Jökull - 01.11.1998, Blaðsíða 8

most certainly from the 1440 AD and 1416 AD erup-
tions at Katla, but the origin of the dark tephra layer is
uncertain (Fig. 5). The Öræfajökull marker tephra is
identified in four profiles as a thin and discontinuous
white layer of very fine ash. It is not preserved at
other locations, which is not unexpected because the
area is at the distal edge of the Öræfajökull ash fall
(Þórarinsson, 1958). Just below the Öræfajökull
Fig. 1. A map of the study area showing the outcrop relationship between the Leiðólfsfell cone group and the 1783-84 Laki lava
flow, location of measured sections and soil profiles and other features mentioned in the text. The geologic features indicated in
the key are: 1. Rootless vents (crater symbol), explosion craters (open circles) and fall deposit (dark gray shading), 2. Portions
of the Laki lava flow field that are flanking the main channel and are characterized by slabby pahoehoe and 'a'a flow surfaces, 3.
The 'main lava stream' of the Laki lava flow, 4. Slab pahoehoe lava units (lava breakouts); point of origin is indicated by U-
shaped symbol, the broken lines outline the boundaries between units, and the arrows indicate the flow directions. Locations of
measured sections are shown as filled circles; numbers next to circles identify section location (5;_____) and thickness of the
Leiðólfsfell tephra (_;88). Locations A an B are referred to in text.
- Jarðfrœðikort sem sýnir afstöðu Skaftáreldahrauns og gígþyrpingarinnar við Leiðólfsfell og staðsetningu mældra sniða.
Skýringar: 1. Gervigígaþyrping; sprengigígar eru sýndir sem hvít hringlaga tákn, gjallgígar og gjóska sem skyggð (dökk grá)
svœði. 2-4. Skaftáreldahraun, 2. Óskilgreint hraun 3. Megin hraunáin, 4. Helluhraunstaumar með uppbrotið yfirborð
(undanhlaup); upptök einstakra flœðieininga eru sýnd sem U-laga tákn og brotnar línur gefa til kynna hraunjaðra og örvarnar
sýna flœðistefnu hraunsins. Staðsetning mœldra jarðvegssniða er sýnd sem punktai; talnagildin gefa til kynna sniðanúmer (5;_)
og þykkt Leiðólfsfellsgjóskunnar (_;88). FjaUað er um staði Aog B í texta.
6
JÖKULL, No. 46, 1998