Skaftafellsjökull - Iceland EarthCache

Welcome to Skaftafellsjökull

Skaftafellsjökull, an outlet glacier of Vatnajökull, Europe’s largest ice cap, offers visitors a breathtaking yet sobering view of Iceland’s dynamic geological history. This EarthCache invites you to explore the powerful forces that shape glaciers, observe evidence of past and present glacial retreat, and learn how these icy giants sculpt the landscape.

WARNING: Weather conditions in this region can change rapidly. Dress appropriately, stay on marked trails, and do not attempt to walk on the glacier without a certified guide. The EarthCache owner is not responsible for any injuries or accidents. Please exercise caution and come prepared.

The Geological Story of Skaftafellsjökull

Skaftafellsjökull is a temperate glacier, meaning its ice is close to melting point, allowing it to move and shape the land beneath it. Like all glaciers, it forms from compressed snow accumulating over thousands of years, transforming into dense glacial ice under immense pressure. Over time, gravity pulls the glacier downhill, eroding rock and transporting sediments in the process.

This glacier is part of the greater Vatnajökull ice cap, which covers approximately 8% of Iceland. During the Last Glacial Maximum (~20,000 years ago), glaciers like Skaftafellsjökull extended much farther, covering most of Iceland. However, with warming temperatures, they began to retreat, leaving behind the dramatic landscapes we see today.

Key Geological Features at Skaftafellsjökull

As you observe the glacier and surrounding terrain, take note of these important glacial landforms:

• Moraine Deposits: These ridges of unsorted rock and debris mark the former extent of the glacier. Skaftafellsjökull has left multiple moraines as it has retreated, providing a visible timeline of its movements.
• Glacial Striations: Scratches and grooves on bedrock surfaces, caused by rocks embedded in the moving ice. These striations indicate the glacier’s past movement direction.
• Glacial Till: A mix of clay, sand, gravel, and boulders deposited directly by the glacier. Unlike river sediments, till is unlayered and contains a chaotic mixture of rock sizes.
• Outwash Plain (Sandur): A vast, flat area formed by glacial meltwater carrying and depositing sediments. The Skeiðarársandur plain, near Skaftafell, is one of the largest examples in the world.
• Proglacial Lagoons: As the glacier melts, meltwater pools at its edge, forming glacial lakes. These lakes often contain icebergs that calve from the glacier’s snout.

How Do Glaciers Shape the Land?

Glaciers are among the most powerful agents of erosion and deposition. Skaftafellsjökull, like other glaciers, reshapes the landscape through three main processes:

1. Plucking: The glacier freezes onto bedrock, then pulls chunks of rock away as it moves. This creates jagged cliffs and deepened valleys.
2. Abrasion: Rocks embedded in the glacier act like sandpaper, scraping against the bedrock and leaving polished surfaces with striations.
3. Deposition: As the glacier melts, it drops the sediments it carried, forming features like moraines, drumlins, and eskers.

The Skaftafell region is a prime example of U-shaped valley formation, which occurs when a glacier erodes a previously V-shaped river valley, widening and deepening it. The valley surrounding Skaftafellsjökull exhibits classic signs of this process.

The Impact of Climate Change on Skaftafellsjökull

Skaftafellsjökull, like many glaciers worldwide, is retreating due to rising temperatures. Scientists have used satellite imagery and GPS measurements to track its decline. Since the late 19th century, the glacier has retreated by several kilometers, with an accelerating rate of loss in recent decades.

Visible signs of glacial retreat include:

• The increasing size of the proglacial lagoon at the glacier’s edge.
• Newly exposed bedrock and moraine ridges, marking past glacier positions.
• Changes in meltwater flow, with increased sediment transport.

By studying glaciers like Skaftafellsjökull, geologists can better understand long-term climate patterns and the potential impacts of global warming on ice-covered regions.

Tasks for This EarthCache

To log this EarthCache, you must visit the site, complete the following tasks, and message me your answers via Geocaching or email:

1. Include "Skaftafellsjökull - Iceland - GCAWPYZ" on the first line.
2. Look at the landscape in front of you. Estimate the distance between the current glacier front and the closest moraine ridge. What does this tell you about the glacier’s recent retreat?
3. Describe the color and texture of the glacier ice. Is it white, blue, or mixed with debris? What does this tell you about its density and composition?
4. Examine the exposed rock surfaces near the viewing area. Do you see any scratches or grooves? Describe their direction and what they reveal about the glacier’s movement.
5. Observe the meltwater streams flowing from the glacier. What color is the water, and what does that suggest about the materials being carried by the flow?
6. In your log, attach a photo of yourself or something belonging to you with Skaftafellsjökull AND the signs at the coordinates in the background. (Note: photos predating the publication of this EarthCache are not accepted.)