Jökull - 01.12.1985, Page 72

Fig. 1. Main morphological zones of
the proglacial sandur deposits, Sól-
heimajökull, Southern Iceland. 1.
mynd. Helstu gerðir landmótunar í ná-
grenni Sólheimajökuls.
northern margin of an extensive valley sandur, bounded
in the south by high paleo-sandur terraces. Within the
proglacial area, twenty-seven distinct paleo-outwash
depositional zones have been identified, both from the
aerial photographs and on the ground, from their mor-
phological features and topographic relations with
moraines and other outwash deposits (Fig. 1).
FIELD METHODS
Measurements of the maximum thallus diameters of
the lichen Rhizocarpon geographicum were undertaken
in each of the twenty-seven sandur zones. Over 300
search areas were established within the proglacial area.
Within each sandur zone, search areas of 200 m2 (8x25
m) were selected on coarse bar deposits and the terrace
surfaces. Within each search area, the maximum dia-
meters of the five largest thalli were recorded, allowing
the single largest thallus, the mean of the five largest
thalli, and the mean of the 25 largest thalli to be
determined for each sandur zone. Although a number
of smaller zones were represented by fewer than about 8
search areas, usually more than 25 search areas were
sampled across the more extensive sandur zones (Table
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70 JÖKULL 35. ÁR