- Two Creekan-aged forest in IL
The Perry Mastodon site located in Glen Ellyn, Illinois, was discovered in 1963 during a residential pond excavation. The site excavation yielded a Mastodon skeleton (Mammut americanum), abundance of macro-invertebrates and wood. Collected samples of animal bones and wood were archived in the Geology Department of Wheaton College (IL) for 50 years before Prof. S. Moshier and Joshua Olsen initiated a paleoenvironmental study of the site and collections in 2012. Site stratigraphy derived from a 11-m core indicates that the basal silt dating around 16,600-14,500 Cal Yrs BP was topped with a thin layer of kettle lake marl dated to ca. 11, 000 cal Yrs BP and tailed by Mid Holocene pit formation dated ca. 7630-7680 Cal Yrs BP (Olsen et al. 2012). The mastodon remains were incased in the silt that comprised cold freshwater gastropods. Bone collagen of the Perry Mastodon is dated between 13,640 and 13,450 Cal Yrs BP. Small-diameter logs and an abundant number of branches of spruce and larch found next to the mastodon bones. Twelve specimens of larch from this collection produced a 92-year tree-ring width chronology. The tree-ring analysis suggests that the Perry site wood may have been used for construction of a hunting trap. Radiocarbon dating of the wood ca. 13,300-13,450 Cal Yrs BP confirms that the young coniferous trees and large branches were contemporaneous to the Perry Mastodon.