Filters: Tags: geoscientific (X) > Types: Downloadable (X)
33 results (9ms)|
Filters
Date Range
Tag Types |
This open-file report presents the results of the USGS Mineral Resources Program activity to compile a national-scale geologic map database to support national and regional level projects, including mineral resource and geo- environmental assessments. The only comprehensive sources of regional- and national-scale geologic maps are state geologic maps with scales ranging from 1:100,000 to 1:1,000,000. Digital versions of these state maps form the core of what is presented here. Because no adequate geologic map exists for the state of Alaska, it is being compiled in regional blocks that also form part of this national database. It is expected that this series will completed by approximately the end of 2007. These...
This data set represents an updated Ecological Subsection Map for Northern Alaska. This revision focused on correcting coding errors identified in the 2012 revision. The 2012 revision was a major revision and it focused on completing the incompletely mapped portion of the southern NPRA, improving mapping of glacial and outwash deposits within the Brooks Foothills, and improving consistency with existing surficial and bedrock geology maps in northern Alaska. The 2012 revisions resulted in 525 ecological subsections, nested within 55 ecosections and 12 ecoregions covering 411,781 km2. Attributes for the polygons include information on physiography, generalized geology, lithology, and referenced information sources....
These digital maps are a reformulation of previously published maps, primarily maps of states. The reformulation gives all the maps the same structure and format, allowing them to be combined into regional maps. The associated data tables have information about age and lithology of the map units, also in a standard format.
Some of the CYR rasters intentionally do not align or have the same extent. These rasters were not snapped to a common raster per the authors' discretion. Please review selected rasters prior to use. These varying alignments are a result of the use of differing source data sets and all products derived from them. We recommend that users snap or align rasters as best suits their own projects. - The Cumulative Impacts analysis included the primary, measurable Change Agent variables that are likely to have the largest and most direct impact in the Central Yukon study area in the future. However, in order to “sum” the impacts, thresholds for meaningful change had to be defined for each variable. Cumulative Impacts are...
Some of the CYR rasters intentionally do not align or have the same extent. These rasters were not snapped to a common raster per the authors' discretion. Please review selected rasters prior to use. These varying alignments are a result of the use of differing source data sets and all products derived from them. We recommend that users snap or align rasters as best suits their own projects. - The Cumulative Impacts analysis included the primary, measurable Change Agent variables that are likely to have the largest and most direct impact in the Central Yukon study area in the future. However, in order to “sum” the impacts, thresholds for meaningful change had to be defined for each variable. Cumulative Impacts are...
This open-file report presents the results of the USGS Mineral Resources Program activity to compile a national-scale geologic map database to support national and regional level projects, including mineral resource and geo- environmental assessments. The only comprehensive sources of regional- and national-scale geologic maps are state geologic maps with scales ranging from 1:100,000 to 1:1,000,000. Digital versions of these state maps form the core of what is presented here. Because no adequate geologic map exists for the state of Alaska, it is being compiled in regional blocks that also form part of this national database. It is expected that this series will completed by approximately the end of 2007. These...
Some of the CYR rasters intentionally do not align or have the same extent. These rasters were not snapped to a common raster per the authors' discretion. Please review selected rasters prior to use. These varying alignments are a result of the use of differing source data sets and all products derived from them. We recommend that users snap or align rasters as best suits their own projects. - The Cumulative Impacts analysis included the primary, measurable Change Agent variables that are likely to have the largest and most direct impact in the Central Yukon study area in the future. However, in order to “sum” the impacts, thresholds for meaningful change had to be defined for each variable. Cumulative Impacts are...
Major ecosystems have been mapped and described for the State of Alaska and nearby areas. Ecoregion units are based on newly available datasets and field experience of ecologists, biologists, geologists and regional experts. Recently derived datasets for Alaska included climate parameters, vegetation, surficial geology and topography. Additional datasets incorporated in the mapping process were lithology, soils, permafrost, hydrography, fire regime and glaciation. Thirty two units are mapped using a combination of the approaches of Bailey (hierarchial), and Omernick (integrated). The ecoregions are grouped into two higher levels using a "tri-archy" based on climate parameters, vegetation response and disturbance...
The Yukon River Lowlands, Kuskokwim Mountains, and Lime Hills were selected by BLM for a Rapid Ecoregional Assessment (REA). These three ecoregions form the basis for the REA study area and were derived from the Unified Ecoregions of Alaska (Nowacki et al. 2001). Major ecosystems have been mapped and described for the State of Alaska and nearby areas. Ecoregion units are based on newly available datasets and field experience of ecologists, biologists, geologists and regional experts. Recently derived datasets for Alaska included climate parameters, vegetation, surficial geology and topography. Additional datasets incorporated in the mapping process were lithology, soils, permafrost, hydrography, fire regime and...
This data set is a digital soil survey and generally is the most detailed level of soil geographic data developed by the National Cooperative Soil Survey. The information was prepared by digitizing maps, by compiling information onto a planimetric correct base and digitizing, or by revising digitized maps using remotely sensed and other information. This data set consists of georeferenced digital map data and computerized attribute data. The map data are in a soil survey area extent format and include a detailed, field verified inventory of soils and miscellaneous areas that normally occur in a repeatable pattern on the landscape and that can be cartographically shown at the scale mapped. A special soil features...
These digital maps are a reformulation of previously published maps, primarily maps of states. The reformulation gives all the maps the same structure and format, allowing them to be combined into regional maps. The associated data tables have information about age and lithology of the map units, also in a standard format.
Hydroelectric power, Alaska's largest source of renewable energy, supplies 20% of the state's electricity in an average water year. In 2012, 37 hydro projects provided power to Alaska utility customers. Hydropower can be generated through projects that store energy by impounding water in a reservoir behind a dam, or projects that provide hydro storage without dam construction through the natural impoundment of existing lakes using a "lake tap" near the bottom of the lake that supplies water to a powerhouse. Other projects increase annual energy production by diverting rivers to exisitng hydroelectric storage reservoirs and power plants. These projects allow more efficient use of existing infrastructure. Smaller...
Some of the CYR rasters intentionally do not align or have the same extent. These rasters were not snapped to a common raster per the authors' discretion. Please review selected rasters prior to use. These varying alignments are a result of the use of differing source data sets and all products derived from them. We recommend that users snap or align rasters as best suits their own projects. - The Cumulative Impacts analysis included the primary, measurable Change Agent variables that are likely to have the largest and most direct impact in the Central Yukon study area in the future. However, in order to “sum” the impacts, thresholds for meaningful change had to be defined for each variable. Cumulative Impacts are...
This data set is a digital soil survey and generally is the most detailed level of soil geographic data developed by the National Cooperative Soil Survey. The information was prepared by digitizing maps, by compiling information onto a planimetric correct base and digitizing, or by revising digitized maps using remotely sensed and other information. This data set consists of georeferenced digital map data and computerized attribute data. The map data are in a soil survey area extent format and include a detailed, field verified inventory of soils and miscellaneous areas that normally occur in a repeatable pattern on the landscape and that can be cartographically shown at the scale mapped. A special soil features...
Global sea level rise, warming water and air temperatures, reduction in sea-ice cover and duration, and increased frequency and strength of storms are associated with high-latitude climate change and, in combination, amplify the effects of coastal erosion and salinization in the Arctic. Patterns of coastal erosion relate to the interrelated factors of coastline elevation, orientation, geomorphology, sediment size and permafrost nature. The average rate of erosion along the Alaska’s Arctic Coast is -1.4 m/y with a range of -18.6 to +10.9 m/y. Analysis of historic aerial photography indicates the rate of erosion along the Beaufort Sea Coast has doubled over the last 50 years while thaw subsidence of this low-relief...
This dataset shows the possible location of alluvial aquaifers based on characteristics of surficial geology. Areas with surficial geology of sand, alluvium, or gravel were assumed to indicate possible locations of alluvial aquifers.
This data set is a digital general soil association map developed by the National Cooperative Soil Survey and distributed by the Natural Resources Conservation Service (formerly Natural Resources Conservation Service) of the U.S. Department of Agriculture. It consists of a broad based inventory of soils and non-soil areas that occur in a repeatable pattern on the landscape and that can be cartographically shown at the scale mapped. The soil maps for STATSGO are compiled by generalizing more detailed soil survey maps (SSURGO) for approximately 15 percent of Alaska where soil survey information exists. More detailed soil survey maps are not available on the remaining 85 percent. For these areas, data on geology, topography,...
Some of the NOS rasters intentionally do not align or have the same extent. These rasters were not snapped to a common raster per the authors' discretion. Please review selected rasters prior to use. These varying alignments are a result of the use of differing source data sets and all products derived from them. We recommend that users snap or align rasters as best suits their own projects. - The Cumulative Impacts analysis included the primary, measurable Change Agent variables that are likely to have the largest and most direct impact on the North Slope study area in the future. However, in order to “sum” the impacts, thresholds for meaningful change had to be defined for each variable. Cumulative Impacts are...
Some of the CYR rasters intentionally do not align or have the same extent. These rasters were not snapped to a common raster per the authors' discretion. Please review selected rasters prior to use. These varying alignments are a result of the use of differing source data sets and all products derived from them. We recommend that users snap or align rasters as best suits their own projects. - The Cumulative Impacts analysis included the primary, measurable Change Agent variables that are likely to have the largest and most direct impact in the Central Yukon study area in the future. However, in order to “sum” the impacts, thresholds for meaningful change had to be defined for each variable. Cumulative Impacts are...
These digital maps are a reformulation of previously published maps, primarily maps of states. The reformulation gives all the maps the same structure and format, allowing them to be combined into regional maps. The associated data tables have information about age and lithology of the map units, also in a standard format.
|
|
