Q U A T E R N A RRYE S E A R C2H1 , 8 5 - 1 0 4 ( 1 9 8 4 )
A YoungerDryasAsh Bed in WesternNorway,and lts Possible
Correlations
with rephra in coresfrom the Norwegian
sea and the
NorthAtlantic
JaN MeNcEnun, SvsN Enrr LrE,l Hanelo FunNEs, INcEn LtsE KnrsrreNssN,2
eNn LErr LOuo3
Department qf Geology, University of Bergen, Alllgt. ll,
N-5000 Bergen, Norv,a-v
Received November 18. 1982
A bed of volcanic ash up to 23 cm thick is found in lacustrine and marine sediments in western
N o r w a y . I t i s f o r m a l l y n a m e d t h e V e d d e A s h B e d , a n d i t s a g e i s a p p r o x i m a t e l y 1 0 , 6 0 0y r B . P . ,
i.e., mid-Younger Dryas. The bed consistsof pure glass having a bimodal basaltic and rhyolitic
c o m p o s i t i o n . T h e g e o c h e m i s t r y o f t h e g l a s s s h a r d s s u g g e s t sa n l c e l a n d i c s o u r c e . B y m e a n s o f
stratigraphic position and geochemistry, the ash is correlated with ash zones founcl in cores from
the continental shelf, the Norwegian Sea, and the North Atlantic.
INTRODUCTION
D E S C R I P T I O NO F T H E B E D
During coring of marine and lacustrine
s e d i m e n t sa r o u n d A l e s u n d i n w e s t e r n
Norway (Figs. l-3), with the primary purpose of studying relative sea-levelchanges,
we found a bed of volcanic glassof Younger
Dryas age at several sites. Earlier, Fegri
(1940)described an ash bed ofsupposed Aller@dage from Jaren (Fig. 2), and Persson
(1967, l97l) describedash from several
levels in Holocene peat bogs in western
Norway. All the glass horizons Perssondescribed were found after chemical treatment of the sediments, no ash bed being
visible in the field.
Tephra beds are unique marker horizons
and have been extensively used for correlation of Quaternary sequences(e.g., Self
and Sparks, l98l). Similarly, for the ash
bed described in this paper the major significance will probably be its potential as a
correlation tool between lacustrine, continental-shelf,and deep-seasequences.
The ash bed occurs in the Alesund area
a s a n e a s i l y r e c o g n i z e db e d i n s e d i m e n t
cores collected from bogs and lakes. At l5
localities it is found in lacustrine sediments
and at 8 localities in sublittoral marine sediments. It occurs at depths of 2.7 to l0 m
below the surface.
The ash bed is dark gray to black when
water saturated, but is light gray when in
dry condition. It consists of nearly 100%
glass particles and is relatively well-sorted
fine sand to coarse silt (Fig. l l). The lower
boundary of the bed is always sharp. The
upper boundary is also often sharp, but at
some sites there is a transition to the overlying sediment. Glass shards are abundant
above the bed proper. The bed is massive
except where it is very thick. In Torvl/myra
and Stettetj@nn,where it is up to 23 and
2l cm thick, respectively, it is faintly laminated in the upper parts.
This ash bed is a notable marker bed. and
we therefore decided to give it a formal
lithostratigraphic name. Initially we (Mang e r u d e / a l . , 1 9 8 0 1L. r y ' m oa n d L i e , 1 9 8 1 )
named it the Sula Ash Bed. However,
Bugge (1980)named an end moraine on the
continental shelf the Sula moraine from an
island with the same name further north.
I P r e s e n ta d d r e s s : N o r s k H y d r o , O i l D i v i s i o n , H a r s t a d b o t n e n ,B o k s 6 4 1 , 9 4 0 1 H a r s t a d , N o r w a y .
I P r e s e n t a d d r e s s : N o r s k H y d r o , R e s e a r c hC e n t e r ,
Boks 4313, 5013 Nygirdstangen, Norway.
I P r e s e n t a d d r e s s :N o r s k H y d r o , O i l D i v i s i o n , B o k s
4313, 5013 Nygirdstangen, Norway.
85
0033-5894/84
$3.00
Copyrighr rO 1984 by the Unjversit'. of Washingron
All riShts of reproduction in any ibrnr reserved.
86
-,
MANGERUD ET AL
ttg: t
Map of northwestern Europe, the North Atlantic
ocean, and the surrounding seas showing
to,id,andthe".ti"";;;;;l
u..u,JanMayen,
*:,*f,:::and I?":"n::"^,1""^u:11:,1,n
Iceland,
LaacherSee.The positionsof?:di:
the investigatedcoresfrom rhe N".th ;;;;;'t^litil';
and v28-14),the NorwegianSea(31-33),
and the Norwegiancontinental
shelf(31-2A)are marked.
We therefore decided to changethe name
for the ash bed and here call it the Vedde
Ash Bed. Vedde is the name of the farm
and the surroundingarea on the islandof
Sula near Alesund(Figs.3 and4), where
the stratotypeis defined. The stratotypeis
located at Lake Gj@lvatnand the p.uttog,
Torvl6myra and Saudedalsmyra.These
threebasinsare so closeto eachother(Fig.
4) that it is obvious that the ash bed o."ui_
ring in them is one identicalunit.
the Pleistocene/Holocene
boundarv.In the
lowerHolocenethereis generallyu bro*n
organicmud. Below it occursa bed poor in
organics,frequentlya graysilt, of ytuneer
D r y a s a g e ( l 1 , 0 0 0 -1 0 , 0 0 0y r B . p . ) , a - n d
below that occurs a more organic_richbed,
normally a brown silty gyttja of Alerdd
age.The lithostratigraphic
boundaries
mav
not be identicalto the boundariesproposei
for the Younger Dryas and AllerOd chro_
nozonesby Mangerudet al. (1974).How_
ever.for simplicityin thispaperwe will use
informally the terms Holocene gyttja,
A G E O F T H E V E D D EA S H B E D
YoungerDryassilt, and Allerld sittygyttja.
In small lakesin westernNorway. as in
We have used two approachesto oUtain
m o s to f n o r t h w e s t e r n
E u r o p e .t h e r ei s a the age of the Vedde Ash:
sedimentation
distinct lithostratigraphic
sequencearound rates and radiocarbondatins.
NORWEGIAN
LATE
GLACIAL
TEPHRA
87
oldest reasonableagesfor the lower and
upper boundariesof the younger Dryas silt
in this areaare 11,100and 10,400yr B.p.,
respectively(Fig. 5), yieldinga maximum
agefor the ash of 10,750yr B.p. Similarilv.
we obtaineda minimumage of 10.a50yr.
using 10,900and 10,000yr for the two
boundaries.We found the most probable
agesfor the boundariesfor the younser
D r y a s s i l t t o b e 1 1 . 0 0 0a n d 1 0 , 2 0 0v r .
yieldingan age of t0.600yr B.p. for ihe
VeddeAsh.
RadiocarbonDating
Frc. 2. Map of western Norway (forlocation see Fig.
l). Sites where an ash bed, probably correlative with
the Vedde Ash Bed, is found are marked with crosses.
For details in the Alesund area, see Fieure 3.
Age Calculatedfrom SedimentationRates
The VeddeAsh occursin the middlepart
of the YoungerDryas silt. To obtain a more
preciselithostratigraphic
position,we measured the thicknessof the silt above and
below the ash (TableI, Fig. 6) and found
that the VeddeAsh occursvery closeto the
center of the YoungerDryas silt.
To calculatethe age,we haveto postulate
a constant sedimentationrate through the
YoungerDryas silt (excludingthe ash).
Based on several radiocarbondates. the
We startedto date two pairs of samples,
one takenjust below and the other just
above the ash bed in Kr6kenesvatnand
(Fig. 5). The weightedmeanfor
Torvl@myra
the two samplesfrom Krikenes (Fig. 5) is
10,510-t 220 yr B.P. In TorvlBmyrathe
sampleabove the ash gave an ageof 9170
-r 90 yr (T-3959)while
a sample slighrly
higherup gave 10,430+ 110 yr B.p. (T3952)(Fig. 5). SinceT-3959,for unknown
reasons,is completely erroneous,it is
omitted from the calculations.The sample
belowthe ashat Torvl/myragave10,640-r
70 yr (T-3960);corrected for the sedimentation rate it indicatesan age of 10,590-*
70 yr B.P. for the ash bed.
Sincethe ashbedprobablywasdeposited
within one year,or at most a few years,we
later dated samplesincludingequal sediment thicknesses
belowand abovethe ash.
For Lerstadvatnwe obtained10.680-r g0
yr (T-4381),
and for Lillerestjpnn10,390-r
r40 yr B.P. (T-4382)(Fie. 5).
The weightedmean for the four given
datesfor the ashbed is 10,600-r 50 yr B.p.
when both age and standarddeviation are
roundedoff to nearestl0 yr, as is done for
all datesin this paper.
Based on both the calculationof sedimentationrates and the radiocarbondates,
we concludethat the most probableagefor
the VeddeAsh Bed is 10,600conventional
toC yr with a subjectivelyestimated
standard deviationof -r 60 yr, which takes into
88
MANGERUD ET AL
Lerstadvatn
Ratvikvatn
I
Slettebakktjonn
Sk;ervikmyra
\
Lilterestj@nn Steltetl@nn
FIc'3. MapoftheAlesundarea'[email protected].
I n N o r w e g i a n - v a t n m e a n s l a k e , - t j @ n na s m a l l l a k e . a n d _ m v r a a b o s .
_
r .1r :s: i:.y " t
various "geological uncertain-
DE'OSITIONAL 'ROCESSES
The ash bed occurs in both lacustrineand
marine sediments, indicating that the particles came into the area through the air and
not by ice-rafting, which could have been
an alternative interpretation if the tephra
were found only in marine sediments(e.g.,
Ruddiman and Glover, 1972).
We assume that the ash was deposited as
a blanket with a more-or-lessuniform thickness over the landscape. However, in the
lacustrine sediments the bed has a vari-
a b l e t h i c k n e s s ,c l u e t o s u b s e q u e n tr e d e p o s i t i o n o f t h e t e p h r a i n t o t h e l a k e s .T h i i i s
clearly demonstrated in Torvlpmyra and
S a u d e d a l s m y r ab o g s , w h i c h w e r e s m a l l
lakes when t-heash was deposited (Fig. 4,
inset). A brook that drains the mountain
slope ended in the paleo-lake Torvl@myra.
Close to the brook inlet the ash bed is 23
c m t h i c k , b u t i t d e c r e a s e st o 5 c m o n l y 5 0
m further east (Fig. 4, inset). Saudedals_
myra is downstream from [email protected],and
the latter has acted as a sediment'trap; in
Saudedalsmyra the ash bed is only 6 cm
thick near the inlet brook, but decreasesto
l cm in the center of the lake.
"
.
saudedarsmyr"
)"...
\
dft-
t l,
_;*':
il] t
''J
':t
L
fir"ro.y,a
\
Ftc' 4' Map showing the stratotype area for the Vedde Ash Bed (for
location see Fig. 3). The inset
shows the lakes that, during the Younger Dryas, occupied parts of
the area of the present day bogs
S a u d e d a l s m y r aa n d T o r v l @ m y r a .T h e c r o s s e sm a r k c o r i n g p o i n t s ,
a n d t h e s c a l e st h e t h i c k n e s s o f t h e
ash bed in the corresponding core.
NORWEGIAN
LATE GLACIAL
T A B L E l . T u r c x N n s s o F r H E L A C U S T n T NySo u N c e n
D n y n s S I t - ' rA
' B O V ET H E V g o o g A s u C e l c u L e r n o a s
Ppncgrracn ol rgl Toral TurcrNnss or rHE Srr_r
( N o T r N C t _ u D I NT
GH E A s H )
Number
of cores
Lerstadvatn"
Torvlpmyra
Saudedalsmyra
Svortavatn
Skjervikmyra
Engjavatn
Dekkjavatn
LassehaugtjOnn
Krikenesvatn
Mean of 43 corcs
Mean of 9 localities
22
4
4
5
4
Average 7r of silt
bed above the ash
47.8
60.-5
5l.u
5t.4
55.5
39
28
38
/1
-50.0
46.8
" Two cores with extremely
thin silt above the ash (Fic. 6)
arc omitted.
Similar distributions are seen also in
other lakes. The conclusion is that the
tephra was efficiently transported into the
lakes through the brooks. This interpretat i o n s u g g e s t sa r e l a t i o n s h i p b e t w e e n t h e
volume of ash within a lake and the size of
its drainage area. We therefore plotted the
thickness of the ash bed versus the ratio of
drainage area/lake area (Fig. 7), and found
a clear relationship indicating an original
thickness of the ash blanket corresponding
to a thickness of 2-3 mm of the compacted
Vedde Ash. The original loose-packedash
blanket must have been considerably
thicker.
There appears to be no correlation between the thickness of the ash bed and the
thickness of the rest of the Younger Dryas
silt (Fig. 8), indicating thar the depositional
processes were different for the two sediment types. This has not, however, been
investigated for most of the lakes, and the
sedimentological environments differ considerably between lakes. Also, in several
lakes the Younger Dryas silt is largely composed of diatom skeletons produced within
the water column.
M O R P H O L O G I CD E S C R I P T I O NO F T H E
ASH PARTICLES
The following descriptions of the Vedde
Ash are mainly based on binocular micro-
TEPHRA
89
scope studies, with magnification up to
80 x . The main criteria in the morphologic
description are the color, shape, and vesicularity-all important diagnostic characters for tephra beds (Westgateand Gorton,
l 9 8 l) .
The ash consists exclusively of aphyric
vitric shards of which 80 to 90% are colorless, transparent fragments, the remainder being pale to dark brown (Fig. 9).
The colorless materials are divided into
three groups:
(a) Thin, slightly curved platy shards,
representing fragments of broken walls of
gas bubbles.
(b) Oblong fragments characterized by
three- and four-winged cross-section.Lines
and wrinkles along the particle occur frequently. These are fragments of the seams
between bubbles. Fragments of groups a
and b are the most common in the Vedde
Ash Bed.
(c) Irregular fragments of white pumice.
The brown-colored grains also occur in
three forms:
(d) Similar to type a, rhe color is pale
brown and fine parallel stripes are
common.
(e) Like type b, but the fragments seem,
on average, to be somewhat thicker.
(f) Dark-brown, blocky vesicular particles. The vesicles vary in size, shape, and
number.
GRAIN SIZE
The grain size of four samples was measured with a polarizing microscope, using a
magnification of 320. In random traverses
the two longest axes were measured of the
first 100 grains. The brown and colorless
glass shards were counted separately,
without showing any difference in the relation between the two measuredaxes (Fig.
l0). However, all the largest grains are thin
colorless shards. The shortest axis is significantly larger for the brown grains, but
was not measured.
90
MANGERUD ET AL
-s
H$
ia
€s
*cl.
vi5
3ao
:oc
=8
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Jylcm
trnm
RnYl'
nm$
g
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--
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g8t:_=_l
ffi
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-;=
31ffi
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=
= f f i
ffiffi
N 6
L E G E N D; M l
ffiEAE{W
===
==ffi88ffi Il#J
==
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E=e=Fffi
-
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-B
!*
B:m ffi=t='
r\ir
Ec*:BI
' t
{;
ffi ffi==s=m
lQQQff{
il6[00{00
6+r
+ E
r50
i.
::"xl i::m
m
9l 2cm
fitrtr "e mffff
r :
:
E.d
r.1
;6
/6/cm
.ts
-sb
5 o
ffi
lM';J
o 6
l"#l l,l,l
I mI
lMMl
t*t t+t lHl
l^^t^l l^i"l liil
gyttio-------(Horocenel
Locustrine
El
F_-_-l
!---r
Lo"r.,rin. lominoted sondlilt |/ounger Dryos)
,
Locusirinesilt__ _ _ _ _ _ _ (younger Dryos)
W
Lo"r.nin. silty gyttio ----(AlterOd
ond otder)
M t't'l 16r;n. sedimenis, moinly ,ilr (Differeni oges)
I
u.ro"o., ".,
FIc. 5. The cores from Krikenes (Fig. 2) and the Alesund area (Fig. 3) with radiocarbon dates
relevant to the age of the Vedde Ash Bed. The depth (e.g.,787 cm) is indicated for top of the cores;
and the base ofthe Vedde Ash is 50 cm below that. The numbers after the names (e.g., 502-05-03)
are the core numbers.
From Lerstadvatn one sample covering
the entire ash bed, here being only I cm
thick, was analyzed. From Torvl@myra
three samplesfrom depths of 640, 634, and
. Shallow basln
+ Degp balin
,
o
o
o
t
5
Lersiod -
5kiervik-
Stetteti0nn
Torvlov
8
o
Y ^,loximum observed thicknesr
A Minimum observed thickness
I Estimoted meon thickness
E
'6
I
E
4
o
-
q
625cm were analyzed, but showed no stratigraphic trend in grain size. The sample
from Lerstadvatn has significantly more
smallgrains(Fig. l1) than the samplesfrom
I
'=
o
1
2
s n
3
;
;
;
;
t
b
Thickness of silt below the ash(6)
Frc. 6. The relative position of the Vedde Ash within
the Younger Dryas silt at Lerstadvatn. In the deep
basin (the modern lake) it is depositedat a maximum
depth of 9.6 m, and in the shallow basin (the modern
bog near the western shore) at a maximum depth of
5 . 7m .
The rotio droinoge oreo / loke oreo
FIc. 7. Thicknessofthe ash bed versusthe ratio
drainagearea,/lakearea for basins where we have suffrcient information. The subjectively drawn regression
line indicates primarily a thickness of 2-3 mm for the
ash blanket (ratio drainagearea"/lakearea = 1).
NORWEGIAN
LATE GLACIAL
TEPHRA
91
probablybecausesomeof the the latter (Fig. 12), it obviously does not
Torvl@myra,
See area'
finest grains were transportedin suspen- originate from the Laacher
active midvolcanically
a
is
sion through the small paleo-lakeTorvl@- Jan Mayen
number of
l
a
r
g
e
a
w
h
e
r
e
i
s
l
a
n
d
myra, while the much larger Lerstadvatn o c e a n i c
Holocene
the
in
occurred
have
was a more efficient sedimenttrap. If this eruptions
and
(lmsland,
Hiksdal
A.
1978b;
interpretationis correct, the samplefrom and earlier
geoThe
data).
unpublished
Lerstadvatnshows most accuratelythe J. Mangerud,
of the Jan Mayen
original grain-sizedistribution of the ash c h e m i c a l c o m p o s i t i o n
d
i
ffers significantly
h
o
w
e
v
e
r
,
fall. This distribution is rather similar to v o l c a n i c s ,
Ash (Fig. 12) and
Vedde
the
of
that
that of ash from the eruption of the Ice- from
not regarded as
therefore
are
former
landicvolcanoAskja in 1875found in Nor- the
area'
the
source
wegianombrogenicbogs(Persson,1967)' representing
There are many historical records of ashWalker (1971) plotted mean grain size
from Icelandic volcanic eruptions in
falls
(MdO) and sorting (o$) versus distance
(Thorarinsson, 1981c),the last
Scandinavia
from the eruption source. If we use the
v
i
t
r
i
c
a
s hf r o m t h e H e i m a e ye r u p t i o n '
b
e
i
n
g
shortestdistanceto Iceland(1000km)' our
n
e
ar Bergen in 1973 (J' Manc
o
l
f
e
c
t
e
d
s a m P l e s( M d O : 3 ' 6 ) a r e o n W a l k e r ' s
g
e
r
u
d
'
s
c
o
l
l
e
c t i o n ) . P e r s s o n ( 1 9 6 7' l 9 7 l )
boundaryline on the coarsesidefor Md$,
v
o
l
canic glass from Iceland in
d
e
s
c
r
i
b
e
d
but they are not as well sortedas the sector
Swedish peat bogs. Taking
and
Norwegian
givenby him.
S O U R C EA R E A SF O RT H E V E D D EA S H
There are three areas in northwestern
Europe where volcanic eruptions are
known to have occurredin the last 15'000
yr and thereforeare the most probablecandidatesas sourceareasfor the VeddeAsh:
the Laacher Seearea in the Eifel district of
westernGermany,the islandof Jan Mayen,
a n d l c e l a n dt F i g . l ) .
The youngestwidespreadashesfrom the
LaacherSeeareaare approximately1l '000
yr old and were spreadas far north as Gotland and Bornholmin the Baltic Sea(e.g''
Usinger,1978;Juvign6.1980;Risseet a/',
1980).The Vedde Ash is slightly younger
than the LaacherSeeash, and becauseits
geochemistryis completelydifferentfrom
J
|
+
?
'Shallow basin
+Deepb6srn
:
;6 3
Ei 2
S o
6Br
o Tffi-Ir'
O
5
r , t r
10
' '
ol th€ Younggr
Thlckn€3s
(stcopi
lh€ ssh) (cm)
' 1 "
15
Dtyla
"
1
20
llll
Frc. 8. The thicknes: of the ash bed versuslhe rest
(same cores
of the Younger Dryas silt in Lerstadvatn
as used for Fig. 6).
into account the transport possibilities, the
geochemical composition (Fig. 12) clearly
suggeststhat the Vedde Ash originated
from lceland or from submarine areas
around Iceland.
The thickness of the Vedde Ash' some
1300km from the probable source, suggests
that even if it had been deposited during
exceptionalweather conditions, it must
have originated from a catastrophic eruption. The production of such an enormous
ash layer consisting of pure glass is compatible with a subglacial or subaquatic
eruption. About 10,600yr B.P. most of lceland was covered by an ice sheet (Einarsson. 1968, 1973;Andersen' 1981);
hence, the assumption of a subglacialor subaquatic eruption does not suggest some
specific volcanoes as the source of the
Vedde Ash.
G E O C H E M I S T R YO F T H E V E D D E A S F ,
Electron microprobe analyses of the vitric fragments were carried out with an
ARL SEMQ and a standardwavelength dispersive technique (Reed, 1975), using an
accelerating voltage of 15 V and a beam
current of 5 nA. A mixture of minerals, synthetic oxides, and pure metals were em-
92
MANGERUD ET AL
Frc. 9. Scanningelectron microscopephotos of glass shardsfrom the Vedde Ash. The letters indicate the different types describedin the text. Types A and D, and B and E look similar under SEM.
The bars are 100 um.
NORWEGIAN
LATE GLACIAL
93
TEPHRA
S I L T
)
6
, , '
c
/
/.
r.i
' '
. . j . r .. . r . . . , _ /
f -*:1'.*j>':f..
f -.|;irl:..
'
-sb''-'ro'-ft-
:
1
\.,
. uotourless g
lass sha
sE-h;,d;
ic.Eurcs
lri Brown
g l a s s shards
B r o w n glass
shards
,*O.r"^ff,
Length ot a axis (!rm)
F t c . 1 0 . A p l o t o f t h e l o n g e s t( a ) a x i s v e r s u s t h e n e x t
l o n g e s t ( b ) a x i s o f t h e g l a s s s h a r d s i n o n e s a m p l ef r o m
T o r v l o m y r a ( c o r e 5 0 2 - 3 2 - 0 1d. e p r h 6 1 4 c m ) .
l l
//
Torvl6myro
634
625
',/
/
/' l-nr-o",
or sraire'l
l--Estimatedweight]
./
,',"f.,**T
ployed as standards. Net peak intensities,
n size (!m)
corrected for dead-time effects and beam_
Ftc. l l. Grain-size distribution of the Vedde Ash.
current drift as monitored from the obiec_ g i v e n
as cumulative frequency of number of glass
t i v e a p e r t u r e . w e r e r e d u c e db y M A G I C I V s h a r d s ( t h e I o n g e s t a x i s a s
measuredin the micrcr( C o l b y , 1 9 6 8 ) . T h e a v e r a g e m i c r o p r o b e scope). For the samples from Torvl@myra, the
num_
analyses are shown in Thbles 2 and 3. All b e r s i n d i c a t e t h e d e p t h i n c e n t i m e t e r s . T h e d a s h e d
Na2O values are omitted because of sisnif_ curve is the sample from Lerstadvatn, recalculated to
show cumulative weight-percentdistribution. as nor_
i c a n t l o s s d u r i n ga n a l y s i s .
m a l l y p r e s e n t e df o r s e d i m e n t s .
Compositionallythe Vedde Ash is bi_
modal, being of basic and rhyolitic com_
positions, with a gap in SiO2 between 5g and72Vo.Comparedwith typical examples
F r c . 1 2 . C o m p a r a t i v eS i O 2 / K 2 Or e l a t i o n s h i p sb e t w e e n
t h e V e d d e A s h ( c r o s s - h a r c h e da)n d f i e l d s o c i u p i e d b v
v o l c a n i c sf r o m l c e l a n d .J a n M a y e n . a n d L a a c h e rS e e .
Data sources: The Vedde Ash-Fig. l3B; Laacher See
(28 analyses)-Duda anil Schmincke (197g);
Jan
M a y e n ( 2 5 4 a n a l y s e s ) - S . M a a l 6 e ( u n p u b l i s h e dd a r a ) ,
Imsland (1980); Iceland (439 analyses)_Carmichael
(1964), Bailey and MacDonald (1970),
Gr0nvold
(1972), Thorarinsson and Sigvaldason (1972).
Ja_
k o b r s o n a t u l . t 1 9 7 3 .1 9 7 8 t .S i g v a l d a s o n( 1 9 7 4 ) S
, tein_
thorsson (1977), Wood (197g), Jakobsson 0979).
. u r n e s { u n p u b l i s h e dd a r a ) .
W o o d e r o l . ( 1 9 7 9 1F
of Icelandicmagmatictrends tFig. l3t, it
appearsthat the VeddeAsh belongsto the
transitionalalkalineseries,represented,
for
e x a m p l e ,b y t h e w e l l - k n o w nv o l c a n o e s
Hekla, Vatnafioll,and Katla. For this mas_
matic series,Jakobsson(l9lg) definesbI_
saltic andesiteson the basisof MgO con_
tent, i.e., 2% < MgO < 4.5To.Usingthis
classification, there are about equal
amountsof basaltand basalticandesitein
the VeddeAsh (Table2).
The basalticcomponentof the Vedde
Ash is very similar in compositionto the
basalticasheserupted from Katla (Fie.
l3D). and Eldgie(p. tmsland,t982writren
communication).
Particularlythe high TiO2
content (about 4.5%) of the Katla and
Eldgiabasaltlavasand tephra(Jakobsson,
1979;Einarssonel al., 1980),higherthan in
any other Icelandicbasalt,is a very char_
acteristic geochemicalfeature, and indeed
comparableto the Vedde Ash (average
433% TiO2, Table2). In historicaltimes.
Katla has erupted only basaltictephra,
though traces of acid to intermediatexe_
94
MANGERUD ET AL
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NORWEGIAN
LATE GLACIAL
TABLE 3. Avrnecn MrcnopnonrANalysps or. Asn
ZoNE I rN rue Nonrs ArleNrrc OcEaN
Rhyolite
v28-14" K-708-1, v28-t4
(n:10)' (n:6)
(n-6)
K_708_l
(n:3)
si02
Al2o3
Ti02
FeOt
MnO
Mgo
CaO
Kzo
48.46
14.49
1.70
I1.33
0 .l 9
7.92
l1.80
o.22
48.63
14.04
2.O2
12.00
0.25
7.50
11.47
0.24
70.25
13.73
0-42
3 . 75
0.17
o,23
t.30
3.01
69.47
13.95
0.20
3.89
0 .I I
0. t4
1.32
2.91
Total
9 6 . 11
96.15
92.86
91.99
o Core V28-14,depths
1 0 9a n d I l 2 - I 1 4 c m ( K e l l o g g
et a\.,1978).
' C o r e K - 7 0 8 - 1 ,d e p t h
59 cm (Ruddimanand Glover.
1972,1975\.
' n - number of analyses.
TEPHRA
95
clusioncan be drawn, partly due to the lack
of chemicaldataon prehistoricKatla ashes.
Another possible,but less likely, expla_
nation is that the bimodal Vedde Ash rep_
resents ashes from two simultaneous,
major Icelandiceruptions,i.e., one producing the basaltic to basaltic andesite
ashes,the other producingthe rhyolitic
ashes,or morelikely in Iceland(p. Imsland.
1982,written communication),one prod,ucingthe basaltand another prodtrcingthe
intermediateand acid components.Accordingto Jakobsson(1979),such a coin_
cidencemay have taken place once in Ice_
land in historical time, althoughit is more
common that a small eruption occurs si_
multaneouslywith a large one (p. Imsland,
1982,written communication).
SEARCHFOR ASH BEDS OF
nolithsand pumicedo occurin these(Thor_
D I F F E R E NA
T G E SI N T H E
arinsson,1975;Einarsson
et al.,l9g0).This
AIesuruo
AREA
may, however, have been different in pre_
In order to use the VeddeAsh Bed as a
historic times, as Jakobsson(1979,p. 36)
stratigraphic
marker, it is important to
writes:
know if ash beds of different agesexist in
No intermediate or acid eruptions appear to
the area. We have thereforecounted -covslass
have been assigned to the swarms by any author,
particlesin cores from Lerstadvatn,
though Thorarinsson (1975) mentions that most
ering the time span from approximately
of the tephra layers from Katla contain inter_
12,300to 9000yr B.P. (Fig. 14).
mediate and acid grains. In soil profiles south of
Myrdalsjrikull at least four coarse grained light
Constantvolume(1-cm3)sampleswere
tephra layers can be seen, two of which are astaken continuouslythrough the cores. The
sociated with dark layers. It appears probable
organic matter was removed and Lycooo_
that these acid layers originate from beneath
dium
spore tablets (Stockmar, l97lj were
Myrdalsjokull, probably from the Katla area.
added.Glassand other minerogenicparti_
S. Thorarinsson(1982,written communi_ cles larger than
15 pm were countedunder
cation) statesthat at least two, and prob_ a polarizingmicroscope.
A glass-particle_
ably many more, prehistoricKatla beds influx diagram(Fig.
l4) was constructedin
contain small amounts of light tephra be_ the same way
as pollen-influx diagrams.
sidesthe dominatingdark tephra.A char_ The method used
is similar to that de_
acteristic feature of the rhyolitic ashesre_ scribedby Kaland
and Stabell09gl) for
ported here is their high total FeO content diatoms.
The sedimentation
ratesare based
(Tables2 and 3). Accordingro H. Sigurdsson on the
mean of severalradiocarbondates
(1983,written communication),rhyolitic from
different lakes. The uncertaintiesare
obsidianswith this featureare known from consideredinsignificant
for the main trends
the nunataks on the rim of the Katla of the glass-influx
diagram.
caldera.Thus, possiblythe VeddeAsh rep_
Glassshardswerefoundin everysample,
resentsa major Katla eruption, yielding and they frequently
constituted5-10% of
both basalticto basalticandesiteand rhyol the minerogenicparticles,
even durine the
litic tephra,but we stressthat no firm con_ Late Weichselian
where the organic co"ntent
96
MANGERUD ET AL
Hekla
Vestmannaeyjar
Thingmuli
a
o
Y
60
S i O z( % )
FeOr(%)
98
MANGERUD
E
E
a
o
o
% glass ol
minerogenic particles
ET AL
Influx ot glass shards
no/cm2 year
1C,200
10,600
11.O00
FIc. 14. Frequencyofglassshardsinsedimentscoveringtheperiod9000-l2,300yrB.P.inLerstadvatn. The given ages are means for several dates from different lakes. See Figure -5for legend for lithos t r a t i g r a p h y .T h e u p p e r c o r e ( c o v e r i n g t h e p e r i o d 9 0 0 0 - 1 0 , 2 0 0y r B . P . ) i s f r o m t h e d e e p e s tb a s i n a n d
penetrated the Younger Dryas silt, which is used for correlation of the two cores. The lower core
( f r o m 1 0 , 2 0 0y r B . P . a n d d o w n w a r d s ) i s f r o m t h e s h a l l o w b a s i n .
and in the core from Krikenes (Figs. 2 s a m p l e i s c o a r s e r t h a n 6 3 p m . T h e a s h
and 5).
found approximately l0 cm above the hoFrom Blom@y(Fig. 2); (Mangerud,1970) rizons dated 10,380 -f 170 (T-33624) and
no wholecoreis available.In a bulk sample 1 0 , 5 4 0+ 1 7 0y r ( T - 1 0 4 0 ) ,a n d 5 0 c m b e l o w
of the upper5 cm of the YoungerDryassilt, a l e v e l d a t e d 1 0 , 2 8 0 ' - 1 8 0 y r B . P . ( T g l a s si s a b u n d a n t .I n S e k k i n g s t a d t j / n n , 3583,4).These dates are within the range of
Sotra (Krzywinsky and Stabell,1982),a the dates we obtained for the Vedde Ash.
distinct ash bed, nearly I cm thick, was
F e g r i ( 1 9 4 0 ,p p . 1 0 3 - 1 0 5 ) d e s c r i b e da n
found in sublittoralmarine silt at a depth of ash layer at Eigebakken, Jeren (Fig. 2), asll27 cm. Accordingto Krzywinskiand Sta- sumed to be of Aller@d age, and he sugbell (1982)(Fig. 15),the ash bed is in the g e s t e d a p o s s i b l e c o r r e l a t i o n w i t h t h e
middleor lower part of the YoungerDryas. Laacher See ash. However, Frechen (1952)
In the basinat 38 m altitudeat Yrkje (An- demonstrated that the Eigebakken ash did
undsenand fieldskaar, 1983),there is a not originate from the Laacher See area.
very distinct glass peak at 692-694 cm The strong increase of nonaboreal pollen
depth,the 63-pmfractionbeingnearlypure below the ash layer at Eigebakken may inglass.However,only a smallportionof the dicate that the ash is of Younger Dryas age,
NORWECIAN LATE CLACIAL
F i e t dd e t j n e db y . - t h e V e d d eA s h \ - z
. Sognesjoen
r T h ec o n t .s h e l f
@Norwegon Seo
A
,ul
8
99
TEPHRA
l
o -
North Atlontic Oceon/////.
t \ ' 1 2 8 - 1, t1 1 2 - l 1 4 c m
^ V 2 8 - 1 4 l, 0 9 c m
oK708-1,59cm
+ K 7 0 8 - 1 , 6 0 c m A s hZ l
o
L
6
*
ool
> (
frnm (in,'rdc<^n 1qR7)
F€ot($)
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--q.--
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'r--r
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53
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rt
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/ x)'
L
.
,{
\Ke-J
/
N/
sro2($)
2
3
FeOr/ MgO(%)
"ch zone I from fhe Norltr Al"lantic, the Norwegian Sea. "n.l the
FIC- 15. The geochemioryof
Norwegian continerrtal she'lf compared with thear'€dal€ Aslt3ed.For
our samples each plot represenls
o n e a n a l y s i s . A c c o r d i n g t o S i g u r d s s o n( 1 9 8 2 )h i s r h y o l i t i c s a m p l e i s t h e m e a n o f 2 0 a n a l y s e s ,t h e r w o
basic sampleseach the mean of three analyses.
100
MANGERUD ET AL
a reinterpretation with which K. Frgri
(198l, personal communication), agrees.
All the ash beds described from south of
Krikenes may possibly correlate with the
Vedde Ash; at present, this seemsto be the
most likely, though not proven, conclusion.
North of Alesund an ash bed has recently
been found in several basins around Krist i a n s u n d ( F i g . 2 ) ; ( O . I . J o h a n s e n ,K . E .
Henningsmoen, and J. L. Sollid, 1982,personal communication). The lithostratigraphic position suggests that it is the
Vedde Ash.
s c r i b e db y G o d v i k ( 1 9 8 1 ) ,S t e n s l a n d( 1 9 8 2 ) ,
and Jansen et al.(in press) (Table 2). They
show great similarities in all respects with
the Vedde Ash except for some minor discrepanciesregarding FeO and CaO (Fig. 15,
Table 2). We therefore conclude they all
should be correlated with the Vedde Ash, a
correlation supported by all the above cited
authors.
Fciroe Islands
On the Fdroe Islands a 7-mm-thick gray
ash bed is described and dated to approximately 9200 yr B.P. (Waagstein and JoContinental Shelf and l,lorwegian Sea
h a n s e n , 1 9 6 8 ;J o h a n s e n ,1 9 7 5 ) .T h i s a s h i s
ln marine sediments bioturbination may
clearly younger than the Vedde Ash, but is
efficiently mix the glass with sediments
mentioned here because it may be correabove and below. In all the marine cores
lated with deep-sea ash beds (Sigurdsson
mentioned below, the ash beds were only
and Loebner, 1981).The F;iroe Islands proidentified through the counting of particles.
file did not penetrate the Younger Dryas,
An ash bed was found both in a core outand thus it is unknown whether the Vedde
s i d e M a r s t e i n , B e r g e n( K . B j @ r k l u n d ,1 9 8 1 ,
Ash is present at greater depth.
personal communication), and on the continental slope (Fjreran, 1980)before we discovered it in lacustrine sediments.The age Iceland
estimates were, however, much more unIn Iceland a detailed tephrochronology
certain due to the problems of radiocarbon has been establishedfor the last 7000-8000
dating of marine sediments.
yr (Thorarinsson, l98lb). Investigations of
In several cores from Sognesjpen (Fig. o l d e r a s h b e d s a r e h a m p e r e d b y m u c h
2 ) , S t e n s l a n d( 1 9 8 2 )a n d S e l a n d ( 1 9 8 1 )d e - s l o w e r p e a t a c c u m u l a t i o n . T h e r e f o r e , a t
scribe ash beds, and in at least one core p r e s e n t i t i s i m p o s s i b l e t o c o r r e l a t e t h e
there are two distinct ash zones. The geo- Vedde Ash with a particular tephra bed in
chemistry of the glass in the two zones, Iceland.
however, is identical and, for both beds,
similar to the Vedde Ash (Fig. 15, Table 2).
North Atlantic
It is unknown whether these two beds repThe North Atlantic ash zone I has apresent two ashfalls with identical composiproximately
the same stratigraphicposition
t i o n , o r r e d e p o s i t i o no f a s i n g l e a s h f a l l .
Ash, and is extensively used
(1981)
four
as
the
Vedde
has found one ash bed in
Godvik
(e.g., Ruddiman and Mcthe
for
correlations
cores from the Norwegian trench on
Ruddiman et al., 1977',
1973,
1981;
Intyre,
continental shelf southwest of Sognesjgen
( F i g . l ) . J a n s e n( 1 9 8 1 )a n d J a n s e ne t a l . ( i n Kellogg et al., l9l8 Duplessy et al., 1981).
press) describe an ash bed in many cores The most recent age estimates bracket the
from the continental slope and the Norway a g e o f t h e a s h p e a k b e t w e e n l 1 , 0 0 0a n d
Basin in the southern part of the Norwegian 9000 yr B.P., the most probable age being
Sea. The cores are from a maximum water 9800 yr B.P. (Duplessy e/ al., l98l; Ruddiman and Mclntyre, l98l). Ruddiman anc
depth of 2285 m.
g
e
o
c
h
e
m
i
c
a
l
l
y
Glover (1912, 1975)demonstrated that ash
s
a
m
a
n
a
l
y
z
e
d
We have
ples of glass from some of the cores de- zone I was deposited from sea ice and ice-
NORWEGIAN
LATE GLACIAL
bergs drifting out of the Norwegian Sea
through the Denmark Strait between Iceland and Greenland.
A sample of ash zone 7 from core K-708I and two samples from core V28-14 (Fig.
l) were kindly provided by W. Ruddiman,
A. Mclntyre, and T. Kellogg. The North
Atlantic basaltic ashes contain microphenocrysts of olivine and plagioclase,
whereas all investigated samples of the
Vedde Ash are aphyric.
Our results combined with those of Sigu r d s s o n ( 1 9 8 2 )i n d i c a t e t h a t a s h z o n e I
contains three geochemical populations
(Fie. l5):
(a) A rhyolitic component that is similar
to the Vedde Ash. This component makes
up the bulk of both ash zone I and the
Vedde Ash. All the analyzed rhyolitic glass
shards from the Vedde Ash proper, the continental shelf, the Norwegian Sea, and the
North Atlantic plot as one group for all elements (Fig. l5).
(b) A basaltic and andesitic component
that is similar to the Vedde Ash, or plots on
its extended trend (Fig. l5).
(c) A basaltic component that differs entirely from the Vedde Ash in having much
lower TiO2, FeOt, and K2O contents and
higher Al2O3, MgO, and CaO contents
(Thble 3, Figs. l5A,B). In the MgO/FeOt
diagram (Fig. l5C) they define a FeOt enrichment with decreasing MgO, typical of
the tholeiitic trend and in strong contrast to
the other ashes dealt with in this study.
Similar contrasts are apparent in the SiO2
and TiO2 vs FeOt/MgO diagrams (Figs.
l5D,E). Most, if not all, of our analysesof
the basaltic shards from ash zone | (Thble
3, Fig. l5) should be included in this group.
We cannot point out why Sigurdsson
(1978) and we obtained different distributions (Fig. l5) of the basaltic and andesitic
shards from ash zone L One explanation
may be that we analyzed slightly different
stratigraphiclevels; alternatively,the selection of grains for analysis was not random.
Whatever the explanation, the analysestog e t h e r d e m o n s t r a t et h a t t w o p o p u l a t i o n s ,
TEPHRA
l0l
representing two different eruptions, are
present.
The similar geochemical composition of
the bulk of glass shards does not unambiguously demonstrate that ash zone I contains the Vedde Ash until it is proven that
there were no other eruptions with a similar
composition in the time interval in question. However, according to H. Sigurdsson
(1983. written communication). the Vedde
Ash and ash zone I are atypical for rhyolitic
glassesfrom Iceland, in having a very high
iron content. If the rhyolitic component of
the Vedde Ash and ash zone I does not represent the same eruption, the alternative
might be that they represent two different
huge eruptions of the same volcano, probably Katla. The atmospheric transport of
the Vedde Ash from Iceland to Norway led
to a considerable deposition of ash in the
Norwegian Sea, which at that time was ice
covered most of the year (Jansenet al., in
press); thus a transport by drifting ice to
the North Atlantic, as postulated by Ruddiman and Glover (1972, 1975)for ash zone
l . a p p e a r sv e r y l i k e l y .
We conclude that the bulk (populations a
and b) of ash zone I in the North Atlantic
is derived from the same ashfall as the
Vedde Ash. However, ash zone I also contains shardsfrom at least one other eruptive
source. This appears very likely as ash
zone I contains ash originally deposited on
drifting ice close to lceland and certainly
also ash from icebergs from the Younger
Dryas ice sheet in Iceland. More detailed
work on ash zone 1 will probably demonstrate that it contains shards from additional eruptions, possibly in a stratigraphic
order.
If the correlation of the Vedde Ash and
ash zone I is correct. the conclusion is that
the time scale for the North Atlantic (e.g.,
Ruddiman and Mclntyre, 1973,l98l) is
some hundreds of years off. This has considerable implications for the interpretations of the oceanic and climatic development during the Younger Dryas and Early
Holocene.
r02
MANGERUD ET AL
C O N C L U S I O NC
SO N C E R N I N T
GH E
G E O G R A P H I C ADLI S T R I B U T I O N
From the Iceland region the Vedde Ash
spreadeastward,beingthus far found in the
southernpart of the NorwegianSea,on the
Norwegian continentalshelf, and in lacustrine and marine sedimentsin western
Norway. The width of the ash plume as it
reached Norway appearsto have been at
l e a s t 5 0 0 k m , b u t p o s s i b l yw a s m u c h
greater. The N-S distribution in Norway
should be easily mappablein lake sediments.Thereis a good chancethat the ash
rain also reached the FAroe and Shetland
islands.Possiblythe ash will also be found
in Denmarkand southernSweden,and perhapsevenin the varvedclay,in which case
it could provide an important correlation
tool.
The spreadof the ash to Norway was
probably a very short-lived event, due to
extremeweatherconditionsspanningonly
a few days. If the eruptionwas longer,the
wind direction may have changed,thus
giving the ash a wider distribution around
Icelandthan is indicatedby the width of the
plume reachingNorway.
The bulk of ash zone I in the North Atlantic is probably ash from the sameeruption as the VeddeAsh, primarilydeposited
on seaice in the NorwegianSeaand trans_
ported with the ice through the Denmark
Strait into the North Atlantic.
ACKNOWLEDGMENTS
Ash samples were kindly provided by, and the re_
sults discussed with, William F. Ruddiman and Andrew Mclntyre (Lamont-Doherty Geological Obser_
vatory, Columbia University), Thomas B. Kellogg
(University of Maine), BjOrg Stabell (Universitv
;i'
Oslo). lnge Aarserh. Karl Anundsen. Kjell Bjorklund,
J o h n y C o d v i k , E y s t e i n J a n s e n ,K n u t K r z y w i n s k i , a n d
Dag Stensland (University of Bergen). W. F. Rud_
diman and T. B. Kellogg also read through an earlier
draft of the manuscript. pall Imsland and Sigurdur
T h o r a r i n s s o n { U n i v e r r i l y o f l c e l a n t l ) p r o v i d e - dd a t a
from Icelandic volcanoes, commented on our interpretations, and read the manuscript critically. Sven
Maaloe (University of Bergen) permitted us to use un_
published data from Jan Mayen. All the radiocarbon
analyses were made at the Trondheim laboratorv.
under supervision of Reidar Nydal and Steinar Gul_
liksen. The interpretations ofthe dates were on several
occasions discussed with S. Gulliksen. Eivind SOnsle_
gaard, Hans-Petter Sejrup. and John lnge
Svendsen
collected some of the cores. Ellen Irgens and Jane
Ellingsen made the drawings. Michael Talbot kindly
corrected the English language. The journal,s critical
reviewers, H.-U. Schmincke and Haraldur Sig_
urdsson, suggested several improvements. H. Sig_
urdsson also provided extremely valuable data for
the
correlations. The work was supported by the Norwe_
gian Research Council for Science and the Humanities
(NAVF) through a gran.t (ro Mangerud)
under IGCpproject 24. To all these persons and institutions
we
proffer our sincere thanks.
REFERENCES
A n d e r s e n , B . G . ( l 9 S l ) . L a r e W e i c h s e l i a ni c e
sheets
in Eurasia and Greenland. 1n ..The Last Great
Ice
Sheets" (G. H. Denton and T. S. Hughes, Eds.),
pp. 3-66. Wiley, New york.
A n u n d s e n , K . , a n d F j e l d s k a a r , W ( 1 9 S 3 ) .O b s e r v e d
and theoretical late Weichselian shore_levelchanses
related to glacier oscillations at yrkje. southw-est
Norway. In "LaIe- and postglacial oscillations
of
glaciers: glacial- and periglacial forms,, (H.
S c h r o e d e r - L a n z , E d . ) , p p . 1 3 3 _1 7 0 .B a l k e m a . R o t _
terdam.
B a i l e y , D . K . , a n d M a c D o n a l d , R . ( 1 9 7 0 ) .p e r r o c h e m _
ical variations among mildly peralkaline (comendite)
obsidians from the oceans and continents. Conlrlbutions to Mineralogy and petrology 2g,340_351.
Baldridge, W. S., McGetchin, T. R., and Frey. F
A.
( I973). Magmaric evolution of
Hekla, lcelani. C.rn_
tributions to Mineralogy and petrology 42, 245_
258.
Bugge, T. (1980). @vre lags geologi pi kontinentalsok_
kelen utenfor Mpre og Tipndelag. Continental Shelf.
Institute lO4.
Carmichael, L S. E. (1964). The petrology of Thingmuli, a Tertiary volcano in eastern Icelan<1.Journil
of Petrology 5, 435-460.
C o l b y , J . W . ( 1 9 6 8 ) .1 n " A d v a n c e s i n X - R a y A n a l v s i s , ,
tJ. B. Newkirk. C. R. Mallell. and H. C. pteimer.
Eds.t. Vol. I l. plenum, New york.
Duda, A.. and Schmincke, H.-U. (1973).
euarernary
basanites, melilite nephelites and tephites from thl
Laacher See area (Germany). Neues Jahrbuch
filr
Minerulogie Abhandlungen 132, I _33.
D u p l e s s y ,J . C . , D e l i b r i a s , G . , T i r r o n , J . L . , p u j o l ,
C.,
and Duprat, J. (1981).Deglacial warming of the
northeastern Atlantic Ocean: Correlation with the
paleoclimatic evolution of the European
continent.
Palaeogeography, palaeoclimatology, palaeo_
ecology,35,12l-144.
Einarsson, E. H., Larsen, G., and Thorarinsson.
S.
(1980). The Solheimar lephra layer
and the Katla
eruption of - 1357. Acta Naturalia Islandica 2g.
1-24.
N O R W E G I A N L A T L GLACIAL
TEPHRA
103
"Jardfradi:
Soga bergs og
Einarsson, Th. (1968).
"
lands. Heimskringla, Reykjavik.
"Arctic
E i n a r s s o n , T h . ( 1 9 7 3 ) .G e o l o g y o f l c e l a n d . I n
Geology" (M. G. Pilcher, Ed.), Vol. 19, pp. 171173. American Association of Petroleum Geolo'
gists,Memoir
"Kvarterstratigrafiske unders/Fjeran, T. (1980).
kelser av sedimentkjerner fra kontinentalskriningen
utenfor M/re." Thesis, University of Bergen.
Frechen, J. (1952). Die Herkunft der spiitglazialen
Bimstuffe in mittel- und siiddeutschen Mooren.
Geologi sche J ahr b uc h 67, 209-230.
stratigraphy and paleoclimatology of Norwegian Sea
d e e p - s e ac o r e s . B o r e a s 7 , 6 l - 7 3 .
Krzywinski, K., and Stabell, B. (1982). Late
Weichselian sea level changes at Sotra, Hordaland,
"The
Response of Diatom
western Norway. 1n
Floras during Late Quaternary Shore Line Displacement in Southern and Western Norway," pp.2'7ll5. B. Stabell, D. Sc. thesis, University of Oslo.
L a r s e n , E . , a n d M a n g e r u d , J . ( 1 9 8 1 ) .E r o s i o n r a t e o f
a Younger Dryas cirque glacier at Kr6kenes,
western Norway. Annals of Glaciology 2, 153-158.
L a r s e n , G . , a n d T h o r a r i n s s o n , S . ( 1 9 7 8 ) .H a a n d o t h e r
acid Hekla tephra layers. Jokull 27,28-46.
Fagri, K. (1940). Quartiirgeologische Untersuch"En
lito-og biostraL/mo, L., and Lie, S. E. (1981).
ungen im westlichen Norwegen: II. Zur spiitquarm
a
rine og limniske
t
i
g
r
a
f
i
s
k
u
n
d
e
r
s
/
k
e
l
s
e
a
v
A
r
b
o
k
tdren GeschichteJarens. Berpens Museums
sedimenter i Alesundomridet." Thesis, University
Naturvitenskapelig rekke 7, 1 -201.
"Kvarteer
of Bergen.
stratigrafi i Norskerenna,
Godvik, J. (1981).
Mangerud, J. (1970). Late Weichselian vegetation and
vest for Sogn." Thesis, University of Bergen.
"Structural
ice-front oscillations in the Bergen district, western
and Petrochemical
Grdnvold, K. /1972).
Norway. Norsk Geografisk Tidsskrift 24, l2l-148.
Studies in the Kerlingarfi@ll Region, Central IceMangerud, J., Andersen, S. T., Berglund, B. E., and
land." Ph.D. thesis. University of Oxford.
Donner, J. J. (1974). Quaternary stratigraphy of
Imsland, P. (1978a). The petrology of Iceland, some
Norden, a proposal for terminology and classificageneral remarks. Nordic Volcanological Institute
tion. Boreas 3, 109-128.
78/08.
Mangerud, J., Larsen, 8., Longva, O., and S@nsteImsland, P. (1978b). The geology ofthe volcanic island
gaard, E. (1979). Glacial history of western Norway
Jan Mayen, Arctic Ocean. Nordic Volcanobgical
1 5 , 0 0 0 - 1 0 , 0 0 0B . P . B o r e a s 8 , 1 ' 7 9 - 1 8 7 .
78/13.
Institute
M a n g e r u d ,J . , L i e , S . 8 . , L @ m o ,L . , K r i s t i a n s e n ,
Imsland, P. (1980). The petrology of the volcanic isI. L., and Furnes, H. (1980). Et vulkansk askelag
land Jan Mayen, Arctic Ocean. Nordic Volcanofra Yngre Dryas pi Sunnmgre. Geobgnytt 15.
lo g ic al I ns tit ute. 80/03.
Persson, C. (1967). Forsok till tefrok-ronologisk daJakobsson, S. P (1979). Petrology of recent basalt of
tering i tre norska myrar. Geologiska Foreningens i
the eastern volcanic zone, lceland. Acta Naturalia
Stockholm FQrhandlinger 89, 181- 197.
Islandica 26, 103.
J a k o b s s o n , S . P . , J o n s s o n , J . , a n d S h i d o , F . ( 1 9 7 8 ) . Persson, C. (1971). Tephrochronological investigation
of peat deposits in Scandinavia and on the Faroe
Petrology of the western Reykjanes Peninsula, lcelslands.,Sveriges Geologiska Undersdkning Serie
land. Journal o.f Petrology 19, 669-'105.
J a k o b s s o n ,S . P . , P e d e r s e n ,A . K . , R p n s b o , J . G . , a n d
Melhcior Larsen, L. (1973). Petrology of mugearitehawaiite: Early extrusives in the 1973 Heimaey
eruption, Iceland. Lilhos 6, 203-214.
"Sen-kvartar stratigrafi og tidlig
Jansen, E. (1981).
diagenese i sedimenter fra det s/r-pstlige Norskehav." Thesis, University of Bergen.
Jansen,E., Sejrup, H.-P., Fieran, T., Hald, M., Holtedahl, H., and Skarbo, O. (in press). Late
Weichselian paleooceanography of the southeastern
Norwegian Sea. Norsk Geologisk Tidsskrift.
Johansen, J. (1975). Pollen diagrams from the Shetland
and Faroe islands. New Phytologist 75' 369-38'7.
J u v i g n 6 , E . ( 1 9 8 0 ) .V u l k a n i s c h e S c h w e r m i n e r a l ei n r e zenten Boden Mitteleuropas. Geologische Rundschau 1980.982-996.
K a l a n d , P - E . , a n d S t a b e l l , B . ( 1 9 8 1 ) .M e t h o d s f o r a b solute diatom frequency analysis and combined
diatom and pollen analysis in sediments. Nordit
Journal of Botany 1,697-700.
K e l l o g g , T . 8 . , D u p l e s s y , J . C . , a n d S h a c k l e t o n ,N . J .
(1978). Planktonic foraminiferal and oxygen isotopic
c 6s6.
"Electron
Microprobe AnalReed, S. J. B. (1975).
yses." Cambridge Univ. Press, Cambridge, Mass.
Risse, R., Schminche, H.-U., Bogard, P. v. d., and
Worner, G. (1980). Dispersal of the Laacher See
Tephra. International Association of Sedimentologists. First European Meeting, Bor:hum 255.
Ruddiman, W. F., and Glover, L. K. (1972). Vertical
mixing of ice-rafted volcanic ash in North Atlanlic
sediments. Geobgical Society of America Bulletin
83.2817-2836.
R u d d i m a n , W . F . , a n d G l o v e r , L . K . ( 1 9 7 5 ) .S u b p o l a r
North Atlantic circulation at 9300 yr B.P.: Faunal
evidence. Quaternary Research 5, 361-389.
Ruddiman, W. F., and McIntyre, A. (1973).Timetransgressive deglacial retreat of polar waters from
the North Atlantic. Quaternary Research 3, l17I 30.
R u d d i m a n , W . F . , a n d M c l n t y r e , A . ( 1 9 8 1 ) .T h e N o r t h
Atlantic Ocean during the last deglaciation. Paleogeography, Paleoclimatology, Paleoecolosy 35,
1 4 5- 2 1 4 .
Ruddiman, W. F., Sancetta,C. D., and Mclntyre, A.
104
MANGERUD
(1977). Glaciall Interglacial response rate of subpolar
North Atlantic waters to climatic change: The record in oceanic sediments. Philosophical Transactions o.f the Royal Society of London 280, ll9-142.
Seland, R. T. (1981). "Biosrratigrafiske og
a k u s t i s k e u n d e r s / k e l s e r i S o g n e s j @ e n . "T h e s i s ,
University of Bergen.
Self, S., and Sparks, R. S. J. (Eds.) (198t). "Tephra
Studies." Reidel. Dordrecht.
S i g u r d s s o n , H . , a n d L o e b n e r , B . ( 1 9 8 1 ) .D e e p - s e a
record of Cenozoic explosive volcanism in the
North Atlantic. /n "Tephra Studies" (S. Self and
R. S. J. Sparks,Eds.), pp. 289-316. Reidel, Dordrecht.
Sigurdsson, H. (1982). Utbreidsta islendskra gj6skulaga 6 botni Atlanthafs. 1n "Eldur er i Nordri," pp.
l 1 9- 1 2 7. S 6 g u f 6 l a g ,R e y k j a v i k .
S i g v a l d a s o n ,G . E . ( 1 9 7 4 ) . B a s a l t s f r o m t h e c e n t r e o f
the assumed Icelandic mantle plume. Journal of petrology 15,497-524.
S t e i n t h o r s s o n ,S . ( 1 9 7 7 ) . T e p h r a l a y e r s i n a d r i l l c o r e
from the Vatnaj/kull ice cap. Jpkull 27, 2-27.
Stensland, D. (1982). "sedimentologiske og
a k u s t i s k e u n d e r s @ k e l s e ri S o g n e s j p e n . " T h e s i s ,
University of Bergen.
Stockmar, J. (1971). Thblets with spores used in absolute pollen analysis. Pollen et Spores 13, 615621.
Thorarinsson, S. (1975). Katla og ann6ll Kritlugosa.
Arb6k Ferdoftlulqs Islantls 1975, 124-149.
Thorarinsson, S. (l98la). Tephra studies and tephrochronology: A historical review with special reference to Iceland. 1n "Tephra Studies" (S. Self and
R . S . J . S p a r k s ,E d s . ) ,p p . l - 1 2 . R e i d e l ,D o r d r e c h t .
Thorarinsson, S. (l98lb). The application of tephrochronology in Iceland.In "Tephra Studies" (S. Self
ET AL
a n d R . S . J . S p a r k s , E d s . ) , p p . 1 0 9 _ 1 3 4 .R e i d e l .
Dordrecht.
Thorarinsson, S. (l98lc). Greetingsfrom Iceland.
Ash-falls and volcanic aerosols in Scandinavia. Geo_
g r a J i s k aA n n a l e r 6 3 a , 1 0 9 - 1 1 8 .
T h o r a r i n s s o n , S . , a n d S i g v a l d a s o n ,G . E . 0 9 7 D . T h e
Hekla eruption of 1970.Bulletin Vok.anologique 36,
269-288.
Tomasson, J. (1967). Hekla's magma. In ..lceland and
M i d o c e a n R i d g e s " ( S . B j @ r n s s o nE
, d.), Vol. 3g, pp.
1 8 0 - 1 8 9 . S o c i e t a sS c i e n t i a r u m I s l a n d i c a , R i t .
U s i n g e r , H . ( 1 9 7 8 ) . B o l l i n g - I n t e r s t a d i a lu n d L a a c h e r
Bimstuff in einem neuen Spiitglazial-profil aus dem
VallensgArd Mose/tsornholm. Mit pollen-grossensta_
tistischen Tiennung der Birken. Danmarks Geolo_
g i s k e U n d e r s ; t g e l s e ,A r b o g 1 9 7 7 ,5 _ 2 9 .
W a a g s t e i n ,R . , a n d J o h a n s e n ,J . ( 1 9 6 8 ) .T i e v u l k a n s k e
askelag fra Far@erne. Medtlelelser Dansk Geolopisk
Forening 18,257-264.
W a l k e r , G . P L . ( 1 9 7 1 ) . G r a i n - s i z e c h a r a c t e r i s t i c so f
pyroclastic deposits. Journal oJ Geoktgy 79, 696_
714.
W e s t g a t e ,J . A . , a n d G o r t o n , M . p . ( l 9 g l ) . C o r r e l a t i o n
techniques in tephra studies. In .'Tephra Studies"
(S. Self and R. S. J. Sparks, Eds.), pp. 73_94.
Reidel. Dordrecht.
Wood, D. A. (1978). Major and trace element variations in the Tertiary lavas of eastern Iceland and
their significance with respect to the Iceland seo_
c h e m i c a f a n o m a l y . J ( ' u r n d l o f p e t r t t l 1 t g . 11.9 , 1 9 3 436.
Wood, D. A., Joron, J.-L., Tieuil, M., Norry, M., and
fbrney, J. (1979).Elemental and Sr isotope varia_
tions in basic lavas from Iceland and the sur_
rounding ocean floor. Contrihutions to Mineralopy
antl Petntlttgl'70, I l9-139