off - home | cambridge university press€¦ · bristlecone pine samples on the d6m4 11 scale were...

11
[RnDtocnaaoN, VOL 28, No. 2H, 1986, P 969-979] RADIOCARBON AGE CALIBRATION BACK TO 13,300 YEARS BP AND THE 14C AGE MATCHING OF THE GERMAN OAK AND US BRISTLECONE PINE CHRONOLOGIES MIN7.E STUIVER*, BERND KROMER**, BERND BECKERt and C W FERGUSON+ INTRODUCTION cases Stuiver, 1982 International Study Group, 1982. The use of ues however is not a simple matter because K depends on countin th the recent establishment of an unbroken West European tree- uence spanning the past 7272 Years Pilcher et al 1984 the calibra- the 14C time scale was advanced considerably. It is now possible to chronology as an independent cross-check on the 8681-Year US one Pine series Ferguson & GraYbill, 1983. There also are oppor- for 14C matching wiggle matching between the older portion of tlecone Pine series and floating not tied to the present parts of the German Oak sequence. Linick Suess and Becker 1985 used this h in matching the earliest part of the Bristlecone Pine series with au 6 Main 4/1 1 Becker, 1983 series and thus established a D6M4 o" point tree-ring no. 1 of 72 15 BC. report here 49 high-precision measurements of the D6M4 11 Table 1). Fifteen Bristlecone Pine samples with dendrochronolo - gi- termined ages (6480-6470, 63 0-6350> and 5805-5685 BC also easured Table 2). 14C age matching of the new results confirms the 11 ring 1 age of 7215 BC within a few decades. ving anchored the available 50 Years of the D6M4 11 series to the c scale in this manner results in the 14C age calibration curve from 200 Yr BC given in Figures 3 and 4. A comparison of the D6M4 ts with the Lake ofClouds varve series Stuiver, 1970, 1971) proves ability of this varve sequence for 14C age calibration. This leads in ation with adjusted Swedish varve dates, to tentative age calibration back to 13,300 cal BP (Fig . TECHNIQUE AND INTERCALIBRATION lulose was prepared from all wood samples. The analytical proce- volving sample preparation and CO2 gas counting were discussed sly Stu iver Robinson & Yang, 1979 Stuiver 8c Quay, 98O, 1981). d deviations as well as off sets, need to be considered for an assess- the reliability of the calibration curve. d Deviation e reported standard deviation o in a 14C age determination is tradi- calculated from the Poisson statistics of the accumulated sample ndard counts. This procedure can only underestimate the statistical the laboratory determinations because other factors ao sample nd counting voltage variabilitY also play a role. To account for the 2 al variance r an error multiplier K can be used for well-defined a versity of Washington, Seattle versitat Heidelber versitat Hohenheirn, Stuttgart versity of Arizona, Tucson; deceased March 24, 1986. and sample age. The following relationship applies: 2 Ka _ + c c or K = 1 +1I acl / 2 Standard errors r for Seattle 4-day-counts are ca 17 Years for 1 in the 2000-4000 Yr range. An analysis of reproducibility of duplica leads to an upper limit for K of 1.5 to 1.6 Stuiver & Pearson 1986. tution of K = 1.5 in equation 1 Yields a aa of 19 Years> or 2 K= 1+(191 o.c The dependence of K on counting time or age is illustrated by t lowing examples: 1 Counting the sample twice as long reduces cr by a factor Here the K value Eq 3 is 1.9. 2 Having an older sample with half the 14C activity increases o approximate factor of 1.4. The K value for samples this old is nearly Clearly, K values can be used only within the confines of d counting conditions. The errors in the 14C ages listed in this paper are all based on co statistics alone. According to Eq 3, the error "multiplier" for sam the age range given and for 4-day counts would be 1.3. Off-sets 2 The variance o accounts for the degree of reproducibility of th surements made within a single laboratory. It does not account for s atic errors. Such errors may reflect a simple off-set (caused, e by a activity level of the standard), or they may reflect age-dependent ano egif the "dead" time in counting, which depends on sample a would be imPortant and uncorrected for). 14 The C timescale calibration requires independent determina the 14C activities by two or more laboratories. The magnitude of the o between different laboratories can be estimated from the differen measured 14C ages of duplicate samples. A comparison of 214 sample pairs of wood of identical age, but ferent geographic regions gave an age difference of 0.6 Yr between 969 https://doi.org/10.1017/S0033822200060252 Downloaded from https://www.cambridge.org/core. IP address: 54.39.106.173, on 22 Oct 2020 at 14:58:58, subject to the Cambridge Core terms of use, available at https://www.cambridge.org/core/terms.

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Page 1: off - Home | Cambridge University Press€¦ · Bristlecone Pine samples on the D6M4 11 scale were obtained by 14C matching. The match- ing is imprecise for two samples, and the resulting

[RnD

tocnaaoN, V

OL

28, N

o. 2H,

1986, P 969-979]

RA

DIO

CA

RB

ON

AG

E C

AL

IBR

AT

ION

BA

CK

TO

13,300 YE

AR

S BP A

ND

TH

E

14C A

GE

MA

TC

HIN

G O

F TH

E

GE

RM

AN

OA

K A

ND

US B

RIST

LE

CO

NE

PINE

CH

RO

NO

LO

GIE

S

MIN

7.E ST

UIV

ER

*, BE

RN

D K

RO

ME

R**, B

ER

ND

BE

CK

ER

t and C

W FE

RG

USO

N+

INTRODUCTION

cases Stuiver, 1982 International Study G

roup, 1982. The use of K

val- ues

however is not a sim

ple matter because K

depends on counting time

With the recent establishm

ent of an unbroken West E

uropean tree- ring sequence spanning the past 7272 Y

ears Pilcher et al 1984

the calibra- tion of the

14C tim

e scale was advanced considerably. It is now

possible to use this chronology as an independent cross-check on the 8681-Y

ear US

Brist1econe Pine series

Ferguson & G

raYbill, 1983. T

here also are oppor- tunities unities for

14C m

atching w

iggle matching

between the older portion of

the Bristlecone Pine series and floating not tied to the present parts of the

South Germ

an Oak sequence. L

inick Suess and B

ecker 1985

used this approach in m

atching the earliest part of the Bristlecone Pine series w

ith the D

onau 6 Main 4/1

1 B

ecker, 1983 series and thus established a D

6M4

1 1 "zero" point tree-ring no.

1 of 72 15 B

C.

We report here 49 high-precision m

easurements of the D

6M4

11 series T

able 1). Fifteen B

ristlecone Pine samples w

ith dendrochronolo -

gi-

callY determ

ined ages (6480-6470, 63 0-6350>

and 5805-5685 B

C

also w

ere measured T

able 2). 14C age m

atching of the new results confirm

s the D

6M4

11 ring 1 age of 7215 B

C w

ithin a few decades.

Having anchored the available

50 Years of the D

6M4

11 series to the calendric scale in this m

anner results in the 14C age calibration curve from

6470 to

200 Yr B

C

given in Figures 3 and 4. A com

parison of the D6M

4 1 1 results w

ith the Lake ofC

louds varve series Stuiver, 1970, 1971) proves

the reliability of this varve sequence for 14C

age calibration. This leads

in com

bination with adjusted Sw

edish varve dates, to tentative age calibration results back to 13,300 cal B

P (Fig .

TE

CH

NIQ

UE

AN

D IN

TE

RC

AL

IBR

AT

ION

Cellulose w

as prepared from all w

ood samples. T

he analytical proce- dures involving sam

ple preparation and CO

2 gas counting were discussed

previously Stu iver Robinson &

Yang, 1979 Stuiver 8c Q

uay, 98O

, 1981). Standard deviations

as well as off sets, need to be considered for an assess-

ment of the reliability of the calibration curve.

Standard Deviation

The reported standard deviation o in a 14C

age determination is tradi-

tionally calculated from the Poisson statistics of the accum

ulated sample

and standard counts. This procedure can only underestim

ate the statistical error in the laboratory determ

inations because other factors ao sam

ple purity and counting voltage variabilitY

also play a role. T

o account for the 2

additional variance r

an error multiplier K

can be used for well-defined

a

*University of W

ashington, Seattle **U

niversitat Heidelber

tUniversitat H

ohenheirn, Stuttgart +

University of A

rizona, Tucson; deceased M

arch 24, 1986.

and sample age.

The follow

ing relationship applies: 2 K

a _ +

c

c

or

K =

1

+1I acl / 2

(1)

(2)

Standard errors r for Seattle 4-day-counts are ca 17 Years for 14C

ages in the 2000-4000 Y

r range. An analysis of reproducibility of duplicate runs

leads to an upper limit for K

of 1.5 to 1.6 Stuiver &

Pearson 1986. Substi-

tution of K =

1.5 in equation 1

Yields a aa of 19 Y

ears> or

2 K

=

1+(191

o.c

(3)

The dependence of K

on counting time or age is illustrated by the fol-

lowing exam

ples: 1

Counting the sam

ple twice as long reduces

cr by a factor of 1.4.

Here the K

value E

q 3 is 1.9.

2 H

aving an older sample w

ith half the 14C activity increases o

by an approxim

ate factor of 1.4. The K

value for samples this old is nearly 1.3.

Clearly,

K values can be used

only within

the confines of defined counting conditions.

The errors in the 14C

ages listed in this paper are all based on counting statistics alone. A

ccording to Eq 3, the error "m

ultiplier" for samples of

the age range given and for 4-day counts w

ould be 1.3.

Off-sets

2 T

he variance o accounts for the degree of reproducibility of the m

ea- surem

ents made w

ithin a single laboratory. It does not account for system-

atic errors. Such errors may reflect a sim

ple off-set (caused, e by a w

rong activity level of the standard), or they m

ay reflect age-dependent anomalies

egif the "dead" time

in counting, which depends on sam

ple activity,

would be im

Portant and uncorrected for). 14

The

C tim

escale calibration requires independent determination of

the 14C activities by tw

o or more laboratories. T

he magnitude of the off-sets

between different laboratories can be estim

ated from the differences in

measured 14C

ages of duplicate samples.

A com

parison of 214 sample pairs of w

ood of identical age, but of dif- ferent geographic regions gave an age difference of 0.6 Y

r between B

elfast

969

https://doi.org/10.1017/S0033822200060252D

ownloaded from

https://ww

w.cam

bridge.org/core. IP address: 54.39.106.173, on 22 Oct 2020 at 14:58:58, subject to the Cam

bridge Core terms of use, available at https://w

ww

.cambridge.org/core/term

s.

Page 2: off - Home | Cambridge University Press€¦ · Bristlecone Pine samples on the D6M4 11 scale were obtained by 14C matching. The match- ing is imprecise for two samples, and the resulting

970

Min

ze S

tuiv

er B

ernd

Kro

mer

Ber

nd B

ecke

r an

d C

W F

ergu

se n

and

Seat

tle

Stui

ver

& P

ears

on,

1986

). T

hese

214

sam

ples

wer

e al

l <

4500

y r o

ld. The

Sea

ttle

labo

rato

ry a

lso

part

icip

ated

in

the

Gla

sgow

int

erna

tiona

l ca

libra

tion

proj

ect

(Int

erna

tiona

l St

udy

Gro

up,

1982

. T

he s

ix m

easu

red

sam

ples

w

ith a

ppro

xim

ate

age

of 5

000

14C

r

BP,

di

ffer

ed f

rom

the

y

grou

p av

erag

e by

17

Yr

aver

age

of t

hree

est

imat

es),

with

the

Sea

ttle

ages

bei

ng

olde

r. A c

ompa

riso

n of

dat

a w

ith t

hree

oth

er l

abor

ator

ies

of s

ampl

es i

n th

e 1

000-

8000

Yr

BP

rang

e yi

elds

som

ewha

t la

rger

dif

fere

nces

. T

he

4C a

ges

of 1

9 sa

mpl

es o

f th

e G

erm

an O

ak c

hron

olog

y T

able

1

diff

er 2

9 ±

10

yr

from

the

ir L

a ol

la c

ount

erpa

rts

whi

ch a

re w

ood

sam

ples

with

mid

-poi

nt

ages

up

to 3

.5 Y

r di

ffer

ent

from

the

Sea

ttle

set

Lin

ick,

Sue

ss &

Bec

ker ,

1985

. Six

sam

ple

pair

s T

able

3

Yie

ld a

n ag

e di

ffer

ence

of 2

±

12

bet

wee

n th

e Se

attle

and

Hei

delb

erg

labo

rato

ries

. The

lar

gest

dif

fere

nce

is b

etw

een

Seat

tle a

nd T

ucso

n w

here

the

14C

ages

of

13 B

rist

leco

ne P

ine

sam

ple

pair

s 58

05-5

685

BC

> T

able

2

& L

inic

k et

al

1986

di

ffer

by

52 ±

8

Yr.

Fo

r th

e la

tter

thre

e co

mpa

riso

ns

the

Seat

tle 14

C

ages

are

on

aver

age

all

on t

he

youn

ger s

ide.

T

he s

tand

ard

devi

atio

ns in

the

off

-set

s ar

e ba

sed

on c

ount

ing

stat

istic

s of

the

labo

rato

ry r

esul

ts a

lone

. T

he a

pplic

atio

n of

K v

alue

s of

ca

1.5

to t

he

resu

lts o

f all

labo

rato

ries

inv

olve

d w

ould

bri

ng th

e of

f-se

ts,

with

the

exce

p-

tion

of T

ucso

n-Se

attle

with

in 2

o o

f th

e qu

oted

err

or.

The

dif

fere

nces

in

age

dete

rmin

atio

ns o

f di

ffer

ent

labo

rato

ries

nee

d fu

rthe

r in

vest

igat

ion

and

the

user

of

calib

ratio

n cu

rves

sho

uld

real

ize

that

of

f-se

ts o

f a

coup

le o

f de

cade

s ar

e po

ssib

le w

hen

calib

ratio

n cu

rves

of

a si

ngle

lab

orat

ory

used

. The

se s

mal

l di

ffer

ence

s ar

e of

cour

se r

elat

ivel

Y

unim

port

ant

for t

he p

relim

inar

y ca

libra

tion

back

to

13,3

00 Y

r B

P.

14C

M

AT

CH

ING

OF

TH

E B

RIS

TL

EC

ON

E

PIN

E A

ND

DO

NA

U

6

MA

INE

4/1

1 SE

RIE

S

The

Ger

man

Oak

14C

ages

of

the

50-Y

r se

ctio

n of

the

floa

ting

D6M

4 11

chr

onol

ogy

are

liste

d in

Tab

le 1

an

d pl

otte

d in

Fig

ure

1 to

the

lef

t. A

lso

plot

ted

in t

he s

ame

grap

h ar

e th

e 14

C ag

es o

f tw

o B

rist

leco

ne P

ine

sam

ples

. T

he r

ing

num

bers

of

the

6480

-647

0 an

d 63

70-6

350

BC

B

rist

leco

ne P

ine

sam

ples

on

the

D6M

4 11

sca

le w

ere

obta

ined

by

14C

mat

chin

g. T

he m

atch

- in

g is

im

prec

ise

for t

wo

sam

ples

, and

the

res

ultin

g ze

ro p

oint

ea

r 1

fixi

ng

of th

e D

6M4

11 s

erie

s at

19

0 B

C m

ay b

e of

f by

a f

ew d

ecad

es. T

here

is a

lso

good

agr

eem

ent

of t

he a

bove

Bri

stle

cone

Pin

e 14

C ag

es w

ith H

eide

lber

g an

d L

a ol

la

Lin

ick,

Sue

ss &

Bec

ker,

198

5 re

sults

on

the

D6M

4 11

ser

ies

Fig

1, r

ight

sid

e).

Thi

s co

nfir

ms

the

ca

190

BC

sta

rt o

f the

Ger

man

Oak

se

quen

ce.

The

14C

ages

of

the

two

Bri

stle

cone

Pin

e sa

mpl

es a

lso

agre

e w

ith B

ris-

tle

cone

Pin

e da

tes

obta

ined

pre

viou

sly

at L

a ol

la B

runs

et al

19

83.

Seat

- tle

and

La

olla

res

ults

are

com

pare

d w

ith e

ach

othe

r on

the

lef

t si

de o

f Fi

gure

2.

To

the

righ

t is

a c

ompa

riso

n of

the

abso

lute

ly d

ated

Sea

ttle

Bri

s-

tleco

ne P

ine

date

s T

able

2

of th

e 58

05-5

685

BC

int

erva

l an

d th

e L

a ol

la

D6M

4 11

re

sults

cal

ibra

ted

on

a 21

5 B

C

zero

poi

nt

Lin

ick,

Su

ess

&

Be

985)

. ck

er 1T

he un

wei

ghte

d av

erag

es o

f th

e da

ta s

ets

wou

ld h

ave

been

eq

ual i

f at

7

f the

D6M

4 11

ser

ies

had

star

ted

234

BC

.

anal

ysis

of

Bri

stle

cone

Pin

e an

d G

erm

an O

ak d

ates

giv

es a

T

he a

bove

of

the

D6M

4 1

1 se

ries

in

the

7190

-723

4 ze

ro p

oint

14C

age

dete

rmin

atio

n Y

ear

BC

ra

nge.

The

new

res

ults

are

ent

irel

y co

mpa

tible

with

the

21

5 B

C

dete

rmin

atio

n of

Lin

ick

et a

l 19

86

and

this

dat

e fo

r th

e st

art

of t

he

D6M

4 11

has

the

refo

re b

een

adap

ted

for t

he c

alcu

latio

ns o

f th

e 01

4C va

l-

ues

give

n in

Tab

le 1

. Si

mila

rly,

ado

ptio

n of

the

2 15

BC

sta

rt g

ives

the

Fig-

-

ures

3 a

nd 4

14

C

age

calib

ratio

n cu

rves

. T

he s

udde

n de

part

ure

from

a

rath

er s

moo

th 14

C ag

e tr

end

at 7

014

BC

is

base

d on

a s

ingl

e ag

e de

term

ina-

tio

n. I

ndep

ende

nt c

onfi

rmat

ion

is n

eede

d be

fore

too

muc

h si

gnif

ican

ce i

s at

tach

ed to

thi

s an

omal

y.

The

unc

erta

inty

in

the

star

ting

date

of

the

D6M

4 11

ch

rono

logy

ca

used

by

'4C

age

mat

chin

g m

ay a

dd a

sys

tem

atic

un

cert

aint

y of

a f

ew

deca

des

to t

he s

tand

ard

devi

atio

ns a

lrea

dy g

iven

in

the

grap

hs.

TH

E L

AK

E O

F T

HE

CL

OU

DS

VA

RV

E C

HR

ON

OL

OG

Y

The

14C

mat

chin

g of

the

Oak

and

Bri

stle

cone

Pin

e se

ries

mak

es it

pos

si-

ble

to c

ompa

re tr

ee-r

ing-

deri

ved

D14

C va

lues

ba

ck t

o 21

5 B

C

with

var

ve-

deri

ved

z 1C

val

ues

from

Lak

e of

the

Clo

uds

sedi

men

t ba

ck to

10 0,

200

yr B

P

Stui

ver,

119

70,

1971

). T

he S

eattl

e m

easu

rem

ents

of

the

D6M

4 11

se

ries

w

ith

215

BC

ca

libra

tion

and

the

Lak

e of

the

Clo

uds

data

are

in

&4C

go

od a

gree

men

t fo

r th

e 84

00-9

200

Yr

BP

inte

rval

Fi

g 5)

. T

he m

ore

exte

n-

sive

var

ve d

ata

set

also

agr

ees

with

the

La

olla

res

ults

of t

he D

onau

ser

ies

Lin

ick,

Sue

ss &

Bec

ker,

19

85

aver

aged

ove

r ce

ntur

ies

in F

ig 6

, 60

00-

9200

Yr

BP

inte

rval

). C

lear

ly, t

he L

ake

of th

e C

loud

s va

rve

seri

es h

as b

een

show

n to

be

a re

liabl

e in

dica

tor o

f at

mos

pher

ic D

14C

chan

ge.

The

old

er p

ortio

n of

the

Lak

e of

the

Clo

uds

varv

e ch

rono

logy

can

be

varv

e ch

rono

logi

es i

n a

sim

ilar

man

ner

as t

ree

'4C

mat

ched

with

flo

atin

g ri

ngs.

A s

uita

ble

cand

idat

e is

the

Sw

edis

h va

rve

chro

nolo

gy. T

he y

oung

er

port

ion

of t

his

chro

nolo

gy,

as u

sed

by T

aube

r 19

70

was

der

ived

fro

m

varv

es s

tudi

ed a

t a

sing

le s

ite

From

m,

1971

). T

his

part

of t

he c

hron

olog

y ap

pear

s le

ss r

elia

ble

than

the

old

er p

art

of th

e se

quen

ce w

here

the

chr

o no

logy

has

bee

n de

rive

d fr

om s

ever

al c

lose

ly o

verl

appi

ng v

arve

dep

osits

. Fo

r th

e pu

rpos

es o

f ext

endi

ng th

e L

ake

of th

e C

loud

s ch

rono

logy

, we

con-

si

dere

d th

e Sw

edis

h va

rve

segm

ent

with

Tau

ber,

s (1

970)

14C

ages

bet

wee

n 86

00 a

nd 1

2,3

50 y

r B

P to

be

"flo

atin

g,"

and

mat

ched

the

olde

r pa

rt o

f th

e L

ake

of th

e C

loud

s ch

rono

logy

with

the

you

nger

par

t of

the

floa

ting

Swe-

di

sh s

egm

ent.

Thi

s yi

elds

the

var

ve-d

eriv

ed D

C

val

ues

back

to

13,3

00 Y

r B

P gi

ven

in F

igur

e 6.

14

14

The

C

mat

chin

g of

the

Lak

e of

the

Clo

uds

C a

ges

with

the

cor

re-

spon

ding

one

s of

the

Swed

ish

chro

nolo

gy P

oint

s to

war

ds a

sho

rtag

e in

the

Sw

edis

h va

rve

coun

t. T

he o

ff se

t w

as p

revi

ousl

y es

timat

ed a

t 80

0 va

rves

St

uive

r, 1

and

is 1

000

varv

es w

hen

the

two

olde

st 14

C ag

es o

f the

Lak

e of

the

Clo

uds

chro

nolo

gy a

re m

atch

ed. A

par

t of

the

disc

repa

ncy

as

h

been

.. so

lved

by

a re

-eva

luat

ion

of th

e va

rved

sed

imen

t in

the

Ang

erm

anal

ven

val-

le

y w

hich

res

ulte

d in

an

addi

tiona

l 36

5 va

rves

Cat

o 19

85.

An

anom

aly

of

400

to 6

00 v

arve

s m

ay st

ill e

xist

nea

r 10

,000

cal

BP.

http

s://

doi.o

rg/1

0.10

17/S

0033

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0006

0252

Dow

nloa

ded

from

htt

ps://

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ambr

idge

.org

/cor

e. IP

add

ress

: 54.

39.1

06.1

73, o

n 22

Oct

202

0 at

14:

58:5

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ubje

ct to

the

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brid

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ore

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Page 3: off - Home | Cambridge University Press€¦ · Bristlecone Pine samples on the D6M4 11 scale were obtained by 14C matching. The match- ing is imprecise for two samples, and the resulting

Radiocarbon A

ge Calibration B

ack to 13,300 Years B

P 971

The anom

aly appears smaller for the revised Sw

edish chronology near 1 0,700 R

P. The end of the Y

ounger Drvas has a revised date of 10,700 ±

50 1985

which is in good agreem

ent with the annual ice

varves Strom

ber g layer count of the sam

e event of 1 0,720 ±

75 yr Ham

mer et al, 1986).

The he

age of the end of the Younger D

rYas w

as estimated at 10 0,000 ±

75

r by Ham

mer C

lausen and Tauber

1986. According to our 14C

match-

ing Y w

ith the Lake of the C

louds chronology, and using Tauber's (970)

evaluation of Swedish 14C

dates the corresponding cal B

P date is 10,9 0,970

+

_ 1 10 Y

r (the standard deviation is based on the fact that 1

the age conver- sion sion does not take into account the century type 14C

oscillations and 2the standard deviation in the 14C

age is 75 yr). T

he three methods

varve counting, ice stratigraphY, and a m

ixture of '4C

matching and varve counting lead to a cal B

P age for the end of the Y

ounger D ryas of respectively, 10,700

± 50, 10,720

± 75, and 10,970

±

110 Yr. It is possible that the m

atching method overestim

ates the cal BP age

by a few hundred years, w

hich would correspond for the pre-10,500 cal B

P

interval to a reduction in 014C values of 3%

Fig 6

and a reduction in age anom

alies of ca 250 Yr (Fig

A final evaluation aw

aits a more precise assessm

ent of the 14C ages and

varve counts of the first 2000 Years of the Sw

edish chronology. The Figure

calibration curve is only approxim

ate in the pre-10,500 cal B

P portion w

here errors of a few hundred years certainly area possibility.

TIM

E-SC

AL

E C

AL

IBR

AT

ION

B

EY

ON

D 10,000 Y

EA

RS B

P

Following the reasoning given in the previous section, the age calibra-

tion based on tree rings averaged over centuries and L

ake of the Clouds

varves can be extended to 13 3,300 cal BP using the earlier portion of the

Swedish varve chronology. T

he Figure data prior to 10'500 B

P are based 14

on C

matching w

ith the Swedish varve chronology.

The older part of the Figure

calibration curve w

here conventional '4C

ages appear at least 1000 Y

r too young, may need future adjustm

ent w

hen other chronologies become available. A

s discussed in the previous section

the pre-10,500 cal BP age anom

alies may be over-estim

ated in Fig- ure 7 by a few

hundred years. It also should be noted that at 10,000 Yr B

P

the first 300 Years of the age anom

aly are due to the use of the "short" 5568-Y

r half-life for a conventional 14C

date. The Figure

data set of

course also neglects the details of the century type oscillations. A

n excel- re

data is X=

1.05R

470, where X

is the lent approxim

ation cal B

P age and R the

14C age B

P.

AC

KN

OW

LE

DG

ME

NT

S

The

14C w

ork of the Quaternary Isotope L

aboratory is supported by N

SF grants FAR

-8115994 and AT

M-8318665. P M

Grootes review

ed the

manuscript w

hereas P W

ilkinson, P Reim

er, and T B

raziunas assisted in the m

easurements and calculations.

RE

FER

EN

CE

S

Becker,

B, 1983, T

he long-term radiocarbon trend of the absolute G

erman O

ak tree-ring chronology, 2800 to 800 B

C

in Stuiver M

and Kra

RS

eds Internatl

14C conf,

11 th Proc: R

adiocarbon, v 25, no. 2. P 197-203. B

runs, M

Rhein

M

Linick

R W

and Suess H

E

1983, The atm

ospheric 14C

level in the 7th m

illenium B

C: PA

CT

, v 8, p 511-516. C

ato, I, 1985, The definitive connection of the Sw

edish geochronolo1;'cal time scale w

ith the resent, and the new

date of the zero year in Doviken, northern Sw

eden: Boreas, v 14,

P

Y

P

117-122.

Fer son, C

W and G

raYbill, D

A, 1983, D

endrochronologY of B

ristlecone Pine: A progress

' report, in Stuiver M

and Kra

R S eds

Internatl 14C conf, 11th

Proc: Radiocarbon

v 25, no. 2, p 287-288.

Fromm

, E, 1970, A

n estimation of errors in the Sw

edish varve chronology, in Olsson, I U

, ed, R

adiocarbon variations and absolute chronology, Nobel sym

posium,

12th: New

York,

John WileY

& Sons, p 163-172.

Ham

mer, C

U, C

lausen, H B

and Tauber, H

, 1986, Ice-core dating of the Pleistocene-Holo

cene bounda applied to a calibration of the 14C

time scale

in Stuiver M

and Kra

R S ,

eds Internatl

4C conf, 12th

Proc: Radiocarbon

v 28, no. 2A.

International Study Group, 1982, A

n interlaboratorY com

parison of radiocarbon measure-

ments in tree-rings: N

ature, v 298, p 619-623. L

inick, T W

, Long, A

, Dam

on, P E and Ferguson, C

W, 1986, H

igh precision radiocarbon dating of B

ristlecone Pine from 6550 to 5350

BC

, in Stuiver,

M and K

ra, R S, eds,

Internatl 14C conf, 12th

Proc: Radiocarbon

this issue. L

inick, T W

, Suess, H E

and Becker, B

, 1985, La

olla measurem

ents of radiocarbon in south G

erman O

ak tree-ring chronologies: Radiocarbon, v 27, p 20-32.

Pilcher, R

, Baillie,

M G

L, Schm

idt, B and B

ecker, B, 1984, A

7,272-Year tree-ring chro

nology for western E

urope: Nature, v 312, p 150-152.

Stromber

, B, 1985,

Revision of the late

lacial Swedish varve chronology: B

oreas, v 14,

g g

P 101-105.

Stuiver M

1970

Long-term

14C variations

in Olsson

I U ed

Radiocarbon variations and

absolute chronology, Nobel sym

posium, 12th: N

ew Y

ork, John WileY

&

Sons, p 197- 213.

-----1971 , Evidence for the variation of atm

ospheric 14C content in the L

ate w

ater- nar, in T

urekian, K K

, ed, The L

ate Cenozoic glacial ages: N

ew H

aven, Yale U

niv Press, Y

P

57-70.

-----1982, A high-Precision calibration of the A

D radiocarbon tim

e scale: Radiocar-

bon, v 24, p 1-26. Stuiver, M

and Pearson, G W

, 1986, High-Precision calibration of the radiocarbon tim

e scale, 1950 A

D-500 B

C, in Stuiver

M and K

ra R

S eds Internatl 14C

conf, 12th, Proc: Radio-

carbon, this issue. Stuiver,

M and Q

uay, P D, 1980, C

hanges in atmospheric carbon-14 attributed to a variable

sun: Science, v 207, p 11-19. -----1981

Atm

ospheric 14C changes resulting from

fossil fuel CO

2 release and cosmic

ray flux variability: Earth Planetary Sci L

etters, v 53, p 349-362. Stuiver

M

Robinson

S W and Y

ang, I C

1979, 14C

dating to 60,000 Years B

P with propor-

tional counters in B

erger R

and Suess H

F, eds R

adiocarbon dating, Internatl 1 C

conf , 9th, Proc: B

erkeley, Univ C

alifornia Press, p 202-215. T

auber, H, 1970, T

he Scandinavian varve chronology and C14 dating, in O

lsson, I U,

ed, R

adiocarbon variations and absolute chronology, Nobel sym

posium,

12th: N

ew Y

ork, John W

ileY &

Sons, p 173-196.

https://doi.org/10.1017/S0033822200060252D

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bridge Core terms of use, available at https://w

ww

.cambridge.org/core/term

s.

Page 4: off - Home | Cambridge University Press€¦ · Bristlecone Pine samples on the D6M4 11 scale were obtained by 14C matching. The match- ing is imprecise for two samples, and the resulting

972

d. m

8300

8200

8100

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7600

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Min

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w

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ard

devi

atio

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eriv

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rom

cou

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atis

tics

only

, vs

ring

num

ber

of th

e D

6M4/

11 G

erm

an O

ak s

erie

s. T

he t

wo

Bri

stle

cone

Pin

e da

ta p

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s as

sum

e an

age

of

7190

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BC

for

rin

g nu

mbe

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Rig

ht: H

eide

lber

g, L

a ol

la,

and

Seat

tle 14

ag

es v

s ri

ng n

umbe

r of

the

D6M

4/11

ser

ies.

http

s://

doi.o

rg/1

0.10

17/S

0033

8222

0006

0252

Dow

nloa

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from

htt

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ambr

idge

.org

/cor

e. IP

add

ress

: 54.

39.1

06.1

73, o

n 22

Oct

202

0 at

14:

58:5

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ubje

ct to

the

Cam

brid

ge C

ore

term

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Page 5: off - Home | Cambridge University Press€¦ · Bristlecone Pine samples on the D6M4 11 scale were obtained by 14C matching. The match- ing is imprecise for two samples, and the resulting

Radiocarbon A

ge Calibration B

ack to 13,300 Years B

P 973 .

7900 +

- LA JO

LLA B

RIS

TLE

CO

NE

PIN

E

200

.

:i( -SE

AT

TLE

BR

IST

LEC

ON

E P

INE

7800 -

¢ - LA JO

LLA G

ER

MA

N O

AK

7100

7700

7600

7000

6900

7500

6800

i 7400

6700

7300 l

I

i I

I I

I I

6600 - 6550

6450

6350

6250

6150

6050

5950

YE

AR

B

.C.

I I

i 1

i I

i J

5850

5750

5650

5550

Fig 2. L

e : L

ajolla and Seattle Bristlecone Pine 14C

ages. Right: Seattle B

ristlecone Pine 14C ages com

pared to LaJolla ages of the G

erman O

ak chronology w

ith ring 1 of the D

6M4/11 series at

7215 Yr B

C). V

ertical bars denote hr in the measurem

ent.

https://doi.org/10.1017/S0033822200060252D

ownloaded from

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bridge Core terms of use, available at https://w

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Page 6: off - Home | Cambridge University Press€¦ · Bristlecone Pine samples on the D6M4 11 scale were obtained by 14C matching. The match- ing is imprecise for two samples, and the resulting

cal

BP

9350

9250

9150

9050

8950

8850

8750

8650

8400

8300

a

8100 m

7600

7500

7400

7300

7200

7100

7000

6900

6800

6700

cal

6C

Figs

3,

4.

14

C

time-

scal

e ca

libra

tion

deri

ved

from

th

e G

erm

an

Oak

ch

rono

logy

(w

ith

ring

1

of

the

D6M

4/11

se

ries

at

72

15

yr

BC

).

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w

idth

of

th

e ca

libra

tion

curv

e is

ba

sed

on

stan

dard

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viat

ions

de

rive

d fr

om

coun

ting

stat

istic

s on

ly

(see

te

xt).

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Page 7: off - Home | Cambridge University Press€¦ · Bristlecone Pine samples on the D6M4 11 scale were obtained by 14C matching. The match- ing is imprecise for two samples, and the resulting

cal BP

8950

8850

8750

8650

8550

8450

8350

8250

8400

:-1-

-i

I

I

1

1

I

I

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I

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Page 8: off - Home | Cambridge University Press€¦ · Bristlecone Pine samples on the D6M4 11 scale were obtained by 14C matching. The match- ing is imprecise for two samples, and the resulting

976

Min

ze S

tuiv

er B

ernd

Kro

mer

Ber

nd B

ecke

r an

d C

W F

er u

son

150

LAKE OF THE CLOUDS VARVES

100

50

9200

9000

8800

8600

8400

YEAR

BP

Fig

5.

A c

ompa

riso

n of

014C

valu

es d

eriv

ed f

rom

Lak

e of

the

Clo

uds

varv

es a

nd S

outh

Ger

man

Oak

tree

-rin

g sa

mpl

es.

14C

ag

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ount

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Page 9: off - Home | Cambridge University Press€¦ · Bristlecone Pine samples on the D6M4 11 scale were obtained by 14C matching. The match- ing is imprecise for two samples, and the resulting

977 Radiocarbon Calibration Back to 13,300 Years BP Age

150

100

50

0

r

r..

O

O

O

x LA JOLLA OAK (CENT. AVG.)

O SEATTLE OAK (CENT. AVG. )

c3 LAKE OF THE CLOUDS VARVES

A SWEDISH VARVES

14000 12000 10000

YEAR BP

. X I

II X XX

XX

r

X

X X X

? T.

..r

i

8000 6000

Fig 6. Century-averaged 14C values derived from La olla Lmick S uess & Becker, 1985) and Seattle measurements of the South German Oak chronology (with ring 1 of D6M4/11 at 7215 BC). Fi ( Also given are z' 4C values r, 970, 1971) and Swedish (Tauber, 1970) varve chronology. The standard error in the century averages is a few per mil or rived from the Lake of the Clouds Stuive de less.

https://doi.org/10.1017/S0033822200060252D

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bridge Core terms of use, available at https://w

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Page 10: off - Home | Cambridge University Press€¦ · Bristlecone Pine samples on the D6M4 11 scale were obtained by 14C matching. The match- ing is imprecise for two samples, and the resulting

9 78

M

inze

Stu

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Ber

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rom

er B

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AG

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EA

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AK

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CLO

UD

S V

AR

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S

L

SW

ED

ISH

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AR

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S

W

Q

Cal

BP

6000

4000

Fig

7.

Cen

tury

-ave

rage

d 14

C ag

es o

f th

e So

uth

Ger

man

Oak

chr

onol

ogy.

The

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e of

the

Clo

uds

and

Swed

ish

varv

e ch

rono

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dat

a w

ere

deri

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from

the

14C

ages

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979 Radiocarbon Age Calibration Back to 13,300 Years BP

TABLE 2 TABLE 1

Ferguson's Bristlecone Pine series Becker s D6M4/11 series with ring 1 matched at 7215 BC

Standard deviations are based on counting statistics only. Standard deviations are based on counting statistics only.

Ring Year Year No. of Radiocarbon

no. BC BP rings age

18.5 7197.5 9146.5 2 8250 ± 40 +82.8 ± 5.0

28.5 7187.5 9136.5 4 8170 ± 23 +92.3 ± 2.9

142.0 7174 9123 5 8143 ± 23 +94.2 ± 2.9

52.0 7164 9113 5 8742 ± 23 +93.0 ± 2.9 72.0 7144 9093 5 8184 ± 23 +81.6 ± 2.9

82.5 7133.5 9082.5 6 8114 ± 22 +92.8 ± 2.7

107.0 7109 9058 5 8163 ± 23 +82.9 ± 2.9

132.0 7084 9033 5 8123 ± 22 +85.0 ± 2.7

157.0 7,059 9008 5 8081 ± 23 +87,4 ± 2.9

167.0 7049 8998 5 8018 ± 22 +94.6 ± 2.7 187.0 7029 8978 5 8016 ± 23 +92,3 ± 2.9

202.0 7014 8963 5 7841 ± 23 +114.3 ± 2.9

205.0 7011 8960 11 7954 ± 11 +93,3 ± 1.4

217.0 6999 8948 5 7950 ± 32 +97.3 ± 4.0

232.0 6984 8933 5 7984 ± 25 +90.7 ± 3.1

255.0 6961 8910 11 7979 ± 17 +88,3 ± 2.1 257.0 6959 8908 5 7947 ± 24 +92.4 ± 3.0

278.5 6937.5 8886.5 6 7932 ± 23 +91.6 ± 2.9 285.0 6937 8880 11 7945 ± 30 +89.0 ± 3.7

297.0 6919 8868 5 7964 ± 23 +84.8 ± 2.9 317.0 6899 8848 5 7961 ± 22 +82,6 ± 2,7

322.0 6894 8E43 5 7973 ± 50 +80.3 ± 6.2

342.0 6874 8823 5 7989 ± 19 +75.6 ± 2,4

347.0 6869 8810 5 8020 ± 23 +70.8 ± 2.9

365.5 6850.5 8799.5 4 7990 ± 24 +72,q ± 3.0

387.5 6828.5 8777.5 u 7996 ± 25 +68.8 ± 3.1

402.0 6814 8763 5 7945 ± 21 +73.7 ± 2.6 414.0 6802 8751 3 7916 ± 24 +76.0 ± 3.0 431.0 6785 8731+ 3 7912 ± 24 +7'+.3 ± 3.0

451.0 6765 8714 3 7913 ± 23 +71.6 ± 2.9 457.0 6759 8708 5 7903 ± 22 +72.1 ± 2.7

462.0 6754 8703 5 7882 ± 23 +714.3 ± 2.9

462.5 6753.5 8702.5 G 7924 ± 23 +68.6 ± 2.9

477.0 6739 8688 5 7587 ± 21 +71.7 ± 2.6

497.0 6719 8668 5 7900 ± 23 +67.4 ± 2.5

502.5 6713.5 8662.5 6 7893 ± 22 +67.6 ± 2.7

517.0 6699 8648 5 7910 ± 22 +63.5 ± 2.7

525.0 6691 8640 11 7887 ± 22 +65.5 ± 2.7 542.5 6673.5 8622.5 6 7804 ± 16 +74.3 ± 2.0

556.5 6659.5 3608.5 G 7877 ± 23 +62,7 ± 2.9

574.5 66+1.5 8590.5 10 7811 ± 21 +69.2 ± 2.6 589.5 6626.5 8575.5 10 7806 ± 20 +67.9 ± 2.5 618.5 6597.5 8546.5 4 7756 ± 23 +70.8 ± 2.9 641.5 6574.5 8523.5 6 7774 ± 22 +65.5 ± 2.7 663.5 6552.5 8501.5 8 7654 ± 1 4 +78,6 ± 1.7

680.5 6535.5 8484.5 3 77u3 ± 22 +64.5 ± 2.7 704.0 6512 8461 5 7731 ± 17 +63.1 ± 2.1

719.5 6496.5 8445.5 4 7654 ± 17 +71 ,3 ± 2,1

742.0 6474 8423 5 7605 ± 17 +75.0 ± 2.1

L* no.

10000 10001

10002 10003 10005 10006 1 000'/ 10008 10009 10010 10071

10012 10013

u 1 001

10015 10016 10017 10018 10019 10020 10021

10022 10023 10024 10025 10026 10027 10028 10029 10030 10031

10032 10033 10034 10035 10036 10037 10038 10039 10040 1 ooui

10042 10043 10044 10045 10046 10047 10048 10049

Year Year No. of Radiocarbon BC BP rings age 14 DC

QL no.

6475 8424 10 7636 ± 23 +64.2 ± 3.1 1006

6360 8309 20 7427 ± 22 +84.1 ± 3.0 10063

5805 77514 10 6926 ± 14 +78.9 ± 2.0 10062

5795 7744 10 6915 ± 21 +79,2 ± 2,9 10061

5785 77314 10 6935 ± 20 +75.2 ± 2.7 10060

5775 7724 10 6934 ± 22 +74.0 ± 3.0 10059

5765 7714 10 6897 ± 16 +77.6 ± 2.2 10058

5755 770+ 10 6893 ± 17 +76.9 ± 2,4 10057

571+5 7694 10 6904 ± 20 +74.1 ± 2.7 10056

5735 768+ 10 667 ± 20 +77.7 ± 2.8 10055

5725 7674 10 6820 ± 20 +82.7 ± 2.7 1005

5715 7664 10 6853 ± 20 +77.0 ± 2.8 10053

5705 7654 10 6799 ± 20 +82.9 ± 2.7 10052

5695 7644 10 6802 ± 20 +&1.2 ± 2.7 10051

5685 7634 10 6799 ± 20 +80.3 ± 2.7 10050

TABLE 3

Seattle and Heidelberg measurements of duplicate samples of Becker D6M4 11

wood. Standard deviations are based on counting statistics only.

Heidelberg Seattle Ring Radiocarbon Radiocarbon no. age BP age BP Difference

556.5 7884 ± 22 7887 ± 22 -3 ± 31

502.5 7925 ± 22 7893 ± 22 32 ± 31

562.5 7959 ± 22 7924 ± 23 35 ± 32 285 7996 ± 20 7945 ± 30 51 ± 36 255 7960 ± 22 7979 ± 17 -19 ± 28 205 8010 ± 20 7951 ± 11 56 ± 23

* uaternaY Isotope Lab (Seattle) r

https://doi.org/10.1017/S0033822200060252D

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