Taconite Inlet Project




Sampling for radiocarbon dating was hindered by a lack of macro organic material in the long cores throughout the lake. A whole mollusk valve and shell fragments were retrieved from the base of three cores well below the onset of the laminated sediments. Sediment was sampled from the varved sediments and submitted for humin and humic acid extraction in an attempt to independently confirm the varved nature of the entire sequence of sediments. Carbon extractions from the sediment samples provided only extremely small quantities of carbon (<0.01 µ g). Results from the radiocarbon dating failed to confirm the varve chronology and major dating reversals and inconsistencies with the dated shells make all of the dates from within the laminated sediments highly suspect.



*Note: cores 72A and 72B were retrieved as one core and split for transport. Samples with WHOI prefix were determined at Woods Hole Oceanographic Institute. Samples with CAMS prefix were determined at Lawrence Livermore National Laboratory from targets prepared at the University of Colorado.

Long-core varve record index page

Lake sediments index page