Jökull - 01.12.1993, Page 36

Figure 1. Northeast Iceland with placenames mentioned in the text. The major outline of topography is given by
the streams and by the altitude of a few topographical highs. — Staðsetningarkortfyrir rannsóknasvœðið við
Þistilfjörð og Bakkaflóa ásamt hœð helstu fjalla og staðarnöfnum sem komafyrir í greininni.
about 900 m high mountains south thereof is younger,
made of 0.7-3 Ma old lava fiows and sediments. The
Melrakkaslétta peninsula west of the study area (Fig-
ure 1) is part of the northern neo-volcanic zone of
Iceland with bedrock formations less than 0.7 Ma old
(Jóhannesson and Sæmundsson, 1989). Thelandscape
there is characterized by glacial erosion as well as by
recent volcanism and tectonic activity, with subaerial
lava flows and subglacially formed hyaloclastite ridges
and table mountains (Pétursson, 1991).
Relative sea-level changes in this area and the
glacial retreat after the last glaciation, were first stud-
ied by Thoroddsen (1905-06) who mapped the ge-
ology of the area and recognized that the whole re-
gion had been ice-covered. He also concluded that
the land had been submerged by the sea, registered
raised shorelines at different altitudes and correlated
their formation with raised shorelines in other parts
of the country (Thoroddsen, 1904). According to
Pjeturss (1910) glacial landforms in the Þistilfjörður
34 JÖKULL, No. 43, 1993