Greinar (Vísindafélag Íslendinga) - 01.01.1976, Síða 37

35
in the survey line immediately to tlie east. This shows that the
anomalies are generally older than the shaping of the shelf sur-
face. A possible correlation between individual localized anomalies
off the Snaefellsnes peninsula, and Late Quaternary volcanism on
and close to the peninsula, was suggested by Thors and Kristjans-
son (14). However, the additional data obtained since then have
emphasized differences in scale and age between these two types
of features, and a detailed study of bathymetric profiles offshore
is needed to test the correlation.
C. Distribution of geophysical anomalies off Western Iceland
The data of Tables I and II, and Figs. 2, 3 and 4, confirm that
a zone, unusually numerous in volcanic centers of order 10 km size
each, runs westwards to at least 120 km from the Snaefellsnes
peninsula. This is illustrated in Fig. 7, where each circle in areas
9, 7 and 10 represents an anomaly region. On shore, circles re-
present central volcanoes inferred from published surface geolo-
gical maps (16) and geophysical evidence (1,4). It must be stres-
sed that the number and locations of on-shore central volcanoes
in Fig. 7, especially outside South-Westem Iceland, are very ten-
tative due to incomplete coverage by stratigraphic and geophysical
mapping (K. Saemundsson, pers. comm. 1975).
North of Western Iceland, unpubhshed magnetic records from
profiles 1 through 6 of the “Komet” 1971 cruise (17) have kindly
been made available to the Science Institute. In the area north of
Iceland enclosed in Fig. 7, no magnetic anomalies of the central-
volcano type were identified. Neither do such anomalies occur in
Icelandic survey results from the vicinity of that area (L. Kristjans-
son, unpublished data) and no significant localized gravity anoma-
lies were found there (G. Palmason, pers. comm. 1975).
Few magnetic tracks are available in the Faxaflói bay area,
south of Snaefellsnes, and the only gravity and magnetic anomaly
known with certainty is region S of Fig. 5. In a profile running
WNW from the Reykjanes peninsula, obtained by the survey ship
“Prospekta” for Shell Oil Co. in 1971 (here smoothed by a 3-km
wide window and published by permission), the field has very