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At least 685 records · Page 38Linked to original sources
USGS1869

Preliminary Field Report of the United States Geological Survey of Colorado and New Mexico

SIR : In accordance with your instructions dated Washington, April 1, 1869, I have the honor to transmit my preliminary field report of the United States geological survey of Colorado and New Mexico, conducted by me, under your direction, during the past season. A portion of your instructions is as follows : “You will proceed to the field of your labors as soon as the necessary arrangements can be made and the season will permit, and your attention will be especially directed to the geological, mineralogical and agricultural resources of the Territories herein designated; you will be required to ascertain the age, order of succession, relative position, dip, and comparative thickness of the different strata and geological formations, and examine with care all the beds, veins, and other deposits, of ores, coals, clays, marls, peat, and other mineral substances, as well as the fossil remains of the different formations; and you will also make full collections in geology, mineralogy, and paleontology, to illustrate your notes taken in the field.”

Colorado, New Mexico↗
USGS1977

Report on preliminary data for Madison Limestone test well no.1, NE1/4 SE1/4 section 15, T. 57 N., R. 65 W., Crook County, Wyoming

This report provides the preliminary data for the Madison Limestone test well no. 1 in Crook County, Wyoming, including test-well history, geology of the test well, hydrologic testing, and geochemistry. The test well was drilled to a depth of 4,341 feet to determine the water-resource potential of the Madison Limestone and associated rocks to meet future water needs in a 188,000 sq mi region that includes the coal-rich area of the Northern Great Plains. Drilling and testing were designed to yield a maximum of stratigraphic, structural, geophysical, and hydrologic information. All significant water-bearing units contain relatively freshwater (less than 2,000 mg/liter dissolved solids). Three water-bearing units, which are now cased off, may be potential sources of ground water in the area of the test well. These are the Hulett Sandstone Member of the Sundance Formation, the Minnekahta Limestone, and the upper sandy part of the Minnelusa Formation. (Woodard-USGS)

Open-File Report↗
USGS2015

Reconnaissance stratigraphic studies in the Susitna basin, Alaska, during the 2014 field season

The Susitna basin is a poorly-understood Cenozoic successor basin immediately north of Cook Inlet in south-central Alaska (Kirschner, 1994). The basin is bounded by the Castle Mountain fault and Cook Inlet basin on the south, the Talkeetna Mountains on the east, the Alaska Range on the north, and the Alaska–Aleutian Range on the west (fig. 2-1). The Cenozoic fill of the basin includes coal-bearing nonmarine rocks that are partly correlative with Paleogene strata in the Matanuska Valley and Paleogene and Neogene formations in Cook Inlet (Stanley and others, 2013, 2014). Mesozoic sedimentary rocks are present in widely-scattered uplifts in and around the margins of the basin; these rocks differ significantly from Mesozoic rocks in the forearc basin to the south. Mesozoic strata in the Susitna region were likely part of a remnant ocean basin that preceded the nonmarine Cenozoic basin (Trop and Ridgway, 2007). The presence of coal-bearing strata similar to units that are proven source rocks for microbial gas in Cook Inlet (Claypool and others, 1980) suggests the possibility of a similar system in the Susitna basin (Decker and others, 2012). In 2011 the Alaska Division of Geological & Geophysical Surveys (DGGS) and Alaska Division of Oil and Gas, in collaboration with the U.S. Geological Survey, initiated a study of the gas potential of the Susitna basin (Gillis and others, 2013). This report presents a preliminary summary of the results from 14 days of helicopter-supported field work completed in the basin in August 2014. The goals of this work were to continue the reconnaissance stratigraphic work begun in 2011 aimed at understanding reservoir and seal potential of Tertiary strata, characterize the gas source potential of coals, and examine Mesozoic strata for source and reservoir potential

Alaska↗
USGS1934

Preliminary geological report on the Salt Plains reservoir site, Oklahoma

Following a request from the U.S. Bureau of Biological Survey, the writer was assigned by the Director of the U.S. Geological Survey to make a preliminary geological investigation of the Salt Plains area in Oklahoma. He spent the period from January 13 to January 22, 1934, in the field making this study. (available as photostat copy only)

Open-File Report↗
USGS1946

Stratigraphy and structure of the area of the Killik, Chandler, Anaktuvuk, and Colville Rivers, Alaska

This report deals with results of field and laboratory studies carried out to May 1946 by the Geological Survey, largely as part of the Navy Department's program of petroleum investigations in northern Alaska. The immediate purpose of the work has been to collect and interpret stratigraphic and structural data pertinent to drilling in the Umiat area. Field studies were made during the summers of 1944 and 1945 in the drainage areas of the Colville, Killik, Chandler, and. Anaktuvuk Rivers (fig. 1). Paleontologic and microlithologic studies, together with stratigrahica1 and structural analysis of the areas, were carried out in the petroleum laboratory in Fairbanks. This work led. to preparation of a preliminary report submitted. in December, 1945. Additional detailed studies, in the Survey laboratories and offices in Washington, D. C., have resulted in some modification of earlier conclusions and changes in illustrations. The changes are minor and have no significant bearing on drilling in the Umiat area. The present report is accompanied. by revised conies of figures 1, 2, 3 (sheet 1) and. 5. These illustrations should be substituted for the comparable figures of the preliminary report. Figures 3 (sheet 2), 4, and. 6 of the earlier report stand unchanged and should, be added to the illustrations accompanying the present report. It is believed that work to date has revealed the general geologic picture of the area and. that the sequence of Upper Cretaceous rocks is established. The section of rocks in Umiat Test No. 1 has been approximately located within the sequence. This report, and the work on which it is based was done under the supervision of George O. Gates, who has contributed. much to the study.

Alaska↗
USGS1983

A seismic study of Yucca Mountain and vicinity, southern Nevada; data report and preliminary results

From 1980 to 1982, the U.S. Geological Survey conducted seismic refraction studies at the Nevada Test Site to aid in an investigation of the regional crustal structure at a possible nuclear waste repository site near Yucca Mountain. Two regionally distributed deployments and one north-south deployment recorded nuclear events. First arrival times from these deployments were plotted on a location map and contoured to determine traveltime delays. The results indicate delays as large as 0.5 s in the Yucca Mountain and Crater Flat areas relative to the Jackass Flats area. A fourth east-west deployment recorded a chemical explosion and was interpreted using a two-dimensional computer raytracing technique. Delays as high as 0.7 s were observed over Crater Flat and Yucca Mountain. The crustal model derived from this profile indicates that Paleozoic rocks, which outcrop to the east at Skull Mountain and the Calico Hills, and to the west at Bare Mountain, lie at a minimum depth of 3 km beneath part of Yucca Mountain. These results confirm earlier estimates based on the modeling of detailed gravity data. A mid-crustal boundary at 15 ? 2 km beneath Yucca Mountain is evidenced by a prominent reflection recorded beyond 43 km range at 1.5 s reduced time. Other mid-crustal boundaries have been identified at 24 and 30 km and the total crustal thickness is 35 km.

Open-File Report↗
USGS1995

K1-95-HW: Cruise report 1995 - Preliminary results, phase III: Sediment chemistry and biological sampling survey

Mamala Bay, off the south shore of the island of Oahu, has been used as a repository of dredged material primarily from Pearl and Honolulu Harbors for over a century. The U.S. Geological Survey, U.S. Army Corps of Engineers, and the U.S. Environmental Protection Agency are conducting an integrated study on the distribution and character of dredged materials as well as the effects of dredged material on the marine environment. A three phase study is providing information to evaluate the effects on seafloor substrate and the benthic fauna. The studies include geophysical profiling and imaging, bottom photography, sampling, chemical and physical analyses of sediment, and evaluations of the benthic population, population density, and adverse impacts to the benthic fauna. Phase 1, conducted in 1993, inventoried the seafloor via remote sensing. Sidescan sonar and subbottom profilers characterized the seafloor in and around the disposal sites, and the resulting products reveal the character and extent of the dredged material. These data were used to plan Phase 2 in 1994, a sampling program that employed subbottom profilers, video and still photography, and seafloor sampling to ground truth the sonar mosaic and identify the seafloor substrates responsible for the various acoustic signatures on the sonar images and subbottom profiles. Box coring provided the samples necessary to distinguish dredged material from native sediment, and for the chemical analyses used to determine contaminant concentrations. Phase 3 studies conducted in June of 1995 consisted of box core sampling for chemical and biological analyses. Specific studies include: infaunal taxonomy and population density, bioassay/bioaccumulation, sediment chemistry, and post-disposal resuspension and transport. The 1995 survey, conducted June 14 through 17, resulted in the collection of 39 box cores from 20 different stations. Multiple box cores were composited at 7 different locations occupied in 1994, to provide the material required for the 7 bioassay and bioaccumulation analyses currently underway (Figure 1). Seventeen of the 20 stations occupied provided the biological samples for the benthic infaunal identification and population density study conducted by Dr. Julie Brock of the University of Hawaii, and the sediment chemistry analyses conducted (and completed) by Quanterra Environmental Laboratories (Figure 1). Seven of the 20 stations occupied in 1995 were occupied in 1994, and provide the data for direct comparison of sediment chemistry at the same sites from two consecutive years. The sum total of the data collected from all three phases of the monitoring program will provide the U.S. Army Corps of Engineers and the U.S. Environmental Protection Agency with the information required to make informed decisions as to the management of the South Oahu disposal site in Mamala Bay.

Hawai'i↗
USGS1962

Preliminary geologic report on the 1961 U.S. expedition to Bellingshausen Sea, Antarctica

Five areas of outcrop were examined along 120 miles of the coast of the Bellingshausen Sea east of the Thurston Peninsula. Hornblende quartz diorite is the principal rock in the area and occurs in a body of batholithic dimensions. The quartz diorite contains inclusions of older granulitic rock and is cut by mafic dikes. An island in Paradise Harbor on the Palmer Peninsula was also examined briefly.

Science↗
USGS2025

Preliminary field report of landslide hazards following Hurricane Helene

Executive Summary This report reflects our knowledge regarding the widespread landslide activity associated with Hurricane Helene observed during the U.S. Geological Survey’s (USGS) mission assignment to North Carolina in October 2024. The material in this report was originally prepared for the Federal Emergency Management Agency under mission assignment DR-4827-NC. The data and commentary in this report are reflective of a report provided to the Federal Emergency Management Agency (FEMA) on October 18, 2024, as well as information provided in briefings at the Buncombe County Emergency Operations Center. The report has been modified for public dissemination. This assessment was based on systematic visual examination and mapping of landslide locations from aerial and satellite imagery, visual and photographic observations from low-level helicopter overflights and conversations with local landslide experts from the North Carolina Geological Survey and Appalachian Landslide Consultants PLLC, and more than 50 years of combined landslide hazard professional experience of the mission-assigned field team. No systematic field investigations were done by the USGS. While responding to the event, the USGS did not identify any landslides that posed an immediate major threat to recovery personnel in parts of nine counties in North Carolina (Avery, Buncombe, Henderson, McDowell, Mitchell, Polk, Rutherford, Watauga, and Yancey); however, threats from renewed landslide activity may remain heightened in localized areas for months or even years. Known areas of the most abundant landslide occurrence include Bat Cave, Lake Lure, Chimney Rock, Swannanoa, Black Mountain, Fairview, steep areas in Asheville, and the Blue Ridge Parkway. The USGS shared detailed locations of known landslides with the Emergency Operations Centers. The thousands of landslide scars on hillsides and landslide deposits on flatter ground may present some threat to recovery activities. Soil and rocks will continue to erode from newly exposed landslide scars and may pose a threat to people and infrastructure who are immediately nearby. In general, the steeper and taller the landslide scar, the greater the potential threat. This threat is heightened during periods of rainfall and increases with the duration and intensity of rainstorms. Very heavy rainfall, or repeated rainfall events during short periods, could also initiate new landslides on steep slopes. Excavation of landslide deposits, particularly excavation of those deposits directly adjacent to steep slopes, may also pose a threat to nearby people and equipment. An interagency collaborative mapping effort led by the USGS that informed this assessment identified 1,155 landslide locations by the October 2024 briefings, but that number increased to 2,217 in a final reviewed version of the locations published in January 2025. Locations were mapped from satellite imagery, fixed-wing and helicopter surveys, media and social media, and field reports in the 3 weeks following the passage of the remnants of Hurricane Helene. USGS products outlined in this report are publicly available and include geotagged photographs from aerial reconnaissance, hazard models, an interactive view of mapped landslide locations, and landslide safety and education resources.

North Carolina, South Carolina, Tennessee, Virgini↗
USGS1948

Preliminary geologic report of Sadlerochit River area, 1948

"The Sadlerochit River area" is the name that has been applied for purposes of convenience to that portion of the eastern part of the northern Alaska shown in Figure 1. The map covers an area of about 1400 square miles. The center of this map is a point approximately 55 miles southwest of Barter Island, 90 miles west of the International Boundary, and 180 miles east of Umiat.

Alaska↗
USGS1978

Preliminary geologic report on the Harris Lake area, northeastern Minnesota

Intense faulting and fracturing in the Harris Lake area) northeastern Minnesota are documented by detailed field studies. Faults are identified chiefly by the disruption of mappable layers within sequences of plagioclase and plagioclase-olivine cumulates. Most layers grade from olivine-rich bottoms to plagioclase-rich tops and were probably deposited by density currents. Faults trend principally N35?E, N05?W, and N40?W. The recognition of intense faulting and fracturing in this region and an understanding of the currents responsible for cumulate deposition establish a basic geologic framework with important local and regional implications.

Open-File Report↗