Geoscience Reference
In-Depth Information
NPHI
RHOB
Depth
(m)
0.75
%
-0.15
Zone
GR
API
0
250 1.45
g/cc
2.95
Grain size and
sedimentary structures
2210
SAND
2215
CLAY
VF
FMCVCG PC
FA 3
2220
FA 4
FA 3
2225
2230
2235
2240
FA 5
2245
2250
2255
2260
FA 4
FA 2
FA 3
FA 4
FA 2
FA 1
2265
FA 2
2270
FA 3
Fig. 12. Wireline log response and core interpretation of typical facies associations within the Åre 1 Zone (see Fig. 9 for
facies association descriptions, example from well 6507/8-4). Note the 'blocky' signature on the GR log corresponding to a
multi-storey fluvial channel sandstone. A thick package of coals and carbonaceous claystones towards the top of the Åre 1
Zone corresponds to the lower part of the Coal Marker. (See Fig.  6A for core description legend and Fig.  4 for
abbreviations).
that restricted the fluvial channel lateral mobility
and migration (e.g. Gradzinski et al ., 2003).
Multi-storey vertical stacking of fluvial channels
(e.g. Fig.  12) may also indicate stable channel
positions and a tendency of channels to aggrade
vertically when the accommodation space
allowed for it. Abundant internal scour surfaces
suggest multiple phases of cut and fill, pointing
towards a braided or anastomosing style of river
systems (Gjelberg et al ., 1987; Gradzinski et al .,
2003; Makaske, 2001; Mjøs & Prestholm, 1993;
Pedersen et al ., 1989). The channels of the Åre 1
and 2 Zones probably reflect deposition in river
reaches characterised by a combination of both
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