Drumlin field at Múlajökull, central Iceland

• Main Author: Þorbjörg Helga Hilmarsdóttir 1961-
• Other Authors: Háskóli Íslands
• Format: Thesis
• Language: English
• Published: 2013
• Subjects: Jarðfræði; Múlajökull; Malarásar; Jöklarannsóknir; Arnarfell; Arnarfell hið Mikla; Breiður; Mikla; glacier; Hofsjökull; Ice cap; Iceland
• Online Access: http://hdl.handle.net/1946/14009

Múlajökull is a surge-type outlet glacier draining the Hofsjökull ice cap to the southeast where the 7 km wide tongue descends from an altitude of about 1800 m down to approximately 650 m above sea level, where it penetrates through 2 km wide gap between the two mountains, Arnarfell hið mikla and Hjartafell. Múlajökull margin has been monitored on a fairly regular basis since 1932 and since 1989 the mass-balance has been surveyed. Since 1995 the Múlajökull glacier margin has retreated considerably revealing a drumlin field consisting of more than 50 drumlins. The morphology and sedimentology of the drumlins were studied during fieldwork in the summer of 2010 and from a series of aerial photographs from 1995 – 2008. The drumlins are composed of multiple beds of till deposited by bed deformation and lodgement. The uppermost till layer and the youngest one truncate the older ones with an erosion surface that parallels the drumlin form. Hence, the drumlins are formed by a combination of subglacial depositional and erosional processes. The result of the fieldwork indicates that each till bed is associated with surges of Múlajökull glacier. The Múlajökull drumlin field is considered to be active and therefore a unique analogue to Pleistocene drumlin fields. Múlajökull er skriðjökull Hofsjökuls sem gengur til suðausturs úr um 1800 m hæð yfir sjó niður í um 650 m hæð þar sem 7 km breiður jökuljarðarinn dreifir úr sér eftir að hafa þröngvað sér í gegn um 2 km breiða kverk á milli Arnarfells hins mikla og Hjartafells. Reglubundnar rannsóknir við Múlajökul hófust 1932 með mælingum á legu sporðsins og hefur afkoma jökulsins verið mæld árlega síðan 1989. Múlajökull hefur hörfað töluvert síðan 1995 og vegna þessarar hörfunar hefur stærsta einstaka þekkta þyrping jökulalda í myndun, um 50 talsins, komið í ljós. Landmótun, bygging og lögun jökulaldanna var rannsökuð í útivinnu sumarið 2010 með greiningu og samanburði loftmynda frá 1995 – 2008. Jökulöldurnar samanstanda af nokkrum jökulurðarlögum sem hafa sest þarna til vegna ...