Ob. Lian et al., OPTICAL DATING STUDIES OF QUATERNARY ORGANIC-RICH SEDIMENTS FROM SOUTHWESTERN BRITISH-COLUMBIA AND NORTHWESTERN WASHINGTON-STATE, Canadian journal of earth sciences, 32(8), 1995, pp. 1194-1207
The suitability of optical dating using 1.4 eV (infrared) excitation f
or determining the time of deposition, or compaction, of organic-rich
sediments and peat is assessed with measurements on seven samples from
six different lithostratigraphic units. One is of zero age, two have
associated C-14 ages, three are known to have been deposited during an
interglaciation, and one is similar to 1 Ma old. The samples yield sa
tisfactory optical ages ranging from 0 to over 100 ka. We conclude tha
t the Muir Point Formation (southern Vancouver Island) and the Whidbey
Formation (northwestern Washington State) were both deposited during
delta(18)O stage 5, as previously deduced from other evidence. The age
obtained from the similar to 1 Ma sample was significantly too low. T
he optical dating method is simpler and more precise than thermolumine
scence dating, and is recommended for future work.