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Keith A. Labay

Publications and source records attributed to Keith A. Labay.

At least 37 records · Page 2Linked to original sources
USGS2012

Geologic map of the Cook Inlet region, Alaska, including parts of the Talkeetna, Talkeetna Mountains, Tyonek, Anchorage, Lake Clark, Kenai, Seward, Iliamna, Seldovia, Mount Katmai, and Afognak 1:250,000-scale quadrangles

In 1976, L.B. Magoon, W.L. Adkinson, and R.M. Egbert published a major geologic map of the Cook Inlet region, which has served well as a compilation of existing information and a guide for future research and mapping. The map in this report updates Magoon and others (1976) and incorporates new and additional mapping and interpretation. This map is also a revision of areas of overlap with the geologic map completed for central Alaska (Wilson and others, 1998). Text from that compilation remains appropriate and is summarized here; many compromises have been made in strongly held beliefs to allow construction of this compilation. Yet our willingness to make interpretations and compromises does not allow resolution of all mapping conflicts. Nonetheless, we hope that geologists who have mapped in this region will recognize that, in incorporating their work, our regional correlations may have required some generalization or lumping of map units. Many sources were used to produce this geologic map and, in most cases, data from available maps were combined, without generalization, and new data were added where available. A preliminary version of this map was published as U.S. Geological Survey Open-File Report 2009–1108. The main differences between the versions concern revised mapping of surfical deposits in the northern and eastern parts of the map area. Minor error corrections have been made also.

Alaska↗
USGS2011

Alaska Geochemical Database (AGDB)-Geochemical data for rock, sediment, soil, mineral, and concentrate sample media

The Alaska Geochemical Database (AGDB) was created and designed to compile and integrate geochemical data from Alaska in order to facilitate geologic mapping, petrologic studies, mineral resource assessments, definition of geochemical baseline values and statistics, environmental impact assessments, and studies in medical geology. This Microsoft Access database serves as a data archive in support of present and future Alaskan geologic and geochemical projects, and contains data tables describing historical and new quantitative and qualitative geochemical analyses. The analytical results were determined by 85 laboratory and field analytical methods on 264,095 rock, sediment, soil, mineral and heavy-mineral concentrate samples. Most samples were collected by U.S. Geological Survey (USGS) personnel and analyzed in USGS laboratories or, under contracts, in commercial analytical laboratories. These data represent analyses of samples collected as part of various USGS programs and projects from 1962 to 2009. In addition, mineralogical data from 18,138 nonmagnetic heavy mineral concentrate samples are included in this database. The AGDB includes historical geochemical data originally archived in the USGS Rock Analysis Storage System (RASS) database, used from the mid-1960s through the late 1980s and the USGS PLUTO database used from the mid-1970s through the mid-1990s. All of these data are currently maintained in the Oracle-based National Geochemical Database (NGDB). Retrievals from the NGDB were used to generate most of the AGDB data set. These data were checked for accuracy regarding sample location, sample media type, and analytical methods used. This arduous process of reviewing, verifying and, where necessary, editing all USGS geochemical data resulted in a significantly improved Alaska geochemical dataset. USGS data that were not previously in the NGDB because the data predate the earliest USGS geochemical databases, or were once excluded for programmatic reasons, are included here in the AGDB and will be added to the NGDB. The AGDB data provided here are the most accurate and complete to date, and should be useful for a wide variety of geochemical studies. The AGDB data provided in the linked database may be updated or changed periodically. The data on the DVD and in the data downloads provided with this report are current as of date of publication.

Data Series↗
USGS2011

Fossil locations and data for the Taylor Mountains, and parts of the Bethel, Goodnews, and Dillingham quadrangles, southwestern Alaska

Information about fossils collected by U.S. Geological Survey, State of Alaska, academic, and industry geologists that have been reported in literature or archived in reports from the former U.S. Geological Survey Branch of Paleontology and Stratigraphy are compiled on a plate and table in this report to provide comprehensive paleontologic age data for the Taylor Mountains quadrangle area in southwestern Alaska. The reports used to compile the table in this report were submitted by recognized paleontologic experts. Some of the information is derived from reports that date back almost 100 years. Many of the data are available in more detail in the Alaska Paleontological Database (http://www.alaskafossil.org/). The 287 entries in this table are shown on the accompanying plate, on which symbols representing the entries are color-coded by geologic age. This report represents the most comprehensive and most recently updated compilation of paleontologic data for this area.

Open-File Report↗
USGS2011

Surficial geologic map of the Gates of the Arctic National Park and Preserve, Alaska

The Gates of the Arctic National Park and Preserve (GAAR) is centered over the central Brooks Range of northern Alaska. To the west, it abuts the Noatak National Preserve; its eastern boundary is the transportation corridor occupied by the Dalton Highway and the Alyeska Pipeline. The GAAR extends northward beyond the northern flank of the Brooks Range into the southern Arctic Foothills. Its southern boundary lies beyond the south flank of the Brooks Range within foothills and depositional basins of interior Alaska. The accompanying surficial geologic map covers all of the GAAR with the addition of a 10-km (6.2-mi) belt or "buffer zone" beyond its boundaries. A narrower (5-km) buffer zone is employed where the GAAR extends farthest north and south of the Brooks Range, in the north-central and southwestern parts of the map area, respectively. The surfical geologic map incorporates parts of ten surficial geologic maps previously published at 1:250,000 scale. In addition, a small part of the buffer zone mapped in the southwest corner of the map area was compiled from unpublished surficial geologic mapping of the Shungnak 1:250,000-scale quadrangle. Each of those individual maps was developed from (1) aerial and surface observations of morphology and composition of unconsolidated deposits, (2) tracing the distribution and interrelation of terraces, abandoned meltwater channels, moraines, abandoned lake beds, and other landforms, (3) stratigraphic study of exposures along lake shores and river bluffs, (4) examination of sediments and soil profiles in auger borings and test pits, and exposed in roadcuts and placer workings, and (5) analysis of previously published geologic maps and reports. The map units used for those maps and employed in the present compilation are defined on the basis of their physical character, genesis, and age. Relative and absolute ages of the map units were determined from their geographic locations and from their stratigraphic positions and radiocarbon ages.

Alaska↗
USGS2010

Stream-sediment samples reanalyzed for major, rare earth, and trace elements from seven 1:250,000-scale quadrangles, south-central Alaska, 2007-09

During the 1960s through the 1980s, the U.S. Geological Survey conducted reconnaissance geochemical surveys of drainage basins throughout most of the Iliamna, Lake Clark, Lime Hills, and Talkeetna 1:250,000-scale quadrangles and parts of the McGrath, Seldovia, and Tyonek 1:250,000-scale quadrangles in Alaska. These geochemical surveys provide data necessary to assess the potential for undiscovered mineral resources and provide data that may be used to determine regional-scale element baselines. This report provides new data for 1,075 of the previously collected stream-sediment samples. The new analyses include a broader spectrum of elements and provide data that are more precise than the original analyses. All samples were analyzed for arsenic by hydride generation atomic absorption spectrometry, for gold, palladium, and platinum by inductively coupled plasma-mass spectrometry after lead button fire assay separation, and for a suite of 55 major, rare earth, and trace elements by inductively coupled plasma-atomic emission spectrometry and inductively coupled plasma-mass spectrometry after sodium peroxide sinter at 450 degrees Celsius.

Data Series↗
USGS2010

Stream-sediment samples reanalyzed for major, rare earth, and trace elements from ten 1:250,000-scale quadrangles, south-central Alaska, 2007-08

During the 1960s through the 1980s, the U.S. Geological Survey (USGS) conducted reconnaissance geochemical surveys of the drainage basins throughout most of the Anchorage, Bering Glacier, Big Delta, Gulkana, Healy, McCarthy, Mount Hayes, Nabesna, Talkeetna Mountains, and Valdez 1:250,000-scale quadrangles in Alaska as part of the Alaska Mineral Resource Assessment Program (AMRAP). These geochemical surveys provide data necessary to assess the potential for undiscovered mineral resources on public and other lands, and provide data that may be used to determine regional-scale element baselines. This report provides new data for 366 of the previously collected stream-sediment samples. These samples were selected for reanalysis because recently developed analytical methods can detect additional elements of interest and have lower detection limits than the methods used when these samples were originally analyzed. These samples were all analyzed for arsenic by hydride generation atomic absorption spectrometry (HGAAS), for gold, palladium, and platinum by inductively coupled plasma-mass spectrometry after lead button fire assay separation (FA/ICP-MS), and for a suite of 55 major, rare earth, and trace elements by inductively coupled plasma-atomic emission spectrometry and inductively coupled plasma-mass spectrometry (ICP-AES-MS) after sodium peroxide sinter at 450 degrees Celsius.

Open-File Report↗
USGS2009

Geologic Map of the Yukon-Koyukuk Basin, Alaska

This map and accompanying digital files represent part of a systematic effort to release geologic data for the United States in a uniform manner. All the geologic data in this series will be published as parts of the U.S. Geological Survey Data Series. The geologic data in this series have been compiled from a wide variety of sources, ranging from state and regional geologic maps to large-scale field mapping. The data are presented for use at a nominal scale of 1:500,000, although individual datasets may contain data suitable for use at larger scales. The metadata associated with each release will provide more detailed information on sources and appropriate scales for use. Associated attribute databases accompany the spatial database of the geology and are uniformly structured for ease in developing regional- and national-scale maps. The 1:500,000-scale geologic map of the Yukon-Koyukuk Basin, Alaska, covers more than 200,000 square kilometers of western Alaska or nearly 15 percent of the total land area of the state. It stretches from the Brooks Range on the north to the Kuskokwim River and lower reaches of the Yukon River on the south and from Kotzebue Sound, Seward Peninsula, and Norton Sound on the west to the Yukon-Tanana Uplands and Tanana-Kuskokwim Lowlands on the east. It includes not only the northern and central part of the basin, but also the lands that border the basin. The area is characterized by isolated clusters of hills and low mountain ranges separated by broad alluviated interior and coastal lowlands. Most of the lowlands, except those bordering Kotzebue Sound and Norton Sound, support a heavy vegetation cover. Exposures of bedrock are generally limited to rubble-strewn ridgetops and to cutbanks along the rivers. The map of the Yukon-Koyukuk Basin was prepared largely from geologic field data collected between 1953 and 1988 by the U.S. Geological Survey and published as 1:250,000-scale geologic quadrangle maps. Additional data for parts of the Wiseman, Ruby, Medfra, and Ophir quadrangles came from 1:63,360-scale quadrangle maps published by the Alaska Division of Geological and Geophysical Surveys. The map also incorporates some unpublished field data for the Ruby quadrangle collected by R.M. Chapman between 1944 and 1977 and for parts of the Tanana, Bettles, Norton Bay, and Candle quadrangles collected by W.W. Patton, Jr. and others between 1954 and 1985. Sources of geologic map data for each of the eighteen 1:250,000-scale quadrangles used in compiling this 1:500,000-scale map of the Yukon-Koyukuk Basin as well as sources of general geologic information pertaining to the entire map area are provided in the 'Sources of Information' section.

Scientific Investigations Map↗
USGS2008

Combined high-resolution LIDAR topography and multibeam bathymetry for northern Resurrection Bay, Seward, Alaska

A new Digital Elevation Model was created using the best available high-resolution topography and multibeam bathymetry surrounding the area of Seward, Alaska. Datasets of (1) LIDAR topography collected for the Kenai Watershed Forum, (2) Seward harbor soundings from the U.S. Army Corp of Engineers, and (3) multibeam bathymetry from the National Oceanic and Atmospheric Administration contributed to the final combined product. These datasets were placed into a common coordinate system, horizontal datum, vertical datum, and data format prior to being combined. The projected coordinate system of Universal Transverse Mercator Zone 6 North American Datum of 1927 was used for the horizontal coordinates. Z-values in meters were referenced to the tidal datum of Mean High Water. Gaps between the datasets were interpolated to create the final seamless 5-meter grid covering the area of interest around Seward, Alaska.

Alaska↗
USGS2007

Submarine slope failures near Seward, Alaska, during the M9.2 1964 earthquake

Following the 1964 M9.2 megathrust earthquake in southern Alaska, Seward was the only town hit by tsunamis generated from both submarine landslides and tectonic sources. Within 45 seconds of the start of the earthquake, a 1.2-km-long section of waterfront began sliding seaward, and soon after, ~6-8-m high waves inundated the town. Studies soon after the earthquake concluded that submarine landslides along the Seward waterfront generated the tsunamis that occurred immediately after the earthquake. We analyze pre- and post-earthquake bathymetry data to assess the location and extent of submarine mass failures and sediment transport. New NOAA multibeam bathymetry shows the morphology of the entire fjord at 15 m resolution. We also assembled all older soundings from smooth sheets for comparison to the multibeam dataset. We gridded the sounding data, applied corrections for coseismic subsidence, post-seismic rebound, unrecovered co-seismic subsidence, sea-level rise (vertical datum shift), and measurement errors. The difference grids show changes resulting from the 1964 earthquake. We estimate the total volume of slide material to be about 211 million m3. Most of this material was transported to a deep, flat area, which we refer to as “the bathtub”, about 6 to 13 km south of Seward. Sub-bottom profiling of the bathtub shows an acoustically transparent unit, which we interpret as a sediment flow deposit resulting from the submarine landslides. The scale of the submarine landslides and the distance over which sediment was transported is much larger than previously appreciated.

Alaska↗
USGS2007

3D Visualization of Earthquake Focal Mechanisms Using ArcScene

We created a new tool, 3D Focal Mechanisms (3DFM), for viewing earthquake focal mechanism symbols three dimensionally. This tool operates within the Environmental Systems Research Institute (ESRI®) GIS software ArcScene® 9.x. The program requires as input a GIS point dataset of earthquake locations containing strike, dip, and rake values for a nodal plane of each earthquake. Other information, such as depth and magnitude of the earthquake, may also be included in the dataset. By default for each focal point, 3DFM will create a black and white sphere or “beach ball” that is oriented based on the strike, dip, and rake values. If depth values for each earthquake are included, the focal symbol will also be placed at its appropriate location beneath the Earth's surface. In addition to the default settings, there are several other options in 3DFM that can be adjusted. The appearance of the symbols can be changed by (1) creating rings around the fault planes that are colored based on magnitude, (2) showing only the fault planes instead of a sphere, (3) drawing a flat disc that identifies the primary nodal plane, (4) or by displaying the null, pressure, and tension axes. The size of the symbols can be changed by adjusting their diameter, scaling them based on the magnitude of the earthquake, or scaling them by the estimated size of the rupture patch based on earthquake magnitude. It is also possible to filter the data using any combination of the strike, dip, rake, magnitude, depth, null axis plunge, pressure axis plunge, tension axis plunge, or fault type values of the points. For a large dataset, these filters can be used to create different subsets of symbols. Symbols created by 3DFM are stored in graphics layers that appear in the ArcScene® table of contents. Multiple graphics layers can be created and saved to preserve the output from different symbol options.

Data Series↗
USGS2007

Geoscience for Alaska's D-1 lands: A preliminary report

Purpose of This Report This interim report follows from the June 2006 recommendations to Congress by the BLM concerning disposition of the d-1 lands. That report recommended lifting of a significant number of d-1 PLOs, through the ongoing land management process within the BLM (e.g. resource management planning areas), or through Congressional action. The strategic actions outlined in this document refer only to Federal lands under US Bureau of Land Management (BLM) jurisdiction that 1) are affected by temporary withdrawals from mineral entry and mineral leasing by PLOs made pursuant to the Section 17(d)(1) of the ANCSA; 2) have been identified by the BLM as candidates for possible lifting of these PLOs and restrictions (U.S. Bureau of Land Management, 2006); and 3) lie outside of current Federal parks, preserves, monuments, refuges, reserves, wilderness areas and military installations that are closed to mineral entry, because within those areas the potential lifting of the d-1 restrictions has no practical effect. The resulting lands discussed here comprise approximately 121,000 km2 (29.9 million acres) of Alaska (Table 1) that, pending final resolution of Native and State land claims, will or may remain under Federal (BLM) control, and could be opened to mineral entry. For the purposes of this report, only these 29.9 million acres will hereafter be referred to as 'd-1' lands. This report gives a brief overview of the spatial distribution and physiographic setting, mineral occurrences, and mineral resource potential of the d-1lands. It outlines further geoscience information which could be compiled, collected, and evaluated in order to make a more accurate and comprehensive examination of the potential for undiscovered, locatable mineral resources on these Federal lands. This information is intended to provide guidance to USGS program managers and Federal land managers on matters of future exploration, access needs, and consequences of land status changes.

Alaska↗
USGS2005

Preliminary integrated geologic map databases for the United States: Kentucky, Ohio, Tennessee, and West Virginia

The growth in the use of Geographic Information Systems (GIS) has highlighted the need for regional and national digital geologic maps attributed with age and lithology information. Such maps can be conveniently used to generate derivative maps for purposes including mineral-resource assessment, metallogenic studies, tectonic studies, and environmental research. This Open-File Report is a preliminary version of part of a series of integrated state geologic map databases that cover the entire United States. The only national-scale digital geologic maps that portray most or all of the United States for the conterminous U.S. are the digital version of the King and Beikman (1974a, b) map at a scale of 1:2,500,000, as digitized by Schruben and others (1994) and the generalized digital version (Reed and Bush, 2004) of the Geologic Map of North America (Reed and others, 2005a, b) compiled at a scale of 1:5,000,000. The present series of maps is intended to provide the next step in increased detail. State geologic maps that range in scale from 1:100,000 to 1:1,000,000 are available for most of the country, and digital versions of these state maps are the basis for this product. In a few cases, new digital compilations were prepared (e.g. Ohio, South Carloina, South Dakota) or existing paper maps were digitized (e.g. Kentucky, Texas). Also as part of this series, new regional maps for Alaska and Hawaii are being compiled and ultimately new state maps will be produced. The digital geologic maps are presented in standardized formats as ARC/INFO export (.e00) files and as ArcView shape (.shp) files. Accompanying these spatial databases are a set of five supplemental attribute tables that relate the map units to detailed lithologic and age information. The maps for the CONUS have been fitted to a common set of state boundaries based on the 1:100,000 topographic map series of the United States Geological Survey (USGS). When the individual state maps are merged, the combined attribute tables can be used directly with the merged maps to make derivative maps. No attempt has been made to reconcile differences in mapped geology across state lines.

Kentucky, Ohio, Tennessee, West Virginia↗
USGS2004

World heritage site - Bien du Patrimoine Mondial - Kluane/Wrangell-St. Elias/Glacier Bay/Tatshenshini-Alsek

The four parks depicted on this map make up a single World Heritage Site that covers 24.3 million acres. Together, they comprise the largest internationally protected land-based ecosystem on the planet. The United Nations Educational, Scientific and Cultural Organization (UNESCO) established the World Heritage Program in 1972 for the identification and protection of the world?s irreplaceable natural and cultural resources. World Heritage Sites are important as storehouses of memory and evolution, as anchors for sustainable tourism and community, and as laboratories for the study and understanding of the earth and culture. This World Heritage Site protects the prominent mountain ranges of Kluane, Wrangell, Saint Elias, and Chugach. It includes many of the tallest peaks on the continent, the world's largest non-polar icefield, extensive glaciers, vital watersheds, and expanses of dramatic wilderness. [Les quatre parcs figurant sur cette carte ne constituent qu?un seul site du patrimoine mondial recouvrant plus de 99 millions de km2, ce qui en fait le plus grand ecosysteme terrestre protege par loi internationale. En 1972, L?UNESCO (l?organisation des Nations Unies pour les sciences, l'education et la culture) a etabli le programme du patrimoine mondial afin d?identifier et de proteger les ressources naturelles et culturelles irremplacables de notre plan?te. Si les sites du patrimoine mondial sont si importants c'est parce qu'ils representent a la fois des livres ouverts sur l?histoire de la Terre, le point de depart du tourisme durable et du developpement des collectivites, des laboratoires pour etudier et comprendre la nature et la culture. Ce site du patrimoine mondial assure la protection des chaines de montagnes de Kluane, Wrangell, Saint Elias, et Chugach. On y trouve plusieurs des plus hauts sommets du continent, le plus grand champ de glace non-polaire du monde, d?immenses glaciers, des bassins hydrologiques essentiels, et de la nature sauvage a perte de vue. ]

Scientific Investigations Map↗
USGS2003

Preliminary geologic map of the northeast Dillingham quadrangle (D-1, D-2, C-1, and C-2), Alaska

Open-File Report 03-105 contains a digital geologic map database for the northeast part of the Dillingham 1:250,000-scale quadrangle, specifically the D-1, D-2, C-1, and C-2 1:63,360-scale map sheets. The report includes: A Postscript file showing the geologic map on a topographic and land-grid base, and containing a Correlation of Map Units diagram (CMU), and a List of Map Units. (Note the size of the map when printed at publication scale (1:100,000) is 30 by 24 inches (76 by 61 cm). A PDF document providing Introductory text, Description of Map Units (DMU), References, and a table of radiometric ages. A collection of ARC/INFO (http://www.esri.com, Environmental Systems Research Institute) version 7.2.1 coverages (as export files) of the elements of the geologic map, including: a. Network coverage containing the geologic polygons, contacts, and faults, b. Annotation coverage containing the geologic unit labels and leaders, c. Point coverage containing the radiometric age sample localities, d. Template files containing the lookup table structure used to produce the map. Data to populate the template files is provided in comma-separated value (.csv) text files as follows: napkey.csv plutonkey.csv geoline.csv e. Network coverage containing the Correlation of Map Units (CMU) for the map. Portable Document Format (.pdf) files consisting of: a. Introductory text, Description of Map Units (DMU), References, and a table of radiometric ages for the map. b. A graphic of the map as in the Postscript file above. FGDC compliant metadata for the digital data files (coverages). The Correlation of Map Units and Description of Map Units are in a format similar to that of the USGS Geologic Investigations Series (I-series) maps but have not been edited to comply with I-map standards. Even though this is an Open-File Report and includes the standard USGS Open-File disclaimer, the report closely adheres to the Stratigraphic Nomenclature of the U.S. Geological Survey. ARC/INFO symbolsets (shade and line) as used for these maps have been made available elsewhere as part of Geologic map of Central (Interior) Alaska, published as a USGS Open-File Report (Wilson and others, 1998, http://geopubs.wr.usgs.gov/open-file/of98-133-a/). This product does not include the digital topographic base or land-grid files used to produce the map, nor does it include the AML and related ancillary key and other files used to assemble the components of the map. A Postscript file showing the geologic map on a topographic and land-grid base, and containing a Correlation of Map Units diagram (CMU), and a List of Map Units. (Note the size of the map when printed at publication scale (1:100,000) is 30 by 24 inches (76 by 61 cm). A PDF document providing Introductory text, Description of Map Units (DMU), References, and a table of radiometric ages. A collection of ARC/INFO (http://www.esri.com, Environmental Systems Research Institute) version 7.2.1 coverages (as export files) of the elements of the geologic map, including: a. Network coverage containing the geologic polygons, contacts, and faults, b. Annotation coverage containing the geologic unit labels and leaders, c. Point coverage containing the radiometric age sample localities, d. Template files containing the lookup table structure used to produce the map. Data to populate the template files is provided in comma-separated value (.csv) text files as follows: napkey.csv plutonkey.csv geoline.csv e. Network coverage containing the Correlation of Map Units (CMU) for the map. Portable Document Format (.pdf) files consisting of: a. Introductory text, Description of Map Units (DMU), References, and a table of radiometric ages for the map. b. A graphic of the map as in the Postscript file above. FGDC compliant metadata for the digital data files (coverages). The Correlation of Map Units and Description of Map Units are in a format similar to that of the USGS Geologic Investigations Series (I-series) maps but have not been edited to comply with I-map standards. Even though this is an Open-File Report and includes the standard USGS Open-File disclaimer, the report closely adheres to the Stratigraphic Nomenclature of the U.S. Geological Survey. ARC/INFO symbolsets (shade and line) as used for these maps have been made available elsewhere as part of Geologic map of Central (Interior) Alaska, published as a USGS Open-File Report (Wilson and others, 1998, http://geopubs.wr.usgs.gov/open-file/of98-133-a/). This product does not include the digital topographic base or land-grid files used to produce the map, nor does it include the AML and related ancillary key and other files used to assemble the components of the map.

Alaska↗
USGS2001

Use of Landsat MSS and TM imagery to improve reconnaissance geologic mapping in the Ruby quadrangle, west-central Alaska: A section in Geological studies in Alaska by the U.S. Geological Survey, 1999

By using Multispectral Scanner (MSS) and Thematic Mapper (TM) satellite images, the spatial relation of units JMtu (mafic, ultramafic, and sedimentary rocks, undivided) and PzZrqs (pelitic and quartzitic schist) of Wilson and others (1998) from the northeastern portion of the Ruby 1:250,000-scale quadrangle geologic map was further defined. The MSS image was first analyzed using spectral signatures to separate and highlight pixels associated only with the units of interest. This approach was ineffective at separating the units from areas of the image with similar spectral signatures, but it did show that unit JMtu and associated areas consistently had a high brightness value, while unit PzZrqs and associated areas consistently had a low brightness value. Consequently, a new approach was developed using spectral enhancement to emphasize the differences between these high- and low- brightness areas. Once the TM image was obtained, the spectral signature separation and spectral enhancement approaches were again tested, but the results were similar to those found using the MSS image. By using the results from the spectral enhancement of the MSS image in combination with current ground-truth data, the locations of units JMtu and PzZrqs in the Ruby quadrangle were reinterpreted.

Alaska↗