Groote Eylandt - Oxide ore

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Location - Australia, Northern Territory

Age (of protore) - 97 Ma Cennomanian

Original size - 44 million tonnes of Mn at 48%, 184 Mt at 40%

Current production 1.6 Mt of ore /yr at 48 % or 0.77 Mt Mn (3rd in world)

Strat Column

References

Pracejus, B., and Bolton, B.R., 1992, Geochemistry of supergene manganese oxide deposits, Groote Eylandt, Australia: Economic Geology, v. 87, p. 1310-1335.

Pracejus, B., Bolton, B.R., Frakes, L.A., and Abbott, M., 1990, Rare-earth element geochemistry of supergene manganese deposits from Groote Eylandt, Northern Territory, Australia: Ore Geology Reviews, v. 5, p. 293-314.

Varentsov, I.M., 1996, Manganese Ores of Supergene Zone: Geochemistry of Formation: Dordrecht, Kluwer Academic Publishers, 342 pp.

Ferenczi, P.A., 2001, Iron ore, manganese and bauxite deposits of the Northern Territory, Northern Territory Geological Survey Report 13.

major elements - trace elements - rare-earth elements - REE normalized - isotopes

Major Elements, oxide percent

 

 

 

%

%

%

%

%

%

%

%

%

%

%
MnO
Fe2O3t
SiO2
Al203
CaO
MgO
K2O
Na2O
TiO2
P205
LOI

Average

 
Combined
60.08
4.51
10.56
4.38
0.19
0.24
1.49
0.25
0.32
0.11
4.0
Average Pracejus
62.20
4.25
8.09
4.13
0.09
0.35
1.82
0.21
0.32
0.22
  
1 Radial pyrolusites
70.76
3.86
3.40
3.00
0.04
0.12
0.42
0.09
0.32
0.14
  
2      Hardgrounds   
69.85
1.29
4.20
2.70
0.07
0.90
0.81
0.20
0.22
0.21
  
3 Laminar mangcretes
56.94
4.29
11.20
6.30
0.13
0.12
2.10
0.42
0.48
0.16
  
4 Cemented pisolite
63.53
3.86
5.00
4.70
0.10
0.55
1.92
0.31
0.27
0.18
  
5 Uncemented pisolite
64.69
3.00
7.70
5.40
0.06
0.17
0.54
0.09
0.40
0.14
  
6 Cemented oolite
67.53
2.00
4.50
3.40
0.10
0.68
0.55
0.16
0.23
0.16
  
7 Concretions
63.40
7.29
3.10
3.20
0.13
0.12
4.48
0.26
0.27
0.37
  
8      Uncemented oolite
59.91
3.29
9.20
4.90
0.14
0.95
0.89
0.24
0.37
0.16
  
9 Massive mangcrete
58.75
9.44
5.30
4.90
0.13
0.07
3.63
0.22
0.43
0.37
  
10      Siliceous ores
54.88
1.57
24.00
2.70
0.08
0.10
1.92
0.20
0.17
0.16
  
11 Digital Concretions
53.97
6.86
11.40
4.20
0.06
0.05
2.75
0.11
0.38
0.44
  
12 Spherulites
14.20
23.88
31.80
16.60
0.06
0.12
0.34
0.03
1.27
0.09
  
13 Chocolate ores
12.65
10.73
38.80
24.00
0.03
0.07
0.43
0.05
2.35
0.05
  
14      Laterites
6.46
17.88
38.80
23.40
0.01
0.05
0.36
0.03
2.00
0.05
  
15 Fe pisolites
6.20
66.64
9.70
5.70
0.01
0.05
0.25
0.03
0.42
0.89
  
16 Fe pipe walls
2.32
19.16
47.80
19.60
0.01
0.02
0.22
0.01
1.62
0.05
  
17 Kaolinitic clays
0.77
8.58
57.70
21.50
0.01
0.03
0.17
0.01
1.60
0.05
  
Average Varentsov
58.0
4.8
13.0
4.6
0.3
0.1
1.2
0.3
0.3
0.0
4.0
18
cemented pisoliths
75.1
2.89
1.6
0.86
0.47
na
0.27
0.28
0.11
na
1.54
19
fine pisoliths in kaolin matrix
74.3
2.45
2.9
0.98
0.47
na
0.27
0.28
0.16
na
1.34
20
fine-grained cryptomelane
72.1
1.98
0.8
1.78
0.28
na
3.51
0.29
0.19
0.004
3.29
21
fine-grained pyrolusite
70.4
2.23
2.4
2.64
0.31
na
1.67
0.4
0.21
na
3.12
22
nodular cryptomelane
68.3
2.45
1.0
2.13
0.63
0.11
0.77
0.34
0.12
na
5.83
23
cemented pisoliths
68.0
3.99
5.5
2.06
0.39
0.11
1.6
0.28
0.32
na
2.13
24
pisoliths in kaolin matrix
67.1
3.12
6.5
4.44
0.16
na
0.33
0.23
0.3
na
2.69
25
cemented ooliths
67.0
1.98
8.6
2.87
0.21
na
0.78
0.1
0.27
0.004
2.18
26
cemented pisoliths
66.6
1.78
12.7
1.56
0.31
na
0.41
0.28
0.11
na
1.22
27
lumpy pyrolusite
65.0
2.91
6.8
4.46
0.47
na
1.65
0.4
0.18
na
3.42
28
fine cryptomelane + lithiophorite
65.0
3.17
4.3
4.67
0.27
na
2.44
0.19
0.22
0.002
5.13
29
lateritic ore
64.1
3.18
9.4
3.26
0.08
na
0.61
0.28
0.23
na
3.8
30
oolitic ore
62.0
4.23
8.6
6.18
0.16
na
0.7
0.34
0.35
na
3.54
31
uncemented ooliths
61.0
3.13
8.0
4.63
0.31
0.23
0.82
0.28
0.35
na
6.72
32
lateritic ore
58.8
3.34
14.8
3.69
0.31
na
0.51
0.28
0.35
na
3.89
33
fine-grained cryptomelane
53.2
14.65
10.9
1.81
0.27
na
2.4
0.29
0.34
0.004
3.9
34
fine-grained pyrolusite
52.5
3.56
22.4
5.45
0.21
na
0.33
0.1
0.38
0.004
3.52
35
very fine ooliths
52.1
1.31
20.4
5.64
0.23
na
2.44
0.62
0.3
na
4.03
36
cryotomelane + kaolinite
45.2
7.94
16.8
9.58
0.31
na
1.85
0.51
0.58
na
6.36
37
pisoliths in lateritic matrix
43.2
9.04
16.1
10.75
0.27
0.07
1.22
0.19
0.59
0.004
7.96
38
nodules
31.1
17.85
30.4
6.57
0.16
na
0.87
0.34
0.4
na
5.53
39
laterite
29.7
4.69
47.4
5.98
0.27
na
0.61
0.1
0.43
0.004
3.68
40
laterite
21.5
7.92
41.4
14.67
0.27
na
0.83
0.1
0.86
0.004
7.12
41
fine pisoliths
17.7
16.98
28.8
19.42
0.28
0.05
0.72
0.1
1.07
0.02
10.37
42
kaolinite
8.3
8.71
50.9
18.74
0.42
na
0.61
0.1
0.94
0.02
8.8
43
sand
3.2
2.15
77.3
10.53
0.27
na
0.28
0.1
0.54
0.04
4.31
44
fragmental laterite
1.0
56.42
16.1
12.92
0.28
0.07
0.28
0.1
0.94
0.09
11.44

 

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
avg both
9406
96
 15 97 29 151 40 52 399 4 370 69 107 60
avg Pracejus
13527
96
 15 116 29 151 40 5 4 370 107 49
1
1700
23
16
52
28
46
122
4
6
398
77
36
2     
10200
75
14
92
1
198
2
1
1
171
86
59
3
10200
74
16
113
1
62
2
1
1
509
80
63
4
16200
95
15
90
43
132
41
9
4
201
98
38
5
8100
55
16
72
70
98
58
6
5
245
85
63
6
18800
77
15
139
73
342
57
8
6
331
115
43
7
10900
119
15
159
1
112
2
1
1
123
121
33
8     
15300
83
15
129
79
440
97
8
6
329
137
61
9
6600
169
16
169
17
90
56
15
8
360
136
63
10     
4300
149
15
135
1
84
2
1
1
251
118
33
11
46500
131
16
131
1
59
2
1
1
1154
122
47
12
4600
51
56
73
7
63
49
23
16
513
66
198
13
2100
40
24
50
1
22
2
1
1
261
50
258
14     
1400
42
41
44
5
13
51
24
17
302
51
244
15
900
50
23
190
120
324
112
16
5
864
191
119
16
2300
20
37
33
32
2
57
14
9
287
45
209
17
200
18
40
25
2
3
10
14
14
137
43
193
avg Varentsov
5284
77
52
794
69
70
18
806
55
57
192
84
44
19
2060
96
46
367
91
71
20
6270
83
104
688
74
67
21
7703
117
48
567
28
80
22
26601
91
65
2445
80
87
23
2687
90
20
283
89
44
24
896
68
48
218
72
69
25
5464
79
41
629
42
53
26
2150
70
55
1348
20
65
27
2597
93
56
482
58
49
28
1433
107
42
514
157
40
29
5374
56
20
1549
36
47
30
358
87
60
244
78
102
31
8509
94
77
4350
59
96
32
9315
65
58
850
56
104
33
4030
78
42
701
55
53
34
1075
66
41
133
112
76
35
9673
65
90
721
48
23
36
7613
47
30
517
99
89
37
10837
72
58
286
88
124
38
358
46
59
174
35
58
39
2150
na
na
na
na
na
40
3583
71
20
207
53
104
41
1881
59
61
208
46
409
42
4030
76
61
432
63
110
43
1881
36
42
448
48
53
44
1075
45
20
21
56
150

blank or na = not reported; bd = below detection

Rare-earth elements, ppm

 
Sample
La
Ce
Pr
Nd
Sm
Eu
Gd
Tb
Dy 
Ho 
Er 
Tm 
Yb
Lu
avg Pracejus 45 101 64.64 18.74 4.073 23.04 4.545
1 77 292 213 68.1 12.8 49.4 3.6
2      40 29 52 14.8 3.5 17.3 4.4
3 36 117 36 9.7 2 16.4 2.8
4 53 74 54 13.9 3.3 19.2 5.1
5 44 51 58 12.1 3.7 20.9 7.1
6 52 55 90 22.7 6.5 24.8 6.9
7 37 116 34 13.7 2.2 20.7 2.6
8      54 80 66 17.7 4.3 21.6 3.8
9 38 170 41 12.5 2.3 25.5 4.4
10      35 75 40 12.4 2.5 13.9 3.5
11 29 52 27 8.5 1.7 23.7 5.8
12 27 146 37 9.8 1.1 45.3 3.6
13 21 227 26 5 0.6 23.2 2.4
14      22 158 30 7.3 1.1 29.6 2.8
15 17 64 20 12.4 bd 93.5 6.5
16 11 35 11 1.5 bd 31 1.5
17 9 28 12 0.7 0.2 7.9 0.7

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 122.62 105.54 98.74 90.91 81.11 46.81 75.28 18.33 0.99 0.58 7.34 0.59 0.61
1 209.81 305.12 266.04 299.58 294.81 147.13 161.44 14.52 1.29 0.67 14.45    
2      108.99 30.30 83.54 73.14 64.07 40.23 56.54 17.74 0.32 0.67 6.14
3 98.09 122.26 63.12 50.63 41.99 22.99 53.59 11.29 1.55 0.48 8.69
4 144.41 77.32 94.09 75.95 60.17 37.93 62.75 20.56 0.66 0.62 7.02
5 119.89 53.29 92.75 81.58 52.38 42.53 68.30 28.63 0.51 0.71 4.19
6 141.69 57.47 131.43 126.58 98.27 74.71 81.05 27.82 0.42 0.84 5.09
7 100.82 121.21 61.32 47.82 59.31 25.29 67.65 10.48 1.54 0.40 9.62
8      147.14 83.59 108.23 92.83 76.62 49.43 70.59 15.32 0.66 0.67 9.60
9 103.54 177.64 70.09 57.67 54.11 26.44 83.33 17.74 2.09 0.39 5.84
10      95.37 78.37 67.08 56.26 53.68 28.74 45.42 14.11 0.98 0.58 6.76
11 79.02 54.34 48.48 37.97 36.80 19.54 77.45 23.39 0.88 0.37 3.38
12 73.57 152.56 58.41 52.04 42.42 12.64 148.04 14.52 2.33 0.16 5.07
13 57.22 237.20 42.45 36.57 21.65 6.90 75.82 9.68 4.81 0.17 5.91
14      59.95 165.10 47.43 42.19 31.60 12.64 96.73 11.29 3.10 0.23 5.31
15 46.32 66.88 33.22 28.13 53.68 bd 305.56 26.21 1.70 1.77
16 29.97 36.57 19.29 15.47 6.49 bd 101.31 6.05 1.52 4.96
17 24.52 29.26 19.12 16.88 3.03 2.30 25.82 2.82 1.35 0.26 8.69

Isotopes
Sample
 TC % TOC % Ccarb % δ13C pdb δ18O pdb δ18O smow Stotal % δ34S sulfide 87Sr/86Sr

 

 

 

 

Stratigraphy from Ferenczi 2001. Click here for full-sized pdf version.