Dating Deglaciation

In order to find the rate of deglaciation, I found the oldest and youngest sample from each dataset. I then found the distance between those points, as well as the time difference of the samples. The distance of the points divided by the time between the samples gives the rate of deglaciation for that dataset. The above figure shows that the macrofossil radiocarbon dating technique had the highest speed of retreat, at 74.55 meters per year. The bulk density radiocarbon dating technique produced a deglactiation rate of 30.14 meters per year. Lastly, the cosomogenic nuclide dating technique produce the slowest rate of 23.45 meters per year. It is worth noting that the macrofossil dataset took place in a much smaller window of time, 5500 years versus 14500 years in the other two datasets, which could explain its high rate of retreat.

As far as accuracy, I would expect the cosmogenic nuclide dating to be the most accurate of the three techniques. Cosmogenic dating seems to have fewer assumptions, and allows the sample to be dated directly, rather than using an organic proxy. When using an organic proxy to measure sediment, you are assuming that the organic material is the same age as the sediment or material of interest; when using the cosmogenic nuclide technique this assumption is not necesarry, as you can measure the object of interest directly. The graph plotting the points of cosmogenic samples also lines up to Lambeck's graph of sea level rise during that period of glaceation better than the other two sampling methods, further showing that cosmogenic nuclide dating is the most accurate of the three.