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At least 1,405 records · Page 78Linked to original sources
USGS1969

Geology of the Reventado River Watershed, Costa Rica, Part A, General geology

Irazu volcano, a large composite cone, consists of interbedded lava flows, lahars, and ash beds. This rock sequence, named the Irazil Group, has been divided into four formations; from the base: Reventado Formation, Sapper Formation, Birris Formation, and Cervantes Formation. Only the Reventado and Sapper Formations crop out in the Reventado watershed. The Reventado Formation consists of at least four widespread medium-gray finely prophyritic lava flows and interbedded lahar and some ash. Where not excessively jointed, lava flows within the formation are structurally sound and generally fresh. The Sapper Formation also consists of interbedded lava, lahar, and ash; lavas are black dense and coarsely porphyritic and in the middle part of the watershed are structurally sound if not excessively jointed. In the upper part of the watershed Sapper lavas are deeply altered, pyritic and structurally unsound. At least three major inactive and six major active landslides have been recognized in the Reventado watershed, all apparently in the Sapper Formation. Mudflows in the Reventado watershed have been supplied with debris from the caving of oversteepened stream banks and to a lesser extent from the active landslides.

Open-File Report↗
USGS1971

An annotated bibliography of fauna and flora described from the Dockum Group of Triassic age in eastern New Mexico and West Texas

This annotated bibliography was prepared by Warren I. Finch from a rough copy compiled by the late James C. Wright in either late 1967 or early 1968 as an aid to his understanding of the stratigraphic distribution of uranium deposits in Triassic rocks of the Southern high Plains. He did not finish it, inasmuch as several references listed are not annotated. Nevertheless, it is fairly complete for North American literature for years prior to 1967, but it does not contain any papers published in Europe, several of which are pertinent. A few papers oil localities in Wyoming, the Colorado Plateau region, and Mexico are annotated for the purposes of generic and stratigraphic comparison. Wright collated many of the data; cross references are abundant. The bibliography is presented as prepared by Wright; editing was held to a minimum. No additional check was made of the source materials for accuracy of the data--for example, spellings of fossil names. The stratigraphic nomenclature is that: used in the reports cited and may or may not conform to that currently accepted by the U.S. Geological Survey. A list of non-annotated references cited in the annotations was added.

New Mexico, Texas↗
USGS1972

The hydraulic geometry of some Alaskan streams south of the Yukon River

Channel geometry surveys were conducted to determine bankfull stage, discharge, and other hydraulic parameters at 22 locations along the proposed route of the trans-Alaska pipeline corridor south of the Yukon River. Combined with the records from gaging stations located at some of the sites, the data are sufficient to describe some of the channel and flow characteristics typical of each of two major hydrologic areas, the Yukon River Region and the South-Central Region. Although each region follows general hydrologic trends, least squares relations indicate each exhibits its own particular deviations. Average values of the hydraulic and geometric properties of rivers were used to illustrate their application to practical engineering problems, namely the computation of depth of channel scour and of bedload discharge. For design purposes, caution is recommended when making computations based on average values. In the absence of other data, however, the average data become useful predictive tools.

Alaska↗
USGS1972

Placer deposits of Alaska

Placer deposits, in addition to their intrinsic value, serve as indicators of areas of potential development of lode deposits. Any possibility that Alaska may again become an important source of metallic mineral commodities depends in part on an inventory of placer deposits and a knowledge of the geology of their source areas. Information on Alaska's placer deposits is far from complete. Many mining camps have been at best the subject of only cursory examination by geologists or mining engineers at liberty to publish the results of their studies. Many placers are vaguely known from unconfirmed reports that someone was working on a creek, in many instances a creek bearing a name that cannot now be identified with any particular stream. Such data are, of course, practically valueless and were generally ignored in preparing the report. Other major gaps in our knowledge result from the lack of bedrock exposures in many areas where valuable placer deposits were mined, a circumstance that made impossible the determination of lode sources and their mode of occurrence during reconnaissance studies of mining districts. And the reluctance of many prospectors to divulge data on their claims has undoubtedly caused some deposits to be "lost" or overlooked.

Alaska↗
USGS1974

GEOPAC

GEOPAC .consists of a series of subroutines to primarily process potential-field geophysical data but other types of data can also be used with the program. The package contains routines to reduce, store, process and display information in two-dimensional or three-dimensional form. Input and output formats are standardized and temporary disk storage permits data sets to be processed by several subroutines in one job step. The subroutines are link-edited in an overlay mode to form one program and they can be executed by submitting a card containing the subroutine name in the input stream.

Open-File Report↗
USGS1974

A tabulation of K-Ar, Rb-Sr, and Pb-α ages obtained for materials within the United States (including Alaska and Hawaii) during the years 1965 through 1968

This tabulation of ages has been made as a convenience to anyone desiring a quick reference to ages published in the United States and Puerto Rico from 1965 through 1968. This tabulation does not include all published K-Ar, Rb-Sr, or Pb-α ages, but is probably 98 percent complete. Many of the radiometric ages published in abstracts, footnotes, personal communications, and even some articles are not included as sample localities are lacking or are not sufficiently detailed to be of value. Such ages are often published in a subsequent article with detailed sample locations and geologic interpretation. There may be some duplication of ages in this tabulation. The references listed are either the original source for an age or the best source in regard to sample location, decay constants, interpretation, etc. A minor number of unpublished radiometric ages from Ph.D. or M.S. theses are also listed in this tabulation. The tabulated ages are systematized according to year and state. All ages published during a specific year (i.e. 1965) are grouped together, with the ages listed under the name of the state in which the sample was collected. The states are alphabetized. The dated sample is described as to rock type, location, material analyzed, age(s) determined, radiometric method used, and published reference (by first author only). The complete reference is listed at the end of the tabulation for each specific year. To answer questions about geologic interpretation, decay constants, or location, one must review the source reference.

Open-File Report↗
USGS1975

History of irrigation and characteristics of streamflow in northern Nebraska

Five streams drain the northern part of Nebraska and are tributaries to the Missouri River above Yankton, S. Dak. This report presents statistical data at 29 gaging sites on four of the streams, namely, White River, Ponca Creek, Niobrara River, and Bazile Creek. The fifth stream, Hat Creek, drains a small area in the extreme northwest corner of the State. Because there are no gaging stations on Hat Creek in Nebraska, only the description of the basin is included. The only station on Hat Creek is near Edgemont, S. Dak., and it does not reflect streamflow characteristics in Nebraska. Two major irrigation projects have been constructed in the Niobrara River basin since gaging of streamflow began, therefore the complete record of water discharge at some gaging stations includes periods before and after streamflow was affected by diversions to upstream projects. The Whitney Irrigation Project was in operation on the White River before streamflow records were obtained. Streamflow records presented in this report have been computed from data that represent 1974 conditions of development and water use.

Nebraska↗
USGS1975

Selected stratigraphic sections of Cambrian and Ordovician rocks in Arizona, New Mexico, and western Texas

Information from 68 surface localities that I visited was used in the preparation of a report on the Cambrian and Ordovician rocks of Arizona, New Mexico, and western Texas (Hayes, 1975). Descriptions of the stratigraphic sequence at many of these localities have been published in various reports and a majority of those descriptions are reasonably good if not excellent. The rocks at some other localities are either so poorly exposed or faulted or altered that neither useful nor trustworthy sections are measurable there. Included herein are descriptions of part or all of the Cambrian and Ordovician sequence at three localities where the sections have not been described previously in the literature, at two localities whose excellent sections have previously been presented only in generalized graphic form, and at five localities whose previously published descriptions are at considerable variance with my observations in some way (fig. 1). It is doubtful if interest in any of these sections is sufficiently widespread at this time to justify formal publication of these descriptions but they are presented here for those few persons who may have special interest in them. Enclosed in parentheses following the name of each section is the locality number used in my published report (Hayes, 1975). Color terminology for the rocks are adapted from the Rock Color Chart. Bedding thicknesses, when not given in inches, are approximately as follows: thin-bedded for beds up to 6 inches thick, medium-bedded for beds 6 inches to 2 feet thick, thick-bedded for beds 2-5 feet thick; massive for beds more than 5 feet thick. All the sections in this report were measured with the capable assistance of George C. Cone. Fossil collections referred to in this report are described in Hayes (1975).

Arizona, New Mexico, Texas↗
USGS1976

Interpretation and description of seismic data from Lower Cook Inlet, Alaska

A coarse grid of 480 kilometres of seismic lines was collected in lower Cook Inlet, Alaska between Homer on the north and Cape Douglas on the south. Paper and mylar copies of the seismic sections and shot point maps are available to the public from NOAA in Boulder, Colorado. The seismic data shows two strong reflections that have been interpreted as returns from erosional surfaces and a third reflection that represents the acoustic basement. From indications in the seismic data, shallow reflectors onlap to the northwest; deep reflectors onlap to the southeast. A major structural feature in lower Cook Inlet is an east-trending transbasin arch here informally named the Augustine-Seldovia arch. Anticlines smaller than the arch trend approximately northeast and may offer good structural traps for petroleum where they intersect the arch.

Alaska↗
USGS1976

Tilt changes of short duration

Section I of this report contains a classification scheme for short period tilt data. For convenience, all fluctuations in the local tilt field of less than 24 hours duration will be designated SP (i.e., short period) tilt events. Three basic categories of waveshape appearance are defined, and the rules for naming the waveforms are outlined. Examples from tilt observations at four central California sites are provided. Section II contains some coseismic tilt data. Fourteen earthquakes in central California, ranging in magnitude from 2.9 to 5.2, were chosen for study on four tiltmeters within 10 source dimensions of the epicenters. The raw records from each of the four tiltmeters at the times of the earthquakes were photographed and are presented in this section. Section III contains documentation of computer programs used in the analysis of the short period tilt data. Program VECTOR computes the difference vector of a tilt event and displays the sequence of events as a head-to-tail vector plot. Program ONSTSP 1) requires two component digitized tilt data as input, 2) scales and plots the data, and 3) computes and displays the amplitude, azimuth, and normalized derivative of the tilt amplitude. Program SHARPS computes the onset sharpness, (i.e., the normalized derivative of the tilt amplitude at the onset of the tilt event) as a function of source-station distance from a model of creep-related tilt changes. Program DSPLAY plots the digitized data.

Open-File Report↗
USGS1977

Index of published surface-water quality data for Oklahoma 1946-1975

Surface-water-quality data for Oklahoma have been published by the U.S. Geological Survey in cooperation with various State agencies on an annual basis since 1949. The published data represents 2,733 station-years of data from 527 stations, ranging from one sample from a station once during the thirty--year period to a continuously operating daily station were more than one hundred samples were collected in a year. The last comprehensive index was published in 1963; since that time various unpublished indexes have been in use, none of which were complete. Most of the water-quality data collected and published prior to 1970 was for the common inorganic constituents such as, calcium, magnesium, sodium, alkalinity, chloride and sulfate. Since 1970 other types of data such as the minor or trace metals, organic compounds including pesticides, nutrients, oxygen resources, and biologic information have been collected and published with ever increasing frequency. This index was designed to provide the data user a means of rapid search for stations by downstream order (Table 2), county (Table 4), and alphabetically by stream or station name (Table 1). Table 1 also provides a breakdown of the data into 10 broad water-quality categories.

Open-File Report↗
USGS1977

Background studies for appraising subsidence in the Texas Gulf Coast region

Significant ground movement has accompanied the extraction of large quantities of fluids from the subsurface at many localities. The possibility of both horizontal and vertical ground movement--subsidence, fissuring, growth faulting--in the Gulf Coast region, caused by the withdrawal of large volumes of deep formation fluids, is of major concern. Although widespread subsidence has resulted from intensive pumping of ground water, huge withdrawals from shallow oil and gas fields, and mining of sulfur and salt, little information is available on possible subsidence caused by deep fluid extractions. As far as is known, none of the major fields in the Gulf Coast region has subsided appreciably as a result of deep oil and gas production. Of special concern in this study are field evidence of or specific research regarding subsidence directly related to geopressured-fluid withdrawals. If deep reservoirs have the same general stress-strain characteristics as shallower reservoirs, appreciable subsidence could accompany major extraction of deep fluid. A reconnaissance of the type and extent of background data available for such a subsidence appraisal was made as a first step in investigating the possibility of land subsidence associated with the exploitation of geopressured reservoirs in the Gulf Coast. This study was limited to the Texas Gulf Coast south of the landward boundary of Miocene deposits. Visits were made to offices of Federal and State agencies and industries, to determine the type and extent of data available for interpreting subsidence potential in the Texas Gulf Coast. This report summarizes the findings of this reconnaissance investigation, including the names and agencies of those contacted and the nature and extent of pertinent data available. Although a tremendous amount of basic data is available in governmental and private files, the task of collecting and interpreting these data and the limitations or lack of some types of data, in terms of subsidence prediction, create major problems.

Texas↗
USGS1977

Computer program for the calculation of grain size statistics by the method of moments

A computer program is presented for a Hewlett-Packard Model 9830A desk-top calculator (1) which calculates statistics using weight or point count data from a grain-size analysis. The program uses the method of moments in contrast to the more commonly used but less inclusive graphic method of Folk and Ward (1957). The merits of the program are: (1) it is rapid; (2) it can accept data in either grouped or ungrouped format; (3) it allows direct comparison with grain-size data in the literature that have been calculated by the method of moments; (4) it utilizes all of the original data rather than percentiles from the cumulative curve as in the approximation technique used by the graphic method; (5) it is written in the computer language BASIC, which is easily modified and adapted to a wide variety of computers; and (6) when used in the HP-9830A, it does not require punching of data cards. The method of moments should be used only if the entire sample has been measured and the worker defines the measured grain-size range. (1) Use of brand names in this paper does not imply endorsement of these products by the U.S. Geological Survey.

Open-File Report↗
USGS1977

A description of the index of active Florida water data collection stations and a user's guide for station or site information retrieval using computer program Findex H578

A computerized index of water-data collection activities and retrieval software to generate publication list of this information was developed for Florida. This system serves a vital need in the administration of the many and diverse water-data collection activities. Previously, needed data was very difficult to assemble for use in program planning or project implementation. Largely descriptive, the report tells how a file of computer card images has been established which contains entries for all sites in Florida at which there is currently a water-data-collection activity. Entries include information such as identification number, station name, location, type of site, county, information about data collection, funding, and other pertinent details. The computer program FINDEX selectively retrieves entries and lists them in a format suitable for publication. Updating the index is done routinely. (Woodard-USGS)

Open-File Report↗
USGS1977

Preliminary analysis of lineaments and engineering properties of bedrock, Penobscot Bay area, Maine

A remote sensing study of coastal and near coastal Maine was undertaken to identify bedrock features of possible importance to construction. Major lineaments were identified that separate the region into four distinct terrains. Within each terrain, smaller lineaments and other physiographic features show distinctive and consistent patterns, reflecting similarities in bedrock lithology and structure. The major linear features are given the following provisional geographic names: I. Lewiston line 2. Merrymeeting lineament 3. Dover-Foxcroft line 4. Orland lineament 5. Union lineament These linear or curvilinear trends are caused by lithologic contrasts, joints, faults, or foliation in the middle and lower Paleozoic phyllites, schists, gneisses, and granite intrusives. Initial field and laboratory results from a pilot study of bedrock engineering conditions indicate that variations in rock strength and fracture spacing are controlled by lithology, intensity of structural deformation, and alteration. At several locations in the study area faults and major joints are alined with a major lineament. Strength anisotropy ratios are as high as 10 in the foliated rocks but near 1 in the granites. The higher compressive strength direction commonly is perpendicular to foliation and to lineament trends which, in turn, are parallel to faults, major joints, or foliation. Fracture spacing in rocks in the field study area averages 0.5 m for granite and ranges from 0.2 cm to 0.75 m, with an average of 0.15 m, in metamorphic rocks. Diagnostic indications useful for estimating certain construction conditions are shown by point-load and uniaxial compressive strengths. Values for fresh rock range from less than 30 MN/m 2 for weakly bonded phyllite to more than 350 MN/m 2 for dense andesite and metasiltstone. Rock workability is directly related to compressive strength and spacing of joints.

Open-File Report↗
USGS1978

Results and interpretation of geophysical studies near the Picacho Fault, south-central Arizona

Earth fissuring attributed to ground-water withdrawal occurs throughout south-central Arizona. A large zone of active fissures is located near Picacho, Arizona on the eastern rim of a large subsidence bowl. The main fissure has been named the Picacho fault. During February and March 1977, approximately 6.5 km of seismic-refraction lines were run across the Picacho fault to investigate subsurface conditions down to the crystalline basement. In addition, two lines of close-spaced gravity stations were made across the fault. The gross geologic features inferred from the gravity data agree with the seismic interpretations. Six layers were interpreted from the seismic refraction data: three layers of unconsolidated alluvium, two of denser rock of varying porosity, and the basement rock. Three significant basement faults were identified. These faults appear to lie almost directly beneath the surface fissures. Abrupt slope changes in the alluvial layers and an abrupt velocity change in the denser compacted sediments seem to be related spatially to the surface fissures. In addition there are lateral velocity differences within the basement fault blocks. In the overlying sediments a facies change in a 3.0 km/sec layer is suggested by the abrupt lateral velocity increase from 3.0 km/sec to 3.7 km/sec. This apparent facies change may in fact represent a fault plane extending upwards from the westernmost basement fault. This fault plane may even extend farther into the unconsolidated overlying sediments, inferred from basinward increases in slope, subtle basinward decreases in velocity, and a basinward elevation decrease in the top of the zone of saturation.

Open-File Report↗
USGS1977

Geochemistry of the Mattole River in Northern California

The chemical composition of streams can vary greatly with changing discharge during storm runoff. These chemical changes are related to the pathways of various water parcels from the time they fall as rain until they enter the stream, and to the interactions between water and sediment during transport downstream. In order to understand better the chemical variations during storms, an extensive investigation was made of the Mattole River, a chemically clean coastal stream in Mendocino County, California. The Mattole drains a topographically mature basin of 620 sw km which has relief of about 1200 m, a long summer dry season, and mean annual rainfall of about 2300 mm. The stream flow is composed of seasonally varying proportions of four flow components, namely, surface runoff, quick-return flow (rainfall having brief and intimate contact with the soil before entering the surface drainage), delayed-return flow, and base runoff. Each component is identified by its characteristic chemistry and by the time delay between rainfall and entrance into the stream. Information is also presented on rain chemistry, adsorption reactions of suspended sediments in the fresh and brackish environments, and compositional variation of river sediments with particle size. (Woodard-USGS)

Open-File Report↗
USGS1978

Gazetteer of coastal and offshore features of the Gulf of Alaska north of 54° N latitude

This gazetteer, the first of three to be released, presents names of seafloor features of the Gulf of Alaska and coastal features north of 54° N latitude between Cross Sound to the east and Unimak Island to the west. Also included are Prince William Sound and Cook Inlet but not the fiords, channels, and shoreline of southeast Alaska that make up the "Inside Passage" and Alexander Archipelago.

Alaska↗