Jökull - 01.12.1989, Page 27

Fig- 3. Simplified profile of the Fossvogur layers between Reykjavík Airport and Nauthólsvík. The westem-
most part of the section is now hidden by a land-fill. l)The Reykjavík olivine tholeiite basalts. 2)Till.
3) Layered silt. 4) Silty marine deposits. 5) Shells. 6) Gravel deposits. 7) Airport runway.
Mynd 3. Einfaldað þversnið af Fossvogslögunum milli Reykjavíkurflugvallar og Nauthólsvíkur. Vestasti hluti
sniðsins hefur nú verið hulinn af uppfyllingu. 1) Reykjavíkurgrágrýti. 2) Jökulurð. 3) Lagskipt méla. 4) Fín-
kornótt sjávarset. 5) Skeljar. 6) Malarríkt set. 7) Flugbraut.
Eiðistorg (Fig. 2). Shell-rich sediments were found
when the foundations for the buildings were exca-
vated some years ago. Samples AAR-3A and AAR-
3B were collected at this site.
Marine shell-bearing sediments are found in
places on top of the Fossvogur layers. In the spring
of 1963, Guðmundur Kjartansson collected shells in
the basement pit of Hótel Loftleiðir, at the Reykja-
vík Airport. The samples were sent for dating to
Uppsala in Sweden (U-412 to U-415 in Table I,
Kjartansson and others, 1964). Three of the samples
were from the same shell. No description of the
strata at this location is available,* but according to
the radiocarbon dates presented here the shells are
younger than the topmost till of the Fossvogur
layers.
THE AGE OF THE FOSSVOGUR LAYERS
In the following discussion regarding the age of
the fossil shells and the shell-bearing strata, the
referred age is not calendar age, but conventional
radiocarbon age based on the half-life of radioactive
i The geological notebooks of Kjartansson in the National Library of Iceland have a short description of this sampling: "19. feb.
1963. Safnaði skeljum úr uppgreftri á Rvíkurflugvelli, þar sem grafið hefur verið fyrir húsi Loftleiða. Fór þangað eftir ábendingu
Guðbjarnar Guðmundssonar (frá Böðmóðsstöðum) sem þama er verkstjóri. Guðbjöm gaf mér upp eftirfarandi kóta (m y.s.): Kjall-
aragólf 11,14 - gólf á 1. hæð 14,40 - bílastæði 13,80. Þessar tegundir fundust: Saxicava arctica (urmull) - Pecten islandicus (mjög
mikið) - Jvlya truncata (allmikið) - Macoma calcaria - Buccinum undatum (2 kuðungar) - Amauropsis islandica (1 kuðungur) -
Balanus sp. (urmull)".
JÖKULL, No. 39, 1989 25