A New Tree-Ring Width, delta-13C and 14C Investigation of the Two Creeks Site
CitationLeavitt, S. W., & Kalin, R. M. (1992). A new tree-ring width, delta-13C and 14C investigation of the Two Creeks site. Radiocarbon, 34(3), 792-797.
DescriptionFrom the 14th International Radiocarbon Conference held in Tucson, AZ, May 20-24, 1991.
AbstractWe have made isotopic and dendrochronologic measurements on material collected from the Two Creeks site. Radiocarbon dating of outside wood of four logs yielded an average age of 11,760 +/100 BP, in good agreement with results of Broecker and Farrand (1963) over 25 years ago. The range of 11,640 +/160 to 11,900 +/160 BP suggests a period of forest growth of 200-300 years, consistent with a ring-width chronology established by Kaiser (1987). Ring counting of five specimens gave a range of individual tree ages from 110 to 182 years, and width measurements indicate very low year-to-year variation in ring size. However, preliminary cross-dating of five samples produced a 202-year floating chronology. Stable-carbon isotope chronologies on cellulose from five-year ring groups show delta-13C scatter among trees typical of that found within modern sites, with some matches of isotopic maxima and minima. Some downward delta-13C trends may result from physiological response to rising lake levels (and/or cooling temperatures) at the site, which also produced very narrow rings in the outer ca. 50 +/20 years.