Skip to main content
U.S. flag

An official website of the United States government

Dot gov

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Https

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

Search Results

164511 results.

Alternate formats: RIS file of the first 3000 search results  |  Download all results as CSV | TSV | Excel  |  RSS feed based on this search  |  JSON version of this page of results

Page 4923, results 123051 - 123075

Show results on a map

Publication Extents

Not all publications have extents, not all extents are completely accurate
Improved population estimates through the use of auxiliary information
Douglas H. Johnson
C.J. Ralph, J. M. Scott, editor(s)
1981, Book chapter, Estimating numbers of terrestrial birds. Cooper Ornithological Society Studies in Avian Biology
When estimating the size of a population of birds, the investigator may have, in addition to an estimator based on a statistical sample, information on one of several auxiliary variables, such as: (1) estimates of the population made on previous occasions, (2) measures of habitat variables associated with the size...
Boulder deposits and the retreat of mountain slopes, or ' gully gravure' revisited
H. H. Mills
1981, Journal of Geology (89) 649-660
Observations on mountains composed chiefly of shale and capped with Tuscarora Sandstone in the Valley and Ridge province of southwest Virginia suggest that slopes retreat by a process similar to but different from Bryan's (1940) "gully gravure." The process appears to operate as follows: Bouldery alluvium protects the floors of...
Designation of principal water-supply aquifers in Minnesota
D. G. Adolphson, J. F. Ruhl, R. J. Wolf
1981, Water-Resources Investigations Report 81-51
Fourteen aquifers, ranging from Quaternary to Precambrian in age, have been identified as the principal sources of water to wells in Minnesota. Half the municipal population anc nearly all the rural population depend on water from these aquifers. Buried and surficial sand and gravel aquifers of Quaternary age occur in...
Geohydrologic reconnaissance of the Crofton Unit, northeastern Nebraska
S.J. Kent, R. A. Engberg, M. J. Ellis
1981, Water-Resources Investigations Report 81-58
This report describes the results of a reconnaissance of the sources, location, quantity, and quality of ground water in the proposed irrigation project area called the "Crofton Unit," an area of approximately 350 square miles in northeastern Nebraska.Precambrian Sioux Quartzite underlies the entire study area. Throughout most of the area,...
Water type and suitability of Oklahoma surface waters for public supply and irrigation, Part 3: Canadian, North Canadian, and deep fork river basins through 1979
Jerry D. Stoner
1981, Water-Resources Investigations Report 81-80
Water-quality data through 1979 in the Canadian, North Canadian, and Deep Fork River basins within Oklahoma were examined for water type and suitability for public water supply and irrigation use. Of 105 stations with available data, 47 stations or 45 percent were considered to have sufficient data for analysis. The...
K-Ar ages on intrusive and altered zones in the Chignik and Sutwik Island quadrangles: A section in The United States Geological Survey in Alaska: Accomplishments during 1979
Frederic H. Wilson
1981, Report, The United States Geological Survey in Alaska: Accomplishments during 1979 (Circular 823-B)
Continued K-Ar dating of intrusive rocks and hydrothermal alteration zones in the Chignik and Sutwik Island quadrangles of the Alaska Peninsula, supplemental to that by Wilson, Detterman, and Silberman (1978) and Wilson (1978), has refined our knowledge of the ages of the igneous rocks and clarified relations between altered zones...
Notes on sedimentation activities calendar year 1980
U.S. Interagency Advisory Committee on Water Data- Subcommittee on Sedimentation
1981, Report
This report is a digest of information furnished by Federal agencies conducting sedimentation investigations on work in progress or planned, important findings, new methods, new publications, laboratory and other research activities, and other pertinent information. The material has been organized by major drainage regions in the conterminous United States, Alaska,...
Determination of sub-microgram amounts of selenium in geological materials by atomic-absorption spectrophotometry with electrothermal atomisation after solvent extraction
R. F. Sanzolone, T. T. Chao
1981, The Analyst (106) 647-652
An atomic-absorption spectrophotometric method with electrothermal atomisation has been developed for the determination of selenium in geological materials. The sample is decomposed with a mixture of nitric, perchloric and hydrofluoric acids and heated with hydrochloric acid to reduce selenium to selenium(IV). Selenium is then extracted into toluene from a hydrochloric...
The partitioning of copper among selected phases of geologic media of two porphyry copper districts, Puerto Rico
R. E. Learned, T. T. Chao, R. F. Sanzolone
1981, Journal of Geochemical Exploration (15) 563-581
In experiments designed to determine the manner in which copper is partitioned among selected phases that constitute geologic media, we have applied the five-step sequential extraction procedure of Chao and Theobald to the analysis of drill core, soils, and stream sediments of the Rio Vivi and Rio Tanama porphyry copper...
1980 Water resources program in Oregon
U.S. Geological Survey
1981, Report
The Water Resources Division investigates and reports on the occurrence, quantity, quality, distribution, and movement of surface and underground water. Work of the Division is described in detail later in this report....
Potential for geophysical experiments in large scale tests
James H. Dieterich
1981, Geophysical Research Letters (8) 653-656
Potential research applications for large-specimen geophysical experiments include measurements of scale dependence of physical parameters and examination of interactions with heterogeneities, especially flaws such as cracks. In addition, increased specimen size provides opportunities for improved recording resolution and greater control of experimental variables. Large-scale experiments using...
Economics and coal resource appraisal: strippable coal in the Illinois Basin ( USA)
E. D. Attanasi, E.K. Green
1981, Southern Economic Journal (47) 742-752
Coal-resource appraisals generally describe the location and general characteristics of coal beds. Estimates are made of the average overburden depth (depth of the coal bed below the surface), bed thickness, and perhaps certain chemical properties of the coal [1]. Although such resource compilations represent an important initial step, neither they...
Design of exploration and minerals-data-collection programs in developing areas
E. D. Attanasi
1981, Socio-Economic Planning Sciences (15) 347-352
This paper considers the practical problem of applying economic analysis to designing minerals exploration and data collection strategies for developing countries. Formal decision rules for the design of government exploration and minerals-data-collection programs are derived by using a minerals-industry planning model that has been extended to include an exploration function....