Publications
Filter Total Items: 1434
A 3-Dimensional Model of Water-Bearing Sequences in the Dominguez Gap Region, Long Beach, California A 3-Dimensional Model of Water-Bearing Sequences in the Dominguez Gap Region, Long Beach, California
A 3-dimensional computer model of the Quaternary sequence stratigraphy in the Dominguez gap region of Long Beach, California has been developed to provide a robust chronostratigraphic framework for hydrologic and tectonic studies. The model consists of 13 layers within a 16.5 by 16.1 km (10.25 by 10 mile) square area and extends downward to an altitude of -900 meters (-2952.76 feet). Ten...
Authors
Daniel J. Ponti, Kenneth D. Ehman, Brian D. Edwards, John C. Tinsley, Thomas Hildenbrand, John W. Hillhouse, Randall T. Hanson, Kristen McDougall, Charles L. Powell, Elmira Wan, Michael Land, Shannon Mahan, Andrei M. Sarna-Wojcicki
From buttes to bowls: Repeated relief inversion in the landscape of the Colorado Piedmont From buttes to bowls: Repeated relief inversion in the landscape of the Colorado Piedmont
Mesas and buttes of the central Colorado Piedmont are composed of at least two distinct rock types, which differ in their cohesiveness and resistance to erosion. The lower parts of the exposed stratigraphic section are poorly cemented, Upper Cretaceous to Middle Eocene sandstones of the Dawson Formation. The caprocks are composed of one or more resistant formations of Late Eocene age...
Authors
M.L. Morgan, Vincent Matthews, F. Gutierrez, J.P. Thorson, Richard F. Madole, P.R. Hanson
Surface-exposure ages of Front Range moraines that may have formed during the Younger Dryas, 8.2 cal ka, and Little Ice Age events Surface-exposure ages of Front Range moraines that may have formed during the Younger Dryas, 8.2 cal ka, and Little Ice Age events
Surface-exposure (10Be) ages have been obtained on boulders from three post-Pinedale end-moraine complexes in the Front Range, Colorado. Boulder rounding appears related to the cirque-to-moraine transport distance at each site with subrounded boulders being typical of the 2-km-long Chicago Lakes Glacier, subangular boulders being typical of the 1-km-long Butler Gulch Glacier, and angular...
Authors
Larry Benson, Richard F. Madole, P. Kubik, Richard R. McDonald
Corrigendum to “Age model for a continuous, ca 250-ka Quaternary lacustrine record from Bear Lake, Utah–Idaho” [Quaternary Science Reviews 25 (2006) 2271–2282] Corrigendum to “Age model for a continuous, ca 250-ka Quaternary lacustrine record from Bear Lake, Utah–Idaho” [Quaternary Science Reviews 25 (2006) 2271–2282]
No abstract available.
Authors
S.M. Colman, D. S. Kaufman, C. Heil, J.W. King, Walter E. Dean, Joseph G. Rosenbaum, R. M. Forester, J.L. Bishcoff, M. E. Perkins, John McGeehin
Sediment geochemical records of productivity and oxygen depletion along the margin of western North America during the past 60,000 years: Teleconnections with Greenland Ice and the Cariaco Basin Sediment geochemical records of productivity and oxygen depletion along the margin of western North America during the past 60,000 years: Teleconnections with Greenland Ice and the Cariaco Basin
Many sediment records from the margins of the Californias (Alta and Baja) collected in water depths between 60 and 1200 m contain anoxic intervals (laminated sediments) that can be correlated with interstadial intervals as defined by the oxygen-isotope composition of Greenland ice (Dansgaard–Oeschger, D–O, cycles). These intervals include all or parts of Oxygen Isotope Stage 3 (OIS3; 60...
Authors
Walter E. Dean
Geology Geology
This map shows the ages and types of rocks that lie at or near the land surface throughout the United States. It does not show surficial materials such as soil and glacial deposits, except where Quartenary sedimentary materials cover extensive areas and obscure underlying bedrock materials. The map is a generalization and simplification of the "Geologic Map of North America," published...
Authors
John C. Reed, Charles A. Bush
Late quaternary paleoseismology of the southern Steens fault zone, northern Nevada Late quaternary paleoseismology of the southern Steens fault zone, northern Nevada
The 192-km-long Steens fault zone is the most prominent normal fault system in the northern Basin and Range province of western North America. We use trench mapping and radiometric dating to estimate displacements and timing of the last three surface-rupturing earthquakes (E1-E3) on the southern part of the fault south of Denio, Nevada. Coseismic displacements range from 1.1 to 2.2 ?? 0...
Authors
S. F. Personius, A. J. Crone, M. N. Machette, S. A. Mahan, J.B. Kyung, H. Cisneros, D. J. Lidke
Loess records: North America Loess records: North America
No abstract available.
Authors
H.M. Roberts, D.R. Muhs, E. Arthur Bettis
Global Data Toolset (GDT) Global Data Toolset (GDT)
According to the United Nations Environment Programme World Conservation Monitoring Centre (UNEP-WCMC) approximately 60 percent of the data contained in the World Database on Protected Areas (WDPA) has missing or incomplete boundary information. As a result, global analyses based on the WDPA can be inaccurate, and professionals responsible for natural resource planning and priority...
Authors
Jill J. Cress, Jodi L. Riegle
Paleoecology reconstruction from trapped gases in a fulgurite from the late Pleistocene of the Libyan Desert Paleoecology reconstruction from trapped gases in a fulgurite from the late Pleistocene of the Libyan Desert
When lightning strikes the ground, it heats, melts, and fuses the sand in soils to form glass tubes known as fulgurites. We report here the composition of CO2, CO, and NO contained within the glassy bubbles of a fulgurite from the Libyan Desert. The results show that the fulgurite formed when the ground contained 0.1 wt% organic carbon with a C/N ratio of 10-15 and a ??13C of -13.96
Authors
Gonzalez R. Navarro, S. A. Mahan, A.K. Singhvi, R. Navarro-Aceves, J.-L. Rajot, C.P. McKay, P. Coll, F. Raulin
Dune fields: mid-latitudes Dune fields: mid-latitudes
No abstract available.
Authors
Jielun Sun, D.R. Muhs