correlation between hot spot activities and geomagnetic paleointensity correlation between hot spot...

Correlation between Hot Spot Activities and Geomagnetic Paleointensity

Correlation between Hot Spot Activities and Geomagnetic Paleointensity:Indicating Mantle Plume Rising Speeds

H. B. WANG, R. ZHU, Y. J. CHEN and W. J. MORGAN

Peking University, C.A.S. and Princeton University

2006 WPGM, July 27th, 2006


Earth’s interior

&

Geomagnetism

Field in the outer core extend to the surface


(Morgan, 1971)

Mantle Plumes and Hot spots

(Lay et al., 1998)


Long-term trends in paleointensity in the last 82 Ma, which is after the CNS ( use 90 Ma to calculate)

Database: PInt03 (plus) and New SBG collections

Data selecting criteria:

(1) Age: from 90 Ma to present

(2) Thellier method with positive pTRM checks

(3) ≥ 2 specimens for each cooling unit

(4) Exclude data during magnetic polarity transition

(5) VDM or VADM error of each cooling unit ≤ 30%

(6) Every 3 Ma window for averaging mean VDM or VADM

Totally 823 and 96 data were selected.

(Tauxe, 2006, in press)


Paleointensity variation

0 10 20 30 40 50 60 70 80 90 100AG E (M a)

0

5

10

15

20

25

VD

M o

r V

AD

M (

102

2 A

m2)

CNS


Stability tests on paleointensity, using various criteria

0 10 20 30 40 50 60 70 80 90A ge (M a)

-2

-1

0

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

VD

M o

r VA

DM

(1

022 A

m2 )

0 10 20 30 40 50 60 70 80 90

A ge (M a)

-2

-1

0

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

VD

M o

r V

AD

M (

10

22 A

m2 )

0 10 20 30 40 50 60 70 80 90

A ge (M a)

-1

0

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

VD

M o

r V

AD

M (

10

22 A

m2 )

0 10 20 30 40 50 60 70 80 90A ge (M a)

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

VD

M o

r V

AD

M (

10

22 A

m2 )

0 10 20 30 40 50 60 70 80 90

A ge (M a)

0

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

VD

M o

r V

AD

M (1

022

Am

2 )

0 10 20 30 40 50 60 70 80 90

A ge (M a)

0

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

VD

M o

r V

AD

M (1

022

Am

2 )


Hawaiian-Emperor seamount chain

160 165 170 175 180 185 190 195 200 205 210

Longitude

160 165 170 175 180 185 190 195 200 205 210

15

20

25

30

35

40

45

50

55

La

titu

de

1 5

2 0

2 5

3 0

3 5

4 0

4 5

5 0

5 5

- 8 0 0 0

- 7 0 0 0

- 6 0 0 0

- 5 0 0 0

- 4 0 0 0

- 3 0 0 0

- 2 0 0 0

- 1 0 0 0

0

1 0 0 0

2 0 0 0

3 0 0 0

0 M a7.2 M a

48.1 M a

56.2 M a

64.7 M a

42.4 M a

27.7 M a

10.3 M a

38.6 M a


Hawaiian hot spot activity: volume flux

0 10 20 30 40 50 60 70 80 90

AG E (M a)

-2

0

2

4

6

8

Ha

wai

ian

Vol

ume

flux

(m3/s

) (Van Ark and Lin, 2004)


Hot spot activity correlates with geomagnetic paleointensity

About 3~5 Ma phase lag.

0 10 20 30 40 50 60 70 80 90 100AG E (M a)

-4

0

4

8

12

16

Mea

n V

DM

or

VA

DM

(10

22 A

m2)

-4

0

4

8

12

16

Haw

aiia

n R

esid

ual V

olum

e F

lux

(m3/s

)

CNS



About 3~5 Ma phase lag.

0 10 20 30 40 50 60 70 80 90 100AG E (M a)

-4

0

4

8

12

16

Mea

n V

DM

or

VA

DM

(10

22 A

m2)

-4

0

4

8

12

16

Haw

aiia

n R

esid

ual V

olum

e F

lux

(m3/s

)

CNS

?


Louisville seamount chain

180 185 190 195 200 205 210 215 220 225

Longitude

180 185 190 195 200 205 210 215 220 225

-55

-50

-45

-40

-35

-30

-25

-20

Latit

ude

-55

-50

-45

-40

-35

-30

-25

-20

-10000

-9000

-8000

-7000

-6000

-5000

-4000

-3000

-2000

-1000

063.8 M a

0 M a

42 M a

17.5 M a


Louisville hot spot activity: volume flux

0 10 20 30 40 50 60 70AG E (M a)

-0 .5

0

0.5

1

1.5

2

Loui

svill

e V

olum

e flu

x (m

3/s

)


0 10 20 30 40 50 60 70 80 90 100AG E (M a)

-4

0

4

8

12

16

VD

M o

r V

AD

M (

102

2 A

m2)

-1

0

1

2

3

4

Loui

svill

e R

esid

ual

Vol

ume

Flu

x (m

3/s

)W

ith P

hase

Lag

of 9

Ma

CNS


Already shifted phase lag of 9 Ma.



Already shifted phase lag of 9 Ma.

0 10 20 30 40 50 60 70 80 90 100AG E (M a)

-4

0

4

8

12

16

VD

M o

r V

AD

M (

102

2 A

m2)

-1

0

1

2

3

4

Loui

svill

e R

esid

ual

Vol

ume

Flu

x (m

3/s

)W

ith P

hase

Lag

of 9

Ma

CNS


Discussions:

Assuming the outer core and plume roots influence each other, then heat and magma rise slowly in plumes.

Assuming when paleointensity is higher, the outer core convects more vigorously and conducts more heat and energy to mantle plumes.

Fluid outer core

plumes

Influence each other

Seamount chains

Heat conducting

Hawaii 7.4 Mg/s lag: 3 Ma

Louisville 2.0 Mg/s lag: 9 Ma

(Malamud and Turcotte, 1999)


Conclusions:

(1) The correlations show the connection between crust and core

(2) Some hot spots are originated from the CMB. Mantle plumes lead the connection between hotspots and outer fluid core.

(3) With the ~3 Ma and ~9 Ma phase lags, we estimated average plume rising speeds of ~1.0 m/yr for Hawaii and ~ 0.3 m/yr for Louisville.


Acknowledgements:

We thank:

People in Paleomag Lab, IGG, Chinese Academy of Sciences

People in ITAG, SESS, Peking University

Drs. Jian Lin, Emily Van Ark, Keke Zhang and Lisa Tauxe

This work was supported by NSFC grants (40221402), Chinese Academy of Sciences and Peking University.

Wang, H. B., R. Zhu, Y. J. Chen and W. J. Morgan, (2006), Correlation Between Hotspot Activity and Geomagnetic Paleointensity, Eos Trans. AGU, 87(36), West. Pac. Geophys. Meet. Suppl., Abstract U44B-05


Thanks!

http://www.paleomag.net [email protected]

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