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Henry C. Berg

Publications and source records attributed to Henry C. Berg.

At least 19 recordsLinked to original sources
USGS2006

Preliminary integrated geologic map databases for the United States: Digital data for the geology of southeast Alaska

The growth in the use of Geographic Information Systems (GIS) has highlighted the need for digital geologic maps that have been attributed with information about age and lithology. Such maps can be conveniently used to generate derivative maps for manifold special purposes such as mineral-resource assessment, metallogenic studies, tectonic studies, and environmental research. This report is part of a series of integrated geologic map databases that cover the entire United States. Three national-scale geologic maps that portray most or all of the United States already exist; for the conterminous U.S., King and Beikman (1974a,b) compiled a map at a scale of 1:2,500,000, Beikman (1980) compiled a map for Alaska at 1:2,500,000 scale, and for the entire U.S., Reed and others (2005a,b) compiled a map at a scale of 1:5,000,000. A digital version of the King and Beikman map was published by Schruben and others (1994). Reed and Bush (2004) produced a digital version of the Reed and others (2005a) map for the conterminous U.S. 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 of this product. The digital geologic maps presented here are in a standardized format as ARC/INFO export files and as ArcView shape files. Data tables that relate the map units to detailed lithologic and age information accompany these GIS files. The map is delivered as a set of 1:250,000-scale quadrangle files. To the best of our ability, these quadrangle files are edge-matched with respect to geology. When the maps are merged, the combined attribute tables can be used directly with the merged maps to make derivative maps.

Alaska↗
USGS1984

Geologic map of southeastern Alaska

Southeastern Alaska is underlain by sedimentary, volcanic, intrusive, and metamorphic rocks of Quaternary to Cambrian, and probable Proterozoic age. These rocks have been classified on the geologic map and in this pamphlet into units that emphasize the regional distribution of lithically similar and generally coeval geologic units. The distribution, age, stratigraphic or intrusive relations, and metamorphic and structural characteristics of the map units are described below in the Description of Map Units, and the temporal relations between units are shown on the Correlation of Map Units (Plate). Figure I shows the primary sources of information used in compiling the geologic map.

Alaska↗
USGS1982

The Alaska Mineral Resource Assessment Program: Guide to information about the geology and mineral resources of the Ketchikan and Prince Rupert quadrangles, southeastern Alaska

The Ketchikan and Prince Rupert 1-degree by 2-degree quadrangles, which encompass about 16,000 km2 at the south tip of southeastern Alaska, have been investigated by integrated field and laboratory studies in the disciplines of geology, geochemistry, geophysics, and Landsat data interpretation to determine their mineral-resource potential. Mineral deposits in the study area have been mined or prospected intermittently since about 1900, and production of small tonnages of ores containing gold, silver, copper, lead, zinc, and tungsten has been recorded. Extensive exploration and development currently (1981) is underway at a molybdenum prospect about 65 km east of Ketchikan. Our mineral-resource assessment indicates that the area contains potentially significant amounts of those metallic commodities, as well as of molybdenum, iron, antimony, and barite. The results of these studies have been published in a folio of maps accompanied by descriptive texts, diagrams, tables, and pertinent references. The present report serves as a guide to these investigations, provides relevant background information, and integrates the component maps and reports. It also describes revisions to the geology based on studies completed since the folio was published and includes a list of specific and general references on the geology and mineral deposits of the study area.

Alaska↗
USGS1977

Platinum, palladium, and rhodium in volcanic and plutonic rocks from the Gravina-Nutzotin belt, Alaska

The Gravina-Nutzotin belt of Middle (?) Jurassic to middle Cretaceous sedimentary and volcanic rocks in south and southeastern Alaska includes concentrically zoned ultramafic complexes known to contain platinum-group metals. Previous isotopic, petrologic, and geologic studies suggested a close relation in time and space between the volcanic rocks and the ultramafic complexes. Interpretation of 40 analyses for platinum, palladium, and rhodium in volcanic and plutonic rocks of the belt indicates a strong geochemical correlation between the two groups of rocks and is in support of their being cogenetic either from directly connected magma chambers and flows or indirectly by selective concentration processes from similar mantle material.

Alaska↗
USGS1976

Selected field data collected in 1975, northeastern Craig Quadrangle, southeastern Alaska

This report consists of a computer printout of geologic field data recorded by H.C. Berg from July 2 to July 20, 1975 in the part of the Craig (CR) 1:250,000-scale quadrangle northeast of Clarence Strait (figs. 1 and 2). It contains edited and revised observations on structure, lithology, mineralogy, metamorphism, and mineral occurrences. Areas covered by the observations include southern Etolin and adjacent islands and part of Cleveland Peninsula, including 5 sites in the Ketchikan (KC) quadrangle immediately adjacent to the Craig quadrangle (fig. 2). A preliminary geologic map incorporating the data has been released (Berg and others, 1976). The printout includes the latitude-longitude coordinates of each field station, so that the user can locate the observations within a few metres on larger-scale topographic maps than figure 2. The purpose of this report is to provide an organized file of detailed field observations to supplement and amplify a companion geologic map. The combined reports thus constitute a complete record of available information to serve as wide a range of potential users as possible. The information in this report was transferred from geologic fieldsheets (fig. 3) to computer storage using the method described by Hudson and others (1975). A. Marianne Fujii transcribed the data from the fieldsheets; Betsy Yount and Frances Wahl helped to update the computer file and prepare it for publication; and Bruce Salem wrote the interactive computer program that greatly facilitated entry of the fieldnotes into the computer file.

Alaska↗
USGS1973

Use of machine-processable field notes in a wilderness mapping project (Granite Fiords area), southeastern Alaska

For reconnaissance geologic mapping and mineral resource evaluation of the Granite Fiords wilderness study area, we developed and used a system of machine-processable field notes. Preprinted field forms standardize notes and serve as checklists that insure collection of all available data. The use of this system cut in half the time required to record data at an outcrop. The system consists of three related but different types of preprinted field sheets, a key to abbreviations and codes, and a set of written instructions. The field sheets include a station sheet for basic outcrop data, a specimen sheet for rock samples, and a geochemical sheet for materials to be chemically analyzed. Data on the field sheets are keypunched on standard IBM cards, then arranged in subfiles and retrieved by using a card sorter. Our system is designed specifically for a region of granitic and metamorphic rocks but is easily modified for use in different geologic terranes. We offer four guidelines for developing a system of machine-processable field notes: (1) Time and money spent to develop the system must be worth its anticipated benefits. (2) The system should be as flexible as possible. (3) It is necessary to tailor the system to a particular geologic terrane or project objective. (4) The system should be as simple and self-explanatory as possible.

Alaska↗