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Table 7 Fluid production from the antigorite + brucite reaction, calculated vs measured

From: The role of the antigorite + brucite to olivine reaction in subducted serpentinites (Zermatt, Switzerland)

Bulk rock

Bc in wt %1

Bulk H2O1

T °C1

Bulk H2O2

T°C2

Olivine wt %2

Fluid wt %2

LOI

Mg# Ol1,2,3

Mg# Atg1,2,3

Mg# Bc1,2,3

Mg# Chl1,2,3

Mg# Cpx1,2,3

Density change1/2%4

Zermatt

 Lhz*

4.8

11.7

376

8.3

501

22.3

3.4

9.2

261

931

931

981

841

2781/2922

         

742

972

972

992

942

5.1

         

953

933

  

983

 

 Lhz**

Talc present

     

No fluid

       

 Hzb*

6.75

13.2

359

8.4

512

30.8

4.8

11.3

211

941

921

  

2716/2898

         

802

982

982

  

6.7

 Hzb**

1.23

12.5

533

11.7

546

5.1

0.8

      

2649/2698

              

1.8

 Dun*

18.3

15.1

309

1.7

530

86.3

13.4

3.6

111

911

901

991

 

2696/3257

         

892

982

982

  

20.8

Dun**

12.1

14.6

529

5.5

546

55

11.5

      

2637/2954

              

12

EPMA*

16.8

15.2

480

2.8

543

77.7

12.4

6.3

681

971

971

991

 

2636/3129

         

952

992

992

952

 

18.7

         

953

973

    

 EPMA**

14.6

15

533

4.1

551

66.8

8.9

      

2609/3023

              

15.9

Primitive mantle, IODP

 PM*

4.3

11.3

400

8.4

501

19.5

2.9

 

311

931

931

981

851

2795/2922

         

742

972

972

992

942

4.5

 PM**

Talc present

             

 Hzb*

10.4

13.8

333

6.6

518

47

7.2

 

151

911

911

  

2703/2989

         

852

982

982

  

10.6

 Hzb**

4.8

13.2

529

9.8

544

20.6

3.4

      

2637/2772

              

5.1

 Dun*

13.3

14.2

287

4.8

518

60.8

9.4

 

81

901

891

  

2711/3088

         

862

982

982

  

13.9

 Dun**

6.7

13.6

529

8.7

530

29.1

4.9

      

2652/2815

              

6.1

  1. Ol-in calculated at 2 GPa, Bc-out at 2.5 GPa
  2. Sources of bulk rock compositions: Zermatt bulk; for phase diagram computation from Li et al. (2004a, 2004b): Lhz = average bulk rock # 16–19 (meta-lherzolites), Hzb = average bulk rock #1–8 & 10–14 (meta-harzburgites), Dun = bulk rock sample lg 15 (meta-dunites)
  3. EPMA bulk from the quantitative map (Fig. 10)
  4. Primitive mantle (PM) from McDonough and Rudnick (1999) (Table 1)
  5. IODP Hzb = average abyssal meta-harzburgites (n = 48), Dun = average abyssal meta-dunites (n = 20): From Deschamps et al. (2013) (Table 1)
  6. 1. LOI’s [wt% H2O] from Li et al. (2004a, 2004b). 2. As soon as talc is present brucite is absent
  7. * All iron as FeO = FeOtot
  8. ** Bulk − FeOtot
  9. 1Calculated at Ol-in [wt% H2O]
  10. 2Calculated at Bc-out [wt% H2O]
  11. 3Natural olivines at Bc-out Measured with EPMA
  12. 4Density change in kg/m3 and in mass%