Jökull


Jökull - 01.12.1964, Side 10

Jökull - 01.12.1964, Side 10
Fig. 2. The 1890-moraine short W of Kringilsá. The scar to the left goes down to the ice core, showing that the ice-free moraine cover is only about 1.5 m thick in this place. Photo: S. Thorarinsson, Sept. 5, 1962. of Jökulkvísl, which existed before the 1890- advance, and in all probability they date back to the 1810-advance, which thus has brought the ice margin a little farther than the 1890- advance in that area. Todtmann describes a large terminal mo- raine in Kringilsárrani about 1.5 km south of the “hraukar”, ancl regards this moraine to be the 1810-moraine, which had been overridden by the ice during the 1890-advance. (Todtmann 1955, p. 261). This may be true, although it does not quite agree with Kjerulf’s report of the 1890-advance. Todtmann mentions that the Askja tephra of 1875 is founcl in the foldings of the uppermost layers of these moraines. Ac- cording to my investigations in 1962 the south- ern limit of the 1875-tephra sector is definitely north of the “hraukar” (cf. the isopach map, fig. iv in Thorarinsson 1963). However, wind drifted 1875-tephra may be found south of the “hraukar”, because, at 13 cm depth and some cm upwards the soil in section Cf 16a (fig. 6) is lighter in colour than the underlying soil, and there is no doubt that the light colour is caused by wind drifted dust from the 1875 tephra layer. I am, however, a little doubt- ful as to the possibility of recognizing it as far south as the “1810” moraine. I would think it more likely that the tephra mentioned by Todtmann as the 1875 one is the Öræfajökull tephra of 1362. SOIL SECTIONS JUST NORTH OF HRAUKAR Sept. 4th, 1962, I measured a soil section about 10 m north of Hraukar on the E part Fig. 3. Position of section Cf 16a (indicated by an arrow to the farthest left) north of Hrauk- ar on Kringilsárrani. View towards E. Photo: S. Thorarinsson, Sept. 4, 1962. Fig. 4. The same area as on fig. 3 (cf. the arrow) but viewed towards W. Relative height of the “hraukar” to the left is 18 m. During the first summers after the 1890-advance melt- water from the ice margin has eroded a lateral bed through the loessial soil cover down to the ground moraine. Photo: S. Thorarinsson, Sept. 4, 1962. JÖKULL 1964 68

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