Dating Deglaciation

Graphs- Showing Plotted Data

Calculations

For the bulk sediments, Glover's Pond, NJ (40.94˚N, 12,100 years) was the southernmost point and Miller Brook, VT (44.47˚N, 10,500 years) was the northernmost point. Using the ruler function on google Earth I was able to measure the distance between these points. Then I took the difference of years and divided the distance of 404.51 km by the different of years (11700 years) that gave me a calculated rate of retreat of 0.034km a year or 34.573 meters a year. I did the same process for the two other calculations and found a rate of 251.76m/year for macro fossils, and 39.85 m/year for Cosmogenic Nuclide dating.

The Macro-fossil retreat rate seemed to show the fastest retreat of 251.76 meters a year, while the bulk sediment and the Cosmogenic dating showed slower rates of about 35-40 meters a year. There is a degree of uncertainty and error within the microfossils, as there is a period of time before any organic material grew upon the recently glaciated area. Bulk sediment dating also has a degree of uncertainty as multiple different carbon sources are used from the samples. The cosmogenic data seems to be the most accurate set of data as it is the only one to line up with the data from Lambecks paper. His data and the rate of sea level rise match up with the data collected from the Laurentian Ice-sheet.