27th of June

This blog was originally posted on the Environment and Society in a Changing Arctic Blog on July 3, 2014.

by Lauren Krone and Samantha Morrow

Today was our first full day at Tarfala! After a restful morning and a leisurely breakfast, we hiked along the river and then up onto a lateral moraine. Moraines are piles of rock and debris that were once carried or moved by a glacier, and end up in piles, which reveal the glaciers shape and path at one point in time. We learned that lateral moraines are formed along the sides of a glacier, as compared to terminal moraines that form at the end of a glacier.

The first thing we did on the moraine was to measure the lichen that had grown on the rocks. Lichen are a symbiosis of algae and fungus. The alga does the photosynthesis, while the fungus collects nutrients from the rocks. Since photosynthesis requires sunlight, lichen can only start to grow once the glacier retreats. This allows us to date the age of the moraine by looking at the size in diameter of the lichen. Such a process is called lichen dating. Lichen growth curves are created by looking at how big lichen are on surfaces where the age is known, such as abandoned mines or old forests. These curves are then applied to the lichen on the moraines, at an average rate of 0.4mm per year.

We split up into groups, and measured different areas of the moraine. This included the inside, top, and
outside of the moraine. We found that the top of the moraine was roughly 200 years old, while the inside of the moraine was only exposed about 100 years ago.

In addition to dating the moraine, we discussed possible problems with using lichen to find the age of the moraine. First, there is difficulty in finding perfectly circular lichen, making the diameter a difficult thing to measure correctly. The uneven growth patterns are due to uneven mineral distribution in the rocks along with micro-topography of the rocks. Moreover, there is a possibility that new landslides or rock falls may cover a moraine, or cause rocks to flip or expose new surfaces. This may make a moraine look younger than it really is, because younger lichen will have colonized the newly exposed rock.

After we were finished working with the lichen on the moraine, a group went on an optional hike up the opposite side of the valley. This gave us a view of the glacier Storglaciaren which we will get to go out on tomorrow! Can’t wait!

27th of June

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Week 2

This blog was originally posted on the Environment and Society in a Changing Arctic Blog on June 25, 2014.

by Lauren Krone and Samantha Morrow

During week two we focused on land-formation and changes due to glacial movement and climate change in the Arctic regions. In the beginning of the week we discussed how climate change is affecting the arctic region more than other parts of the world. This is due in large part to energy transfers in both ocean and atmospheric currents. Pole ward heat transport occurs as extra energy from the tropics is exported to the poles, creating larger increases in temperature at the poles. Specifically, the Arctic is heating faster due to local feedback effects of albedo when the ice melts, and the Arctic has greater amplitudes in the rosby waves in the atmosphere.


Later in the week we looked at glacial dynamics and movement. Over time, as snow falls and layers on itself, it changes in shape and density. Snow begins as feathery and delicate flakes. As it settles and packs it changes to more hardened grain-shaped textures. It also continuously melts and refreezes. This increases density, changing from 200 kg/m3 to 840 kg/m3 over the course of about 120 years. In addition, as the ice increases in density air gets trapped in the glacier. This has recently been used to analyze the atmosphere’s composition over time.

There are three main types of glacial movement, depending on different characteristics of the glacier.
Internal deformation, or creep, occurs when the glacier is frozen to the bedrock, and this movement dominates for cold-based glaciers. Glaciers can also move by sliding across the bed, or basil sliding, within warm-based glaciers. The final type of movement is deformation or flow of underlying sediment sliding across till, which also occurs for warm-based glaciers. Furthermore, different parts of the glacier move at different velocities. The center of a glacier moves much faster than the edges due to less friction. The glacier can also be divided in to two parts. The top half is know as the accumulation zone, where snow and ice increase from snowfall, wind-drift, and avalanching. The bottom half is know as the ablation zone, where ice leaves the glacial system due to melting, calving, and sublimation. In the middle of these two zones is the ideal place to take ice cores for examining the atmosphere, because snow falls straight down at that spot, as opposed to curving away from the initial point.

At the end of the week we looked at how glaciers affected Stockholm in particular. The esker in the glacier covering Stockholm created hills, which used to be the bed of a river. As Stockholm was built, part of the esker was flattened and the material was used for building. In addition, water moves easily through the esker, and as it moves it is cleaned. This was convenient, because wells at the top of the esker would produce clean water, providing the city with a reliable resource. Another affect of the glacier on Stockholm’s landscape is the constant land-rise of the city, creating the appearance of sea levels falling. This is due to glacial isostatic rebound, occurring at about 3 mm per year. We were able to observe these effects in person. We visited King Carl IX’s fishing house from the late 1600s. While it used to be on the edge of the water, we had to walk several meters to reach today’s edge, providing us with a clear representation of the land being created from the isostatic rebound. We finished the week by discussing different periglacial processes and landforms, which we hope to see in the Arctic!

Week 2

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