Publications
Filter Total Items: 1425
Isotopic signatures of black tektites from the K‐T boundary on Haiti: Implications for the age and type of source material Isotopic signatures of black tektites from the K‐T boundary on Haiti: Implications for the age and type of source material
U‐Th‐Pb, Rb‐Sr, and Sm‐Nd isotopic signatures of corroded, but unaltered, black glassy tektites from Cretaceous‐Tertiary (K‐T) boundary rock on Haiti are not consistent with their derivation from an impact on MOR‐derived oceanic crust or continental regions involving middle Proterozoic or older crustal material. Two single‐grain and two batches of these tektites yielded present‐day ∍Nd =...
Authors
Wayne R. Premo, G. A. Izett
Allochthonous impact-shocked rocks and superimposed deformations at the Beaverhead site in southwest Montana Allochthonous impact-shocked rocks and superimposed deformations at the Beaverhead site in southwest Montana
Upward-pointing shatter cones in sandstones of uncertain age (Middle Proterozoic? to Lower Cambrian?) and older crystalline basement rocks are exposed over an area of approximately 25 × 8 km in southwestern Montana. These shatter cones, together with pseudotachylites and breccias of various types (particularly in basement gneisses), are inferred to be products of a meteorite or cometary...
Authors
R.B. Hargraves, Karl S. Kellogg, P.S. Fiske, S.B. Hougen
Effects of weather and soil characteristics on temporal variations in soil-gas radon concentrations Effects of weather and soil characteristics on temporal variations in soil-gas radon concentrations
Concentrations of radon-222 in soil gas measured over about 1 yr at a monitoring site in Denver, Colorado, vary by as much as an order of magnitude seasonally and as much as severalfold in response to changes in weather. The primary weather factors that influence soil-gas radon concentrations are precipitation and barometric pressure. Soil characteristics are important in determining the...
Authors
R. Randall Schumann, Douglass E. Owen, Sigrid Asher-Bolinder
Chapter 4: Cretaceous thrusting and Neogene block rotation in the northern Portneuf Range region, southeastern Idaho Chapter 4: Cretaceous thrusting and Neogene block rotation in the northern Portneuf Range region, southeastern Idaho
The Putnam thrust has long been recognized as an important Mesozoic structure in the northern Portneuf Range, southeastern Idaho. At most localities, the thrust places Ordovician rocks above Permian and Pennsylvanian rocks, although near its southeastern extent, it ramps laterally downsection to the southeast. At its southeasternmost exposures, Cambrian rocks are juxtaposed above...
Authors
Karl S. Kellogg
Uranium-series age estimates of corals from Quaternary marine sediments of southern Florida Uranium-series age estimates of corals from Quaternary marine sediments of southern Florida
No abstract available.
Authors
D.R. Muhs, Barney J. Szabo, L. McCartan, P.B. Maat, C. A. Bush, R. B. Halley
The extent of temporal smearing in surface-temperature histories derived from borehole temperature measurements The extent of temporal smearing in surface-temperature histories derived from borehole temperature measurements
The ability of borehole temperature data to resolve past climatic events is investigated using Backus-Gilbert inversion methods. Two experimental approaches are considered: (1) the data consist of a single borehole temperature profile, and (2) the data consist of climatically-induced temperature transients measured within a borehole during a monitoring experiment. The sensitivity of the...
Authors
Gary D. Clow
Aminostratigraphy and oxygen isotope stratigraphy of marine terrace deposits, Palos Verdes Hills and San Pedro areas, Los Angeles County, California Aminostratigraphy and oxygen isotope stratigraphy of marine terrace deposits, Palos Verdes Hills and San Pedro areas, Los Angeles County, California
No abstract available.
Authors
D.R. Muhs, G. H. Miller, J. F. Whelan, G. L. Kennedy
Strontium isotope geochemistry of calcite fracture fillings in deep core, Yucca Mountain, Nevada--A progress report Strontium isotope geochemistry of calcite fracture fillings in deep core, Yucca Mountain, Nevada--A progress report
No abstract available.
Authors
Zell E. Peterman, John S. Stuckless, Brian D. Marshall, Shannon A. Mahan, Kiyoto Futa
Relations among hydrocarbon reservoirs, epigenetic sulfidization, and rock magnetization; Examples from the South Texas coastal plain Relations among hydrocarbon reservoirs, epigenetic sulfidization, and rock magnetization; Examples from the South Texas coastal plain
This paper focuses on the association between concentrations of iron disulfide (FeS 2 ) minerals in the shallow subsurface and underlying hydrocarbon accumulations. Such FeS 2 concentrations are the result of migration of either H 2 S or organic constituents from the underlying hydrocarbons. The H 2 S from reservoirs is produced inorganically from sulfate in the reservoir rocks at high...
Authors
Martin B. Goldhaber, Richard L. Reynolds
Holocene Treeline Fluctuations in the Northern San Juan Mountains, Colorado, U.S.A., as Indicated by Radiocarbon-Dated Conifer Wood Holocene Treeline Fluctuations in the Northern San Juan Mountains, Colorado, U.S.A., as Indicated by Radiocarbon-Dated Conifer Wood
An early to mid-Holocene warm period with greater than present-day monsoonal circulation is indicated by evidence in the northern San Juan Mountains of southwestern Colorado. Fifty radiocarbon ages of coniferous wood fragments, and several other radiocarbon ages of willow fragments, woody peat, and organic sediment associated with conifer remains, recovered from six sites at or above...
Authors
Paul E. Carrara, Deborah A. Trimble, Meyer Rubin
U-Th-Pb Isotopic Systematics of Lunar Norite 78235 U-Th-Pb Isotopic Systematics of Lunar Norite 78235
No abstract available.
Authors
Wayne R. Premo, M. Tatsumoto