Geoscience Reference
In-Depth Information
(a)
PEN-Y-BRYN
1988 south-east working face
m
0
30
16
1986 west working face
m
12
5
8
4
3
4
1
0
41,160 + 890
- 810
2
Section A
Section B
Section C
60,600 + 4500
- 2900
40,570 + 860
- 780
bedrock
grey Lower Gravels
biogenic sediments
grey Lower (Welsh) Till
coarse brown Intermediate Gravels
reddish brown Upper (Irish Sea) Till
laminated grey silty clay
(b)
Zones
050100
10
10
55555
10 20
30
5
10 20
5000
40 50
10 20 30 40 50
0 0 0 0 0 0
2 4
2 3
2 2
2 1
2 0
l-f
1 9
1 8
1 7
1 6
1 5
1 4
1 3
1 2
1 1
1 0
9
8
7
6
5
4
3
2
1
l-e
l-d
l-c
l-b
l-a
Trees Shrubs
Dwarf shrubs
% loss on ignition
scale (10% units)
less than 0.6%
Others
(C)
Zones
0
50 100
1017 10203040 102030555555555 102030 102030405060
0
20 40 60 80 100
2 1
1 9
1 7
1 5
1 3
1 1
9
7
5
3
1
-1
lII-c
lII-b
lII-a
Trees Shrubs
Dwarf shrubs
% loss on ignition
scale (10% units)
less than 0.6%
Others
Figure 23.10 Generalized Late Quaternary stratigraphy at Pen-y-bryn, Caernarfon (a) and the detailed palynology (pollen
analysis) of organic sediments probably representative of Marine Oxygen Isotope Stage (MIS) stages 5c (b) and 5a (c), underlying
the glacigenic sediments. Low tree pollen and high shrub, grass and sedge content, identified by their Latin names, in (b) are
indicative of a sheltered riverine habitat in a tundra environment, contrasting with developing birch-pine-spruce forest in (c).
Sources: (a) Addison & Edge (1992) and (b, c) Chambers, Addison, Blackford & Edge (1995)
 
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