Thermoluminescence (TL) and infra-red stimulated luminescence (IRSL) a
ges have been determined for loess from the Columbia Plateau region of
southeast Washington and northeast Oregon, U.S.A. The IRSL ED values
and ages appear to be tending towards a maximum level lower than that
of the TL ED values and ages. In general, the TL ages are in stratigra
phic order and agree well with the ape control, in the form of C-14 an
d TL dated tephra units derived from various eruptions of Mount St Hel
ens. (C) 1997 Elsevier Science Ltd.