Jökull

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Jökull - 01.12.1956, Qupperneq 14

Jökull - 01.12.1956, Qupperneq 14
Fig. 11. Hólárjökull 1891 or 1892. Photo Fr. W. W. Howell. THE AGE OF THE MORAINE AMPFII- THEATRE OF KVÍÁRJÖKULL. In order to find out the age of the moraine amphitheatre of Kvíárjökull I visited that glacier on Sept. 16th 1955 together with Sigurdur Björns- son in Kvísker and dug the profiles De 28 and De 31 shown on fig. 3. In Oct. 1955 Sigurdur Björnsson on my request dug three more pro- files, De 27, 29 and 30 on fig. 3. The location of these profiles is shown on the map fig. 7. De 27 is dug on the E slope of Kambsmýrar- kambur N of the outflow of Kvíá eystri, De 28 is on a gravel terrace which is a continuation of the outer slope of Kambsmýrarkambur and clearly of the same age. De 29 and 30 are dug on the outer slope of Kvíármýrarkambur and De 31 on the NW slope of the innermost of two small moraine hillocks, Kvíárhólar, (fig. 13) that form a continuation of Kvíármýrar- kambur towards S on the W side of Kvíá vestri. These hillocks may formerly have been directly connected with Kvíármýrarkambur and later separated by water erosion. The profiles measured show without doubt that the lower parts of the outer slopes of Kvíár- mýrarkambur and Kambsmýrarkambur are much older than the 1362 eruption. From field studies it was evident, however, that the crest of Kvíár- mýrarkambur is very young, in all probability from the 1870’s, and the contact between the recent moraine and the underlying older one is clearly visible on the aerial photos of 1954. Thus the glacier tongue had in the 1870’s near- ly exactly the same extension as it had at the time when the moraine amphitheatre was ori- ginally formed. As to the age of these moraines, it is possible to fix it somewhat closer than merely stating that they are prehistoric. Be- tween the northern end of Kvíármýrarkambur and the steep southern slope of Stadarfjall there is a breach named Kambsskard. This place name is found in an ecclesiastical deed (máldagi) of the church of Hnappavellir from 1343 — per se a proof of Kviármýrarkambur being still older. A small basaltic prehistoric but definitely postglacial lava flow has spread over the gravel plain SW of Kambsskard and can be followed to the breach where it dis- appeares under moraine. The source of this lava is on the E side of Kvíárjökull and the lava has flowed to southwest at a time when Kvíárjökull did not reach the lowland and that must have been sometime during the Postglacial Warm Period. My impression from a short visit — aclmittedly too short for a sufficiently thorough study — was that the lava flow is older than Kvíármýrarkambur. Consequently that moraine ridge should be younger than the Postglacial Warm Period, and as it certainly is prehistoric it seems to me most reasonable to regard both Kvíármýrarkambur and Kambsmýrarkambur as 12

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Jökull

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