Publications
Filter Total Items: 880
High-precision 40Ar/39Ar age spectrum dating of sanidine from the Middle Pennsylvanian Fire Clay tonstein of the Appalachian basin High-precision 40Ar/39Ar age spectrum dating of sanidine from the Middle Pennsylvanian Fire Clay tonstein of the Appalachian basin
40Ar/39Ar plateau age spectra of seven sanidine samples from the Fire Clay tonstein (Middle Pennsylvanian), collected along a 300-km traverse in the Appalachian basin, range from 310.3 to 311.4 Ma. All plateau ages agree, within the limits of analytical precision, with their respective total gas ages. This agreement, together with the reproducibility between samples, suggests the...
Authors
Michael Kunk, Charles L. Rice
40Ar/39Ar chronology and volcanology of silicic volcanism in the Davis Mountains, Trans-Pecos Texas 40Ar/39Ar chronology and volcanology of silicic volcanism in the Davis Mountains, Trans-Pecos Texas
Field studies and 40Ar/39Ar dating reveal that silicic volcanism in the Davis Mountains part of the Trans-Pecos Texas volcanic field occurred in six episodes at 0.3 m.y. intervals between 36.8 and 35.3 Ma. Additionally, two groups of silicic intrusions were emplaced at 34.6 and 32.8 Ma. This episodicity is similar to that determined for volcanic fields dominated by ash-flow tuffs, yet...
Authors
Christopher D. Henry, Michael Kunk, W. McIntosh
40Ar 39Ar age constraints on neogene sedimentary beds, Upper Ramparts, half-way Pillar and Canyon village sites, Porcupine river, east-central Alaska 40Ar 39Ar age constraints on neogene sedimentary beds, Upper Ramparts, half-way Pillar and Canyon village sites, Porcupine river, east-central Alaska
40Ar/39Ar ages of volcanic rocks are used to provide numerical constraints on the age of middle and upper Miocene sedimentary strata collected along the Porcupine River. Intercalated sedimentary rocks north of latitude 67°10′N in the Porcupine terrane of east-central Alaska contain a rich record of plant fossils. The fossils are valuable indicators of this interior region's paleoclimate...
Authors
Michael Kunk, H. Rieck, T. Fouch, L. Carter
The Pennsylvanian Fire Clay tonstein of the Appalachian basin—Its distribution, biostratigraphy, and mineralogy The Pennsylvanian Fire Clay tonstein of the Appalachian basin—Its distribution, biostratigraphy, and mineralogy
The Middle Pennsylvanian Fire Clay tonstein, mostly kaolinite and minor accessory minerals, is an altered and lithified volcanic ash preserved as a thin, isochronous layer associated with the Fire Clay coal bed. Seven samples of the tonstein, taken along a 300-km traverse of the central Appalachian basin, contain cogenetic phenocrysts and trapped silicate-melt inclusions of a rhyolitic...
Authors
C. Rice, Harvey Belkin, T.W. Henry, R. E. Zartman, Michael Kunk
Digital bedrock geologic map of the Plymouth quadrangle, Vermont Digital bedrock geologic map of the Plymouth quadrangle, Vermont
No abstract available.
Authors
Gregory Walsh, Nicholas Ratcliffe
Geologic, hydrologic, and water-quality data for a multi-aquifer system in Coastal Plain sediments near Millers Pond, Burke County, Georgia, 1992-93 Geologic, hydrologic, and water-quality data for a multi-aquifer system in Coastal Plain sediments near Millers Pond, Burke County, Georgia, 1992-93
No abstract available.
Authors
John Clarke, William Falls, Lucy Edwards, Norman Frederiksen, Laurel Bybell, Thomas Gibson, Ronald Litwin
Digital bedrock geologic map of the Plymouth quadrangle, Vermont Digital bedrock geologic map of the Plymouth quadrangle, Vermont
No abstract available.
Authors
Gregory Walsh, Nicholas Ratcliffe
Paleogene stratigraphy of the Solomons Island, Maryland, corehole Paleogene stratigraphy of the Solomons Island, Maryland, corehole
The Solomons Island corehole was drilled in the hope of obtaining a continuous and more nearly complete section of upper Paleocene and lower Eocene strata than are found in the discontinuous and fragmentary sections in the outcrop belt to the west. Consultation with Harry Hansen (Maryland Geological Survey) on possible drilling sites that were within the limits of our equipment and...
Authors
Thomas Gibson, Laurel Bybell
Preliminary analysis of integrated stratigraphic data from the South Venice corehole, Sarasota County, Florida Preliminary analysis of integrated stratigraphic data from the South Venice corehole, Sarasota County, Florida
No abstract available.
Authors
G. Brewster-Wingard, S.D. Weedman, T.M. Scott, Lucy Edwards, R.C. Green
Palynomorph biostratigraphy of Eocene samples from the Sagavanirktok Formation at Franklin Bluffs, North Slope of Alaska Palynomorph biostratigraphy of Eocene samples from the Sagavanirktok Formation at Franklin Bluffs, North Slope of Alaska
No abstract available.
Authors
Norman Frederiksen, Lucy Edwards, T. Fouch, L. Carter, T. Collett
Digital bedrock geologic map of the Mount Holly and Ludlow quadrangles, Vermont Digital bedrock geologic map of the Mount Holly and Ludlow quadrangles, Vermont
No abstract available.
Authors
Gregory Walsh, Nicholas Ratcliffe, John Dudley, Thomas Merrifield
Digital bedrock geologic map of the Mount Holly and Ludlow quadrangles, Vermont: Database Digital bedrock geologic map of the Mount Holly and Ludlow quadrangles, Vermont: Database
No abstract available.
Authors
Gregory Walsh, Nicholas Ratcliffe, John Dudley, Thomas Merrifield