Developing a 10Be moraine chronology for late-glacial resurgence of the Scandinavian Ice Sheet in Lysefjord, southwestern Norway

October 17, 2023 - Expeditions 2023, Expeditions

Expedition Location: Lysefjord, southwestern Norway

Expedition Dates: August 2023

Field Team Members: 

Tricia Hall Collins  (PhD Student, UMaine) Field Trip Leader, Katie Westbrook (MS Student, UMaine), and Dr. Aaron Putnam (UMaine).

Funding Support: The Robert and Judith Sturgis Family Foundation

 

Background & Study Area:

I completed fieldwork in Lysefjord (figure 1) in southwestern Norway during August 2023
alongside master’s student Katie Westbrook and Dr. Aaron Putnam. We received critical funding
support from the Robert & Judith Sturgis Family Foundation, for which I am grateful. This
fieldwork will serve as the basis for a significant portion of my thesis, which will focus on
clarifying plausible mechanisms for abrupt climate change during the end of the last glacial
period. Katie’s and my datasets will provide a complete chronology of glacial change within
Lysefjord during the end of the last glacial period. Conducting fieldwork was critical because our
work relies on collecting samples from glacially deposited boulders (figure 2). We will
ultimately measure how much 10 Be is contained within quartz grains in each sample, as this
accumulates from cosmic ray bombardment once a boulder has been deposited by a glacier.
From there, we can calculate when in time the glacier deposited each boulder, which will tell us
about ice extent and rates of retreat and readvance.

 

Map of research site - Lysefjord, Norway.
Figure 1: Samples were collected from the mouth of Lysefjord, highland areas north and south of the fjord, as well as the head of the fjord. High-resolution Lidar aided in field mapping and locating ideal areas for sample collection.

 

Photo of Lysefjord erratic boulders near Songesand, Norway.
Figure 2: A photo of a view to the west along Lysefjord shows erratic boulders perched on polished Proterozoic granite near Songesand, Norway. We sampled the center boulder and many like it during the 2023 field campaign.

 

Methods:

To find the best boulders for sampling, we hiked daily (figure 3), drove along Norway’s winding roads, and even took a couple of ferry rides. We used a variety of tools to collect our samples, including a hammer drill (figure 4) to create a hole in the boulder into which we loaded small charges to blast off a sample (figure 5). We shipped our samples home to Maine and are beginning the time-consuming work of crushing the rock samples, cleaning the quartz grains that contain the 10Be isotopes, and finally extracting the 10Be isotopes to send to Lawrence Livermore National Laboratory to measure how much 10Be is contained in our samples. We anticipate having a first batch of data by early 2024.

 

Field crew scouting glacial features.
Figure 3: Tricia and Aaron scouting for promising glacial features on top of the highland plateau south of Lysefjord.

 

Tricia using a hammer drill to extract a sample.
Figure 4: Tricia using the hammer drill to complete a hole in the boulder where we wanted to extract a sample.

 

Field crew setting off a charge to blast off a sample.
Figure 5: Katie setting off a charge (puff of smoke) to blast off a sample.