Constraining post-glacial uplift rates in southern Greenland
Conference Year
January 2019
Abstract
Isostatic rebound, Earth’s crust springing back up due to post-glacial melting or other large mass-unloading events drives changes in sea level as the local surface elevation rises. The rate and behavior of this uplift depends on both the physical properties of Earth’s crust and mantle as well as the rate of unloading. Understanding isostatic rebound rates worldwide is therefore necessary to predicting both local and global sea levels, especially in a warming climate with rapidly increasing ice-loss.
This project aims to compare modern uplift rates to past uplift rates at Kulusuk, southeast Greenland to provide a better understanding of isostatic rebound rates and the complex behavior of the crust beneath Kulusuk. GPS data from Kulusuk exhibit extremely rapid uplift rates of 35 ± 5 mm from 2001-2006. These rates have continued to accelerate as ice melt increases. However, these rates may not accurately represent longer timescales; I have used cosmogenic nuclide dating methods to determine the rate of post-glacial uplift since the last glacial maximum (~12kya) for a vertical transect of samples in Kulusuk, sampled within a kilometer of the modern GPS uplift data. These methods involve in-situ 10Be extraction of purified quartz and accelerator mass spectrometry analysis (AMS) to determine 10Be/9Be ratios. These ratios are used for calculating exposure ages using MATLAB software and comparing these ages to sample elevation and location data to produce an emergence curve and calculate past uplift rates from ~12kya. 10Be extraction has been completed and samples are currently awaiting AMS analysis, so past uplift data is not yet available. When compared to modern uplift rates, past uplift rates will allow us to accurately estimate emergence in the Kulusuk area for centuries to come if rates are similar and will provide insight into the complex behavior of the Kulusuk crust if rates are different.
Primary Faculty Mentor Name
Paul R Bierman
Faculty/Staff Collaborators
Lee B Corbett
Status
Undergraduate
Student College
College of Arts and Sciences
Program/Major
Geology
Primary Research Category
Engineering & Physical Sciences
Constraining post-glacial uplift rates in southern Greenland
Isostatic rebound, Earth’s crust springing back up due to post-glacial melting or other large mass-unloading events drives changes in sea level as the local surface elevation rises. The rate and behavior of this uplift depends on both the physical properties of Earth’s crust and mantle as well as the rate of unloading. Understanding isostatic rebound rates worldwide is therefore necessary to predicting both local and global sea levels, especially in a warming climate with rapidly increasing ice-loss.
This project aims to compare modern uplift rates to past uplift rates at Kulusuk, southeast Greenland to provide a better understanding of isostatic rebound rates and the complex behavior of the crust beneath Kulusuk. GPS data from Kulusuk exhibit extremely rapid uplift rates of 35 ± 5 mm from 2001-2006. These rates have continued to accelerate as ice melt increases. However, these rates may not accurately represent longer timescales; I have used cosmogenic nuclide dating methods to determine the rate of post-glacial uplift since the last glacial maximum (~12kya) for a vertical transect of samples in Kulusuk, sampled within a kilometer of the modern GPS uplift data. These methods involve in-situ 10Be extraction of purified quartz and accelerator mass spectrometry analysis (AMS) to determine 10Be/9Be ratios. These ratios are used for calculating exposure ages using MATLAB software and comparing these ages to sample elevation and location data to produce an emergence curve and calculate past uplift rates from ~12kya. 10Be extraction has been completed and samples are currently awaiting AMS analysis, so past uplift data is not yet available. When compared to modern uplift rates, past uplift rates will allow us to accurately estimate emergence in the Kulusuk area for centuries to come if rates are similar and will provide insight into the complex behavior of the Kulusuk crust if rates are different.