Jökull - 01.01.2016, Page 58

Paweł Molewski and Leon Andrzejewski
Figure 5. Geological structure of the upper part of the studied delta slope, modified from Andrzejewski et al.,
(2005). A: Lithofacial profile. B: Delta deposits from about 0.8 to 1.8 m; C: Model of the fan delta. – Þversnið
(A) og ljósmynd (B) af setlögunum í aurkeilunni í lónstæðinu, ásamt líkani (C) af myndun hennar.
recording a marked shift or change in depositional
environments, possibly associated with a deepening
of the lake. They may have resulted from periodic
damming of the water’s outflow from the lake caused
by the advance of the glacier in the south-western part
of the study area (Figure 10B). In this area the glacier
adjoined the Jökulgrindur ridge. The top of these de-
posits was eroded during a subsequent stage of lower-
ing of the water level within the lake.
The proximal part of the delta deposits were de-
posited on stagnating glacier ice. After the drain-
ing of the ice-dammed lake and degradation of the
glacier snout, a steep ice-contact sedimentary scarp
was formed.
The delta is classified as a steep slope delta, also
known as a Gilbert-type delta. Such deltas develop
in the edge zones of lakes of considerable depth
and steeply sloping bottom, typical of, among oth-
58 JÖKULL No. 66, 2016