uhonua O Hōnaunau National Historical Park lies within the nearly 850-km2 Ki‘ilae watershed, which begins at the crest of Mauna Loa. The Ki‘ilae Watercourse runs through the southern area of the park and empties into Ki‘ilae Bay, but only during periods of extreme rainfall. The waters of Keone‘ele Cove, the ancient royal canoe landing at PUHO, while not formally under NPS jurisdiction, are managed by the park under an agreement with the State of Hawaii. This small embayment is a known haven for sea turtles, which are often found sunning themselves on the near- shore volcanic platform. Impacts to this area include frequent visits by scuba divers and snorkelers to Hōnaunau Bay and a small boat ramp located just to the north of Keone‘ele Cove.

Hawai'i

Hydrogeology, karst, and groundwater availability of Monroe County, West Virginia

Monroe County is in southeastern West Virginia, encompassing an area of 474 square miles. The area consists of karst and siliciclastic aquifers of Ordovician, Silurian, Devonian, and Mississippian age and is in parts of two physiographic provinces: the Valley and Ridge Province to the east of Peters Mountain, and the Appalachian Plateau Province to the west of Peters Mountain. This study was developed in response to inquiries from the Monroe County Commission requesting assessment of the water resources of the county to better understand the quantity of the county’s groundwater resources, for both current [2023] and future demand, and to provide information to support protection and management of the county’s valuable groundwater resources. Various products were developed for this study that provide knowledge with respect to water availability and contamination susceptibility of the karst aquifers within the county. U.S. Geological Survey (USGS) geologists conducted extensive geologic mapping in support of the project, producing (1) a countywide bedrock geologic map, (2) a countywide hydrogeologic map, and (3) a light detection and ranging (lidar)-derived countywide digital elevation model and associated sinkhole map. A significant part of this work was to map in detail the Greenbrier Group at the formation level, which prior to this study had only partially been completed. The report also includes (4) a description of the lithologic units identified as part of the geologic mapping process. U.S. Geological Survey hydrologists completed several additional products for the hydrology part of the effort, including development of (1) a countywide potentiometric surface (water-table) map, (2) a countywide base-flow stream assessment, (3) countywide water-budget estimates, (4) well log surveys for 15 wells to better understand subsurface controls on groundwater flow within the study area, (5) two groundwater tracer tests to better refine the groundwater divide from the northern and southern parts of the karst aquifer in Monroe County; and finally, based on all available data collected for the study including the potentiometric surface map, geologic map, current [2023] and legacy fluorometric groundwater tracer tests, and base-flow stream assessments, (6) groundwater-basin delineations were reassessed for principal groundwater basins within the Greenbrier aquifer. In Monroe County, four principal hydrogeologic settings produce large yields of water for residential, agricultural, and other uses. The most relied upon water-bearing zone with respect to current [2023] public water supply is from springs along Peters Mountain. These springs are derived from intervals of fractured sandstone and resultant alluvial deposits. Groundwater flows downslope through these permeable alluvial deposits and discharges at the contact with less permeable strata, such as the Reedsville Shale. The second most relied upon water-bearing zone in Monroe County is within the karstic Greenbrier Group aquifer, in which the basal Hillsdale Limestone overlies the less permeable Maccrady Shale. This geologic contact between the Hillsdale Limestone and Maccrady Shale is not only targeted as a source of water for agricultural supply but also is targeted as a source of water for residential supply. The third most relied upon water-bearing zone is composed of shallow perched aquifers within the Greenbrier Group. The discontinuous nature of these perched aquifers makes mapping their extent impossible, but they are related to permeable geologic strata, such as karstified limestones with solutionally enhanced permeability that overlies less permeable shale or chert bedrock. During geologic mapping of the county, several of these perched aquifers were documented in the Pickaway, Union, and Alderson Limestones. A fourth zone consists of springs from Ordovician carbonates at the base of Peters Mountain, which are influenced by sinking streams as well as upwelling along faults. In terms of water quantity, the most sustainable springs are those having deeper-sourced flows. Public supplies are a principal source of water used for residential and commercial supply in the region, accounting for 0.49 million gallons per day (Mgal/d) of fresh-water withdrawals (0.14 Mgal/d of groundwater and 0.35 Mgal/d of surface water) for residential and commercial use and serving 6,645 individuals (49.2 percent of the population). An estimated 6,861 people, (50.8 percent of the population) primarily rely on private wells or other unregulated sources, such as springs, and withdraw 0.55 Mgal/d of groundwater for their residential use. Public water supply in the region is primarily (71.4 percent) derived from springs and augmented by stream withdrawals (backup sources mainly during low-flow periods), with the remaining portion (28.6 percent) derived from groundwater withdrawals from wells. For rural residents, however, 100 percent of their withdrawals are derived from groundwater (wells or springs).

West Virginia

Updating the USGS seismic hazard maps for Alaska

The U.S. Geological Survey makes probabilistic seismic hazard maps and engineering design maps for building codes, emergency planning, risk management, and many other applications. The methodology considers all known earthquake sources with their associated magnitude and rate distributions. Specific faults can be modeled if slip-rate or recurrence information is available. Otherwise, areal sources are developed from earthquake catalogs or GPS data. Sources are combined with ground-motion estimates to compute the hazard. The current maps for Alaska were developed in 2007, and included modeled sources for the Alaska-Aleutian megathrust, a few crustal faults, and areal seismicity sources. The megathrust was modeled as a segmented dipping plane with segmentation largely derived from the slip patches of past earthquakes. Some megathrust deformation is aseismic, so recurrence was estimated from seismic history rather than plate rates. Crustal faults included the Fairweather-Queen Charlotte system, the Denali–Totschunda system, the Castle Mountain fault, two faults on Kodiak Island, and the Transition fault, with recurrence estimated from geologic data. Areal seismicity sources were developed for Benioff-zone earthquakes and for crustal earthquakes not associated with modeled faults. We review the current state of knowledge in Alaska from a seismic-hazard perspective, in anticipation of future updates of the maps. Updated source models will consider revised seismicity catalogs, new information on crustal faults, new GPS data, and new thinking on megathrust recurrence, segmentation, and geometry. Revised ground-motion models will provide up-to-date shaking estimates for crustal earthquakes and subduction earthquakes in Alaska.

Quaternary Science Reviews

Preliminary geologic mapping of Cretaceous and Tertiary formations in the eastern part of the Little Snake River coal field, Carbon County, Wyoming

In the 1970s and 1980s, C.S. Venable Barclay conducted geologic mapping of areas primarily underlain by Cretaceous coals in the eastern part of the Little Snake River coal field (LSR) in Carbon County, southwest Wyoming. With some exceptions, most of the mapping data were never published. Subsequently, after his retirement from the U.S. Geological Survey (USGS), his field maps and field notebooks were archived in the USGS Field Records. Due to a pending USGS coal assessment of the Little Snake River coal field area and planned geological mapping to be conducted by the Wyoming State Geological Survey, Barclay’s mapping data needed to be published to support these efforts. Subsequently, geologic maps were scanned and georeferenced into a geographic information system, and project and field notes were scanned into Portable Document Format (PDF) files. Data for seventeen 7½-minute quadrangles are presented in this report. This publication is solely intended to compile the mapping data as it was last worked on by Barclay and provides no interpretation or modification of his work.

Wyoming

Location maps and list of U.S. Geological Survey reports on water resources in Alaska, 1950 to 1988

The objective of this compilation is to provide a listing of water-resources reports in Alaska by location. For the purposes of this report, Alaska has been divided into six geographic sections: Arctic Slope, West, Southwest, East-Central, Southcentral, and Southeast. In addition, reports are cited in the following categories: Statewide and Topical, Trans-Alaska Pipeline System, and Glaciers. The Statewide and Topical reports are not located on maps. The index to the location maps is on the facing page. The numbers on the location maps refer to the bibliographic citations. (Gaps have been left in the numbering system for additional reports in future editions of this compilation.)

Alaska

A 125 year history of topographic mapping and GIS in the U.S. Geological Survey 1884-2009, part 2: 1980-2009

The United States Geological Survey (USGS) entered the mainstream of developments in computer-assisted technology for mapping during the 1970s. The introduction by USGS of digital line graphs (DLGs), digital elevation models (DEMs), and land use data analysis (LUDA) nationwide land-cover data provided a base for the rapid expansion of the use of GIS in the 1980s. Whereas USGS had developed the topologically structured DLG data and the Geographic Information Retrieval and Analysis System (GIRAS) for land-cover data, the Map Overlay Statistical System (MOSS), a nontopologically structured GIS software package developed by Autometric, Inc., under contract to the U.S. Fish and Wildlife Service, dominated the use of GIS by federal agencies in the 1970s. Thus, USGS data was used in MOSS, but the topological structure, which later became a requirement for GIS vector datasets, was not used in early GIS applications. The introduction of Esri's ARC/INFO in 1982 changed that, and by the end of the 1980s, topological structure for vector data was essential, and ARC/INFO was the dominant GIS software package used by federal agencies.

ArcNews

Statewide surficial geologic map of Nebraska underscores Quaternary landscape evolution from the High Plains to the Central Lowland

Surficial geologic mapping in Nebraska has been conducted primarily at the 1:24,000 scale since the mid-1990s, although there have also been limited efforts to map generalized Quaternary and surficial geology within the state and the region. We compiled and evaluated disparate maps (1:24,000–1:1,000,000) and datasets—including geologic, soil and soil parent material, and geomorphic maps as well as LiDAR derivatives—to produce a single 1:500,000 scale surficial geologic map of Nebraska that is the first of its kind. This new map provides a coarse-scale surficial geologic map that will be incorporated into a nationwide U.S. Geological Survey Quaternary geologic map. It also reflects the variation and uniqueness of physical landscapes in the state, where the Great Plains and Central Lowland physiographic provinces meet, further developing a richer interdisciplinary understanding of regional geomorphology in the heart of North America.

Nebraska

Digital version of "Open-File Report 92-181: Geologic map of the Indian Spring quadrangle, San Bernardino County, California"

This is a digital map database version of a previous printed geologic map, U.S. Geological Survey Open-File Report 92–181. The original paper map has been faithfully reproduced as a geologic map database for use in a GIS, and thus does not contain updated geologic information for the map area. This publication consists of three parts: Documentation in the form of a this publication's Open File text, or readme, describing the digital data, how to obtain it, as well as the original map explanation pamphlet. The documentation also consists of FGDC metadata, and a file describing any revisions to the data in this report. All of the documentaion components are available in a variety of file formats. Three Arc/Info (ESRI) formatted coverages of the geologic database, distributed in Arc Interchange (e00) format. The spatial databases in this component of the report consist vector-based GIS datasets that represent geologic contacts, faults, map units, and volcanic vents in the study area, as well as localities of K/Ar samples discussed in the original report, and geologic structure measurements. Plottable map representations of the database at 1:24,000 scale in PostScript and Adobe PDF formats. The plottable files consist of a color geologic map derived from the spatial database, composited with a topographic base map in the form of the USGS Digital Raster Graphic for the map area. Color symbology from each of these datasets is maintained, which can cause plot file sizes to be large.

California

Digital version of "Open-File Report 92-183: Geologic map of the Granite Spring Quadrangle, San Bernardino County, California"

This is a digital map database version of a previous printed geologic map, U.S. Geological Survey Open-File Report 92–183. The original paper map has been faithfully reproduced as a geologic map database for use in a GIS, and thus does not contain updated geologic information for the map area. This publication consists of three parts: 1. Documentation in the form of a this publication's Open File text, or readme, describing the digital data, how to obtain it, as well as the original map explanation pamphlet. The documentation also consists of FGDC metadata, and a file describing any revisions to the data in this report. All of the documentaion components are available in a variety of file formats. 2. Three Arc/Info (ESRI) formatted coverages of the geologic database, distributed in Arc Interchange (e00) format. The spatial databases in this component of the report consist vector-based GIS datasets that represent geologic contacts, faults, map units, and volcanic vents in the study area, as well as localities of K/Ar samples discussed in the original report, and geologic structure measurements. 3. Plottable map representations of the database at 1:24,000 scale in PostScript and Adobe PDF formats. The plottable files consist of a color geologic map derived from the spatial database, composited with a topographic base map in the form of the USGS Digital Raster Graphic for the map area. Color symbology from each of these datasets is maintained, which can cause plot file sizes to be large.

California

Digital version of "Open-File Report 92-179: Geologic map of the Cow Cove Quadrangle, San Bernardino County, California"

This is a digital map database version of a previous printed geologic map, U.S. Geological Survey Open-File Report 92–179. The original paper map has been faithfully reproduced as a geologic map database for use in a GIS, and thus does not contain updated geologic information for the map area. This publication consists of three parts: 1. Documentation in the form of a this publication's Open File text, or readme, describing the digital data, how to obtain it, as well as the original map explanation pamphlet. The documentation also consists of FGDC metadata, and a file describing any revisions to the data in this report. All of the documentaion components are available in a variety of file formats. 2. Three Arc/Info (ESRI) formatted coverages of the geologic database, distributed in Arc Interchange (e00) format. The spatial databases in this component of the report consist vector-based GIS datasets that represent geologic contacts, faults, map units, and volcanic vents in the study area, as well as localities of K/Ar samples discussed in the original report, and geologic structure measurements. 3. Plottable map representations of the database at 1:24,000 scale in PostScript and Adobe PDF formats. The plottable files consist of a color geologic map derived from the spatial database, composited with a topographic base map in the form of the USGS Digital Raster Graphic for the map area. Color symbology from each of these datasets is maintained, which can cause plot file sizes to be large.

California

Geoelectric survey of the Granite Gravel aquifer, Llano Uplift, Central Texas, to determine locations for water wells

An electrical geophysical survey was completed within a small area of the Llano Uplift of central Texas to determine locations to install two water wells in the Granite Gravel aquifer (GGA). Electrical resistivity tomography (ERT) was performed along two 188-m long profiles that intersected at the approximate center of a 100-m by 100-m self-potential (SP) map. The ERT survey was completed to map two-dimensional (2D) electric resistivity distributions in the GGA and the underlying Precambrian Town Mountain Granite (TMG) bedrock, whereas SP mapping was performed to delineate apparent streaming potential anomalies at the land surface that appeared correlated to the subsurface resistivity distributions, which exhibited strong lateral heterogeneity in the upper 35 m of the weathered layer that comprises the GGA. The depth to TMG bedrock, as shown by the resistivity distributions, varied substantially over relatively small profile distances and surface areas; however, the general electrical structure showed resistivity increasing with depth, beginning with a thin electrically conductive layer at the surface characterized by resistivity in the range of about 30–100 Ω-m, followed by a resistivity increase to 300–500 Ω-m at a depth that coincided with the water-table depth observed in the installed water wells. Resistivity of the TMG bedrock was generally greater than 500 Ω-m and exceeded 1000 Ω-m in some locations of the tomograms. Electrical structure beneath the survey area, as shown by the 2D resistivity distributions beneath the ERT profiles, delineated a relatively thick weathered section of GGA that spatially aligned with a conspicuous negative anomaly observed in the SP map after electrode-drift and terrain corrections were made. The combination of ERT and SP mapping guided selection of locations for two productive water wells within the small survey area despite substantial heterogeneity in the weathering profile of the GGA beneath the survey area.

Texas

Identification, prediction, and mitigation of sinkhole hazards in evaporite karst areas

Sinkholes usually have a higher probability of occurrence and a greater genetic diversity in evaporite terrains than in carbonate karst areas. This is because evaporites have a higher solubility and, commonly, a lower mechanical strength. Subsidence damage resulting from evaporite dissolution generates substantial losses throughout the world, but the causes are only well understood in a few areas. To deal with these hazards, a phased approach is needed for sinkhole identification, investigation, prediction, and mitigation. Identification techniques include field surveys and geomorphological mapping combined with accounts from local people and historical sources. Detailed sinkhole maps can be constructed from sequential historical maps, recent topographical maps, and digital elevation models (DEMs) complemented with building-damage surveying, remote sensing, and high-resolution geodetic surveys. On a more detailed level, information from exposed paleosubsidence features (paleokarst), speleological explorations, geophysical investigations, trenching, dating techniques, and boreholes may help in investigating dissolution and subsidence features. Information on the hydrogeological pathways including caves, springs, and swallow holes are particularly important especially when corroborated by tracer tests. These diverse data sources make a valuable database-the karst inventory. From this dataset, sinkhole susceptibility zonations (relative probability) may be produced based on the spatial distribution of the features and good knowledge of the local geology. Sinkhole distribution can be investigated by spatial distribution analysis techniques including studies of preferential elongation, alignment, and nearest neighbor analysis. More objective susceptibility models may be obtained by analyzing the statistical relationships between the known sinkholes and the conditioning factors. Chronological information on sinkhole formation is required to estimate the probability of occurrence of sinkholes (number of sinkholes/km2 year). Such spatial and temporal predictions, frequently derived from limited records and based on the assumption that past sinkhole activity may be extrapolated to the future, are non-corroborated hypotheses. Validation methods allow us to assess the predictive capability of the susceptibility maps and to transform them into probability maps. Avoiding the most hazardous areas by preventive planning is the safest strategy for development in sinkhole-prone areas. Corrective measures could be applied to reduce the dissolution activity and subsidence processes. A more practical solution for safe development is to reduce the vulnerability of the structures by using subsidence-proof designs. ?? 2007 Springer-Verlag.

Conference Paper

Archive of post-Hurricane Charley coastal oblique aerial photographs collected during U.S. Geological Survey field activity 04CCH01 from Marco Island to Fort DeSoto, Florida, August 15, 2004

On August 15, 2004, the U.S. Geological Survey (USGS) conducted an oblique aerial photographic survey off the southwest coast of Florida, from Marco Island to Fort DeSoto, aboard a Navajo Chieftain airplane, tail number N2KK, at an altitude of 500 ft and approximately 1000 ft offshore. These photographs were used to document coastal changes such as beach erosion and overwash caused by Hurricane Charley. They will also be used as baseline data for future coastal change. The oblique photography also served as qualitative ground truthing for the Experimental Advanced Airborne Research Lidar (EAARL) coastal topography and bathymetry data collected on August 16, 2004 (Bonisteel and others, 2009). This report serves as an archive of photographs collected during the August 15, 2004, post-Hurricane Charley coastal oblique aerial survey along with associated flight path maps, KML files, navigation files, digital Field Activity Collection System (FACS) logs, and Federal Geographic Data Committee (FGDC) metadata. Refer to the Acronyms page for expansions of all acronyms and abbreviations used in this report. The USGS St. Petersburg Coastal and Marine Science Center (SPCMSC) assigns a unique identifier to each cruise or field activity. For example, 04CCH01 tells us the data were collected in 2004 for the Coastal Change Hazards (CCH) study and the data were collected during the first field activity for that project in that calendar year. Refer to http://walrus.wr.usgs.gov/infobank/programs/html/definition/activity.html for a detailed description of the method used to assign the ID number. Two separate records of flight navigation were collected during the survey. The first was a continuous ASCII text file from the PLGR that recorded only latitudes, longitudes, and altitudes every 30 sec for the entire flight. No time values were recorded by the PLGR. The second navigation record was recorded by a Trimble Centurion GPS and converted to subtitles on the video, using a Compix Titler unit. The video was shot continuously during the survey. The video subtitles recorded day, month, year, latitude, longitude, and time in hours, minutes, and seconds. In order to produce a digital record of the navigation values that included latitude, longitude, and time, each was manually extracted from the video every 5 min, and these values were matched to the latitude and longitude in the PLGR file. Next, the time was interpolated between these 5-min fixes using Excel to produce time values for each navigation fix recorded in the PLGR file. The location of each photograph taken was determined in the following manner. A Nikon MF-14 data back marks the time each photograph was acquired on the lower right corner of the image in day, hour, and minute format (in UTC). These values were entered from the photographs into an Excel spreadsheet. It is assumed for the purposes of locating the images that the photographs were taken at a constant rate during any given minute of flight. To assign the time value in seconds to each photograph, the number of photographs taken during each minute was evenly distributed across that minute. For example, if 15 photographs were taken during minute 19:00:00, we assume that a picture was taken every 4 sec. The photographs were assigned the time values 19:00:00, 19:00:04, 19:00:08, and so on. The video time navigation file was then merged with the new interpolated photograph file based on time to produce the point of which each photograph was collected. As a result, the positions assigned to each photograph are an estimate of the aircraft position, not the location of the landmark photographed. The photographs provided here are JPEG scanned images of the analog slides. The metadata values for photo creation time, GPS latitude, GPS longitude, GPS position, keywords, credit, artist, caption, copyright, and contact were added to each photograph's EXIF header using EXIFtools (see the Software page). Photographs can be opened directly with any JPEG-compatible image viewer by clicking on a thumbnail on the contact sheet, or, when viewing the Google Earth KML file, by clicking on the marker and then clicking on either the thumbnail or the link below the thumbnail. The KML files were created using the photographic navigation files and the CreateKML JavaScript (see the Software page). To view the survey maps and navigation files, and for more information about these items, see the Navigation page. Figure 1 displays the acquisition geometry. The tables provide detailed information about the assigned location, name, data, and time the photograph was taken along with links to the photo and corresponding 5-min contact sheet. Refer to table 1 and table 2 for details of the northern and southern county photographs, respectively.

Florida

Fire Island National Seashore

These lidar-derived topographic maps were produced as a collaborative effort between the U.S. Geological Survey (USGS) Coastal and Marine Geology Program, the National Park Service (NPS), Northeast Coastal and Barrier Network, Inventory and Monitoring Program, and the National Aeronautics and Space Administration (NASA) Wallops Flight Facility. The aims of the partnership that created this product are to develop advanced survey techniques for mapping barrier island geomorphology and habitats, and to enable the monitoring of ecological and geological change within National Seashores. This product is based on data from an innovative airborne lidar instrument under development at the NASA Wallops Flight Facility, the NASA Experimental Advanced Airborne Research Lidar (EAARL).

New York

EAARL first return topography— Fire Island National Seashore

This Web site contains 31 LIDAR-derived first return topography maps and GIS files for Fire Island National Seashore. These lidar-derived topographic maps were produced as a collaborative effort between the U.S. Geological Survey (USGS) Coastal and Marine Geology Program, the National Park Service (NPS), Northeast Coastal and Barrier Network, Inventory and Monitoring Program, and the National Aeronautics and Space Administration (NASA) Wallops Flight Facility. The aims of the partnership that created this product are to develop advanced survey techniques for mapping barrier island geomorphology and habitats, and to enable the monitoring of ecological and geological change within National Seashores. This product is based on data from an innovative airborne lidar instrument under development at the NASA Wallops Flight Facility, the NASA Experimental Advanced Airborne Research Lidar (EAARL).

New York

New geologic mapping of the northwestern Willamette Valley, Oregon, and its American Viticultural Areas (AVAs)—A foundation for understanding their terroir

A geologic map of the greater Portland, Oregon, metropolitan area is planned that will document the region’s complex geology (currently in review: “Geologic map of the greater Portland metropolitan area and surrounding region, Oregon and Washington,” by Wells, R.E., Haugerud, R.A., Niem, A., Niem, W., Ma, L., Evarts, R., Madin, I., and others). The map, which is planned to be published as a U.S. Geological Survey Scientific Investigations Map, will consist of 51 7.5′ quadrangles covering more than 2,500 square miles, and it will represent more than 100 person-years of geologic mapping and studies. The region was mapped at the relatively detailed scale of 1:24,000 to improve understanding of its geology and its earthquake hazards. More than 100 geologic map units will record the 50-million-year history of volcanism, sedimentation, folding, and faulting above the Cascadia Subduction Zone. The geology contributes to the varied terroir of four American Viticultural Areas (AVAs) in the northwestern Willamette Valley: the Yamhill-Carlton, Dundee Hills, Chehalem Mountains, and Ribbon Ridge AVAs. Terroir is defined as the environmental conditions, especially climate and soils, that influence the quality and character of a region’s crops—in this case, grapes for wine. On this new poster (“New geologic mapping of the northwestern Willamette Valley, Oregon, and its American Viticultural Areas (AVAs)—A foundation for understanding their terroir”), we present the geologic map at a reduced scale (about 1:175,000) to show the general distribution of geologic map units, and we highlight, discuss, and illustrate six major geologic events that helped shape the region and form its terrior. We also discuss the geologic elements that contribute to the character of each of the four AVAs in the northwestern Willamette Valley.

Oregon

US Topo - A new national map series

In the second half of the 20th century, the foundation of the U.S. Geological Survey's national map series was the handcrafted 7.5-minute topographic map. Times change, budgets get squeezed and currency expectations become ever more challenging. The USGS's Larry Moore, who oversees data production operations at two National Geospatial Technical Operations Centers, provides an introduction to the new US Topo quadrangle maps.

Directions Magazine

Geomedia: Mapping Colorado at a fine scale

Currently, only 24 percent of Colorado's spectacular geology has been mapped at the fine scale of 1:24,000. At the same time, the state hosts many geologic hazards. Most maps of Colorado are at much broader scales, failing to show detail of basic geology crucial to safe engineering and building practices in a state that had the third-fastest-growing population during the 1990s. And the 2000 Census showed that the state, despite some economic woes, remains one of the fastest growing. Detailed geologic maps also aid the mineral industries that help fuel such growth. Since 1992, the Colorado Geological Survey (CGS) has mapped 1:24,000-scale quadrangles in high-impact areas under the STATEMAP component of the National Cooperative Geologic Mapping Program. In 2002, CGS completed its 43rd geologic quadrangle map. The long-range plan for the state is to complete 116 high-priority quadrangles in the next 15 years. The survey's approach is to select rapidly growing areas with relatively high potential for hazards and map contiguous quadrangles. In addition to mapping bedrock, CGS geologists have mapped the Quaternary deposits at the surface. Understanding these deposits is extremely important for implementing sound engineering practices because of potential for subsidence and landslides. The CGS mapping has not only yielded information about potential hazards, but also advanced scientific understanding of the state.

Geotimes