Holocene climate and seasonality of shell collection at the Dundas Islands Group, northern British Columbia, Canada—A bivalve sclerochronological approach

摘要: article i nfo To analyze environmental changes and the seasonality of shell collection in British Columbia during Ho- locene, oxygen isotopes were measured from modern archeological (1337-7438 cal yr BP) shells butter clam Saxidomus gigantea. 1697 discrete isotope samples taken two 27 arche- ological with a high temporal resolution (sub-seasonal up to daily). Archeological collected five midden sites on Dundas Islands Group, northern Columbia, Canada. The iso- tope data reveal clear annual cycles, most positive δ 18 Oshell values occurring cold season (slower growth, growth line formation) negative warm sea- son (period faster growth). Whereas remained relatively constant throughout Holocene, reflected considerable variability. Summer observed early late Holocene became approximately 1‰ more around 2500-3000 5500-6000 BP, implying lower salinity Mid-Holocene. Variations isotopic composi- tion marine reflect temperature salinity. Such large are unlikely being caused by alone. Furthermore,