Lacustrine Records of Holocene ENSO Variability

Christopher Moy1 Donald Rodbell2 Geoffrey Seltzer3 Ursula Roehl4 David

Anderson1

1NOAA Paleoclimatology Program

2Geology Dept., Union College

3Dept. Of Earth Sciences, Syracuse University

4University of Bremen

Background

• Sediment core retrieved from L. Pallcacocha displayed abundant light-colored clastic laminae.

• Rodbell et al. (1999) hypothesized that the clastic laminae were deposited during El Nino-induced alluviation events in the drainage basin.

• However, discontinuity and lack of a sediment-water interface precluded investigation of millennial-scale variability.

Objective:

• Utilize a new continuous sediment core and identify the frequency components with wavelet analysis

Geotek Linescan Camera

CORTEX XRF Scanner – Univ. of Bremen

Jansen et al. (1998)

Jansen et al. (1998)

Age Models

Constant Carbon Accumulation Model:

-Distributes age based on carbon content of sediment

Event Model:

-All laminae assigned a value of 6 months based on Rio Chira discharge data

Both models assign higher sedimentation rates to the light-colored laminae

Relationship to Modern ENSO

210 Pb Years (AD)

light

dar k

Ave

rag

e G

ray

Sc

ale

(St d

. D

e v.

Un

its )

2000 1980 1960 1940 1920 1900 1880 1860

Linescan Results

0 2000 4000 6000 8000 10000 12000 140000

50

100

150

200

250R

ed

Co

lor

Inte

nsi

ty

Age (cal yr BP)

0 2000 4000 6000 8000 10000 12000 140000

10

20

30

40

Age (cal yr BP)

Eve

nts

* 1

00 y

r -1

XRF Results

Age (cal yr BP)

0 2000 4000 6000 8000 10000 120000

50

100

150

200

250

Re

d C

ol o

r In

ten

s it y

(K +

TI )

/ F

e

0 2000 4000 6000 8000 10000 120000

0.05

0.1

0.15

0.2

0 2000 4000 6000 8000 10000Time (cal yr BP)

48

163264

128256512

10242048

Per

iod

( yea

rs)

0 2000 4000 6000 8000 10000Time (cal yr BP)

8163264

128256512

1024204840968192

Per

iod

( yea

rs)

-50

0

50

100

150

200

0 2000 4000 6000 8000 10000Time (cal yr BP)

Re

d C

olo

r In

tens

ity

80

21

3

0.5

137

23

5

ENSO Model Comparison

Clement et al. (2000)

0 2000 4000 6000 8000 10000 12000 140000

5

10

15

20

Age (cal yr BP)

0 2000 4000 6000 8000 10000 12000 140000

10

20

30

Nu

mb

er o

f W

arm

Eve

nts

* 1

00

yr-

1

Nu

mb

er

of

Eve

nts

* 1

00

yr-

1

Number Study Record Time Span Resolution

1 North Australia; McGlone et al. (1992) and

Shulmeister and Lees (1995)

Lake Sediment: Pollen

Holocene Inter-Decadal

2 Great Barrier Reef, Australia; Gagan et al. (1998)

Coral: Sr/Ca and 18O

25 Years; ~5400 cal yr BP

Annual

3 Northern New Guinea, Tudhope et al. Coral: 18O 49 Years at ~6500 cal yr BP and ~90 years at 2000-3000 cal yr BP

Annual

4 Ecuador, Rodbell et al. (1999) Moy (2000) Lake Sediment: Grayscale and Color

~12,000 Years Sub-Decadal

5 Coastal Peru, Sandweiss et al. (2001) Midden: Mollusks Holocene Discontinuous

Image from Cole (2001)

Future Work - Laguna Fondococha

0 50 100 150 200 250 300 350 4000

2000

4000

6000

8000

0 50 100 150 200 250 300 350 4000

200

400

600

0 50 100 150 200 250 300 350 4000

50

100

150

200

250

Depth (cm)

K (

cps)

Ti (

cps)

Fe

(cps

)

Conclusions:

•Gradual increase in ENSO event frequency through the Holocene

Driven by orbitally-induced changes in insolation

•Millennial-scale variability centered on 2,000 yrs

•Centennial to ENSO band variance exhibited in the most recent 6,000 yrs of the record

XRF Results

0 2000 4000 6000 8000 10000 120000

100

200

300

K (

cps)

Fe

(cp

s)

0 2000 4000 6000 8000 10000 120000

2000

4000

6000

8000

0 2000 4000 6000 8000 10000 120000

20

40

60

80

Ti (

cps)

Age (cal yr BP)

comp

-2

-1

0

1

2

3

4

0 2000 4000 6000 8000 10000 12000

Pal

lcac

ocha

Fil

tere

d X

RF

Com

posi

te

Com

parison to IRD

events in the N. A

tlantic

Comparison to IRD events in the N. Atlantic

-50

0

50

100

150

200

0 2000 4000 6000 8000 10000Time (cal yr BP)

Re

d C

olo

r I n

t ens

ity

LIA 1 2 3 4 5 6 7 8

Pacific Basin Proxy Records

ENSO Band