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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: 1912

Controls on 222Rn variations in a fractured crystalline rock aquifer evaluated using aquifer tests and geophysical logging Controls on 222Rn variations in a fractured crystalline rock aquifer evaluated using aquifer tests and geophysical logging

Concentrations of 222Rn in ground water may vary considerably within megascopically homogeneous rocks over relatively short distances. Calculations indicate that different hydraulic apertures of water‐bearing fractures may account for variations in dissolved 222Rn concentration measured in domestic water wells completed in fractured Pikes Peak Granite, assuming that all other factors...
Authors
P. F. Folger, E. Poeter, Richard B. Wanty, D. Frishman, W. Day

Evidence for Mesoproterozoic basement in the Carolina terrane and speculations on its origin Evidence for Mesoproterozoic basement in the Carolina terrane and speculations on its origin

No abstract available.
Authors
Paul A. Mueller, Marianne Kozuch, Ann L. Heatherington, Joseph L. Wooden, Terry W. Offield, Robert P. Koeppen, Terry L. Klein, Allen P. Nutman

Devonian conodont biochronology in geologic time calibration Devonian conodont biochronology in geologic time calibration

The conodont-based biochronology of the Devonian Period is calibrated herein on the basis of: (1) a recent, reliable radiometric dating (CLAQUE??-LONG et al. 1992) of a stratigraphic position just above the Devonian-Carboniferous boundary; and (2) new calculations of stage durations based on our estimates and those of a large number of other Devonian workers, which pertain to many...
Authors
Charles Sandberg, W. Ziegler

Petrology and U-PB geochronology of the Robertson River Igneous Suite, Blue Ridge province, Virginia - Evidence for multistage magmatism associated witn an early episode of Laurentian rifting Petrology and U-PB geochronology of the Robertson River Igneous Suite, Blue Ridge province, Virginia - Evidence for multistage magmatism associated witn an early episode of Laurentian rifting

The Late Neoproterozoic (735-702 Ma) Robertson River Igneous Suite includes at least eight plutons ranging in composition from syenogranite to alkali feldspar granite to alkali feldspar syenite. These plutons intruded Mesoproterozoic (1.2-1.0 Ga) gneissic basement of the Blue Ridge anticlinorium in northern and central Virginia during an early episode of Laurentian rifting. Robertson...
Authors
Richard P. Tollo, John N. Aleinikoff

Determination of 15N/14N and 13C/12C in solid and aqueous cyanides Determination of 15N/14N and 13C/12C in solid and aqueous cyanides

The stable isotopic compositions of nitrogen and carbon in cyanide compounds can be determined by combusting aliquots in sealed tubes to form N2 gas and CO2 gas and analyzing the gases by mass spectrometry. Free cyanide (CN-aq + HCNaq) in simple solutions can also be analyzed by first precipitating the cyanide as copper(II) ferrocyanide and then combusting the precipitate...
Authors
Craig A. Johnson

Surface seismic and electrical methods to detect fluids related to faulting Surface seismic and electrical methods to detect fluids related to faulting

In the absence of drilling, surface-based geophysical methods are necessary to observe fault zones and fault zone physical properties at seismogenic depths. These in situ physical properties can then be used to infer the presence and distribution of fluids along faults, although such observations are by nature indirect and become less exact with greater depth. Multiple observations of a...
Authors
Donna Eberhart-Phillips, William D. Stanley, Brian D. Rodriguez, William J. Lutter

Reflexions on Frasnian and Famennian stage boundary decisions as a guide to future deliberations Reflexions on Frasnian and Famennian stage boundary decisions as a guide to future deliberations

The pros and cons of the three conodont-based boundaries of the Frasnian and Famennian Stages and their corresponding GSSPs (Global Stratotype Section and Point) are evaluated in terms of current taxonomic, biostratigraphic, and sedimentologic knowledge. Two of these boundaries are based on easily identified pelagic species, which provide excellent bases for global correlation. The third...
Authors
W. Ziegler, Charles Sandberg
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