Accurate terrestrial glacial chronologies are needed for comparison with the marine record to establish the dynamics of global climate change during transitions from glacial to interglacial regimes. Cosmogenic beryllium-10 measurements in the Wind River Range indicate that the last glacial maximum (marine oxygen isotope stage 2) was achieved there by 21,700 +/- 700 beryllium-10 years and lasted 5900 years. Ages of a sequence of recessional moraines and striated bedrock surfaces show that the initial deglaciation was rapid and that the entire glacial system retreated 33 kilometers to the cirque basin by 12,100 +/- 500 beryllium-10 years.

No abstract

This date list includes most of the archaeologic and geologic samples dated in this laboratory since publication of our last date list (R, 1975, v 17, p 196-215) as well as many samples dated previously which lacked adequate sample information.

This date list includes most of the archaeologic and geologic samples dated in this laboratory since publication of our last date list (R, 1978, v 20, p 210–233), as well as some samples dated previously which lacked adequate sample information.

This date list includes most of the archaeologic and geologic samples dated in this laboratory since publication of our last date list (R., v. 12, p. 577–589), as well as some samples which had previously been dated, but lacked the sample information necessary for publication. Known-age samples, completed in this time period, will be reported elsewhere. The b.p. ages are based upon a.d. 1950, and have been calculated with the half-life value of 5568 yr. All samples were counted at least twice for periods of not less than 1000 minutes each. Errors quoted for each sample are derived from the measurement of the sample, the background, and of several counts of our mid-19th century standard oak sample, but do not include the half-life error. All samples were pretreated with 3N HCl, and some, where noted, were given additional pretreatment with 2% NaOH for the removal of possible humic acid contaminants.