Glacial Deposition

Glacial deposits underlie many notable landforms, of which drumlins and eskers are among the most distinctive. Drumlins are streamlined hills ideally having the shape of a teardrop or inverted spoon. They occur in fields containing dozens or hundreds to thousands of individual drumlins. They are arranged en echelon in broad belts or arcs behind conspicuous ice-margin positions, and the pattern of drumlins is thought to indicate ice flow direction. Drumlins have complicated origins involving deposition, erosion,

FIGURE 12-10 Close-up view of the Tatra Mountain front near Stara Lesna, Slovakia. High peaks include Slavkovsky (S) at 2452 m and Lomnicky (L) at 2634 m, separated by a major glacial valley, Vel'ka Studena dolina (VSD). The glacial valley extends directly into the mountain range, as seen in this view. Kite aerial photo by JSA and SWA, July 2007.

FIGURE 12-10 Close-up view of the Tatra Mountain front near Stara Lesna, Slovakia. High peaks include Slavkovsky (S) at 2452 m and Lomnicky (L) at 2634 m, separated by a major glacial valley, Vel'ka Studena dolina (VSD). The glacial valley extends directly into the mountain range, as seen in this view. Kite aerial photo by JSA and SWA, July 2007.

FIGURE 12-11 Overview of the Polish Tatra Mountains looking toward the southwest from near Toporowa Cyrhla; the city of Zakopane is visible in right background. Notice the linear boundary between the mountain front and the valley in the foreground. Kite aerial photo by SWA and JSA, July 2007.

FIGURE 12-13 Lake Saadjarv drumlin field in eastern Estonia. Lake Saadjarv (left) occupies an elongated trough, and a long, smooth drumlin extends northwestward into the distance on right. Another lake, Soitsjarv, can be seen at extreme upper right. Kite aerial photo by JSA and SWA, September 2000.

FIGURE 12-12 View toward the southeast from Kopa Krolowa Wielka in the Polish Tatras. Zolta Turnia (ZT) peak is 2087 m elevation, and to its right is the head portion of Gasienicowa Dolina (GD), an ice-carved valley. On far right, the foot trail to Hala Gasienicowa can be seen. Kite aerial photo by SWA and JSA, August 2007.

deformation, and meltwater action beneath ice sheets (Menzies and Rose, 1987). Drumlins are common in many formerly glaciated regions, including eastern Estonia (Fig. 12-13).

Eskers are long, fairly narrow ridges of sand and gravel. They may be straight or sinuous, continuous or beaded, single or multiple, sharp- or flat-crested. They vary from a few meters to 10s of m high, and may be <1 to 100s of km in length. Eskers are deposited from various types of meltwater streams under the ice or at the margin of retreating glaciers (Baneijee and McDonald, 1975).

The island of Vormsi and adjacent seafloor in northwestern Estonia are especially well known for eskers (Aber, Kalm, and Lewicki, 2001). These eskers were deposited in

FIGURE 12-13 Lake Saadjarv drumlin field in eastern Estonia. Lake Saadjarv (left) occupies an elongated trough, and a long, smooth drumlin extends northwestward into the distance on right. Another lake, Soitsjarv, can be seen at extreme upper right. Kite aerial photo by JSA and SWA, September 2000.

subglacial tunnels during the final phase of late Pleistocene ice-sheet glaciation of the region. One esker in particular can be traced from the Austergrunne peninsula on the northern side of the island, southward to the peninsula at Rumpo, and across the shallow seafloor to the islets of Rukkirahu and Kuivarahu (Fig. 12-14). Although slightly modified by post-glacial sea action, the morphology of the esker is still quite distinct (Fig. 12-15).

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