Árbók Hins íslenzka fornleifafélags - 06.01.1986, Blaðsíða 6

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ÁRBÓK FORNLEIFAFÉLAGSINS
(Medieval Layer) which is thought to derive from an eruption off Reykjanes froni AD
1226-1227, 1231 or 1340. The uppermost one is a tephralayer called K 1500, thought to
comc from an eruption in Mt. Katla ca. AD 1500. Both the latter layers are of a dark
colour20.
Two layers of tcphra wcre found in Layer 4 in the trenches I-J and K-L well above the
top of Layer 3. House IV was, on thc other hand, well below the top of layer 3 (35—50
cm). No tephra was found anywhcre directly above House IV.
A microscope examination of the tephra layers showed a marked difference betwcen
them. That, and some measurements of the refractive index of the tephralayers, indi-
catcd that the lowcr onc was thc so callcd Medicval Layer and the uppcr one K1500.
Charcoal samples werc sent to Copenhagen for C14-dating. Wood analysis indicated
that they were renrains of Icclandic birch (Betula)2". They were dated to 1100H—75. Aftcr
being revised according to thc Stuiver corrcction thc final date was given as 905—975
AD25'27
In the past specialists have not agreed on the rcliability of the resuits of C14-dating of
Icelandic samples. Some are of the opinion that they give too early a datc while others
regard thc results as reliable29,30,31. No proper research has so far been donc into thc pro-
blcm of thc reliability of C14-datings of Icelandic samples. This must bc bornc in mind
when drawing conclusions from thc results of C14-datings of Icclandic samplcs.
According to the mcagre cvidence fronr the Suðurgata 7 site, it may be concluded that
House IV seems to predate both the tephra layers and is thus oldcr than from 1340 at
least. C14-datings indicate that it was probably in use ca 905-975 AD or evcn a fcw dcc-
ades earlicr or later. Judging from that result, Housc IV scems to rank among thc oldest
cultural rcmains so far found in Rcykjavík.