Jökull - 01.12.1981, Blaðsíða 22

me/ 100g soil me/ 100g soil
CATION EXCHANGE CAPACITY E. TRANSECT VEGETATION COVER E. TRANSECT
Ridge Ridge
Ridge Ridge Ridge Ridge (40) Ridge Ridge Ridge Ridge (40)
Fig. 6. Chemical results from the analysed quadrats.
Mynd 6. Niðurstöður efnagreininga á setmyndunum.
sequence outlined above this outer moraine
probably dates to the turn of the century
showing a maximal extent towards the end of
the 19th century, the main ‘Little Ice Age’
extent of Gljúfurárjökull. The difference in
the age of the surface either side of this feature
is clearly seen in the vegetation evidence with
ericaceous species such as Vaccinium, Empetrum
and Harrimanella (Cassiope hypnoides) occurring
immediately inside the moraine but forming
the dominants in the communities outside it.
Differences in other biogeographical para-
meters can also be seen, especially in percen-
tage vegetation cover and percentage organic
matter (Fig. 6).
CONCLUSIONS
Following detailed survey of the margin
and pro-glacial areas of Gljúfurárjökull in
1979 it has been possible, using sedimento-
logical, biogeographical and surveying infor-
mation to describe the features found and to
suggest a pattern for recent deglaciation. In
summary the following sequence is proposed:
i) A ‘Little Ice Age’ maximum marked by a
clear end moraine which occurred at the
end of the 19th century.
ii) Retreat from this outer margin took place
quite rapidly before a period of relatively
little change in the position of the ice
margin marked now by a complex of
ridges (including 3/4/5/53). This stillst-
20 JÖKULL 31. ÁR