5 
sequently, give no X-ray pattern. X-ray patterns that are obtained 
indicate crystalline sizes less than a few micrometers. : 
Due to the fine grain size of the iron and manganese oxides and 
the manner in which the nodules are formed, the porosity is high and 
the surface area is large. The high porosity allows the nodules to 
take up appreciable quantities of seawater and its contained salts. 
Due to their large active surface area, nodules have been reported 
to be effective converters of unburned hydrocarbons to carbon dioxide 
in automobile exhausts and efficient absorbers of sulfur from stack 
gases.” 
~ There is no clear age pattern in the layers but nodule samples 
exhibit thicker layers on the bottom side. Radiometric dating of the 
nodules indicates very slow growth rates of 0.1 to 0.01 times the aver- 
age sedimentation rate of one meter per million years in the deep 
regions of the ocean where manganese nodules are most commonly 
found. 
CoMPoSsITION 
The composition of manganese nodules can be described in two ways: 
the elemental composition and the mineralogy. 
ELEMENTAL COMPOSITION 
Chemical analyses of nodules from several locations in the Pacific 
Ocean are averaged in Table 2. 
TABLE 2.—PACIFIC MANGANESE NODULES—WEIGHT PERCENTAGES (DRY WEIGHT BASIS)—STATISTICS 
ON 54 SAMPLES 
Element Average Maximum Minimum 
NanvaneSeheeeerrse na eae t en, See See ee 24.2 50.1 8.2 
WOU S 55 ees 55 Ant Sp see re ae a al ee ed ae a een a 14.0 26.6 2.4 
SMO Sse Se SA ee ae es ee es eee 9.4 20.1 1.3 
FAINT ae ee ee ay aS a Pe ae ee ee 2.9 6.9 .8 
SOM Sees Ge See =. SEN ee eee eee er ee 2.6 4.7 1.5 
Calciurmeeeee ences) pisan pend See Se Pes SEC ES eet 1.9 4.4 .8 
MERICSTIT SNe 8 SHEET OS Rees aE See) ee ee Soe ees 7 2.4 1.0 
Nickelaeesseretas wc Werner ane ee Mae AA et Pp ei eae r99 2.0 .16 
Rotassiunieeeutusie ied hele Merehipy pe ki bet) Peck Se Nees yp es Fs .8 Syl 3) 
TREC TE a eR 8 Ren 9 ap eine UN Pr ug ae . 67 ey ll 
Conperseeevets ee. eee eee: are ieee eee es a5) 1.6 . 028 
(COE te 59 Oh ay O tis he CS ee eee here 28 Te yee .35 2.3 . 014 
Banitiineee es a eeere Make h ted Bee Tele AAEN AS ER . 18 . 64 08 
[hea diese AiR ae hE Eee aoe Uh nd ald Amie. oy Cee d ox oe .09 36 02 
Strontilrimeees sere erence ere te ee ee Ma Pei So es . 081 16 024 
ZUTCON IIe eee ae ee SENT ER GS Carer ie 2 heresy uct . 063 12 009 
VETECIRIS 222 eee eee RE ee Les Oe ee eae e . 054 ll . 021 
Molybdenum. J 2h ieies Shido AIRS 2S ae SS . 052 all -01 
7A On ee ae ee Oe ae ed ae ee eer Sere . 047 . 08 . 04 
Buroneeeenete ee crate eepen aoe es eto iies eT Ee Slot . 029 06 007 
Nittriliniperceie Seer ewer edie ry we renin ye tty 2: cy aries wed . 016 045 033 
anthanu serene eee see eer eam. See SOR N ye eh . 016 024 009 
Vitenbiumeen cee ates Pe RRL RED bt Thee! TT le a9) Code . 0031 0066 0013 
CARE ee ASS Se A EE eS OG BR Pe . 001 007 001 
Gallien se Saree: Seem ns Le eT eee ees . 001 . 003 . 0002 
SCANGIU mieten ke) SL eat eae Fs Pee Ney eee ee . 001 . 003 . 001 
SIUC pee ee tie aes Cum ae Oe, NE Rg ANT ee Cag eee . 0003 A O00G Ree ee ee 
Note: In addition to the elements given above, cadmium, tin, arsenic, and bismuth are also found in manganese nodules. 
Source: Cardwell, P. H. Extractive metallurgy of ocean nodules. Mining Congress Journal, November 1973, p. 38. 
2Mero, J. L. Effects of mining sea floor nodules may be drastic for industry, society. 
The Northern Miner, Apr. 20, 1972, pp. 4-5. 
