Unravelling the nature of deep-marine sandstones through the linkage of seismic geomorphologies to sedimentary facies; the Hermod Fan, Norwegian North Sea - From Depositional Systems to Sedimentary Successions on the Norwegian Continental Margin - page 667

Small sub-circular depression

Thick

2-14

Mound Collapse

basin

5-1

Tr ench

Scallops

2-6

5-2

Thin

0 2 km

2-14 2-6 5-1 5-2

1900

2000

2100

SELE_FM

SELE_FM

SELE_FM

SELE_FM

LISTA_FM

2200

LISTA_FM

LISTA_FM

LISTA_FM

2300

0 2km

2-14 2-6 5-1 5-2

1900

2000

2100

2200

2300

0 2km

Balder Formation/Odin Member Sele Formation/Hermod Member

Fig. 14. Large-scale sand remobilisation in the Frøy area, evident in the Sele Formation isochron map and seismic section.
The area can be divided into sand evacuation and sand injection zones. Faults that originate in the Hermod sand and ter-
minate in the Horda Formation clays can be observed locally at the boundaries between these two zones. These faults are
thought to have formed by roof collapse during sand evacuation. Hermod sand in well 25/5-1 appears to have been evacu-
ated to a mound and thereafter fed back into the overlying Balder Formation across a roof collapse fault that juxtaposed
Hermod to Balder.

INTERPRETATION or steep-sided mounds hint at a generic relation-

ship and the most obvious interpretation is one of
lateral transportation of Hermod sand from the
depressions to the mounds which can have anom-
alously high net-to-gross sand content in the Sele
Formation (i.e. well 25/6-1; Fig. 15). The large size
of some discrete depressions or 'collapse basins'

The lack of Hermod Member in a small circular
depression drilled by well 25/5-1, within the
broader Hermod sand fairway (Fig. 2), suggests that
the depressions represent areas of post-depositional
sand evacuation. Their close association to ridges