19 Marine Minerals, Key Resources for the Twenty-First Century II

Tuesday, 23 May 2017
1:30 PM - 4:50 PM
Room 318B

GEOCHEMISTRY OF SMS AS THE ASSESSED CRITERION FOR THEIR MINERAL RESOURCES POTENTIAL

Paper number: 19-4
Program: Theme Sessions
Time: 2:15 PM – 2:35 PM

Authors

  • Svetlana Babaeva Presenting Author
    The All-Russia Scientific Research Institute for Geology and Mineral Resources of the Ocean, Saint-Petersburg
  • Anna Sukhanova
    Saint-Petersburg Mining University, Saint-Petersburg
  • Anna Sukhanova
    The All-Russia Scientific Research Institute for Geology and Mineral Resources of the Ocean, Saint-Petersburg

Abstract

Seafloor massive sulfides (SMS) of the Mid-Atlantic Ridge (MAR) are represented as a real potential reserve of copper to 2040. The most prospective ore fields are located in the North Atlantic active zone of the MAR. In 2012 Russia signed the fifteen-year Contract for exploration of SMS in the Russian Exploration Area (REA). The stated exploration area amounts to 100 units (10 x 10 km each) with the total area of 10,000 km2 in the interval 12ะพ48โ€™ โ€“ 20o54โ€™ N. The culling of 25 promising blocks will be carried during this period. Geochemical specialization of massive sulfide ores depends on content and ratio of Cu, Zn and Fe. The studied fields are identical and characterized by the following geochemical types: Cu-Fe (41%) Fe-S (39%), Cu-Zn (12%), Zn-Cu (5%), Zn-Fe (3%). The inferred resources (IR) of the different geochemical types were calculated for the main economical metals (see table).
Geochemical type of SMS Average content  of  metals    Inferred resources
Cu,% Zn,%  Fe,%  Au,ppm  Cu,kt  Zn,kt Fe,kt Au,t
Cu-Fe 16.7 0.4 29.6 4.1 3979 105 12173 77
Cu-Zn 16.2 8.5 22.9 20.0 677 314 1377 54
Zn-Cu 2.2 29.3 12.8 1.2 2 30 12 0.1
Zn-Fe 0.5 15.0 23.2 0.6 11 327 549 1.3
Fe-S 0.3 0.9 38.1 0.7 130 143 19223 31
Total inferred resources of dry ore mass (TIR) 92 Mt  

The analysis has demonstrated that copper content is the main factor in the ore quality. According to predominant geochemical type and content of Cu and Au, all SMS sites may be attributed to the four groups (see table).

Group  Predominant type  Cu,%  Au,ppm  Cu-IR,kt  TIR,Mt
I Cu-Fe(copper-rich) 28.9 4.4 1493 12
II Cu-Zn 22.6 19.1 1773 8
III Cu-Fe 6.1 1.3 909 22
IV Fe-S 0.9 1.1 625 49

The first two groups of SMS are may be regarded as the 1-st turn perspective objects due to its maximum content and resources of copper (see table). Group I consists Ashadze-1, Pui de Folles. Ashadze-2, Semenov-2, Logatchev-1, Logatchev-2 were combined into group II. Similar to the sulfide deposits on the land by the scale of their gold resources may be compared to average and small deposits (in tons): Ashadze-2 (27.5), Logatchev-1 (22.2), Logatchev-2 (10.8), Semenov-2 (7.1). Formally, group III could be regarded as unique (TIR > 22 Mt). SMS sites of group III have, though, low copper mineral potential and their other parameters need additional studying. As for the main metals, group IV is not of much practical interest at the moment.

Geological Society of America Abstracts with Programs. Vol. 49, No. 4

doi: 10.1130/abs/2017CD-292416

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