Exercise 5 – Palaeic surface and colluvial fans
1) Palaeic surface near Sogndal
Figure 1: Parts of Sognefjorden near Kaupanger. Sogndal airport is located at Haukåsen.
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Figure 2: Detail of Sogndal airport (Haukåsen) and Storehaugfjellet. Contour lines are 20 meters. Scale in lower
left corner.
1) Identify areas you interpret as remnants of the palaeic surface, and V-shaped valleys (gorges) on Figure 1.
[Color the area belonging to the palaeic surface with a color pencil or similar and mark the V-shaped valleys
with a ‘fishbone’ line].
2) Draw a profile along the stippled line in Figure 2 from Storehaugfjellet across the airport to sea level. Indicate
the palaeic surface on the profile.
3) Compare your answer in 1) with Fig. 4 in Nesje and Whillans (1994).
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1) Colluvial fan in Supphelledalen, Fjærland
Figure 3: Colluvial fan in Supphelledalen (see map in Fig. 4 for location).
Figure 4: Map showing lower Supphellebreen (Trollabyrge) and the fan at the opposite side of the valley (circle).
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Figure 5: Detailed map of the fan. Contour lines are 5 m. Scale in lower left corner.
1) Identify the apex of the fan. What is the slope of the fan near the apex and near the toe?
2) Can you see avalanche tracks, levees and lobes on the fan?
3) What is the plan-view radius of this fan? Compare it to the fan in Fig. 2 of Blikra and Nemec (1998).
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