Hostname: page-component-78c5997874-s2hrs Total loading time: 0 Render date: 2024-11-10T08:39:46.506Z Has data issue: false hasContentIssue false

Accuracy of Post-Bomb 137Cs and 14C in Dating Fluvial Deposits

Published online by Cambridge University Press:  20 January 2017

Lisa L. Ely
Affiliation:
Department of Geosciences, University of Arizona, Tucson, Arizona 85721
Robert H. Webb
Affiliation:
U.S. Geological Survey, 1675 West Anklam Road, Tucson, Arizona 85705
Yehouda Enzel
Affiliation:
U.S. Geological Survey, 1675 West Anklam Road, Tucson, Arizona 85705

Abstract

The accuracy and precision of 137Cs and 14C for dating post-1950 alluvial deposits were evaluated for deposits from known floods on two rivers in Arizona. The presence of 137Cs reliably indicates that deposition occurred after intensive above-ground nuclear testing was initiated around 1950. There was a positive correlation between the measured level of 137Cs activity and the clay content of the sediments, although 137Cs was detected even in sandy flood sediments with low clay content. 137Cs is a valuable dating tool in arid environments where organic materials for 14C or tree-ring dating are scarce and observational records are limited. The 14C activity measured in different types of fine organic detritus yielded dates within 1 to 8 yr of a 1980 flood deposit, and the accuracy was species-dependent. However, undifferentiated mixtures of fine organic materials from several post-bomb deposits of various ages repeatedly yielded dates between 1958 and 1962, and detrital charcoal yielded a date range of 1676–1939. In semiarid environments, the residence time of most types of organic debris precludes accurate annual resolution of post-bomb 14C dates.

Type
Research Article
Copyright
University of Washington

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Atwater, B.F. Trumm, D.A. Tinsley, J.D. III Stein, R.S. Tucker, A.B. Donahue, D.J. Jull, A.J.T. Payen, L.A. Alluvial plains and earthquake recurrence at the Coalinga anticline Rymer, M.J. Ellsworth, W.L. The Coalinga, California, Earthquake of May 2, 1983 U.S.G.S. Professional Paper 1487 1990 273 297 Google Scholar
Baker, V.R. Pickup, G. Flood geomorphology of the Katherine Gorge, Northern Territory, Australia Geological Society of America Bulletin 98 1987 635 646 Google Scholar
Baker, V.R. Pickup, G. Polach, H.A. Radiocarbon dating of flood events, Katherine Gorge, Northern Territory, Australia Geology 13 1985 344 347 2.0.CO;2>CrossRefGoogle Scholar
Bishop, P. Campbell, B. McFadden, C. Absence of Caesium-137 from recent sediments in eastern Australia—Indications of catchment processes? Catena 18 1991 61 69 CrossRefGoogle Scholar
Blong, R.J. Gillespie, R. Fluvially transported charcoal gives erroneous 14C ages for recent deposits Nature 271 1978 739 741 CrossRefGoogle Scholar
Durham, R.W. Joshi, S.R. The Pb-210 and Cs-137 profiles in sediment cores from Lakes Matagami and Quevillon, Northwest Quebec, Canada Canadian Journal of Earth Science 147 1980 1746 1750 Google Scholar
Ely, L.L. Baker, V.R. Reconstructing paleoflood hydrology with slackwater deposits, Verde River, Arizona Physical Geography 6 1985 103 126 CrossRefGoogle Scholar
Grootes, P.M. Radioactive isotopes in the Holocene Wright, H.W. Jr. Late Quaternary Environments of the United States Volume 2 1983 University of Minnesota Press Minneapolis 86 105 the Holocene Google Scholar
Hereford, R. Climate and ephemeral-stream processes: Twentieth-century geomorphology and alluvial stratigraphy of the Little Colorado River, Arizona Geological Society of America Bulletin 95 1984 654 668 2.0.CO;2>CrossRefGoogle Scholar
Hereford, R. Modern alluvial history of the Paria River drainage basin, southern Utah Quaternary Research 25 1986 293 311 CrossRefGoogle Scholar
Hupp, C.R. Plant ecological aspects of flood geomorphology and paleoflood history Baker, V.R. Kochel, R.C. Patton, P.C. Flood Geomorphology 1988 Wiley New York 335 356 Google Scholar
Kochel, R.C. Baker, V.R. Paleoflood analysis using slackwater deposits Baker, V.R. Kochel, R.C. Patton, P.C. Flood Geomorphology 1988 Wiley New York 357 376 Google Scholar
Linnick, T.W. Uptake of Bomb-produced Carbon-14 by the Pacific Ocean unpublished Ph.D. dissertation 1975 University of California San Diego Google Scholar
Long, A. Rippeteau, B. Testing contemporaneity and averaging radiocarbon dates American Antiquity 39 1974 205 215 Google Scholar
McHenry, J.R. Ritchie, J.C. Physical and chemical parameters affecting transport of 137Cs in arid watersheds Water Resources Research 13 1977 923 927 Google Scholar
Nydal, R. Increase in radiocarbon from the most recent series of thermonuclear tests Nature 200 1963 212 214 CrossRefGoogle Scholar
Nydal, R. Lovseth, K. Tracing bomb 14C in the atmosphere 1962–1980 Journal of Geophysical Research 88 1983 3621 3642 Google Scholar
Partridge, F.B. Baker, V.R. Palaeoflood hydrology of the Salt River, Arizona Earth Surface Processes and Landforms 12 1987 109 125 Google Scholar
Perkins, R.W. Thomas, C.W. World-wide fallout Hanson, W.C. Transuranic Elements in the Environment 1980 Technical Information Center Springfield, VA 53 82 Google Scholar
Popp, C.J. Hawley, J.W. Love, D.W. Dehn, M. Use of radiometric (Cs-137, Pb-210), geomorphic, and stratigraphic techniques to date recent oxbow sediments in the Rio Puerco Drainage, Grants Uranium Region, New Mexico Environmental Geology and Water Science 3 1988 253 269 Google Scholar
Ritchie, J.C. McHenry, J.R. Gill, A.C. Fallout 137Cs in the soils of three small watersheds Ecology 55 1974 887 890 Google Scholar
Stuiver, M. Becker, B. High-precision decadal calibration of the radiocarbon time scale, AD 1950–2500 BC Radiocarbon 28 1986 863 910 CrossRefGoogle Scholar
Sutherland, R.A. Quantification of accelerated soil erosion using the environmental tracer Caesium-137 Land Degradation and Rehabilitation 1 1989 199 208 CrossRefGoogle Scholar
Webb, R.H. O'Connor, J.E. Baker, V.R. Paleohydrologic reconstruction of flood frequency on the Escalante River, south-central Utah Baker, V.R. Kochel, R.C. Patton, P.C. Flood Geomorphology 1988 Wiley New York 403 418 Google Scholar