Fróðskaparrit - 01.01.1996, Page 121

TWO-WAY TRAVEL TIME (sec)
IMAGING OF BASALT AND UNDERLYING STRUCTURES IN THE FAROESE OFFSHORE AREA ] 25
Figure 5. Profile 3, in the Faroe Bank Basin and rising onto the Faroe Bank Channel Knoll Volcanic Feature.
Note the thickening ofthe Basalt unit apparent relative to Figs. 3 and 4, and the thickening of Subbasalt 2
Towards the Knoll.
region of 25 degrees) unless highly brecciated,
basalts cannot support this geometry (Trewin and
Hole, personal commmunication).
d. The upper contact terminates towards an erosio-
nal unconformity.
Because of these factors, we have concluded that this
unit is most probably sedimentary in nature with an
age older than that of the basalt which overlies it.
6. The underlying unit, Subbasalt 2 (bright pink) dis-
plays characteristic mounded structures upon which
the older unit stratigraphically terminates as descri-
bed above. Reflectors are strong with both broad
peaks and troughs which seem to be indicative of this
unit.
7. The dark pink interval (Subbasalt 3) forms the sur-
face upon which Subbasalt 2 was clearly deposited;
Subbasalt 2 infills its highs and lows but lies con-
formably upon its planar surfaces as well (note re-
spectively characteristics at wd 858 and wd 1247.
This unit is more massive than the overlying units
and discrimination of its boundary with Subbasalt 4
can be difficult, usually depending on difference in
geometry, dip, and reflection character.
8. The deepest unit interpreted is that of the yellow
horizon, Subbasalt 4, which is generally taken as
representing acoustic basement or the basin floor.
This unit can also be heavily block faulted. Some
indications of internal form may be detected with
this unit (ie, wd 858 at a twt of 5.6 seconds) but these
events are discontinuous, cannot be correlated, and
may well represent artefacts.
Profile 2 (Figs. 1 and 4) lies farther south
along the Faroese Margin and crosses the
East Faroe High before descending into the
Faroe-Shetland Channel. The interpreted
units display the characteristics as de-
scribed above, as well as the following no-
table features:
1. Subbasalt 2 is seen to form a large, depositional
mound against the channelward fault edge of the
East Faroe High (EFH) fault block. This unit thins
over the EFH to terminate again against an upfaulted
block near WD 260.