Geology Reference
In-Depth Information
19
Metallogenic Fingerprints of the Congo Shield
with Predictions for Mineral Endowment
Beneath the Congo Basin
Christien Thiart and Maarten J. de Wit
19.1
Introduction
'
'
in the 1950s, are still being mined from its
Archean rocks; and more recently still, since 2012, in
Proterozoic metasediments of the Twangiza, Kamituga,
Lugushwa and Namoya Gold Belt in South Kivu
(Fig.
19.1
; Goosens
2009
). Tin and tungsten deposits occur
across the large scale granitoid province of the Kibaran
(1.3-1.4 Ga Karagwe-Ankole Belt) between the CB of the
DRC and the eastern Lake region of Rwanda and Burundi
and as far south as Katanga. These areas are now sought after
also for their unique Coltan deposits (Columbite-Tantalite
Kivu (Goosens
2009
).
In Katanga, too, uranium and zinc is common; and at
Shinkolobwe, Uranium ore rich in Radium was used to
build the first atom bomb. Ironically, along the opposite,
western margin of the CB, at Okla, rich Uranium placer
deposits in the Eburnean-age Francevillian sequences were
exploited and later studied because of its 17 unique natural
paleo-nuclear reactors at Okla (e.g. Mossman et al.
2005
).
Whilst is it not the purpose of this chapter to describe
these and the many other deposits around the margins of the
CB in detail (for which the reader is referred to other litera-
ture, see for example references in de Wit et al.
2004
;
Schl¨ ter and Trauth
2008
; Goosens
2009
), we are interested
here in determining the mineral resource potential of the
region using the known mineral deposits of Central Africa
(CA), of which there are about 1600 in our database
(Fig.
19.2
; Table
19.1
), together with the known regional
geology. Figures
19.2
and
19.3
shows this simplified Pre-
cambrian geology of Central Africa with the location of all
the mineral deposits used in this study.
Using the mineral deposits information stored in AEON
rediscovered
The Congo Basin (CB) is richly endowed at surface with
alluvial gold, and with alluvial diamond deposits derived
from the sedimentary sequences and kimberlites that intrude
these sequences, and the basin has potential for conventional
oil (Delvaux and Fernandez, Chap.
18
, this Topic, and
unconventional oil and shale gas deposits (Fig.
19.1
).
Beyond that, there is little robust knowledge about other
possible mineral wealth in its sedimentary sequences, or
potential ore deposits in the basement rocks beneath this
large basin. However, flanking the CB are a large variety
of Precambrian mineral-rich basement terranes of the Cen-
tral African and Congo Shields, ranging between 0.5 and
4.0 Ga in age (e.g. de Wit and Linol, Chap.
2
this Topic, and
references therein). Some of these Precambrian terranes host
world class mineral deposits (Fig.
19.1
; Goosens
2009
; and
personal communications, 2014). The latter include the
0.5-0.6 Ga Copper (-Cobalt) deposits of Katanga that were
discovered in 1892 (van Reybrouck
2010
) and remain the
largest of its kind in the world (Goosens
2009
). Similarly
gold deposits have been explored in the northeast (in the Ituri
region near Bunia, and at Kiva, Moto and Kilo) where they
were first discovered as alluvial deposits in 1895 and
exploited in 1926 by state mining enterprises during the
early days of the
'
Congo Free State
'
, and some that were
'
s
G0-GEOID—Gondwana Geoscience Indexing Database (de
Wit et al.
2004
;
http://gondwana.brgm.fr/sig.htm
) and the
simplified Precambrian geology, we first establish distinct
mineral deposit patterns that we term
'
metallogenic finger-
prints
(c.f. de Wit and Thiart
2005
; Thiart and de Wit
2006
,
2008
) of the Precambrian basement of Central Africa (CA;
Fig.
19.2
), and of the Central African Shield and the Congo
'
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