1 Tracing the source to sink patterns of river sediments in East Asian marginal seas by using geochemical methods Shouye YANG, Yanguang DOU, Chao LI State.

1

Tracing the source to sink patterns of river sediments in East Asian marginal seas by using geochemical methods

Shouye YANG, Yanguang DOU, Chao LIState Key Laboratory of Marine Geology, Tongji University, Shanghai, China Zhenxia LIU, Hua YUThe First Institute of Oceanography, SOA, Qingdao, China

International Sediment Trap Workshop and Symposium on Sediment Transport and Sediment on Asian Margins, 23-27 March, 2009 Taiwan

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Research background How to identify the river sediments? Case study: — Discriminations of sediment sources of

the Okinawa Trough during the late Quaternary

Talk outlineTalk outline

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Tibet uplift Monsoon evolution & river evolution

Key questions: Provenance weathering, Chemical flux, Sediment recycling at present and in the geological past

Source to sink

Changjiang R.

Source to sink

East

China

Sea

Yellow Sea

?Cheju Strait

Japan

Sea

Okinaw

a Tro

ugh

Huanghe R.

Huge sediments derived from mega-rivers dominate the sedimentation of the western Pacific marginal seas.

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2004.7 primary

productivity

Asanuma et al., 2005

Freshwater transport from the Changjiang to the Japan Sea could significantly affect the primary production & deep circulation in the Japan Sea.

Senjyu, T et al. (2006, [email protected])

Suspended particles?

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The S2S pattern of river sediments in the Yellow Sea is very complex and much variable during the late Quaternary, which is a big challenging problem for the paleoenvironmental reconstruction.

Yang et al. (2003)Earth-Science Review

Unit: 108

ton/yr

Sediment flux in Sediment flux in the Yellow Seathe Yellow Sea

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Potential sediment provenances in the shelf and open sea

Siliciclastic sediments: S2S

River Basin Estuary Open Sea

River inputVolcanic ash

SE

DGKS9604

Aeoliandust

hydrothermalsource

lateral transportof terrestrial matter

KuroshioCurrent?

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Sediment samples and analytic methods

9

Samples from the Changjiang (Yangtze River) (suspended, bed, floodplain)

Upper reaches Lower

reaches

Middle

reaches

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The first bend of the Changjiang at Shigu

Wujiang River Daduhe and Minjiang Rivers

NW NE

Field work in the Changjiang, 2003-2007

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The Upper Reach:Jinshajiang River at Lijiang, Yunnan Province

The Lower Reach

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Huanghe: Yellow River

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Case study: Okinawa Trough

Core DGKS9604:

Location: west slope of the middle Okinawa Trough

Water depth: 766 m

Core length: 10.76 m (~30 Cal Ka)

Recovery: about 95%

200

38°

30°

26°

34°

1000

200

1000

100

200

DGKS9603

DGKS9604

Yellow Sea

East Chi

na S

ea

0 200km

100

Sea of Japan

120° 124° 128° 132°

Korea

Changjiang

Old HuangheJapan

Kyushu

China

Taiwan

36°

32°

28°

24°122° 126° 130°

Tokara Strait

Ryukyu Islands

CDWAira

AtaKikai

Kurosh

io c

urre

nt

Coas tal current

Cheju Is.

Sediment S2S pattern of the Okinawa Trough during the late Quaternary

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• Sample pre-treatment ：<0.063mm fine-grained samples (elements)

1 N HCl leaching experiment (element & Sr-Nd-Pb isotopes)

• REE and elements ： ICP-MS/ES• Sr-Nd-Pb isotopes ： — TIMS （ modern sediments ） — MC ICP-MS （ Core sediments ）• Mineral chemistry (zircon, garnet, apatite, monazit

e)

Analytic methods

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Geochemical proxies of sediment provenance discrimination

— REE fractionation pattern and parameters including (La/Yb)UCC, (Gd/Yb)UCC, (La/Sm)U

CC, δCe, δEu

— Ratios of conservative elements such as La/Sc, Th/Sc, Ti/Nb, Cr/Th, Ti/Al…..

— Sr-Nd-Pb isotopic systematics

— Mineral chemistry of detrital zircon, monazite, Ti-Fe oxides and garnet grains

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Research background How to identify the river sediments? Case study:

— Discriminations of sediment sources of the Okinawa Trough during the late Quaternary

Talk outlineTalk outline

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Rare earth elemental compositions in the Changjiang sediments

UCC: upper continental crust, T & M, 1985

residual fraction

1N HCl leaching

Yalongjiang

JinshajiangFujiang

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The Korean river sediments are relatively more enriched in LREE than Chinese river sediments, suggesting different source rock compositions in their drainage basins.

Yang, et al. (2002) EPSL

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Characteristic REE parameters and elemental ratios can be treated as reliable geochemical proxies to trace the river sediment sources.

Chinese Rivers

Chinese Rivers

Yang et al., Earth-Science Review, 2003; Chinese Sci Bull., 2004

Korean rivers

Korean rivers

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Korean rivers

Chinese rivers

Korean rivers

Chinese rivers

Yang et al., Earth-Science Review, 2003; Chinese Sci Bull., 2004

Geochemical proxies for discriminating Chinese and Korean river sediments

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Sr-Nd isotopic compositions of the Changjiang suspended sediments

Yang et al., Sci in China, 2007

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Comparison of Sr-Nd isotopes

0.5100

Missi.

Nile

143 144Nd/ Nd

0.5110 0.51300.5120

UCC

AmazonGanges Indus

Mekong

0.700 0.710 0.720 0.730 0.740 0.750 0.760

Missi.

Nile

G/B

World River

87 86Sr/ Sr

Weathered UCC

Loess

Australian shale Huanghe

Changjiang

ChangjiangHuanghe

PAAS

XiangjiangYuanjiang

Ganjiang

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Distinct isotopic compositions exist between East Asian river sediments

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1N HCl-leached fractions of the river sediments show good discrimination results between Chinese and Korean river end-members.

Choi et al. 2007. Marine Chemistry

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Detrital zircon grains from the Changjiang river sediments

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Mineral chemistry of detrital zircon grains from the Changjiang sediments

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Zircon ages of the Changjiang sediments

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Monazite age spectrum of the Changjiang sediments

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Controls of sedimentary geochemical compositions

• Provenance rocks character ： age, type, outcrop area, weathering rate

• Chemical fractionation of minerals during chemical weathering

• Hydrodynamic sorting during transport and deposition ： grain size effect, SPM representative

• Sediment recycling ： complex but important • Sample treatment ： 1 N HCl, residual fraction

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金

沙

江

雅

砻

江

大

渡

河

岷

江沱

江

涪

江

嘉

陵

江

汉

江

赣

江

湘

江

资

江

沅

江

澧水

乌

江

赤水河

横

江牛

栏

江攀枝花

宜宾

重庆

万县

长沙

武汉

南京

CJ-1CJ-2丽江 CJ-3CJ-4

CJ-6CJ-5

CJ-7

CJ-8

CJ-9

CJ-10

CJ-13

CJ-11

CJ-12

N

铜陵三峡大坝

Samplingsite

Metamorphic rocksIgneous rocksSedimentary rocks

Granite Ultrabasic-basicrocks

BasaltSiliciclasticsediments

Carbonaterocks & clasticsediments

Low-grademeta. Rocks

High-grademeta. Rocks

Source rocks in the Changjiang drainage basin

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Increasing ages

Sr isotopic compositions in the source rocks of the Changjiang drainage basin

0.700 0.710 0.720 0.730 0.740 0.750 0.760

87 86Sr/ Sr

0.700 0.710 0.720 0.730 0.740 0.750 0.760

Upper reaches

Mid-Lower reaches

Changjiang

Changjiang

Igneous rock and crystallinebasement in south Himalaya

Carbonate in themiddle-upper valley

Himalayan granite

Late Yesannian granite in Tibet

Emeishan Basalt

River water in thesource area

Archean metamorphic complex

Sinnian-Cambrian silicalite in Hunan and Jiangxi Metamorphic rockin the middle-lower valleyJiangxi

Mesozoic granite

Changjiangestuarine water

Mesozoic igneous rock in lower valley

Cenozoic basaltin the lower valley Ganjiang

YuanjiangXiangjiang

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Nd isotopic compositions in the source rocks of the Changjiang drainage basin

0.5100

143 144Nd/ Nd

0.5110 0.51300.5120

Changjiang

0.5100 0.5110 0.51300.5120

Upper reaches

Mid-Lower reaches

Changj iang

Himalayan graniteEmeishan BasaltKongling

amphibolite

Late Yesannian granite in Tibet

Kongling meta-sedimentary rock

Shoshonite in east Tibet

Igneous rock and crystallinebasement in south Himalaya

Kongling gneiss

Jiangxi Mesozoic granite

Meso-high grade metamorphicrock in central Jiangxi

Mesozoic-Cenozoic basaltin the middle-lower valley

Sedimentary rockin SE Yangtze Block

Alkaline rockin the lower valley

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Acidic igneous rocks dominant in the Korean river basins.

Different climate regimes result in variable weathering intensities.

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Case study Sediment provenances of the middle Okinawa Trough during the last 30 Cal ka

20 0

38°

30°

26°

34°

100 0

200

DGKS9603

DGKS9604

Yellow Sea

East China Sea

100

120° 124° 128° 132°

Korea

Changjiang

Old Huanghe

Japan

Kyushu

ChinaTa

iwan

36°

32°

28°

24°

122° 126° 130°

Tokara Strait

Ryukyu I

slands

CDW AiraAta

Kikai

ODP1202

N

E

Huanghe

YS

CC

ZF

CC

TWC

Kurosh

io Curre

nt

0 200km

N

1000

2 00100

YSWC

Core DGKS9604:

Location: west slope of the middle Okinawa Trough

Water depth: 766 m

Core length: 10.76 m (~30 Cal Ka)

Recovery: about 95%

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Large changes occur in the deglacial periodÄêÁä (C

al a)

TN(%)

.1 .2 .3 .4Éî

¶È(m

)0

1

2

3

4

5

6

7

8

9

10

11

TOC(%)

.5 1.0 1.5 2.0

CaCO3(%)

0 6 12 18 24 30

TOC/TN

0 2 4 6 8 10

OIS 1

OIS 2

OIS 3

37010

33264

30800

27620

21456

16334

12339

35721827

5799

13C

-24 -23 -22 -21 -20δ

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δCe(n)

.88 .96 1.04

δEu(n)

.60 .68 .76

(Gd/Yb)ucc

.90 1.26 1.62

(La/Yb)ucc

.6 1.0 1.4.12 .24 .3680 160 2400 14 28

δ18O (‰, PDB)

-3-11

Mz (phi)

6.25 6.75 7.250

2

4

6

8

10

12

14

16

18

20

22

24

26

28

30

∑ REE (ppm) ∑ REE-flux

OIS1

OIS2

OIS3

Unit 1

Unit 2

K-Ah

AT

Ag

e (

ka

BP

)

CaCO (%)3

REE: abrupt changes occur at ca. 8 ka

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La Ce Pr Nd Sm Eu Gd Tb Dy Ho Er Tm Yb Lu.5

1.0

1.5

2.0

2.5Uni t 1 : < 7.1 ka

Abonormi ty 1: 7.6 kaUni t 2 : 3-8.2ka

Abonormi ty 2 : 25.8 ka

7.6 ka BP< 7.1 ka BP

31-8.2 ka BP

25.8 ka BP

Uni t 1:

Uni t 2:

Sam

ple

/UC

C

REE

REE fractionation patterns

Tephra layer

Sr-Nd isotopes

abrupt changes occur at 8 ka

Unit 2

Unit 1

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Different sediment sources

Aira caldera data after Arakawa et al. (1998); Volcanic rocks data after Shinjo and Kato (2000)

.6 .8 1.0 1.2 1.4.6

.8

1.0

1.2

1.4

1.6

Changjiang

Taiwan sediments

Huanghe

Volcanic rocks

Aira volcanic source

25.8 ka

7.6 ka

Unit 1Unit 2

(La

/Sm

) ucc

(Gd/Yb)u cc

Unit 1Unit 2

ChangjiangHuanghe

Aira volcanic sourceVolcanic rocksTaiwan sedimentstwo tephra layers

Unit 1: 0~ 7.1 ka

Taiwan Source?

Unit 2: 8.2~31 ka

Changjiang-sediments dominated

Dou et al., submitted

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~150 Mt/yr

Shuh-Ji Kao, et al., 2005. TAO

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Variable sediment sources with time

~ LGM

200

38°

30°

26°

34°

1000

200

1000

100

200

DGKS9603

DGKS9604

Yellow Sea

EastChinaSea

0 200km

100

Sea of Japan

120° 124° 128° 132°

Korea

Changjiang

Old Huanghe

Japan

Kyushu

China

Taiwan

36°

32°

28°

24°122° 126° 130°

Tokara Strait

Ryukyu Islands

AiraAta

Kikai

Kurosh

io current

paleo-coastalline at LGM

0~7 ka BP

200

38°

30°

26°

34°

1000

200

1000

100

200

DGKS9603

DGKS9604

Yellow Sea

East China Sea

0 200km

100

Sea of Japan

120° 124° 128° 132°

Korea

Changjiang

Old Huanghe

Japan

Kyushu

China

Taiwan

36°

32°

28°

24°122° 126° 130°

Tokara Strait

Ryukyu Islands

CDWAira

AtaKikai

Kurosh

io c

urre

nt

42

Thanks!