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D.A. Singer

Publications and source records attributed to D.A. Singer.

52 records · Page 3Linked to original sources
USGS1979

The Alaskan Mineral Resource Assessment Program: Background information to accompany folio of geologic and mineral resource maps of the Talkeetna quadrangle, Alaska

The Talkeetna 1° by 3° quadrangle, which consists of about 17,155 km 2 in south-central Alaska, was investigated by integrated field and laboratory studies in the disciplines of geology, geochemistry, geophysics, and Landsat data interpretation for the purpose of assessing its mineral resource potential. Past mineral production has been limited to gold from the Yentna district, but the quadrangle contains potentially significant resources of tin and silver and possibly a few other commodities including chromite and copper. The results of the mineral resource assessment are given in a folio of maps which are accompanied by descriptive texts, diagrams, tables, and pertinent references. This Circular provides background information on these investigations and integrates the component maps. A bibliography cites both specific and general references to the geology and mineral deposits of the quadrangle.

Alaska↗
USGS1977

Long-term adequacy of metal resources

Although the earth's crust contains vast quantities of metals, extraction technologies and associated costs are inextricably bound to three fundamental geological factors — the amount of metal available in the earth's crust in each range of grades, the mineralogical form and chemical state of the metal, and the spatial distribution of the metal. The energy required to recover a given amount of metal increases substantially as grade declines. Most metal is produced from sulphide or oxide minerals, whereas most metal in the crust may be locked in the structures of the more refractory silicates. Recovery from silicate minerals could require orders of magnitude more energy than that used at present as also could exploitation of small, widely scattered or thin, deeply buried deposits. Although specific information on the fundamental factors is not available, each factor must in turn tend to further restrict exploitation. Independence of average grade and tonnage for many deposit types further reduces the availability of rock as a source of metal. In the long term, effects of these factors will be large increases in price for many metals.

Resources Policy↗
USGS1977

The Alaskan Mineral Resource Assessment Program; background information to accompany folio of geologic and mineral resource maps of the McCarthy Quadrangle, Alaska

The McCarthy 1? by 3? quadrangle, in eastern south-central Alaska, contains potentially significant resources of copper and possibly of a few other commodities. This circular and a companion folio of maps represent results of integrated field and laboratory studies in the disciplines of geology, geophysics, geochemistry, and satellite imagery that are designed to provide a modern mineral resource assessment of the quadrangle. The maps are accompanied by descriptive texts, explanatory material, pertinent references, and by a few auxiliary tables and diagrams. This circular provides background information for the mineral resource assessment and integrates the component maps. It also includes a master list of references (see 'Bibliography') relevant to the geology and mineral deposits of the quadrangle.

Circular↗
USGS1977

Mineral resources map of the McCarthy Quadrangle, Alaska

The mineral resources map is an assessment of the occurrence of mineral deposits in the McCarthy quadrangle by area and type of deposit. Descriptions of known mineral deposits and occurrences in the quadrangle provided by MacKevett (1976b) should be used in conjunction with this map. Areas enclosing both known deposits and areas favorable for unfound deposits are delineated in the mineral resources map. Types of deposits known to be widely scattered throughout the quadrangle, such as placer gold, and types with only a slight chance of being in the quadrangle are not delineated. Selection of favorable areas was based on occurrences of known deposits and geologic, geophysical, geochemical, and earth satellite data presented in the McCarthy folio (U.S. Geol. Survey MF maps 773A, B, D-N and Circular 739) and some additional geochemical data published in open-file form (O'Leary and others, 1976). Delineation of boundaries was made by the informed judgment of the team members, but final responsibility rests with the authors of this map.

Alaska↗
USGS1976

The area of influence of an exploratory hole

A method is presented for calculating the area of influence of exploratory drill holes by using the size and shape of resource targets. The solution presented is for elliptical and circular targets, but the method is applicable to any shaped target. The degree to which points have been explored depends upon their distance away from a drill hole and the possible orientations of the target. Several hypothetical examples demonstrate how: (1) maps can be generated that show the degree to which areas within the region of interest have been explored; (2) graphs can be constructed to evaluate the possibility of undiscovered targets of specific sizes and shapes in a region; (3) the sequence of physical exhaustion in a region can be used to make estimates of undiscovered resources.

Economic Geology↗
USGS1976

RESIN, a FORTRAN IV program for determining the area of influence of samples or drill holes in resource target search

A FORTRAN IV program that calculates the area of influence of drill holes or samples with respect to the size and shape of elliptical or circular resource targets is presented. Program options include determination of the degree to which areas within a region have been explored and estimation of probabilities that points are centers of undiscovered deposits. Errors of recognition can be utilized in the program input. ?? 1976.

Computers & Geosciences↗
USGS1976

The Alaskan Mineral Resource Assessment Program: Background information to accompany folio of geologic and mineral resource maps of the Tanacross quadrangle, Alaska

The Tanacross quadrangle, consisting of 17,400 km 2 (6,700 mi 2) in east-central Alaska, was investigated by an interdisciplinary research team for the purpose of assessing the mineral resource potential of the quadrangle. This report provides the background information for a folio of maps on the geology, geophysics, reconnaissance geochemistry, Landsat imagery, and mineral resource evaluation of the quadrangle. Revisions to the previously published geologic map of the Tanacross quadrangle, 18 new potassium-argon ages, and a comprehensive bibliography are also included.

Alaska↗
USGS1976

Mineral resources map of the Tanacross Quadrangle, Alaska

Areas favorable for the occurrence of two types of mineral deposits are delineated on the map. Known deposits and occurrences are also shown on the map and available data on them are provided in table 1. Information from the known deposits combined with geologic, geochemical, geophysical, and earth satellite data presented in the other components of the Tanacross folio provide the basis for the selection of favorable areas. However because bedrock exposure is poor in the Tanacross quadrangle, types of deposits other than those now known to occur may eventually be found, and boundaries of the area delineated as favorable may change as more information, particularly from drilling, is obtained.

Alaska↗
USGS1976

Geochemical maps showing the distribution and abundance of copper in the Tanacross Quadrangle, Alaska

This series of geochemical maps shows the distribution of copper in four sample media: (A) the oxide residue (the oxalic-acid-leachable fraction) of the stream sediment, (B) the minus-80-mesh stream sediment, (C) the ash of streambank sod (mixed organic and inorganic material) collected beneath the water level, and (D) the ash of aquatic bryophytes (mosses). The copper data are plotted on base maps showing generalized geology and the drainage pattern. The map symbols show the sample sites and ranges of values in the following manner: (1) open symbols denote background, (2) small black symbols represent weakly anomalous values, and (3) large black symbols denotes strongly anomalous values. Because the small black symbols represent weakly anomalous values, they are considered to be significant only where they are closely associated with strongly anomalous metal values either in the same sample medium or with anomalous values in other sample media. The ranges of values represented by the symbols are shown on the histograms which accompany the geochemical maps. An explanation of sampling, preparation, and analytical procedures is given in Circular 734, which accompanies this folio. Complete analytical data for geochemical samples collected by the U.S. Geological Survey in the Tanacross quadrangle are available in a U.S. Geological Survey open-file report (O'Leary and others, 1976).

Alaska↗
USGS1975

The Alaskan mineral resource assessment program; background information to accompany folio of geologic and mineral resource maps of the Nabesna Quadrangle, Alaska

The Nabesna quadrangle in south-central Alaska is the first of the l:250,000-scale Alaskan quadrangles to be investigated by an interdisciplinary research team in order to furnish a mineral resource assessment of the State. The assessment of the 17,600-km 2 16,800-mi21 quadrangle is based on field and laboratory investigations of the geology, geochemistry, geophysics, and satellite imagery. The results of the investigations are published as a folio of maps, diagrams, and accompanying discussions. This report provides background information on the investigations and integrates the published components of the resource assessment. A comprehensive bibliography cites both specific and general references to the geology and mineral deposits of the Nabesna quadrangle.

Circular↗
USGS1975

Grade and Tonnage Relationships Among Copper Deposits

Three types of copper deposits-porphyry, strata-bound, and massive sulfide-are described, and the distributions of tonnages and grades for 267 deposits are compared with normal and lognormal frequency distributions. The relationships between grades and tonnages are analyzed by examining the correlation coefficients of these variables. Conclusions reached include the following: (1) Geologic factors influencing tonnage of a particular deposit type are probably distinct from those influencing grade; (2) frequency distributions of tonnages and grades approximate lognormality, making it possible to predict probability of various tonnage-grade classes and to test correlation between variables; (3) no significant correlation was found between tonnage and grade for porphyry or strata-bound deposits; ( 4) significant negative correlation between tonnage and grade was found for the massive sulfide subset, probably reflecting a mixture of high-grade low-tonnage massive ores, low-grade high-tonnage stockwork, and disseminated ores characteristic of some massive sulfide deposits; (5) significant negative correlation was found between tonnage and grade for the mixture of deposit types in the whole sample. Extrapolation on the basis of the negative grade-tonnage correlation shown for the mixed population seems to imply the occurrence of large-tonnage very low grade deposits, which could be important in supplying future copper needs. This extrapolation is misleading, however, for both statistical and geological reasons. Furthermore, large-tonnage very low grade deposits in the porphyry class of the population are found to be very rare occurrences.

Professional Paper↗