A MODERN MULTICENTENNIAL RECORD OF RADIOCARBON VARIABILITY FROM AN EXACTLY DATED BIVALVE CHRONOLOGY AT THE TREE NOB SITE (ALASKA COASTAL CURRENT)

ABSTRACT Quantifying the marine radiocarbon reservoir effect, offsets (ΔR), and ΔR variability over time is critical to improving dating estimates of samples while also providing a proxy water mass dynamics. In northeastern Pacific, where no high-resolution series has yet been established, we sampled ( 14 C) from exactly dated growth increments in multicentennial chronology long-lived bivalve, Pacific geoduck Paneopea generosa ) at Tree Nob site, coastal British Columbia, Canada. Samples were taken approximately decadal intervals 1725 CE 1920 indicate average values 256 ± 22 years (1σ) consistent with existing discrete estimates. Temporal small relative analogous Atlantic records except for an unusually old-water event, 1802–1812. The correlation between sea surface temperature (SST) reconstructed increment width weakly significant (r 2 = .29, p .03), indicating warm generally old, when 1802–1812 interval excluded. This contains oldest (–2.1σ) anomaly, that coincident coldest (–2.7σ) anomalies reconstruction. An additional 32 C spanning 1952–1980 detrended using bomb pulse curve. Significant positive correlations identified data annual El Niño Southern Oscillation (ENSO) summer SST such cooler conditions are associated older water. Thus, relatively stable weak, potentially inconsistent associations climate variables, but capable infrequent excursions as illustrated by cold, interval.