Precambrian Basement of the Congo Basin and Its Flanking Terrains - Geology and Resource Potential of the Congo Basin - page 31

were deformed during the Kibaran Orgogeny. Due to lack of
reliable geophysical data, there is no agreement about the
origin of the allochthonous fragments in the Ubendian Belt,
and whether or not the TC lithosphere may originally have
extended as far south as the Bangweulu Block (e.g. Lawley
et al. 2013 and references therein; and see below).
The eastern margin of the TC comprises mainly Archean
blocks remobilized during the Neoproterozoic at high grades
within the central zone of the Pan African Mozambique belt
(e.g. Fritz et al. 2013 ; Kabette et al. 2012a ; Fig. 2.2 ).
Across the Tanzanian Craton, repeated diamondiferous
kimberlite activity (at 189 Ma [Mwadui] and 53 Ma
[Nzoga]) and young Quaternary volcanoes with magmatic
rocks characteristic of kimberlite (c. Iqwisi), as well as
geochemistry of lithospheric mantle xenoliths, attest to a
cratonic lithosphere with a thickness in excess of 120 km
(e.g. Dawson 1994 ; Rudnick et al. 1998 ; Begg et al. 2009 ;
Brown et al. 2012a , b ).

Bangweulu Block, dated at ~2050 Ma, and with a widespread
volcanic arc sequence (c. Lubufu) that yield U-Pb SHRIMP
zircon ages ranging between 1874 7Ma

and granites (e.g. Mufulira; Fig. 2.5 ) dated at ca. 2 Ga (de
Waele andMapani 2002 ; Rainaud et al. 2005 ). This deformed
(Eburnian) basement is locally intruded by younger
granitoids at 1.6 Ga and between 1000-1050 Ma (c. Serenge;
de Waele et al. 2008 ). It is tectonically overlain by the
Lufilian Arc: a convex Pan-African northward-verging fold
and thrust belt with two principal tectonic nappes that contain
about a 10 km thick Neoproterozoic sequence of
metasediments, known as the Katanga Supergroup (formerly
Kundelungu Supergroup; Lepersonne 1974 ), and famous in
Zambia and DRC for its high-grade Cu-Co mineral deposits.
The deformation style is believed to have been influenced by
evaporites, since the structures resemble salt-tectonism (e.g.
Jackson et al. 2003 ; Selley et al. 2005 ). However, no salt
deposits are preserved, and if this tectonic interpretation is
correct, the evaporites have all been dissolved during the
Pan African deformation and related fluid activity, perhaps
inducing the base-metal mineralization (c.f. El Desouky
et al., 2010 , and references therein).
The Lufilian tectonism has been dated between about
700 Ma and 530 Ma, similar to that of the Damara Belt of
southern Namibia (Kampunzu and Cailteux 1999 ;M ller
2008 ), and to which it is likely linked via northwestern
Botswana (de Wit 2010 ). Here,

8Ma and 1980

2.4.4.2 The Kibaran Belt (s.s.)
Across most of eastern DRC, Rwanda, and Burundi, Pre-
cambrian basement is widely intruded by Mesoproterozoic
granites and these represent the type area of the famous ca.
1.0 Ga Kibaran Belt defined by Cahen et al. ( 1984 ). Several
generations of these granites were recently re-dated, ranging
between 986 17 Ma, but the majority

of the granites are ca. 1375 Ma in age (U-Pb zircon dates;
Tack et al. 2010 ). In the southern part of the belt, granites
(e.g. Kisele and Nyanga; Fig. 2.5 ) have been dated similarly
at 1385 Ma (Kokonyangi et al. 2004 ). Thus, this
1370-1385 Ma age characterizes the main episode of
Mesoproterozoic magmatism and crustal melting in eastern
central Africa, the original type area of the Kibaran (as
defined by Cahen et al. 1984 , but now referred to as the
Kibaran Karagwe-Ankole Belt). Whether the general term
Kibaran should be applied to the younger, near 1.0 Ga, rocks
elsewhere in Africa (e.g. the Irumide, Mozambican,
Namaquan belts) remains an as yet unanswered question.
This is a debate that has not yet been resolved (e.g. Tack
et al. 2010 ; Fernandez-Alonso et al. 2012 ), and is similar to
earlier misunderstandings about the Pan African, which was
originally defined around ca. 500

10 Ma and 1383

in northwest Botswana,

a thick Neoproterozoic sequence of sediments (ca.

541-750 Ma) comprises medium-grade metamorphosed
and deformed Cryogenian rocks, including diamictites and
substantial carbonates interbedded with intermittent BIF.
These metasediments overly a complex granitoid Archean
and Proterozoic basement (recently dated at ca. 2.6 and
2.0 Ga, respectively; U/Pb zircon LA-ICP-MS; de Wit 2012;
Unpublished Report for Tsodilo Resources Ltd.). Any affili-
ation with the Archean block below the Lufilian Fold Belt
remains unknown.
In the Lufilian Arc of southeastern DRC and northern
Zambia, the Katanga (formely Kundelungu) Supergroup
comprises Cryogenian carbonate platform metasediments
(the Roan and Nguba Groups), which locally include
volcanics dated at 760

<

5 Ma (U-Pb zircon date, in Master
et al. 2005 ), and with two glacial conglomerates (Grand and
Petit Conglomerates) basically attributed to the Sturtian and
Marinoan glaciations (e.g. Selley et al., 2005 ; Poidevin
2007 ). At the top, the Supergroup terminates with a rela-
tively thick (~5 km) Redbed foreland basin sequence (e.g.
Wendorff 2003 ), in turn unconformably overlain by about
1 km thick red siltstones of the Biano Group (Master et al.
2005 ). The latter may be correlated to the (Cambrian) upper
Nama Group covering the Damara Belt of Namibia (e.g.
Grotzinger and Miller 2008 ), and the Cambrian Redbeds
across the CS discussed earlier (the Inkisi and Banalia
sequences).

50 Ma (Kennedy 1964 ),
but is presently mostly used for rocks in the range between
500-800 Ma (e.g. see discussion in de Wit et al. 2001 ).
In the type area, the Kibaran Belt is unconformably
overlain by late Mesoproterozoic to Neoproterozoic plat-
form metasediments of the Bukoban Supergroup, with
basalts in the upper part dated at 815 14 Ma (K/Ar

whole-rock date, in Cahen et al. 1984 ).

2.4.4.3 The Lufilian Arc
In Zambia and southeastern DRC, basement consists
of Paleo- to Meso-Proterozoic granite gneisses of the