Publications
Products (journal articles, reports, fact sheets) authored by current and past scientists are listed below. Please check the USGS Pubs Warehouse for other USGS publications.
Filter Total Items: 1829
Estimating limiting age for pleistocene erosional surfaces in central Montana by uranium-series dating of associated travertines
Travertine deposits overlie the highest Number 2 surfaces in central Montana and clasts of travertine occur in gravels on lower Number 2 surfaces. Dating these travertine deposits may provide limits on the ages of surfaces that record intervals of extensive erosion during Pleistocene time. Analysis of three travertine samples from the southeast side of The Park yield an average uranium‐thorium age
Authors
B. J. Szabo, D. A. Lindsey
Devonian eustatic fluctuations in Euramerica
The Devonian System of Euramerica contains at least 14 transgressive-regressive (T-R) cycles of eustatic origin. These are separated into three groups (or depophases) and from Carboniferous cycles by three prominent regressions. Twelve post-Lochkovian T-R cycles are recognized, and they commonly appear to result from abrupt deepening events followed by prolonged upward shallowing. Deepening events
Authors
J.G. Johnson, Gilbert Klapper, Charles Sandberg
A new isostatic residual gravity map of the conterminous United States
In order to display more clearly the gravity anomalies caused by bodies of geologic interest in the crust, a new colored isostatic residual gravity map of the conterminous United States has been prepared using the gravity data set compiled for the Gravity Anomaly Map of the United States (SEG, 1982). The isostatic residual map is based on an Airy-Heiskanen model of local compensation, with the sur
Authors
Robert W. Simpson, Robert C. Jachens, Richard W. Saltus, Richard J. Blakely
Evidence for Quaternary tectonism in the northern Bighorn basin, Wyoming and Montana
Irregularities in the reconstructed gradients of latest Pliocene and Quaternary terraces in the northern Bighorn Basin, northwest Wyoming and south-central Montana, suggest that Quaternary movements have occurred on the Frannie anticline, the Nye-Bowler–Sage Creek fault zone, and the North Pryor fault. This area has been considered tectonically inactive. The timing of the interpreted movements is
Authors
Marith C. Reheis
Bedrock geologic map of the Rainy Lake area, northern Minnesota
No abstract available.
Authors
Warren C. Day
Isotopic and morphologic evidence for the age of the Fordham Gneiss
No abstract available.
Authors
John N. Aleinikoff
Late Devonian icriodontid biofacies models and alternate shallow-water conodont zonation
Recognition of differences in the habitats, apparatuses, and ranges of Late Devonian Icriodus and Pelekysgnathus permits refinement of their biofacies interpretations and construction of an alternate icriodontid zonation. Icriodus is a euphotic genus that predominated in most environments during the early Late Devonian (Frasnian) but died out during the early Famennian. Its apparatus consists of p
Authors
Charles Sandberg, Roland Dreesen
Reflectance spectroscopy: Quantitative analysis techniques for remote sensing applications
Several methods for the analysis of remotely sensed reflectance data are compared, including empirical methods and scattering theories, both of which are important for solving remote sensing problems. The concept of the photon mean optical path length and the implications for use in modeling reflectance spectra are presented. It is shown that the mean optical path length in a particulate surface i
Authors
Roger N. Clark, T. L. Roush
Spectral properties of ice‐particulate mixtures and implications for remote sensing: 1. Intimate mixtures
The spectral properties of water ice‐particulate mixtures are studied for the purpose of deriving the ice and particulate abundances from remotely obtained spectra (particulates referring to nonicy materials in the form of grains). Reflectance levels and ice absorption band depths are a complex function of the single scattering albedo of the particulates embedded in the ice. The ice absorption ban
Authors
Roger N. Clark, Paul G. Lucey
Laurel-McGee and Wheeler Ridge Roadless Areas, California
Geochemical sampling and mine and prospect surveys identified small areas in the Laurel-McGee and Wheeler Ridge Roadless Areas in the eastern Sierra Nevada, California, that have probable potential for the occurrence of small deposits of tungsten and (or) base and precious metals. A number of mines and prospects in or near the roadless areas are in occurrences of one or more of the metals, tungste
Authors
Michael A. Cosca, Donald O. Capstick
Magnetic models of crystalline terrane; accounting for the effect of topography
Igneous rocks commonly have large magnetic susceptibilities so that high topographic relief in crystalline terrane can produce significant anomalies in aeromagnetic surveys. Topographic anomalies are particularly significant in relatively undeformed volcanic terrane because young volcanic rocks generally have large natural remanent magnetizations as well as large susceptibilities. These anomalies
Authors
Richard J. Blakely, V. J. Grauch
Interaction of subsurface brines with oxygenated meteoric water, Ray Point Uranium District, South Texas, USA
No abstract available.
Authors
Martin B. Goldhaber, Richard B. Wanty, J.R. Chatham, R. L. Reynolds, D. Langmuir