Dating Deglaciation
(Cosmogenic Nuclides)
(Cosmogenic Nuclides)
Calculations:
Calculations:
Bulk Sediment:
Bulk Sediment:
Age Range: 22200-10500 years before present, 22200-10500=11700
Age Range: 22200-10500 years before present, 22200-10500=11700
Distance retreated during that time: 426km
Distance retreated during that time: 426km
Distance retreated per year: 426/11700 = 0.03641km per year = 36.41m per year
Distance retreated per year: 426/11700 = 0.03641km per year = 36.41m per year
Macrofossils:
Macrofossils:
Age Range: 18300-12800 years before present, 18300-12800=5500
Age Range: 18300-12800 years before present, 18300-12800=5500
Distance retreated during that time: 406km
Distance retreated during that time: 406km
Distance retreated per year: 406/5500 = 0.07382km per year = 73.82m per year
Distance retreated per year: 406/5500 = 0.07382km per year = 73.82m per year
Cosmogenic Nuclides:
Cosmogenic Nuclides:
Age Range: 27500-13200 years before present, 27500-13200=14300
Age Range: 27500-13200 years before present, 27500-13200=14300
Distance retreated during that time: 340km
Distance retreated during that time: 340km
Distance retreated per year: 340/14300 = 0.02378km per year = 23.78m per year
Distance retreated per year: 340/14300 = 0.02378km per year = 23.78m per year
The graphs created using the data provided show interesting results when it comes to glacial retreat. The graphs of the calibrated age vs latitude for both macrofossils and bulk sediment produce nearly identical results, generally lower latitude values with a few high outliers spread throughout the graph at seemingly regular intervals. The graph for cosmogenic nuclide exposure age vs latitude has a more coherent pattern, with an initial advance of the glacial moraine that shifted to a retreat at around 25000 years before present. The rate of the retreat increased as time went on.
The graphs created using the data provided show interesting results when it comes to glacial retreat. The graphs of the calibrated age vs latitude for both macrofossils and bulk sediment produce nearly identical results, generally lower latitude values with a few high outliers spread throughout the graph at seemingly regular intervals. The graph for cosmogenic nuclide exposure age vs latitude has a more coherent pattern, with an initial advance of the glacial moraine that shifted to a retreat at around 25000 years before present. The rate of the retreat increased as time went on.
The results of the cosmogenic nuclide graph were much different than those of the macrofossils and bulk sediment graphs. However, figure 4 in the paper by Lambeck et al. show that variables such as ice volume equivalent at sea level and grounded-ice volume underwent a shift in the same pattern as the glacial moraines, increasing and decreasing at the same times the moraines advanced and retreated. There is a large area in the cosmogenic nuclide gap without any data (between approximately 13000 and just over 20000 years before present) but the general trend between the two nearest points would almost definitely produce a line similar to that of the graphs on figure 4 in Lambeck's paper.
The results of the cosmogenic nuclide graph were much different than those of the macrofossils and bulk sediment graphs. However, figure 4 in the paper by Lambeck et al. show that variables such as ice volume equivalent at sea level and grounded-ice volume underwent a shift in the same pattern as the glacial moraines, increasing and decreasing at the same times the moraines advanced and retreated. There is a large area in the cosmogenic nuclide gap without any data (between approximately 13000 and just over 20000 years before present) but the general trend between the two nearest points would almost definitely produce a line similar to that of the graphs on figure 4 in Lambeck's paper.