Otjozondu (Otjosondu)

 

Location - Namibia

Age (of portore) - 800 Ma
Original size - 2 million tonnes of Mn  

 

References

Buhn, B., Stanistreet, I.G., and Okrush, M., 1992, Late Proterozoic outer shelf manganese and iron deposits at Otjosondu (Namibia) related to the Damaran oceanic opening: Economic Geology, v. 87, p. 1393-1411.

Bau, M., Bühn, B., and Dulski, P., 1993, Spätproterozoische Mn- und Fe-Formationen im Damara Orogen, Namibia. – II. Lanthaniden als genetische Indikatoren: Geologica et Palaeontologica, v. 27, p. 223-224.

Cabral, A.R., Moore, J.M., Mapani, B.S., Koubová, M., and Sattler, C-D., 2011, Geochemical and mineralogical constraints on the genesis of the Otjosondu ferromanganese deposit, Namibia: hydrothermal exhalative versus hydrogenetic (including snowball-Earth) origins. South African Journal of Geology, v.114, p. 57-76.

Major Elements, oxide percent

 

 

 

%

%

%

%

%

%

%

%

%

%

%

MnO

Fe2O3tot

SiO2

Al2O3

CaO

MgO

K2O

Na2O

P2O5

TiO2

LOI
average
oxide-silicate ore (MnO>20%)
47.2
13.9
14.6
2.08
1.30
0.42
0.53
0.10
0.12
0.15
1.74
Y-4557 braunite 
66.45
4.84
11.53
0.86
0.27
0.16
0.02
0.005
0.04
0.08
1.48
OTJ-03 braunite, hollandite
64.76
9.36
7.27
1.52
0.57
0.17
0.11
0.005
0.07
0.05
4.98
OTJ-02 braunite
62.89
13.35
12.55
0.93
2.86
0.33
0.12
0.005
0.02
0.05
1.5
D52 braunite-hematite-jacobsite
60.7
6.8
11.2
1.38
0.46
0.16
0.16
0.005
0.15
D70 braunite-hematite-jacobsite
60.0
9.1
10.3
1.87
0.66
0.55
0.05
0.1
0.08
Y-4559 braunite
59.94
8.26
12.95
0.82
0.56
0.27
0.14
0.005
0.07
0.15
0.82
E11 braunite-hematite-jacobsite
57.3
4.4
11
2.87
0.39
0.38
0.8
0.005
0.22
E19 braunite-hematite-jacobsite
56.9
5.1
6.6
2.55
0.52
0.38
0.99
0.005
0.11
E15 braunite-hematite-jacobsite
56.2
4.3
12.2
3.18
0.39
0.4
1.1
0.5
0.2
D58 braunite-hematite-jacobsite
55.8
15.8
9.6
1.33
0.48
0.66
0.03
0.005
0.06
OTJ-08 braunite, hollandite
53.96
10.61
17.58
4.68
0.1
0.11
1.31
0.33
0.03
0.39
1.38
D53 braunite-hematite-jacobsite
53.7
5.6
17.3
1.7
1.46
0.85
0.19
0.1
0.2
Y-4556 braunite
53.19
2.75
12.04
0.76
0.52
0.13
0.06
0.005
0.06
0.05
0.96
D71 braunite-hematite-jacobsite
52.7
12.2
10.4
1.01
0.32
0.19
0.2
0.005
0.11
D57 braunite-hematite-jacobsite
47.8
18.3
11.9
0.89
2.72
0.62
0.05
0.1
0.08
OTJ-06A braunite, jacobsite
42.72
26.19
16.56
1.61
1.49
0.3
0.42
0.08
0.07
0.25
1.04
D59 braunite-hematite-jacobsite
42.5
16.6
9.4
1.29
0.7
0.36
0.18
0.1
0.18
E10 braunite-hematite-jacobsite
42.5
21.7
18.4
0.74
1.3
0.97
0.35
0.005
0.14
D60 braunite-hematite-jacobsite
42.3
20.6
10.5
1.76
2.1
0.57
0.03
0.005
0.21
OTJ-05 jacobsite, braunite
42.17
29.84
15.36
1.55
1.87
0.26
0.11
0.005
0.09
0.14
2.34
E14 braunite-hematite-jacobsite
39.9
5
29.2
3.42
1.93
0.18
1.11
0.1
0.19
OTJ-24 braunite, jacobsite
37.13
25.49
20.63
3.73
2.28
0.3
1.48
0.46
0.26
0.2
1.02
OTJ-09A braunite, jacobsite
28.48
12.14
13.34
0.78
0.25
0.1
0.23
0.07
0.04
0.09
1.55
OTJ-06B braunite, Mn-garnet
28.05
13.85
14.17
1.69
2.82
0.15
0.27
0.07
0.04
0.14
0.89
D61 Mn-pyroxene, garnet
23.0
8.9
32.3
8.58
0.66
0.38
3.82
0.3
0.09
OTJ-11 braunite, hollandite
22.74
22.23
21.91
4.12
4.06
0.28
0.85
0.15
0.63
0.21
2.92
D69 Mn-pyroxene, garnet
21.6
43.4
18.9
0.59
3.47
2.2
0.07
0.3
0.31
D66 Mn-pyroxene, garnet
18.8
11.5
42.6
3.66
5.97
0.91
0.5
0.4
0.11
OTJ-10 spessartine-qtz
18.76
24.55
34.29
8.92
3.92
0.72
0.12
0.005
0.25
1.15
0.77
Y-4558 braunite
18.71
15.02
34.03
3.18
10.58
0.33
0.62
0.12
0.31
0.19
1.04
OTJ-23 spessartine-qtz
18.65
22.63
39.9
10.07
3.23
0.8
1.76
0.17
0.11
0.59
0.93
OTJ-09B Mn-garnet, jacobsite
17.59
18.48
25.29
6.27
3.01
0.16
2.27
0.49
0.05
0.25
2.36
Y-4555 braunite, Mn-garnet
14.98
0.62
25.64
1.8
1.35
0.11
0.04
0.005
0.12
0.01
2.38
D56 Mn-pyroxene, garnet
12.7
20.7
50
7.23
0.64
1.19
3.42
0.4
0.29
E18 Mn-pyroxene, garnet
11.4
34
50.3
3.62
0.67
0.22
0.2
0.005
0.26
Y-4560 spessartine-qtz
7.92
17.14
63.99
4.22
0.8
0.47
1.3
0.38
0.01
0.18
1.2
OTJ-22 spessartine-qtz
5.45
7.99
69.56
8.87
1.09
0.38
3.79
0.38
0.08
0.33
0.36
Y-4561 feldspathic qtzite
0.7
24.04
52.75
8.55
1.07
0.85
4.22
1.54
0.06
0.54
0.64
OTJ-13 hematite-qtz
0.49
56.49
40.95
0.85
0.07
0.13
0.07
0.005
0.03
0.1
0.42
OTJ-15 hematite-qtz
0.36
42.62
53.23
1.58
0.14
0.11
0.54
0.03
0.08
0.23
0.56
OTJ-01 quartzite
0.18
2.51
96.08
0.28
0.03
0.01
0.05
0.005
0.01
0.46
0.23
OTJ-21 amphibolite
0.17
15.12
47.66
13.87
3.98
8.15
3.46
1.38
0.19
1.33
4.04
OTJ-16 hematite-qtz
0.13
56.32
39.43
0.69
0.11
0.12
0.17
0.005
0.09
0.09
1.22
OTJ-17 feldspathic qtzite
0.13
7.68
74.14
10.7
2.07
0.15
0.42
3.21
0.01
0.34
0.94
OTJ-19 quartzite
0.09
0.15
98.94
0.31
0.03
0.02
0.06
0.05
0.01
0.02
0.22
OTJ-14 hematite-qtz
0.08
49.69
48.03
0.79
0.16
0.14
0.09
0.005
0.04
0.09
0.54
OTJ-20 feldspathic qtzite
0.05
13.18
68.05
10.66
1.47
0.19
2.49
2.37
0.02
0.33
0.86
OTJ-18 quartzite
0.02
0.87
96.41
1.36
0.05
0.03
0.75
0.13
0.01
0.09
0.13

 

 

Trace elements, ppm

 

 

ppm

ppm

ppm

ppm

ppm

ppm

ppm

ppm

ppm

ppm

ppm

ppm

ppm

ppm

ppm

ppm

ppm

ppm

ppm

 
As
Ba
Cd
Co
Cr
Cu
Mo
Nb
Ni
Pb
Rb
Sc
Sr
Th
U
V
Y
Zn
Zr
average
na
40744
na
9
na
152
na
na
43
na
na
na
na
na
na
183
na
72
88
Y-4557 60 89212 449 31 419 0.015 31 2.00 15 3 52 53 125 67
OTJ-03 228 52936 1.8 203 2.00 383 1 6 18 14 20 3 36 3.1 0.250 21 26 67 37
OTJ-02 145 1164 1.8 158 2.00 356 0.50 0.015 6 2.00 20 2 267 6 1.6 7 35 125 62
D52 34500 5 150 7 38 45 4.3
D70 29100 5 180 9 82 39 19
Y-4559 160 99960 472 24 533 0.015 23 2.00 19 1.00 243 24 210 73
E11 46900 5 160 13 679 111 56
E19 56700 5 30 570 160 72 25
E15 46500 5 160 14 686 114 36
D58 25500 15 370 14 143 105 18
OTJ-08 62 33768 1.5 179 12 146 1 8 9 7 59 3 66 4.2 10.6 1.00 19 32 97
D53 40000 5 60 12 56 40 24
Y-4556 134 178244 272 64 105 0.015 25 2.00 9 3 1736 37 52 48
D71 51100 5 230 18 375 57 95
D57 30900 5 220 9 66 81 18
OTJ-06A 218 59922 1.1 167 28 350 8 8 26 2.00 27 5 209 11.6 9.6 1.00 26 60 127
D59 78800 5 190 7 95 62 29
E10 23500 5 310 10 26 67 577
D60 51700 5 210 7 63 136 27
OTJ-05 314 9047 0.4 237 2.00 505 0.50 10 12 2.00 18 4 136 7.5 4.5 3 26 170 62
E14 49100 5 70 16 621 78 129
OTJ-24 757 48368 1.7 163 30 191 10 6 16 2.00 50 5 145 7.1 0.250 5 37 98 81
OTJ-09A 189 270591 0.7 107 18 182 68 0.015 19 2.00 19 2 737 2.7 0.250 4 24 29 62
OTJ-06B 297 237271 1 68 27 129 31 5 16 2.00 20 3 703 3.7 0.250 3 25 2.00 67
D61 77600 5 170 12 69 36 303
OTJ-11 656 127279 1.1 95 15 84 7 13 11 12 36 14 673 4 0.250 92 53 111 142
D69   12200     39 60     12             21   62 16
D66 51600 5 10 10 53 37 56
OTJ-10 76 42904 0.3 48 35 11 2 16 6 2.00 16 12 470 4.6 0.250 29 13 23 187
Y-4558 574 103632 139 38 113 0.015 11 20 32 6 432 58 71 225
OTJ-23 85 9315 1 77 25 9 0.50 13 16 2.00 48 20 93 2.1 1.8 28 159 67 59
OTJ-09B 378 158808 0.6 87 18 161 39 6 21 2.00 63 5 386 0.100 0.250 6 39 43 27
Y-4555 320 319227 153 19 84 0.015 18 68 14 3 2662 15 43 13
D56 26600 14 150 21 23 44 79
E18 1100 27 10 16 43 103 77
Y-4560 22 19437 127 29 26 0.015 18 25 46 3 46 20 55 130
OTJ-22 19 14779 0.150 18 2.00 8 0.50 8 0.015 12 86 7 134 0.100 0.250 13 7 14 12
Y-4561 135 35470 95 83 21 0.015 30 63 100 8 331 6 31 215
OTJ-13 12 2239 0.9 58 2.00 7 0.50 16 7 2.00 16 2 5 1.5 0.250 33 12 51 60
OTJ-15 19 3314 1.6 40 2.00 22 0.50 16 5 141 24 3 26 1.2 0.250 35 14 32 73
OTJ-01 2 537 4 5 11 8 2 2.00 7 3 1.00 4 13 84
OTJ-21 5 1791 63 10 153 10 108 9 153 36 102 30 139 130
OTJ-16 39 11017 1.1 38 8 2.00 0.50 9 6 6 18 3 52 2 0.250 28 12 16 56
OTJ-17 3 537 6 2.00 7 9 1.00 11 10 4 237 6 47 113
OTJ-19 3 90 1.00 2.00 25 1.00 1.00 5 6 0.50 3 1.50 7 181
OTJ-14 8 1791 0.8 37 2.00 39 0.50 6 6 2.00 15 2 10 2.6 0.250 38 13 8 52
OTJ-20 4 1612 12 2.00 8 1.00 9 19 54 3 234 6 125 111
OTJ-18 2 537 1.00 2.00 18 1.00 1.00 17 21 1 21 5 8 51

 

Rare-earth elements, ppm

 
sample
La
Ce
Pr
Nd
Sm
Eu
Gd
Tb
Dy 
Ho 
Er 
Tm 
Yb
Lu
avg 52.2 163.0 9.9 39.8 8.0 1.9 7.6 1.2 6.8 1.3 3.6 0.5 2.8 0.4
Y-4557 52.7 215 11.8 52.2 11.4 2.81 11.4 1.77 10.2 1.94 5.06 0.68 3.88 0.54
OTJ-03
OTJ-02
D52
D70
Y-4559 51.8 116 8.95 32.9 6.16 1.46 5.53 0.8 4.58 0.88 2.27 0.31 1.78 0.25
E11
E19
E15
D58
OTJ-08
D53
Y-4556 52.2 158 8.96 34.4 6.33 1.53 5.81 0.93 5.74 1.16 3.32 0.46 2.7 0.4
D71
D57
OTJ-06A
D59
E10
D60
OTJ-05
E14
OTJ-24
OTJ-09A
OTJ-06B
D61
OTJ-11
D69                            
D66
OTJ-10
Y-4558 39.6 157 11.4 48 9.4 1.81 8.87 1.6 10.5 2.17 6.74 1.1 7.3 1.07
OTJ-23
OTJ-09B
Y-4555 104 17.8 14.4 30.5 2.13 0.56 1.33 0.18 1.19 0.24 0.66 0.1 0.63 0.1
D56
E18
Y-4560
OTJ-22
Y-4561
OTJ-13 7.6 39.8 1.83 7.1 1.23 0.19 1.15 0.17 0.9 0.17 0.44 0.07 0.43 0.06
OTJ-15 6.3 21.1 1.87 7.6 1.5 0.29 1.56 0.23 1.22 0.22 0.56 0.08 0.49 0.06
OTJ-01
OTJ-21
OTJ-16 9.6 43.6 2.11 8.5 1.38 0.53 1.35 0.18 0.95 0.19 0.5 0.07 0.41 0.05
OTJ-17
OTJ-19
OTJ-14 12.8 74.8 5.2 23.9 5.08 0.96 4.44 0.65 2.94 0.44 0.98 0.14 0.74 0.09
OTJ-20
OTJ-18

Rare-earth elements,

normalized to chondritic values of Taylor & McLennan (1992)
sample
LaN
CeN
PrN
NdN
SmN
EuN
GdN
TbN
YbN
Ce/Ce*
Eu/Eu*
LaN/YbN
avg 142.3 170.3 72.3 56.0 34.5 22.2 24.8 20.1 11.2 1.7 0.8 14.0 1.1853 0.7611
Y-4557 143.597 224.660 86.131 73.418 49.351 32.299 37.255 30.517 15.645 2.020 0.753 9.178
OTJ-03
OTJ-02
D52
D70
Y-4559 141.144 121.212 65.328 46.273 26.667 16.782 18.072 13.793 7.177 1.262 0.764 19.665
E11
E19
E15
D58
OTJ-08
D53
Y-4556 142.234 165.099 65.401 48.383 27.403 17.586 18.987 16.034 10.887 1.712 0.771 13.064
D71
D57
OTJ-06A
D59
E10
D60
OTJ-05
E14
OTJ-24
OTJ-09A
OTJ-06B
D61
OTJ-11
D69                        
D66
OTJ-10
Y-4558 107.902 164.054 83.212 67.511 40.693 20.805 28.987 27.586 29.435 1.731 0.606 3.666
OTJ-23
OTJ-09B
Y-4555 283.379 18.600 105.109 42.897 9.221 6.437 4.346 3.103 2.540 0.108 1.017 111.552
D56
E18
Y-4560
OTJ-22
Y-4561
OTJ-13 20.708 41.588 13.358 9.986 5.325 2.184 3.758 2.931 1.734 2.501 0.488 11.943
OTJ-15 17.166 22.048 13.650 10.689 6.494 3.333 5.098 3.966 1.976 1.440 0.579 8.688
OTJ-01
OTJ-21
OTJ-16 26.158 45.559 15.401 11.955 5.974 6.092 4.412 3.103 1.653 2.270 1.187 15.822
OTJ-17
OTJ-19
OTJ-14 34.877 78.161 37.956 33.615 21.991 11.034 14.510 11.207 2.984 2.148 0.618 11.689
OTJ-20
OTJ-18

sample ID TC % TOC % Ccarb % δ13C pdb δ18O pdb δ18O smow Stotal % δ34S sulfide δ34S barite
Y-4557             1.55 13.8
OTJ-03             0.01
OTJ-02             0.01
D52            
D70            
Y-4559             1.71
E11            
E19            
E15            
D58            
OTJ-08             0.01
D53            
Y-4556           3.47 15.7
D71          
D57          
OTJ-06A           0.94 11.7
D59            
E10            
D60            
OTJ-05             0.05
E14            
OTJ-24             0.52
OTJ-09A             4.84 13
OTJ-06B             4.25 13.4
D61            
OTJ-11             2.05 10.1
D69                
D66            
OTJ-10             0.61
Y-4558             1.53
OTJ-23             0.01
OTJ-09B             2.32 13.1
Y-4555             6.26 16.7
D56            
E18            
Y-4560             0.02
OTJ-22             0.00
Y-4561             0.32
OTJ-13             0.01
OTJ-15             0.00
OTJ-01             0.00
OTJ-21             0.03
OTJ-16             0.12
OTJ-17             0.00
OTJ-19             0.00
OTJ-14             0.01
OTJ-20             0.00
OTJ-18             0.00