FIGURE 13.3 Four stepwise uplifts of the coast of the southern Boso Peninsula, Japan, determined by about 25 carbon-14 dates (from Shimazaki and Nakata, 1980). The open, half-closed, and closed circles indicate samples from above, near, and below the former sea level, respectively. Lower part of figure shows cumulative uplift versus time; line through corners of stairstep plot shows that uplift, inferred to be caused by coseismic faulting, conforms to a time-predictable model.
FIGURE 13.4 Carbon-14 age as a function of dendrochronological age for the past 1000 yr (from Stuiver, 1982). Note deviations from concordance line that have a 100–200-yr period.
humin or humate. Such pretreatment is commonly employed, but it does not remove all forms of contamination by younger carbon. For example, dating studies by Goh et al. (1977) have obtained ages as young as 17,750±2050 ya on humin from deposits whose “best” carbon-14 ages are more than 40,600 ya.
The 230Th/234U disequilibrium method is the most commonly used dating technique of the many based on the radioactive decay series of uranium (Table 13.2; Ivanovich and Harmon, 1982). Because uranium is