Publications
Filter Total Items: 890
Age of the Cenomanian-Turonian boundary in the Western Interior of the United States Age of the Cenomanian-Turonian boundary in the Western Interior of the United States
High precision 40Ar/39Ar laser-microprobe ages of individual sanidines,40Ar/39Ar plateau age spectra on bulk sanidine concentrates, U-Pb zircon ages, and zircon and apatite fission-track ages from three bentonites bracketing the Cenomanian-Turonian boundary in the Western Interior of the United States suggest an age for the boundary of 93.1 ± 0.3 (2σ. The lowermost bentonite comes from...
Authors
B. J. Kowallis, Eric H. Christiansen, Alan L. Deino, Michael J. Kunk, L. Heaman
Geology of the Waterford quadrangle, Virginia and Maryland, and the Virginia part of the Point of Rocks quadrangle Geology of the Waterford quadrangle, Virginia and Maryland, and the Virginia part of the Point of Rocks quadrangle
The bedrock geology of the Waterford quadrangle and of the Virginia part of the Point of Rocks quadrangle consists of a portion of the Middle Proterozoic basement core and its cover sequence on the eastern limb of the Blue Ridge anticlinorium and the adjacent early Mesozoic Culpeper basin. The three major rock associations in this area are: 1) Middle Proterozoic gneisses intruded by late
Authors
William C. Burton, A.J. Froelich, J. S. Pomeroy, K. Y. Lee
Impact of the 1993 floods in the upper Mississippi River basin Impact of the 1993 floods in the upper Mississippi River basin
No abstract available.
Authors
J. C. Dohrenwend, Byron D. Stone
Preliminary analysis of integrated stratigraphic data from the Phred #1 corehole, Indian River County, Florida Preliminary analysis of integrated stratigraphic data from the Phred #1 corehole, Indian River County, Florida
No abstract available.
Authors
S.D. Weedman, T.M. Scott, Lucy E. Edwards, G. L. Brewster-Wingard, J.C. Libarkin
Map showing bedrock surface topography, bedrock outcrops, and areas of shallow bedrock in the northern sheet, New Jersey Map showing bedrock surface topography, bedrock outcrops, and areas of shallow bedrock in the northern sheet, New Jersey
No abstract available.
Authors
Byron D. Stone, Scott D. Stanford, Ron W. Witte
Age and diagenesis of the upper Floridan Aquifer and the intermediate aquifer system in southwestern Florida Age and diagenesis of the upper Floridan Aquifer and the intermediate aquifer system in southwestern Florida
No abstract available.
Authors
Lucy McCartan, S.D. Weedman, G.L. Wingard, Lucy E. Edwards, P. J. Sugarman, M.D. Feigenson, M. L. Buursink, J.C. Libarkin
U-Pb ages of metarhyolites of the Catoctin and Mount Rogers formations, central and southern Appalachians: Evidence for two pulses of Iapetan rifting U-Pb ages of metarhyolites of the Catoctin and Mount Rogers formations, central and southern Appalachians: Evidence for two pulses of Iapetan rifting
No abstract available.
Authors
John N. Aleinikoff, Robert E. Zartman, Marianne Walter, Douglas W. Rankin, Peter T. Lyttle, William C. Burton
Sedimentary patterns across the Paleocene-Eocene boundary in the Atlantic and Gulf Coastal Plains of the United States Sedimentary patterns across the Paleocene-Eocene boundary in the Atlantic and Gulf Coastal Plains of the United States
Fossiliferous clay and sand belonging to calcareous nannofossil Zones NP 9 (latest Paleocene) and NP 10 (earliest Eocene) are widespread in the US Gulf and Atlantic Coastal Plains. Although the thickness of Zone NP 9-NP 10 strata is several times greater in the eastern Gulf Coastal Plain than in the Atlantic Coastal Plain, the hiatus that usually is present between these two zones in...
Authors
Thomas G. Gibson, Laurel M. Bybell
The scientific assessment and strategy team contributions assessing the 1993 flood on the Mississippi and Missouri River basins The scientific assessment and strategy team contributions assessing the 1993 flood on the Mississippi and Missouri River basins
The Scientific Assessment and Strategy Team was formed to provide scientific advice and assistance to federal officials responsible for making decisions with respect to flood recovery in the Upper Mississippi River Basin (above Cairo, Illinois) as a result of the 1993 flooding. The team assembled data from a wide variety of sources within federal, state, and local governments, and the...
Authors
Gary E. Freeman, S. K. Nanda, M. J. Mausback, Ronald E. Erickson, John A. Kelmelis, Byron D. Stone, William H. Kirby, James R. Reel
Flow path studies in forested watersheds of headwater tributaries of Brush Brook, Vermont Flow path studies in forested watersheds of headwater tributaries of Brush Brook, Vermont
An investigation was undertaken into how headwater tributaries of Brush Brook, Vermont, could have average pH differences of almost two units (4.75 and 6.7). Sampling along four tributaries revealed that most of one tributary, below an area of seeps, had consistently higher pH, Ca2+, Mg2+, and K+, and lower Al than other sites. Bedrock mapping showed numerous fractures in vicinity of the...
Authors
Donald S. Ross, R. J. Bartlett, Frederick R. Magdoff, Gregory J. Walsh
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 J. 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 J. Kunk, W. C. McIntosh