IGCP Board; 10th session; Report of the ... - unesdoc - Unesco

to inorganic environments and biological activities.
The Project was sponsored originally by
the IAGOD Commission on Manganese and presently
is conducted with its full cooperation.
Summary of activities. The major activity in
the field of publication is the 3-volume treatise
on Geology and Geochemistry of Manganese,
totalling 1, 333 pages and including 14 papers in
Volume 1 (General Problems: Mineralogy,
Geochemistry and Methods), 22 papers in Volume
2 (Manganese Deposits on Continents), and
15 papers in Volume 3 (Manganese on the Bottom
of Recent Basins). The volumes were edited
by I.M. Varentsov and Gyula Grasselly and
were published by Akademiai Kiado, Budapest.
A comprehensive book on 'Manganese Deposits'
has been published by S. Roy in 1981 through
Academic Press Inc. (London-New York). This
book contains a detailed treatment on the characterization
and genesis of manganese ore deposits
on the floors of present-day basins as well as on
the continents. A third book entitled 'Underwater
Minerals' containing a detailed discussion
and synthesis on the manganese deposits in modern
basins has been published through Academic
Press Inc. (Londo-New York) by D.S. Cronan
in 1980. Besides these books, numerous
papers have been published during the period
under review by the participants of this Project.
Substantial progress has been made in studies
on the manganese deposits on the continents.
Continuous detailed study is in progress on the
super large manganese deposits of the USSR and
two technical sessions, one at Nikopol and the
other at Chiatura were organized and the proceedings
published. The manganese mineralogy
of the polymetallic deposit of Primorye, USSR
has been established. The manganese deposit
at Groóte Eylandt, Australia has been investigated
in detail and evidence of a biogeochemical
origin has been suggested. Stratiform manganese
deposits in the Palapye Group, Central-
Eastern Botswana have been studied and a chemical
sedimentary origin has been suggested for
them. Trace-element geochemistry of the manganese
deposits of Israel and Sinai and of San
Francisco Mine, Jalisco, Mexico has been completed.
In India, detailed studies on the mineralogical
and geochemical changes in manganese
ore deposits due to dynamothermal metamorphism
are being carried out. The deposits undertaken
for such studies are those of Sausar Group,
Aravalli Supergroup, and Khondalite Group where
the grade of metamorphism ranges from
greenschist to granulite facie. In addition, the
unmetamorphosed Mn-oxide deposits of the Proterozoic
Pengagnga beds are being studied in
detail.
At the University of Bern, Prof. Giovanoli and
his group undertook experiments with synthetic
buserite and applied dodecylammonium chloride
to all types of synthetic and natural buserites.
The results show that Na-buserites react properly,
Ca-buserite and Na-birnessite do not
36
yield 100 % and buserites with saturated transition
metal contents do not react at all. No natural
samples could be expanded by dodecylammonium
chloride. Synthesis and investigation of psilomelane,
hollandite, cryptomelane, etc. have been
done. Professor Stumm and his coworkers at
the Zurich Polytechnic studied the surface properties
and colloid chemistry of manganese oxides
and found that Metallogenium manganooxydans
acts as a powerful oxidizing catalyst producing
always Z-disordered mangana te.- At the Hokkaido
University, Japan, studies have been done on
hydrogen isotopic composition of hydrated manganese
minerals. Other laboratory investigations
at various centres include cation absorption by
hydrous MnC>2, structural modification of Mn (IV)
oxides, nature of bixbyite, braunite I and braunite
II, characterization of different manganese silicates
such as Mn-pyroxenes, Mn-pyroxenoids,
winchite etc.
Important contributions have been made to manganese
deposits in present-day basins. Hydrothermally
active areas of manganese deposition on
Mid-Atlantic Ridge at 26° N, Carlsberg Ridge
(Indian Ocean), East Pacific Rise, and other
areas have been undertaken and substantial new
data have been generated. A joint New Zealand
Océanographie Institute /Imperial College, UK
cruise investigated hydrothermal deposits in the
south-westernPacific Ocean and the first collection
of submarine hydrothermal manganese deposit
from an island arc setting was made. The
partition geochemistry of sediments from the Galapagos
Hydrothermal Mounds Field has been established.
Detailed field and laboratory work on the
mode of occurrence, physical characterization,
mineralogy, and geochemical partitioning in coexisting
phases in manganese and ferromanganese
nodules from Central Pacific, North-east Equatorial
Pacific, South-west Pacific and Indian
Ocean helped considerably in unravelling the mystery
of manganese nodule growth in the oceans.
The papers embodying these numerous investigations
are cited in the reference list. Among the
active groups participating in this Project on this
aspect are the Marine Geochemistry Group of
the Federal Institute of Geosciences and Natural
Resources, Hanover, Universities of Clausthal
and Aachen (FRG), Imperial College of Science
and Technology (UK), New Zealand Océanographie
Institute, and NOAA, University of Washington
at Pullman (USA).
Activities planned. It is proposed to continue all
the ongoing programmes under this Project during
1982, A symposium on Manganese Deposits is
scheduled under the joint auspices of the IAGOD
Commission on Manganese and the IGCP Project
111 during the Vlth IAGOD Symposium scheduled
at Tbilisi, USSR in 1982. Already more than
forty abstracts have been received for this technical
session. A business meeting of the Project
also is scheduled during the symposium where
the progress and future plans of the Project will
be discussed.