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J. D. Bliss

Publications and source records attributed to J. D. Bliss.

At least 19 recordsLinked to original sources
USGS2012

Geologic characterization of shelf areas using usSEABED for GIS mapping, modeling processes and assessing marine sand and gravel resources

Geologic maps depicting offshore sedimentary features serve many scientific and applied purposes. Such maps have been lacking, but recent computer technology and software offer promise in the capture and display of diverse marine data. Continental margins contain landforms which provide a variety of important functions and contain important sedimentary records. Some shelf areas also contain deposits regarded as potential aggregate resources. Because proper management of coastal and offshore areas is increasingly important, knowledge of the framework geology and marine processes is critical. Especially valuable are comprehensive and integrated digital databases based on high-quality information from original sources. Products of interest are GIS maps containing thematic information, such as sediment character and texture. These products are useful to scientists modeling nearshore and shelf processes as well as planners and managers. The U.S. Geological Survey is leading a national program to gather a variety of extant marine geologic data into the usSEABED database system. This provides centralized, integrated marine geologic data collected over the past 50 years. To date, over 340,000 sediment data points from the U.S. reside in usSEABED, which combines an array of physical data and analytical and descriptive information about the sea floor and are available to the marine community through three USGS data reports for the Atlantic, Gulf of Mexico, and Pacific published in 2006, and the project web sites: (http://woodshole.er.usg s.gov/project-pages/aggregates/ and http://walrus.wr.usgs.gov/usseabed/)

Conference Paper↗
USGS2007

Tracking acid mine-drainage in Southeast Arizona using GIS and sediment delivery models

This study investigates the application of models traditionally used to estimate erosion and sediment deposition to assess the potential risk of water quality impairment resulting from metal-bearing materials related to mining and mineralization. An integrated watershed analysis using Geographic Information Systems (GIS) based tools was undertaken to examine erosion and sediment transport characteristics within the watersheds. Estimates of stream deposits of sediment from mine tailings were related to the chemistry of surface water to assess the effectiveness of the methodology to assess the risk of acid mine-drainage being dispersed downstream of abandoned tailings and waste rock piles. A watershed analysis was preformed in the Patagonia Mountains in southeastern Arizona which has seen substantial mining and where recent water quality samples have reported acidic surface waters. This research demonstrates an improvement of the ability to predict streams that are likely to have severely degraded water quality as a result of past mining activities. ?? Springer Science+Business Media B.V. 2007.

Environmental Monitoring and Assessment↗
USGS2003

Statistical, economic and other tools for assessing natural aggregate

Quantitative aggregate resource assessment provides resource estimates useful for explorationists, land managers and those who make decisions about land allocation, which may have long-term implications concerning cost and the availability of aggregate resources. Aggregate assessment needs to be systematic and consistent, yet flexible enough to allow updating without invalidating other parts of the assessment. Evaluators need to use standard or consistent aggregate classification and statistic distributions or, in other words, models with geological, geotechnical and economic variables or interrelationships between these variables. These models can be used with subjective estimates, if needed, to estimate how much aggregate may be present in a region or country using distributions generated by Monte Carlo computer simulations.

Bulletin of Engineering Geology and the Environmen↗
USGS2002

Mine and mineral occurrences of Afghanistan

This inventory of more than 1000 mines and mineral occurrences in Afghanistan was compiled from published literature and the files of project members of the National Industrial Minerals project of the U.S. Geological Survey. The compiled data have been edited for consistency and most duplicates have been deleted. The data cover metals, industrial minerals, coal, and peat. Listings in the table represent several levels of information, including mines, mineral showings, deposits, and pegmatite fields.

Open-File Report↗
USGS1994

Modeling surficial sand and gravel deposits

Mineral-deposit models are an integral part of quantitative mineral-resource assessment. As the focus of mineral-deposit modeling has moved from metals to industrial minerals, procedure has been modified and may be sufficient to model surficial sand and gravel deposits. Sand and gravel models are needed to assess resource-supply analyses for planning future development and renewal of infrastructure. Successful modeling of sand and gravel deposits must address (1) deposit volumes and geometries, (2) sizes of fragments within the deposits, (3) physical characteristics of the material, and (4) chemical composition and chemical reactivity of the material. Several models of sand and gravel volumes and geometries have been prepared and suggest the following: Sand and gravel deposits in alluvial fans have a median volume of 35 million m3. Deposits in all other geologic settings have a median volume of 5.4 million m3, a median area of 120 ha, and a median thickness of 4 m. The area of a sand and gravel deposit can be predicted from volume using a regression model (log [area (ha)] =1.47+0.79 log [volume (million m3)]). In similar fashion, the volume of a sand and gravel deposit can be predicted from area using the regression (log [volume (million m3)]=-1.45+1.07 log [area (ha)]). Classifying deposits by fragment size can be done using models of the percentage of sand, gravel, and silt within deposits. A classification scheme based on fragment size is sufficiently general to be applied anywhere. ?? 1994 Oxford University Press.

Nonrenewable Resources↗
USGS1987

Oblique map of the northern Sierra Nevada, California, showing location of gold-bearing areas

More than a third of the gold produced by the United States was mined in California. The bulk of this gold was recovered from the western slope of the northern half of the Sierra Nevada between the Merced River in the south and the Feather River to the north, a distance of about 170 mi. Gold was first discovered, in this region, on the American River at Coloma in 1848, triggering the famed California gold rush. Mining was continuously active, somewhere in the area, from the discovery of gold until World War II when mining was legally prohibited. Dramatic increases in gold prices in the past decade coupled with recent advances in extractive techniques have revitalized prospecting, and major deposits are currently being explored and developed. Gold has been found in a variety of geologic environments in the region. In addition to production from the complex vein systems of the historically famous Mother Lode and associated East Gold Belt and West Gold Belt, large amounts of gold have also been recovered from the Grass Valley-Nevada City and other isolated lode districts and from Tertiary river channels and Quaternary alluvium. This oblique map illustrates the relation of the different gold-bearing environments to each other and to the general terrain of the northern Sierra Nevada. The map was derived from the 1970 U.S. Geological Survey 1:500,000-scale topographic map of California and the 1976 U.S. Geological Survey 1:500,000-scale topographic map of Nevada, using an isometrograph, a mechanical instrument that produces an oblique framework by tracing individual contours. Form lines sketched over this framework graphically portray the physiographic configuration of the region. Relief on the oblique map has a 3:1 vertical exaggeration and appears as if viewed from a 30° angle above the horizon. Locations of lode gold prospects and mines shown on the map were obtained from the U.S. Geological Survey's Mineral Resource Data System (MRDS), a computerized mineral-resource information file, and plotted in their respective locations (D.F. Huber, written commun., 1986). Some locations from two northern counties, missing from the MRDS retrival, were added. The twenty lode mines believed to be the most productive are cited in table 1. A total of nearly 4,000 sites, including both prospects and mines, were initially plotted, but about a third of those were obscured by topography on the oblique map. Locations of Tertiary river channels and gold-dredging fields were taken from published general references modified by examining specific sources and by cursory field examination. Seven of the major dredge fields are identified in table 2.

California↗
USGS1987

CHANGES IN GRADE, VOLUME AND CONTAINED GOLD DURING THE MINING LIFE-CYCLE OF GOLD PLACER DEPOSITS.

Analysis of gold placer data throughout the world suggests that gold grades and volumes cannot be used to distinguish between most types of gold placers. Only the alluvial plain and fan placers are significantly different among the types of gold placers considered. Gold grades and volumes change when working placers go from small-volume methods to large-volume methods. The odds that a placer will be dominantly worked using small-volume methods at the surface are about 5:3. Once small-volume mining has occurred, the odds against subsequent large-volume mining are about 4:1. If a deposit is suitable for large-volume mining and the amount of gold produced from small-volume mining was reported, an estimate of the remaining gold (log//1//0kg) can be made using an equation.

CIM Bulletin↗