Publications
Filter Total Items: 1459
Increasing eolian dust deposition in the western United States linked to human activity Increasing eolian dust deposition in the western United States linked to human activity
Mineral aerosols from dust are an important influence on climate and on marine and terrestrial biogeochemical cycles. These aerosols are generated from wind erosion of surface soils. The amount of dust emission can therefore be affected by human activities that alter surface sediments. However, changes in regional- and global-scale dust fluxes following the rapid expansion of human...
Authors
J. C. Neff, A. P. Ballantyne, G. L. Farmer, N. M. Mahowald, C. C. Landry, J. T. Overpeck, T. H. Painter, C. R. Lawrence, Richard L. Reynolds
Magmatic and tectonic evolution of the Caetano caldera, north-central Nevada: A tilted, mid-Tertiary eruptive center and source of the Caetano Tuff Magmatic and tectonic evolution of the Caetano caldera, north-central Nevada: A tilted, mid-Tertiary eruptive center and source of the Caetano Tuff
The Caetano Tuff is a late Eocene, rhyolite ash-flow tuff that crops out within an ∼90-km-long, east-west–trending belt in north-central Nevada, previously interpreted as an elongate graben or “volcano-tectonic trough.” New field, petrographic, geochemical, and geochronologic data show that: (1) the east half of the “trough” is actually the Caetano caldera, formed by eruption of the...
Authors
David A. John, Christopher D. Henry, Joseph P. Colgan
Palaeoclimate Palaeoclimate
This chapter assesses palaeoclimatic data and knowledge of how the climate system changes over interannual to millennial time scales, and how well these variations can be simulated with climate models. Additional palaeoclimatic perspectives are included in other chapters. Palaeoclimate science has made significant advances since the 1970s, when a primary focus was on the origin of the...
Authors
Eystein Jansen, Jonathan Overpeck, Keith R. Briffa, Jean-Claude Duplessy, Fortunat Joos, Valerie Masson-Delmotte, Daniel Olago, Bette Otto-Bliesner, W. Richard Peltier, Stefan Rahmstorf, Rengaswamy Ramesh, Dominique Raynaud, David Rind, Olga Solomina, Ricardo Villalba, De’er Zhang, Jean-Marc Barnola, Eva M. Bauer, Esther Brady, Mark Chandler, Julia E. Cole, Edward R. Cook, Esla Cortijo, Trond Dokken, Dominik Fleitmann, Masa Kageyama, Myriam Khodri, Laurent Labeyrie, Alexander Laine, Anders Levermann, E. Mosley-Thompson, Daniel R. Muhs, Raimund Muscheler, Tim Osborn, Oyvind Paasche, Frederic Parrenin, Gian-Kasper Plattner, Henry Pollack, Renato Spahni, Lowell D. Stott, Lonnie Thompson, Claire Waelbroeck, Gregory Wiles, James Zachos, Zhangteng Guo
Late Cenozoic drainage history of the southwestern Great Basin and lower Colorado River region: Geologic and biotic perspectives Late Cenozoic drainage history of the southwestern Great Basin and lower Colorado River region: Geologic and biotic perspectives
No abstract available.
Authors
Marith C. Reheis, R. Hershler, David M. Miller
Rocks above the clouds: A hiker's and climber's guide to Colorado mountain geology Rocks above the clouds: A hiker's and climber's guide to Colorado mountain geology
A Colorado mountain geology book written specifically for climbers, scramblers and hikers. A geologic primer for mountain people with range-by-range geological descriptions of Colorado mountains and detailed geologic information on the Fourteeners. Rocks Above the Clouds is the first geology book written for climbers, scramblers and hikers. It is an exploration of how the nature of...
Authors
Jack Reed, Gene Ellis
Lake Manix shorelines and Afton Canyon terraces: Implications for incision of Afton Canyon Lake Manix shorelines and Afton Canyon terraces: Implications for incision of Afton Canyon
Lake Manix, in south-central California, was the terminal basin of the Mojave River until the late Pleistocene, when it drained east to the Lake Mojave Basin. Based on new field observations, radiocarbon ages, and soil development, we propose modifications to previously published hypotheses on the timing of the last 543 m above sea level (masl) highstand of Lake Manix, the timing of the...
Authors
Marith C. Reheis, Joanna L. Redwine
Quantitative estimation of bioclimatic parameters from presence/absence vegetation data in North America by the modern analog technique Quantitative estimation of bioclimatic parameters from presence/absence vegetation data in North America by the modern analog technique
The method of modern analogs is widely used to obtain estimates of past climatic conditions from paleobiological assemblages, and despite its frequent use, this method involved so-far untested assumptions. We applied four analog approaches to a continental-scale set of bioclimatic and plant-distribution presence/absence data for North America to assess how well this method works under...
Authors
R.S. Thompson, K. H. Anderson, P. J. Bartlein
Optically stimulated luminescence age controls on late Pleistocene and Holocene coastal lithosomes, North Carolina, USA Optically stimulated luminescence age controls on late Pleistocene and Holocene coastal lithosomes, North Carolina, USA
Luminescence ages from a variety of coastal features on the North Carolina Coastal Plain provide age control for shoreline formation and relative sea-level position during the late Pleistocene. A series of paleoshoreline ridges, dating to Marine Isotope Stage (MIS) 5a and MIS 3 have been defined. The Kitty Hawk beach ridges, on the modern Outer Banks, yield ages of 3 to 2??ka. Oxygen...
Authors
D. Mallinson, K. Burdette, S. Mahan, G. Brook
Origin and paleoclimatic significance of late Quaternary loess in Nebraska: Evidence from stratigraphy, chronology, sedimentology, and geochemistry Origin and paleoclimatic significance of late Quaternary loess in Nebraska: Evidence from stratigraphy, chronology, sedimentology, and geochemistry
Loess is one of the most extensive surficial geologic deposits in midcontinental North America, particularly in the central Great Plains region of Nebraska. Last-glacial-age loess (Peoria Loess) reaches its greatest known thickness in the world in this area. New stratigraphic, geochronologic, mineralogic, and geochemical data yield information about the age and provenance of Peoria Loess...
Authors
Daniel R. Muhs, E. Arthur Bettis, John N. Aleinikoff, John P. McGeehin, Jossh Beann, Gary Skipp, Brian D. Marshall, Helen M. Roberts, William C. Johnson, Rachel Benton
Geochemical evidence for hydroclimatic variability over the last 2460 years from Crevice Lake in Yellowstone National Park, USA Geochemical evidence for hydroclimatic variability over the last 2460 years from Crevice Lake in Yellowstone National Park, USA
A 2460-year-long hydroclimatic record for Crevice Lake, Yellowstone National Park, Montana was constructed from the ??18O values of endogenic carbonates. The ??18O record is compared to the Palmer Hydrologic Drought Index (PHDI) and Pacific Decadal Oscillation (PDO) indices, as well as inferred discharge of the Yellowstone River. During the last century, high ??18O values coincide with...
Authors
L.R. Stevens, W.E. Dean
SHRIMP-RG U-Pb isotopic systematics of zircon from the Angel Lake orthogneiss, East Humboldt Range, Nevada: Is this really archean crust? SHRIMP-RG U-Pb isotopic systematics of zircon from the Angel Lake orthogneiss, East Humboldt Range, Nevada: Is this really archean crust?
New SHRIMP-RG (sensitive high-resolution ion microprobe-reverse geometry) data confirm the existence of Archean components within zircon grains of a sample from the orthogneiss of Angel Lake, Nevada, United States, previously interpreted as a nappe of Archean crust. However, the combined evidence strongly suggests that this orthogneiss is a highly deformed, Late Cretaceous monzogranite...
Authors
Wayne R. Premo, Pedro Castineiras, Joseph L. Wooden