Dating Deglaciation

Between my most northern and southern bulk sediment data points was 433.31 kilometers. I used the Google Earth ruler tool to figure this out. Using this I can figure out the amount of retreat per year. I started by finding the difference in age (12100-10500) This gave me 1600. I then divided 433.31 by 1600 which gave me an answer of 0.271 kilometers per year.

I then repeated the process for my macrofossil data points. My two points had ages of 14400 and 14900. The distance between them was 401.69 kilometers. 401.69/500= .803 kilometers per year.

I then did the same thing for the cosmogenic nuclide data points. My two points had ages of 25200 and 13200. They were 480.35 kilometers apart. I then did the equation 480.35/12000 = 0.04 kilometers per year, or just about 40 meters.

The bulk sediment data points and the cosmogenic nuclide points seemed to show much slower retreat than the macrofossil data points. The cosmogenic nuclide data points had some of the oldest dates, while bulk sediment had the youngest. However, according to the paper by Lee Corbett, bulk sediment dates may be inaccurate due to carbon recycling. The Vermont macrofossil ages are hundreds of year older due to this. It would be hard to trust the bulk sediment data based on this.

My answers were effected by the two variables, distance and time. The amount of years that have passed for each category was a big influence on the outcome. This is why the bulk sediment data is not really all that trustworthy, because the dates may be inaccurate. The cosmogenic nuclide data seems to match Lambeck's data the most to me. They have older dates that match up really well with the graph A on Figure 1 from his paper.