Associated terrestrial and marine fossils in the late-glacial Presumpscot Formation, southern Maine, USA, and the marine reservoir effect on radiocarbon ages

Quaternary Research
By: , and 

Links

Abstract

Excavations in the late-glacial Presumpscot Formation at Portland, Maine, uncovered tree remains and other terrestrial organics associated with marine invertebrate shells in a landslide deposit. Buds of Populus balsamifera (balsam poplar) occurred with twigs of Picea glauca (white spruce) in the Presumpscot clay. Tree rings in Picea logs indicate that the trees all died during winter dormancy in the same year. Ring widths show patterns of variation indicating responses to environmental changes. Fossil mosses and insects represent a variety of species and wet to dry microsites. The late-glacial environment at the site was similar to that of today's Maine coast. Radiocarbon ages of 14 tree samples are 11,907 ± 31 to 11,650 ± 50 14C yr BP. Wiggle matching of dated tree-ring segments to radiocarbon calibration data sets dates the landslide occurrence at ca. 13,520 + 95/−20 cal yr BP. Ages of shells juxtaposed with the logs are 12,850 ± 65 14C yr BP (Mytilus edulis) and 12,800 ± 55 14C yr BP (Balanus sp.), indicating a marine reservoir age of about 1000 yr. Using this value to correct previously published radiocarbon ages reduces the discrepancy between the Maine deglaciation chronology and the varve-based chronology elsewhere in New England.

Study Area

Publication type Article
Publication Subtype Journal Article
Title Associated terrestrial and marine fossils in the late-glacial Presumpscot Formation, southern Maine, USA, and the marine reservoir effect on radiocarbon ages
Series title Quaternary Research
DOI 10.1016/j.yqres.2011.02.002
Volume 75
Issue 3
Year Published 2011
Language English
Publisher Cambridge University Press
Description 14 p.
First page 552
Last page 565
Country United States
State Maine
City Portland
Other Geospatial Portland
Google Analytic Metrics Metrics page
Additional publication details