Organic, Gas, and Element Geochemistry of Hydrothermal Fluids of the Newly Discovered Extensive Hydrothermal Area in the Wallis and Futuna Region (SW Pacific)
Table 5
Endmember compositions in fluids from the Kulo Lasi and Fatu Kapa vent fields. Kulo Lasi endmembers cannot be extrapolated at Mg = 0. Values presented here for both brine and condensed vapour phases correspond to concentrations in the fluid with the lowest Mg. Elemental compositions in endmember fluids from the various sites of the Fatu Kapa vent field were calculated using the mixing lines (Figure S1) and assuming Mg = 0. Values of the purest fluid were used when linear regression was not possible (). Note that only one sample was available for the site .
Zone
Site
Depth
pH
NaCl
Cl
Si
SO4
Br
Na
K
Mg
Ca
Li
Rb
Sr
Fe
Mn
Cu
Zn
Na/Cl
Br/Cl
Na/K
CH4/Mn
°C
(wt%)
mM
mM
mM
µM
mM
mM
mM
mM
µM
µM
µM
µM
µM
µM
µM
×103
Kulo Lasi
NaCl poor
1475
345
2.24
2.9
497
8.2
8.8
738
388
18.5
24.6
11.6
149
26
7.3
4796
862
14
45
0.78
1.48
21
0.007
Kulo Lasi
NaCl rich
1475
345
2.36
4.3
735
14.6
6.2
1135
612
29.5
26.5
10.9
238
46
3.4
9884
1416
2.5
175
0.83
1.54
21
0.001
Fatu Kapa
Stéphanie
1555
280
3.4
4.5
767
4.7
0.0
1569
532
54.5
0.0
98.9
708
114
282
655
268
6.6
<LOD
0.69
2.05
10
0.76
Fatu Kapa
Carla
1664
280
2.8
3.5
594
4.3
0.0
1132
477
59.9
0.0
31.4
691
105
114
287
53
nm
4.4
0.80
1.90
8
1.37
Fatu Kapa
1572
270
3.7
3.9
665
4.2
0.0
1282
518
66.4
0.0
44.3
751
113
160
28
60
nm
3.4
0.78
1.93
8
1.08
Fatu Kapa
1669
270
4.6
4.5
771
4.6
0.0
1458
580
71.0
0.0
85.9
777
nm
nm
nm
nm
nm
nm
0.75
1.89
8
-
Fatu Kapa
1540
265
4.4
4.1
693
3.7
1.0
1344
533
64.9
1.2
51.1
755
nm
nm
nm
nm
nm
nm
0.77
1.94
8
-
Fatu Kapa
Fati Ufu
1523
300
3.8
4.6
790
4.9
0.0
1589
580
48.2
0.0
85.4
722
nm
nm
nm
nm
nm
nm
0.73
2.01
12
-
Fatu Kapa
Fati Ufu
1503
280
3.3
4.1
700
4.9
0.0
1380
538
40.0
0.0
65.0
583
nm
nm
nm
nm
nm
nm
0.77
1.97
13
-
Fatu Kapa
Tutafi
1580
315
4.1
4.2
713
5.1
0.0
1405
535
52.9
0.0
65.1
635
nm
nm
nm
nm
nm
nm
0.75
1.97
10
-
IAPSO
Standard sw
-
-
-
3.2
546
0.0
28.2
839
468
10.2
53.2
10.3
27
1.3
90
<LOD
<LOD
<LOD
<LOD
0.9
1.5
46
-
Kulo Lasi
Reference sw
1150
-
-
3.2
551
0.1
29.0
833
457
9.8
53.2
10.6
25
4.4
93
<LOD
<LOD
<LOD
<LOD
0.83
1.5
47
-
Fatu Kapa
Reference sw
1488
-
-
3.3
565
0.0
28.8
841
483
10.4
54.5
10.7
22
5.8
<LOD
<LOD
<LOD
<LOD
<LOD
0.85
1.5
46
-
Fatu Kapa
Reference sw
1572
2
-
3.3
557
0.0
28.7
841
477
10.4
54.2
10.8
23
nm
nm
nm
nm
nm
nm
0.86
1.5
46
-
Maximum value when linear regression was not possible; only one sample.