Jökull - 31.12.2001, Page 21

Dating ofthe Fláajökull moraine ridges
AD 2000
1980
1960
1940
1920
1900
--------glaciological measurements
— ------ data lacking
--------data uncertain
\ 1965
1920/25
4'■“1913
~~~~ 1907
1894
Figure 3. Cross-section along the Flólmsárgarðurprofile and recession of Fláajökull in the 2i)th century. Draw-
ing based on a stereoscopic pair of aerial photographs taken in 1989. - Hörfun Fláajökuls frá 1894 samkvœmt
sniði við Hólmsárgarð.
RECESSION OF FLÁAJÖKULL
Age of ridges I, II, III.
The maximum position of Icelandic glacier fronts
dates back to the end of the Little Ice Age (LIA),
the period between 1850 and 1930 (Gudmundsson,
1997). Ahlmann and Thorarinsson (1937) and Thor-
arinsson (1943) identify 1882-1892 as a period in
which Fláajökull reached its maximum. Recession
began in 1894 and Evans et al. (1999) have pro-
vided lichenometric dates of 1870-1894 for the oldest
moraines of Fláajökull. Recent work of Kirkbridge
and Dugmore (2001) demonstrated that lichenome-
try can underestimate the age of glacial landforms in
south Iceland by > 100 yrs. However, it seems that this
does not apply to the Fláajökull moraine ridges.
Between 1894-1903 the glacier front underwent
recession of about 500 m, and from 1903 to 1930,
it retreated an additional 400 m along the Hólmsá
river (Ahlmann and Thorarinsson, 1937). However
Thorarinsson (1943) has argued that between 1903-
1920/25 the glacier front was stable or even advanc-
ing with rapid recession after 1925. Denton (1975)
suggests that advances took place around 1910 and
the early 1920s. It is supported by Einarsson (1993)
JÖKULLNo. 51 19