The NSS Bulletin - ISSN 1090-6924
Volume 37 Number 2: 21-33 - April 1975
A publication of the National Speleological Society

Uranium-Series Dating of Speleothems
R.S. Harmon, Peter Thompson, H.P. Schwarcz and D.C. Ford

Abstract

Uranium-series disequilibrium methods can be used to determine the age of macrocrystalline calcite speleothems, provided: 1) the specimens have sufficient uranium concentrations, 2) the initial state of the system can be determined, 3) the system has not been subject to post-depositional alteration or migration of radioisotopes, and 4) isotope ratios exhibit a progression toward secular equilibrium with time. The 230Th/234u method, with a range of 2000-300,000 BP, has been the most successful of the three uranium-series methods which have been applied to speleothems.

Analyses for speleothems from seven North American karst areas have been selected to illustate the application of speleothem chronology to such geological problems as rates of erosion and sedimentation, the ages of river canyons and terraces, the time and druation of base level stands, speleothem growth rates, the time and duration of low sea level stands, and glacial chronology for the late Pleistocene of North America.

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