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Quaternary history of some southern and central Rocky Mountain basins Quaternary history of some southern and central Rocky Mountain basins

This chapter summarizes the current state of late Cenozoic stratigraphic knowledge in some Rocky Mountain basins (here defined as the structurally low portions of major drainage basins) that have been studied in detail since Scott’s (1965) summary on the nonglacial history of the southern and middle Rocky Mountains. The Quaternary history of few of these basins has been studied as...
Authors
Marith C. Reheis, Robert C. Palmquist, S.S. Agard, Cheryl Jaworowski, Brainerd Mears, Richard F. Madole, Alan R. Nelson, Gerald Osborn

Assessing the natural performance of felsic tuffs using the Rb-Sr and Sm-Nd systems-A study of the altered zone in the Topopah Spring Member, Paintbrush Tuff, Yucca Mountain, Nevada Assessing the natural performance of felsic tuffs using the Rb-Sr and Sm-Nd systems-A study of the altered zone in the Topopah Spring Member, Paintbrush Tuff, Yucca Mountain, Nevada

Core samples of the Topopah Spring Member of the Paintbrush Tuff from drill hole UE25A#1 were analyzed for Sr and Nd isotopes and selected minor and trace elements to constrain the origin of a zcolitized zone associated with the lower vitrophyre. The Sm-Nd radiogenic isotope system was unperturbed by the alteration, but the Rb-Sr system was severely disturbed in the altered zone. The...
Authors
Zell E. Peterman, Richard W. Spengler, Kiyoto Futa, Brian D. Marshall

Age estimates and uplift rates for late Pleistocene marine terraces: Southern Oregon portion of the Cascadia forearc Age estimates and uplift rates for late Pleistocene marine terraces: Southern Oregon portion of the Cascadia forearc

Interest in the Cascadia subduction zone has increased because recent investigations have suggested that slip along plates at certain types of convergent margins is characteristically accompanied by large earthquakes. In addition, other investigations have suggested that convergent margins can be broadly classified by the magnitude of their uplift rates. The authors generated new uranium...
Authors
Daniel R. Muhs, Harvey M. Kelsey, Joseph F. Whelan, Galan W. McInelly

Iron sulfide minerals at Cement oil field, Oklahoma: Implications for magnetic detection of oil fields Iron sulfide minerals at Cement oil field, Oklahoma: Implications for magnetic detection of oil fields

Aeromagnetic anomalies at Cement oil field (Anadarko basin, Oklahoma) have been attributed to authigenic magnetite. The following characteristics of the magnetite, however, indicate that it is contamination introduced by drilling: (1) occurrence as sharp angular blades and as spheres, commonly with metallographic textures typical of industrial alloys and with associated steel and wustite...
Authors
Richard L. Reynolds, Neil S. Fishman, Richard B. Wanty, Martin B. Goldhaber

Influence of climate and eolian dust on the major-element chemistry and clay mineralogy of soils in the northern Bighorn basin, U.S.A. Influence of climate and eolian dust on the major-element chemistry and clay mineralogy of soils in the northern Bighorn basin, U.S.A.

Soil chronosequences in the northern Bighorn basin permit the study of chronologic changes in the major-element chemistry and clay mineralogy of soils formed in different climates. Two chronosequences along Rock Creek in south-central Montana formed on granitic alluvium in humid and semiarid climates over the past two million years. A chronosequence at the Kane fans in north-central...
Authors
Marith C. Reheis

Stop 16: Trench 14 Stop 16: Trench 14

No abstract available.
Authors
Emily M. Taylor, John S. Stuckless, S. S. Levy

Geochemical evidence for suppression of pelagic marine productivity at the Cretaceous/Tertiary boundary Geochemical evidence for suppression of pelagic marine productivity at the Cretaceous/Tertiary boundary

The normal, biologically productive ocean is characterized by a gradient of the 13C/12C ratio from surface to deep waters. Here we present stable isotope data from planktonic and benthic micro-fossils across the Cretaceous/Tertiary boundary in the North pacific, which reveal a rapid and complete breakdown in this biologically mediated gradient. The fluxes of barium (a proxy for organic...
Authors
James Zachos, M.A. Arthur, Walter E. Dean
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