Publications
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Ages of Quaternary Rio Grande terrace-fill deposits, Albuquerque area, New Mexico Ages of Quaternary Rio Grande terrace-fill deposits, Albuquerque area, New Mexico
Results from luminescence dating on 13 samples from the Albuquerque area show that major-drainage fluvial deposits represent significant periods of aggradation that formed paired, correlatable terraces on the east and west margins of the Rio Grande valley . The youngest terrace fills (Primero Alto) formed during late Pleistocene as a result of streamflow variations with climate cooling...
Authors
Shannon Mahan, Byron D. Stone, Ralph R. Shroba
Upper Neogene tephrochronologic correlations in the northern Rio Grande Rift, New Mexico and southern Colorado Upper Neogene tephrochronologic correlations in the northern Rio Grande Rift, New Mexico and southern Colorado
No abstract available.
Authors
Janet L. Slate, Andrei M. Sarna-Wojcicki, Elmira Wan, Daniel Koning, Sean D. Connell, David P. Dethier, David B. Wahl, Michael Perkins
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
Chronology of the last glacial maximum in the upper Bear River Basin, Utah Chronology of the last glacial maximum in the upper Bear River Basin, Utah
The headwaters of the Bear River drainage were occupied during the Last Glacial Maximum (LGM) by outlet glaciers of the Western Uinta Ice Field, an extensive ice mass (???685 km2) that covered the western slope of the Uinta Mountains. A well-preserved sequence of latero-frontal moraines in the drainage indicates that outlet glaciers advanced beyond the mountain front and coalesced on the...
Authors
B.J.C. Laabs, Jeffrey S. Munroe, J. G. Rosenbaum, K.A. Refsnider, D.M. Mickelson, B. S. Singer, M.W. Caffee
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
An optical age chronology of late Quaternary extreme fluvial events recorded in Ugandan dambo soils An optical age chronology of late Quaternary extreme fluvial events recorded in Ugandan dambo soils
There is little geochonological data on sedimentation in dambos (seasonally saturated, channel-less valley floors) found throughout Central and Southern Africa. Radiocarbon dating is problematic for dambos due to (i) oxidation of organic materials during dry seasons; and (ii) the potential for contemporary biological contamination of near-surface sediments. However, for luminescence...
Authors
S. A. Mahan, D.J. Brown
Geologic Map of the Goleta Quadrangle, Santa Barbara County, California Geologic Map of the Goleta Quadrangle, Santa Barbara County, California
This map depicts the distribution of bedrock units and surficial deposits and associated deformation underlying those parts of the Santa Barbara coastal plain and adjacent southern flank of the Santa Ynez Mountains within the Goleta 7 ?? quadrangle at a compilation scale of 1:24,000 (one inch on the map = 2,000 feet on the ground) and with a horizontal positional accuracy of at least 20...
Authors
Scott A. Minor, Karl S. Kellogg, Richard G. Stanley, Theodore R. Brandt
Dust emission from wet and dry playas in the Mojave Desert, USA Dust emission from wet and dry playas in the Mojave Desert, USA
The interactions between playa hydrology and playa-surface sediments are important factors that control the type and amount of dust emitted from playas as a result of wind erosion. The production of evaporite minerals during evaporative loss of near-surface ground water results in both the creation and maintenance of several centimeters or more of loose sediment on and near the surfaces...
Authors
Richard L. Reynolds, James C. Yount, Marith C. Reheis, Harland L. Goldstein, Pat F. Chavez, Robert E. Fulton, John W. Whitney, Christopher C. Fuller, Richard M. Forester
Influence of the diversion of Bear River into Bear Lake (Utah and Idaho) on the environment of deposition of carbonate minerals Influence of the diversion of Bear River into Bear Lake (Utah and Idaho) on the environment of deposition of carbonate minerals
Bear River, the largest river in the Great Basin, had some of its flow diverted into Bear Lake through a series of canals constructed between 1911 and 1918, turning Bear Lake into a reservoir. The prediversion lake had an unusually high Mg2+ : Ca2+ ratio (38 by weight), which resulted in precipitation of CaCO3 as aragonite. The amount and mineralogy of the carbonate did not change...
Authors
W.E. Dean, R. M. Forester, Jordon Bright, R.Y. Anderson
Luminescence ages for alluvial-fan deposits in Southern Death Valley: Implications for climate-driven sedimentation along a tectonically active mountain front Luminescence ages for alluvial-fan deposits in Southern Death Valley: Implications for climate-driven sedimentation along a tectonically active mountain front
Controversy exists over whether alluvial-fan sedimentation along tectonically active mountain fronts is driven by climatic changes or tectonics. Knowing the age of sedimentation is the key to understanding the relationship between sedimentation and its cause. Alluvial-fan deposits in Death Valley and throughout the arid southwestern United States have long been the subjects of study, but...
Authors
M.F. Sohn, S. A. Mahan, J.R. Knott, D.D. Bowman
Numerical dating of a Late Quaternary spit-shoreline complex at the northern end of Silver Lake playa, Mojave Desert, California: A comparison of the applicability of radiocarbon, luminescence, terrestrial cosmogenic nuclide, electron spin resonance, U-se Numerical dating of a Late Quaternary spit-shoreline complex at the northern end of Silver Lake playa, Mojave Desert, California: A comparison of the applicability of radiocarbon, luminescence, terrestrial cosmogenic nuclide, electron spin resonance, U-se
A Late Quaternary spit-shoreline complex on the northern shore of Pleistocene Lake Mojave of southeastern California, USA was studied with the goal of comparing accelerator mass spectrometry (AMS) radiocarbon, luminescence, electron spin resonance (ESR), terrestrial cosmogenic radionuclide (TCN) surface exposure, amino acid racemization (AAR) and U-series dating methods. The pattern of...
Authors
L.A. Owen, Jordon Bright, R.C. Finkel, M.K. Jaiswal, D. S. Kaufman, S. Mahan, U. Radtke, J.S. Schneider, W. Sharp, A.K. Singhvi, C.N. Warren
Late Quaternary stratigraphy and luminescence geochronology of the northeastern Mojave Desert Late Quaternary stratigraphy and luminescence geochronology of the northeastern Mojave Desert
The chronology of the Holocene and late Pleistocene deposits of the northeastern Mojave Desert have been largely obtained using radiocarbon ages. Our study refines and extends this framework using optically stimulated luminescence (OSL) to date deposits from Valjean Valley, Silurian Lake Playa, Red Pass, and California Valley. Of particular interest are eolian fine silts incorporated in...
Authors
S. A. Mahan, D. M. Miller, C.M. Menges, J. C. Yount