Constraining the evolution of river terraces with integrated OSL and cosmogenic nuclide data

Benny Guralnik, Ari Matmon, Yoav Avni, Naomi Porat, David Fink

Research output: Contribution to journalArticlepeer-review

36 Scopus citations

Abstract

We present a framework for consistent incorporation of optically-stimulated luminescence dates with cosmogenic radionuclide concentrations measured in a single alluvial section, and apply it on two late Quaternary terraces in the Negev Desert, Israel, to derive constraints on their evolution. We solve an integrated, self-consistent and co-dependant set of equations to reproduce either dataset based on three model parameters of (i) uniform cosmogenic inheritance, (ii) constant terrace aggradation rate and (iii) subsequent exposure time. A subset of all possible parameter combinations, which approximates the measurements within the uncertainties of their best-fits, yields a better constraint of the alluvial history than that obtained by any of these dating proxies alone. The derived set of common solutions indicates similar paleo-inheritances of ∼1 × 105 10Be atoms g-1 in both terraces; progressive deposition of the higher terrace (T2) began at ∼250 ka, lasted for a period of ∼80 ka, was abandoned at ∼170 ka and since that time has remained intact; the lower terrace (T1) was most likely deposited at ∼3 ka and rapidly abandoned by ∼2 ka. In an alternative interpretation for T2, which treats the two geochronometers separately, this terrace might have experienced discrete events of aggradation at (216 ± 13) ka and deep truncation at 118-29+42 ka, significantly separated in time. In the currently active channel of the Neqarot canyon, contemporary stripping of the lowest terrace located along the stream is suggested by decreasing values of 10Be downstream along the river channel.

Original languageEnglish
Pages (from-to)22-32
Number of pages11
JournalQuaternary Geochronology
Volume6
Issue number1
DOIs
StatePublished - Feb 2011
Externally publishedYes

Keywords

  • Aggradation rate
  • Cosmogenic inheritance
  • Cosmogenic isotopes (Be)
  • Intercomparison of dating proxies
  • OSL

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