International Journal of Geosciences, 2012, 3, 258-279
http://dx.doi.org/10.4236/ijg.2012.31028 Published Online February 2012 (http://www.SciRP.org/journal/ijg)
Na-Metasomatism and Uranium Mineralization during a
Two-Stage Albitization at Kitongo, Northern Cameroon:
Structural and G eoc hemical Evidenc e
Arnaud Patrice Kouske1*, Cheo Emmanuel Suh2, Richard Tanwi Ghogomu1, Vincent Ngako3
1Laboratory of Applied Geology-Metallogeny, Department of Earth Sciences, University of Yaoundé 1, Yaoundé, Cameroon
2Economic Geology Unit, Department of Geology and Environmental Science, University of Buea, Buea, Cameroon
3Mega Uranium Corporation Cameroon PLC, Yaoundé, Cameroon
Email: *pathpatrice@yahoo.fr
Received September 16, 2011; revised November 21, 2011; accepted December 25, 2011
ABSTRACT
Mapping and documentation of lithological varieties and their corresponding geochemistry at the Kitongo uranium mi-
neralization were concerned. The Kitongo U occurrence is hosted by granitic rocks that include interleaved sequences
of metasedimentary and metavolcanic rocks of the collectively termed Poli Group. U-mineralization and Na-metasoma-
tism are related and structurally controlled. The most promising uraniferous bodies are intimately related to intersect-
tions between the ductile ENE-trending faults and the brittle conjugate R’ faults postdating the shearing event. The con-
centration of uranium at fault intersections rather than along individual faults suggests that these zones that are dilata-
tional in nature were also highly permeable and therefore the hydrothermal fluids ponded there could readily precipitate
U therein. A two-stage albitization has altered the foliated granitic host rock and the second albitization that has over-
printed the first one is more effective at fault intersections. Whole rock geochemistry was performed by using ICP-MS
and ICP-AES respectively for major oxides, trace and REE. The U-bearing rock suite exhibits restricted range in SiO2
concentration (62.89% - 70.91%) and Al2O3 (13.16% - 18.59%) and it is poor in MgO (0.02% - 1.03%), CaO (0.24% -
1.88%) and K2O (0.08% - 5.32%). The mineralized rocks are however comparatively richer in Na2O (4.33% - 10.92%)
compared to their barren counterparts. The host granite and associated granodioritic rocks in the area are weakly meta-
luminous, peralkaline, and are calc-alkaline. They are moderately to strongly fractionated and have tholeiitic and sho-
shonitic affinities with moderate to high HFSE (high field strength elements) and LILE (large ion lithophile elements)
enrichment. The Rb/Sr, Rb/Ba and Sr/Ba ratios are 0.31, 0.14 and 1.48, respectively. U content in the mineralized gran-
ite is up to 651 ppm while the non-mineralized rock has only 2.4 ppm U. The REE patterns of the granite show LREE
enrichment and strong Eu negative anomalies (Eu/Eu* = 0.03 to 0.48). The main mineralization stage characterized by
local U, Na, Pb, Zn, Ga, Hf, Sr, Fe, Al, P and Zr enrichments is related to the second albitization event and could proba-
bly be associated in time with the calcite-uranium stage. The identification of fault segments favorable for uranium
mineralization in northern Cameroon (Poli area) is important for understanding the genesis of hydrothermal ore deposits
within continental strike-slip faults and therefore has great implications for exploration strategies.
Keywords: Uranium; Kitongo; Granite; Albitization; Strike Slip Fault; Cameroon
1. Introduction
Low uranium commodity prices over many years up to
the mid-2000s contributed to low expenditure on uranium
exploration and dearth of discoveries of new U deposits
around the world. The Athabasca Basin (Canada) was one
of the few regions in which major uranium discoveries
were made during 1990s and early 2000s [1]. However,
as the principal fuel for the world nuclear power plants,
uranium has become a valuable source of energy in many
countries and increasing demand from emerging econo-
mies such as China and India, and new market potentials
in the Middle East have boosted the search for uranium
deposits worldwide in the last five years [2]. In recent years,
the world market of U has been characterized by an im-
balance between demand and supply and persistently
depressed uranium prices. However, the future for ura-
nium exploration and exploitation is not that pessimistic.
For example, it is projected that available uranium stock-
piles between the period 2006-2020 is ~200 Kt, whereas
the supply deficit of U over the same period is ~180 -
260 Kt [3]. Therefore, in the long term, new U occur-
rences must be sought, explored, mapped and evaluated
*Corresponding author.
C
opyright © 2012 SciRes. IJG
A. P. KOUSKE ET AL. 259
ready for production. This optimism is perhaps responsi-
ble for the renewed interest in uranium exploration espe-
cially in currently non-producing countries like Camer-
oon. This optimism also takes cognizance of the current
outcry against nuclear energy following the Fukushima
incidence in Japan but the authors hold the view that this
will not, at least in the short run, derail the nuclear energy
sector.
The exploration for U in Cameroon, which peaked in
the period between 1971 and 1986 led to the discovery of
two significant uranium occurrences in the country, as
described in the IAEA-Uranium Deposit (UDEPO) data-
base [4]. These include the Lolodorf occurrence (south-
eastern Cameroon) and the Kitongo occurrence (northern
Cameroon). Previous works suggest that the Kitongo ura-
nium occurrence is the result of structurally-controlled
metasomatic replacement in syn-orogenic granitic plutons
of Pan African age intruded along a deep-seated fault [4].
The ore is mainly of disseminated type and although the
mineralization is envisaged to be thick, it has low grade [4].
The “cataclastic” ore type with uraninite as main ore min-
eral, is associated with fault zone; it constitutes the most
economic ore type and has locally a considerable thickness.
The vein type is subordinate with very thin veinlets (<1
cm), but with higher grades (>0.1% U3O8). The historical
U3O8 resources at Kitongo are estimated between 10,000
and 25,000 tones at a grade of 0.1% U3O8 [5]. The miner-
alization is also associated with different alteration proc-
esses. Any, if not most of the deposits that were discov-
ered during previous exploration efforts are included in the
expanded UDEPO database [6]. The resources for many of
these deposits will however require additional exploration
before they are sufficiently well defined to be reliable as
future exploitation candidates. It is against this background
that the present study was carried out.
The work described in this contribution was under-
taken at a time of renewed interest in the Kitongo ura-
nium occurrence for which Mega Uranium Corporation
Cameroon PLC. now has exclusive exploration and re-
serve definition rights (see www.megauranium.com/main/?
kitongololodorf). The primary objective of this study was
to map in greater details the northwestern part of the Ko-
gué batholiths to which the Kitongo uranium mineralize-
tion belongs and to document its lithological varieties and
their corresponding geochemistry. Presently, Mega Ura-
nium is actively engaged in diamond drilling of the Ki-
tongo prospect and such detailed maps and integrated
geochemical data will hopefully assist in the broader un-
derstanding of the controls of uranium mineralization and
its genesis at Kitongo.
2. Regional Geology
The Kitongo U occurrence that belongs to the Kogué gra-
nitic batholiths lies within the Central African Fold Belt
(CAFB) that is regarded as a mobile zone [7-10]. This is
an intermediate domain between the West African Craton
(WAC), the São Francisco-Congo Craton (SFCC) and
enigmatic east Saharan Craton (Figure 1). The CAFB in
Cameroon is bordered in the south by the Ntem complex
(Congo craton) that continues across the Atlantic as the
São Francisco craton in Brazil [11,13]. Northwards and
beyond this unit the so-called “East Saharan Block” (ESB),
almost entirely masked by the Chad basin, is located (Fi-
gure 1). The geology of the northern margin of the CAFB
in Cameroon is known through the well exposed Poli
Group that represents an early Neoproterozoic back-arc
basin formed between 830 and 665 Ma ([14-16].
The CAFB was interpreted as a zone of continent-con-
tinent collision [13,17-27] involving three major land-
masses: the São Francisco-Congo Craton (SFCC), the Eas-
tern Sahara block and the West African Craton [11] (Fi-
gure 1). It comprises two main granulitic rock suites: an
Archaean generation in the forefront basement of the Ou-
banguides chain and a post Archaean generation likely
Pan African within the inner zone of that orogeny [28].
Recent petrologic and isotopic data enable to define
the following three main Pan-African geotectonic units at
the northern boundary of the SFCC: the Yaoundé Group
(southern Cameroon), the Adamawa domain (central Ca-
meroon) and the Poli Group (northern Cameroon) (Fig-
ure 2). The study area is located in the Poli Group (Fig-
ure 3) dominated by metavolcanic and metasedimentary
rocks [14,31]. The lithostratigraphy is poorly defined
because these rocks are interleaved and have been strong-
ly deformed [31-34] although the metavolcanic unit is
widely believed to alternate with metasedimentary units.
The lower metasedimentary unit (Sakje unit) has been af-
fected by medium- to high-grade metamorphism [32,34],
while the upper unit underwent low grade metamorphism.
However in some localities, transition from the low grade
upper sedimentary unit to the Sakjé unit is gradational as
at “Buffle Noir” and in western Poli (Figure 3) [33,35].
In both regions, the upper and lower metasediments show
comparable greywacke composition [14,35]. The metase-
dimentary unit on a wider scale is composed of either pu-
rely volcanogenic clastic rocks (mainly tuffs) or variably
reworked clastic rocks (metagreywackes). Conglomerate
layers are frequently observed in most of the sedimentary
sequences. The metavolcanic unit includes rhyolite and
tholeiitic basalts. The tectonics of the Poli region is mar-
ked by E-W antiform and synform characterizing gentle
folding of a regional flat-lying foliation probably formed
during an early thrust evolution. Many generations of wren-
ch zones in that area crosscut those early folds and folia-
tion related to the thrusting and nappe refolding. These
include the left and right wrench movements: the D2 and
D3 Pan-African phases involving major sinistral and dex-
tral SZ that have almost operated at right angle. The left
Copyright © 2012 SciRes. IJG
A. P. KOUSKE ET AL.
Copyright © 2012 SciRes. IJG
260
Figure 1. Geological sketch map of Central-North Africa (western Gondwana), and location of Cameroon [11] modified from
[12].
wrench movement (ca 613 - 585 Ma) is represented by the
major Balché (BSZ) and “Buffle Noir”-Mayo Baléo shear
zones (BNMB) and the synthetic shear zones represented
by the Godé-Gormaya (GGSZ) and Mayo Nolti shear
zones (MNSZ); the right wrench movement younger in
age (ca 585 - 540 Ma) than the left one is represented by
the “Vallée des Roniers” shear zone (VRSZ) and Demsa
shear zone (DSZ) coeval with down-slip movements par-
allel to the Godé and Gormaya segments [11]. Granitic
intrusions, mainly of Pan-African age, are widespread in
the Poli Group (Figures 2 and 3). A Rb-Sr age of ca 590
± 16 Ma on biotite from these rocks [9] can be approxi-
mated to the emplacement age of the massif. The empla-
cement of post-collisional granitoids was controlled by
strike slip faults. The metamorphism is of medium- to
high-pressure type and localized anatexis resulted in the
genesis of migmatites. The associated plutonism evolved
from calc-alkaline to alkaline compositions [21,36].
at the northwestern margin of the Kogué granitic batho-
liths (note that the northwestern margin of the Kogué
granitic batholiths shall also be referred to as the Kitongo
granite). It covers an area of ~2.34 km2, i.e. ~1.8 km in
length and ~1.3 km in width. Detailed geological data
from the area under study are scarce and are mainly re-
connaissance reports. This area consists of a horst-like
structure with many cliff-faces amongst which the Kiton-
go cliff-face is the most important in extension (average-
ly 250 m of escarpment); it is where galleries were dug.
This cliff-face corresponds to the Kitongo shear zone tra-
ce in 2 dimensional view (Figure 4). Thick overburden
made up of huge number of boulders of various sizes
exhibiting a chaotic aspect hampers observations. How-
ever the continuous aspect of outcrops has enabled map-
ping from which four main rock types were distinguished
hereafter referred to as: the metavolcanic and metasedi-
mentary unit, the fault rocks unit, the granodioritic unit
and the granitic unit. Mafic dikes were also mapped but
are relatively less important.
3. Local Geology
3.1. Lithology 3.1.1. Me t asedimentary and Metavolcanic Unit
The U occurrence mapped in this study (Figures 3 and 4)
referred to as the Kitongo Uranium occurrence is located
These rocks belong to the Poli Group and they outcrop at
the northwest of the Kitongo granite. This unit is essen-
A. P. KOUSKE ET AL. 261
tially made up of interleaved dark grey basic meta-volca-
nic and light grey meta-sedimentary rocks and amphibole-
bearing schist with a strong N045-078E-trending regio-
nal foliation. This unit is crosscut by many faults and
fractures of various strike and dip. In certain areas, qu-
artzo-feldspathic lenses display boudinage subparallel to
the general foliation. S-C fabrics associated with the
early sinistral and late dextral movements are widespread
as well as microfolds with crenulation cleavages.
3.1.2. Fault R ocks
The fault rocks outcrop between the Kitongo granite and
the granodiorite and at some locations they distinctly se-
parate the Kitongo hornblende biotite granite from the
Poli Group sensu strictu (Figure 4). The fault rocks are
characterized by the interpenetration of Poli Group rocks
and granite exhibiting a trellis aspect defining a sinistral
shear zone ~70 m wide within which a well developed
mylonitic foliation (N050-N080E, 70SE to vertical) is
Figure 2. Structural map of the eastern province (coastal region, [11] modified from [29] see location box in Figure 1). 1:
Quaternary sediments; 2: Neogen volcanics; 3: Mesozoic sediments (Benue Trough); 4: Late syntectonic subalkaline grani-
toids; 5: Lom syntectonic basin (meta-sediments, conglomerates, volcanic ashes and lavas); 6: Western Cameroon Domain
(WCD; early syntectonic basic to intermediate calc-alkaline intrusions, 660 - 600 Ma); 7a: Poli Group (active margin Neo-
proterozoic supracrustal and juvenile intrusions) 7b: Yaoundé Group (intracratonic deposits); 8: Massenya-Ounianga grav-
ity highs (10 - 30 mGal); 9: Adamawa-Yadé and Nyong Paleoproterozoic remnants; 10: Craton and inferred craton; 11: Ef-
fective elastic thickness curves (km), [30] ;12 - 17 = Structural elements: 12: Foliation and lineation trends; 13: upright and
overturned antiforms; 14: Main frontal thrust zone (exhumation); 15: Main thrust zone likely associated to crust redoubling
zone; 16: Right lateral sense of wrench movement; 17: Left lateral sense of wrench movement. Large grey arrow represents
regional mainstress direction controlling crust thickening and sinistral wrench movement, respectively.
Copyright © 2012 SciRes. IJG
A. P. KOUSKE ET AL.
262
Figure 3. Geological map of the Poli region, modified from [16]. (1) Post Pan-African cover; (2) Post tectonic Godé type
granitoids/Syn-to-tardi tectonic Kogué type granitoids (Hbl-Bt granites); (3) Hbl-Bt ± Grt Pan-African orthogneisses; (4)
Ms-Chl schists; (5) Goldyna metarhyolites; (6) Ep-Chl Metabasalts; (7) Bt-Ms ± Grt-St-Ky Micaschistes; (8) Bt and Bt-Hbl
gneisses; (9) Undifferentiated gneisses intercalating with bands of Grt-Ky-Bt metapelites; (10) Mylonitic gneisses associated
with Grt-Cpx-Opx-Pl bearing granulitic metabasites; (11) Stike-slip fault; TBF represents the Tcholliré-Banyo Fault which is
the limit between the Adamawa-Yadé Domain and the north-western Domain.
Figure 4. Geological map of the Kitongo Uranium deposit, which is structurally dominated by early ductile PSF ENE-WSW
trending fault and late overprinting brittle conjugate (R’) faults. Intersections between ENE-WSW trending faults and R’
faults are the most important sites for uranium. The terminology PSF is from [37].
Copyright © 2012 SciRes. IJG
A. P. KOUSKE ET AL.
IJG
263
discernable (Figures 4 and 6). Both the granitic rocks
and metasediments/metavolcanics are affected with no
evidence of localized partial melting (Figures 5(a)-(b)
and Figure 7).
granodiorite include a stretching lineation as well as mi-
cro S-C fabric in the groundmass. These features are re-
miniscent of microshearing with mm-cm relative displa-
cements. Three fault sets are recognisable in this unit, na-
mely from the oldest to the youngest, the N022E90, N122-
E90 and N058E90 vertical fault trends. Small ptygmatic
folds are also present. In hand specimen, the following
mineral assemblage is observed: amphibole, plagioclase,
quartz, and biotite and minor muscovite and K-feldspar.
3.1.3. Granod iori ti c Uni t
This rock outcrops at the NW of the Kitongo granite and
it is separated from the latter by the fault rocks (Figure
4). The rock is greenish and crosscut by aplitic veins.
Two generations of granodiorite were distinguished; the
older granodiorite outcropping as large inclusions within
the younger one. The average orientation of the long axes
of these inclusions as well as the mineral lineation in
these plutons are N70-80E. Microstructures within this
3.1.4. Gran i tic Unit
In the study area three granitic facies were mapped. These
are the porphyritic hornblende-biotite granite, the equi-
granular hornblende-biotite granite and the microgranite.
Figure 5. Lithologic features of the Kitongo granite (vertical views). (a) and (b) The trellis aspect of the fault rocks evidencing
the penetration of granite within the amphiboloschist-Poli Group: Amph. sch = amphibloschist, My = mylonites, G = granite,
m.G = micro-granite, M.B = metabasalt; normal fault markers are sub-vertical components of R’ fault system; (c) Gabbroic
dike; (d) Lamprophyric dike on the Kitongo cliff-face.
Copyright © 2012 SciRes.
A. P. KOUSKE ET AL.
264
Figure 6. Equal area lower hemisphere stereonet projection of foliation planes within fault rocks (1, 2, 3, 4, 5 and 7) and Poli
Group (s.s.) (6 & 8) averagely N70 trending direction.
The porphyritic amphibole-biotite granite is a light co-
loured rock characterized by the dominance of euhedral
K-feldspar phenocrysts (2 - 3 cm long), plagioclase feld-
spar and quartz within a biotite-amphibole dominated gro-
undmass. The transition from this granite to the equigra-
nular amphibole-biotite granite is gradational and it is
marked by the steady decline in K-feldspar phenocrysts
to medium grain size (~4 mm) and the incipient appear-
ance of plastic deformation of the Kitongo granite to-
wards its borders. These gradational processes are linked
to magmatic and tectonic events interacting at large scale.
The equigranular amphibole-biotite granite has both pla-
gioclase and alkali feldspar and it is restricted to the Ki-
tongo granite’s margin. The rock is medium-grained (~4
mm) although aggregates of phenocrysts of K-feldspar
are locally observed. Quartz grains are irregular to elon-
gated and together with the alignment of amphibole and
biotite these mineral phases define a strong mineral linea-
tion and foliation. Accessory minerals in this granite fa-
cies include chlorite and/or epidote, aegirine/riebeckite and
disseminated sulphides. The equigranular amphibole-bio-
tite granite exhibits clear petrographic evidence of sub-
stantial post-magmatic recrystallization accompanied by
a two-stage albitization occurring in successive steps. The-
se albitization events are continuous in time and spatially
bound to one another through fuzzy transitions. The first
phase of albitization with weak degree was identifiable
but in the xenoliths zone and in the porphyritic granite.
Copyright © 2012 SciRes. IJG
A. P. KOUSKE ET AL. 265
Figure 7. Lithologic features on the Kitongo SZ. (a) Proto-
mylonite; (b) Ultramylonites, notice the gradational contact
between the granite and amphiboloschist (horizontal view);
(c) Breccias occurring in both granite and fault rocks (ver-
tical view).
The second albitization event was more intense and
overprinted the first. This was only effective around fault
intersections along the Kitongo shear zone and to a lesser
extent on the Zenko plain, where the central (core) zone
is surrounded by alternation of variably altered granites
outwards exhibiting lithologic zoning. It is characterized
by the increase in albite, while quartz and alkali feldspar
decrease without extensive textural changes. Indeed
where this hydrothermal alteration phase is very strong,
albitite facies develop. With respect to the degree of al-
bitization and quartz contents, four sub-facies of the equi-
granular granite were distinguished. These facies, from
the periphery towards the centre are as follows: the relics
of the original equigranular granite; albitized granite;
quartz albitite/episyenite and albitite sub-facies. The al-
bitized granite sub-facies reflect the existence of hydro-
thermal alteration gradient intensity across the granite.
Residual quartz and plagioclase also exist as well as rare
sulphide grains. In addition, transgranular fractures in
this sub-facies are filled in by chlorite and/or epidote.
The quartz albitite/episyenite sub-facies is typified by the
total disappearance of alkali feldspar but few quartz
grains can still be observed. The mineralogy is chiefly
composed of albite, hornblende, aegirine, and accessory
biotite, chlorite and/or epidote. The albitite sub-facies is
characterized by the total replacement of alkali feldspar
by albite. Here albite is either uniformly distributed in
the rock or forms euhedral crystals filling the quartz dis-
solution cavities, or it forms stringers within the inten-
sively mylonitized bands along the Kitongo shear zone.
Albitites are red in colour; quartz is totally absent al-
though silicification is often recognized in association
with secondary calcite along microcracks; the mineral-
ogy comprises albite, aegirine and hornblende, chlorite
and/or epidote. The microgranite is mainly found on the
Zenko plain as 0 - 2 m thick veins and trending N160E
(Figure 4). However, this rock facies is also found
within the fault rocks area (Figures 5(a) and (b)). The
mineralogy includes quartz, K-feldspar and sparse biotite
and amphibole.
3.1.5. Mafic D i kes
A series of N-S-trending gabbroic and lamprophyric dikes
cutting across the granite intrusions are clearly observed
on the Kitongo cliff face. Gabbroic dikes are melanocra-
tic and massive and very hard and are characterized by
inequigranular assemblage made up of fine grains of py-
roxene, hornblende and phenocrysts of plagioclase (Fig-
ure 5(a)). The lamprophyric dikes also occur on the Zen-
ko plain where they are only a few meters thick and trend-
ing N160 (Figure 4). On the cliff face these dikes dip at
40˚ to 50˚ SW and vary between 0.7 to 1.8 m in width
(Figure 5(b)). These dikes are greyish in colour, dense
and fine-grained. The mineral assemblage includes very
fine grains of biotite, hornblende and pyroxene.
3.2. Fault Zone Architecture of the Kitongo U
Occurrence
The fault zone is the single most important feature in the
Kitongo area related to the U concentration. It is there-
fore treated here in greater details. The fault zone at the
Copyright © 2012 SciRes. IJG
A. P. KOUSKE ET AL.
266
Kitongo U occurrence includes the Kitongo SZ charac-
terized by ductile and plastic deformations, and the con-
jugate fault system made up of brittle structures over-
printing the SZ.
3.2.1. The Kitongo SZ
The Kitongo granite margin at the studied locality is out-
lined by the Kitongo shear zone (PSF) well exposed along
the fault rocks. The studied section of the shear zone mea-
sures about 1.6 km in length and its trend varies between
NE to ENE (Figure 4). This is a sinistral shear zone with
two different textures including mylonites and breccias.
The mylonitic fault rock that shows relatively sharp con-
tacts with the granite includes both protomylonites (Fig-
ure 7(a)) and ultramylonites facies (Figures 7(b) and (c))
are commonly associated to stylolites. The plastic defor-
mation at Kitongo includes pervasive mineral lineation
and linear fabrics defined by xenoliths within the grani-
toid. At outcrop scale the mineral lineation has the fol-
lowing attitude: N050-070E, 65˚SE (Figure 8(a)). This
(a)
(b)
Figure 8. Equal area lower hemisphere stereoplots of (a)
mineral lineation; (b) Xenoliths trend.
trend is sub-parallel to the general orientation of the Ki-
tongo SZ. Abundant xenoliths predominantly grey in co-
lour were observed at the study section of the Kitongo
granite. They are mostly lensoid in shape and range from
millimetre to 1.5 m in size and their modal compositions
generally correspond to micro-granodiorite. They are com-
mon in the equigranular granite (Figure 9(a)) and within
the fault rocks (Figures 9(b) and (c)). The xenoliths
alignment defines a fabric that trends N050-066E, 65˚SE
(Figure 8(b)).
Figure 9. Xenoliths on outcrop: (a) Densely packed xeno-
liths within equigranular granite; (b) M ega xenoliths w ithin
the fault rocks; (c) Micro-granodioritic xenoliths containing
porphyritic alkali feldspar (horizontal view).
Copyright © 2012 SciRes. IJG
A. P. KOUSKE ET AL. 267
3.2.2. The Conjugate Fault System
Numerous near-parallel closely spaced and steeply dip-
ping normal faults (R’ fault) and fractures developed at
high but variable angles to the PSF (Figures 4 and 10)
extend into the surrounding granitoid, configuring it into
numerous triangular to irregular blocks (Figure 4). The
sub-vertical component of these conjugate faults and frac-
tures represented on Figure 4 were recorded in fault rocks
(Figures 5(a) and (b)). This conjugate faults system cor-
responds to a younger tectonic event overprinting the PSF.
Breccias occur locally in granite and mylonites as a result
of the intersection of these conjugate faults with the PSF
(Figure 7(c)). Based on the bisectors between the Kiton-
go SZ and these R’ faults, seven fault orientations were
discerned including: the NE-SW-trending (35˚ - 53˚) co-
planar and steeply dipping (70˚ - 85˚NW to vertical), the
ENE-WSW-trending (58˚ - 70˚) steeply dipping to verti-
cal, the E-W-trending (85˚-98˚) steeply dipping (72˚ -
80˚S to vertical), the ESE-WNW-trending (105˚ - 120˚)
steeply dipping (64˚ - 85˚SW to vertical), the SE-NW-
trending (126˚ - 145˚) coplanar and steeply (68˚ - 84˚SW
to vertical), the SSE-NNW-trending (148˚ - 167˚) copla-
nar steeply dipping (67˚ - 88˚WSW, ENE to vertical) struc-
tures and the N-S-trending (010, 170 - 177) coplanar st-
eeply dipping (58˚ - 88˚E or W to vertical) structures.
The ENE-WSW faults system comprises two parallel
faults including the Kitongo SZ (PSF fault) that trends
N050˚ - 080˚, 70SE (Figure 4). These features together
with the late mafic dikes (Figures 5 (c) and (d)) suggest
extensional deformation and the extension direction in-
ferred from stereonet plots of the conjugate faults is par-
allel to the Kitongo SZ (WSW- ENE) (see Figure 11).
4. Radioactivity
Thick overburden at Kitongo masking the most important
part of the mineralized zones has complicated surface
radiometric patterns. Additionally, it has not been possi-
ble to investigate over the Kitongo cliff-face due to its
vertical slope. However radiometric prospection using a
hand held scintillometer over the study area enabled the
identification of four U-anomalies aligned in the same
trend. This spotted mineralization occurred at fault inter-
sections of the ENE-WSW-trending faults and the over-
printing Riedel fault system. The country rock is the horn-
blende-biotite equigranular granite that has experienced
various forms of alteration at these intersections notably
mylonitization along the Kitongo SZ, albitization, hae-
matitization, silica dissolution, chloritization and uranium
mineralization. The intensity of the alteration decreases
away from the intersections that served as pathways for
the hydrothermal fluids. This spatial distribution of min-
eralization at fault intersections therefore reflects an es-
sential relationship between fault movement, mineralize-
ing fluids and subsequent U-ore deposition. Very high
radiometric values, up to 3500 cps (count per second)
were recorded in the red albitites from fault intersec-
tions, while red albitites along the PSF, away from fault
intersections showed only background values as well as
the equigranular granite weakly altered during the first
phase albitization alone. Uranium mineralization is
clearly hosted in aureoles of hydrothermally-altered
rocks and was controlled by the intersections of per-
pendicular to sub-perpendicular fault sets to the ENE-
WSW-trending faults. Additionally, the highest uranium
content, of the order of 0.22% U3O8 was recorded along
the Kitongo SZ at its intersection with the N160E faults
(R’ fault), where red albitites pervade the fault rocks
thus, this intersection is actually the main U-ore hosting
structure (Figure 4).
5. Whole Rock Geochemistry
Samples used in this study were exclusively collected
from outcrops. Whole rock geochemistry was performed
at Alex Steward Laboratory Group (OMAC) in Ireland
after a sample preparation consisting of crushing and pul-
verizing at OMAC Cameroon. The samples were fused
with lithium metaborate and lithium tetraborate at 1000˚C
in a graphite crucible furnace. Processed samples were
then dissolved in dilute HNO3 and analyzed by ICP-AES
for major elements. The same solution was analyzed by
ICP-MS for a suite of elements consisting of trace ele-
ments including REE. The major, trace and REE data for
the representative rock samples from the study area are
given in Table 1.
Figure 10. Illustration of closely spaced and steeply dipping
normal R’ faults overprinting the Kitongo SZ (horizontal
view).
Copyright © 2012 SciRes. IJG
A. P. KOUSKE ET AL.
Copyright © 2012 SciRes. IJG
268
Figure 11. Equal area lower hemisphere stereonet projection of fault planes at the sites of measurement I to V and joints;
these faults correspond to the R’ faults system overprinting the Kitongo. Large black arrows = direction of extention, small
arrows indicate the “slicken side sense” of the movement. Note the NE-SW extension and the associated NW-SE main stress
direction inferred from the Riedel fault model.
5.1. Major Elements whole, the wide distribution of rock types on the K2O vs.
SiO2 diagram (Figure 12(b)) is consistent with the de-
gree of hydrothermal alteration characterized by the de-
pletion in K2O. A definite calc-alkaline differentiation trend
is indicated by all the samples on the Na2O + K2O – FeOt
– MgO (AFM) ternary plot (Figure 12(c)). The Al2O3/
(CaO + Na2O + K2O) versus Al2O3/ (Na2O + K2O) [A/
CNK vs. A/NK] diagram [42] (Figure 12(d)), shows
clustering close to the dividing lines between metalumi-
nous and peralkaline fields but the metaluminous nature
of the granitoids is further substantiated by the presence
of calcic phases such as hornblende.
The equigranular and porphyritic granite have 62.89 -
70.91 wt% SiO2 and Al2O3 values that range from 13.16 -
18.59 wt%. Their MgO content is low, 0.02 - 1.03 wt%
as well as CaO (0.24 - 1.88 wt%) and K2O (0.08 - 5.32
wt%) while they have higher Na2O content (4.33 - 10.92
wt%). The fault rocks have variable composition with
wide variation in major element abundances (57.74 -
70.86 wt% SiO2, 14.63 - 18.06 wt% Al2O3, 1.46 - 3.70
wt% CaO, 5.58 - 9.75 wt% Na2O, 0.50 - 2.81 wt% K2O,
0.93 - 1.07 wt% MgO, 4.52 - 4.99 wt% FeOt) reflecting
geochemical redistribution of elements during fluid cir- On the Harker binary diagrams, granitoids and their
fault rock derivatives form mixed clusters (Figure 13).
An overall decreasing trend of CaO, FeOt, and MgO with
progressive increase of SiO2 signifies the early crystalli-
zation of mafic minerals, while the downward trend of
Al2O3 is consistent with feldspar crystallization. K2O and
Na2O exhibit sympathetic relationship with SiO2 which is
in accordance with the empirical law of differentiation
where orthoclase is enriched in late phase differentiation.
culation within the shear zone. The geochemical classi-
fication of the rock units in the Kitongo area is shown on
the total alkali-silica (TAS) diagram [38] (Figure 12(a)).
Rock samples from the Kitongo U deposit fall in granite
(s.s.) and syenite fields in TAS diagram (Figure 12(a)).
On the basis of the classication scheme [39] (Figure
12(b)) rock specimens of the Kitongo U occurence show
wide distribution from tholeiite to shoshonite series. As a
A. P. KOUSKE ET AL. 269
Hence, a moderate to strong magmatic fractionation is
inferred.
On the geotectonic discrimination diagram based on
multicationic R1-R2 factor [43], the equigranular granite
plots dominantly in the anorogenic field as well as the
microgranite. The granodiorite shows wide distribution
from post-collisional to syn-collisional and late orogenic
fields (Figure 14(a) ).
Table 1. Whole rock chemical composition of selected samples from the Kitongo U occurrence.
Unaltered rocks
Altered and weakly
mineralized rocks Mineralized rocks
Sample ID KIT
1-1
KIT
3-3
KS
9-1
KS
17-2
KS
17-3
KS
5-4
KS
4-3
KS
4-4
KS
5-3
KS
22
KS
2-1
KS
3-1
KS
7-1
KS
8-1
KS
8-2
KS
10
KS
11-2
KS
12-2
KS
23
Major elements
(wt%)
SiO2 70.91 69.78 70.46 67.60 70.86 69.40 65.48 67.07 71.12 57.74 64.59 62.89 64.74 64.82 65.38 63.72 64.02 61.4158.37
TiO2 0.30 0.27 0.50 0.51 0.46 0.27 0.28 0.30 0.26 0.51 0.32 0.26 0.46 0.32 0.31 0.34 0.28 0.570.60
Al2O3 13.16 14.83 14.63 14.02 13.51 14.67 18.10 18.59 14.90 18.06 18.17 17.52 17.13 18.14 18.02 18.06 18.03 17.3716.57
Fe2O3 3.85 3.10 4.52 3.81 3.57 3.63 2.83 2.99 3.45 4.76 3.48 3.35 5.07 4.15 4.11 3.97 3.59 4.994.69
MnO 0.061 0.063 0.096 0.063 0.051 0.063 0.039 0.044 0.063 0.087 0.061 0.067 0.067 0.071 0.065 0.090 0.079 0.0960.121
MgO 0.12 0.20 0.98 1.03 0.85 0.02 0.03 0.04 0.03 1.07 0.16 0.08 0.10 0.07 0.09 0.09 0.11 0.960.93
Cr2O3 0.054 0.035 0.039 0.031 0.053 0.037 0.027 0.026 0.022 0.038 0.027 0.034 0.035 0.027 0.029 0.037 0.028 0.0280.035
CaO 0.81 0.76 1.46 1.88 1.76 0.34 0.24 0.24 0.38 1.82 1.40 0.94 0.70 0.71 0.63 1.33 1.66 1.813.70
Na2O 4.33 5.19 5.58 4.80 7.13 6.63 9.9510.878.53 9.5810.5810.0510.3610.72 10.87 10.92 10.66 9.75 9.03
K2O 5.32 5.21 2.81 3.76 0.53 2.81 0.05 0.06 0.10 0.97 0.09 0.10 0.10 0.10 0.11 0.11 0.08 0.600.50
P2O5 0.04 0.08 0.17 0.14 0.14 0.04 0.15 0.09 0.05 0.19 0.55 0.12 0.11 0.11 0.09 0.09 0.07 0.250.25
LOI 0.26 0.58 0.70 0.34 0.86 0.32 0.84 0.64 0.68 1.88 0.58 1.12 0.44 1.12 0.94 1.46 1.47 1.022.90
Total 99.21 100.09 101.9598.00 99.76 98.25 98.02100.9799.60 96.71100.0196.53 99.33100.35 100.64 100.22 100.0998.8597.70
Trace elements
(ppm)
Sn 2 2 2 4 3 2 2 1 2 2 2 1 3 1 b.d.l. 2 3 2 2
Ba 107.2 541.1 689.1 562.8 520.5 45.6 45.350.241.0647.2 143.6 196.556.422.6 29.2 29.0 24.3 245.5448.9
Nb 112.9 150.4 91.1 97.3 63.0 77.9 149.3130.955.0124.891.8173.983.0 43.9 40.6 52.3 54.9 157.696.6
Ta 0.5 1.2 1.4 2.2 1.7 0.3 0.8 0.9 0.4 0.9 1.0 1.0 0.8 2.6 1.4 1.0 0.6 0.71.2
Zr 692 484 400 333 313 757 559 682 638 521 638 6811189938 888 846 737 482 365
Y 35.3 40.7 33.0 59.9 39.9 27.4 27.5 29.0 24.8 27.9 58.7 39.8 38.8 20.4 21.5 36.6 31.3 36.736.7
Sr 64.0 105.7 181.7 267.1 253.6 13.4 60.950.512.6474.4 211.759.141.162.1 56.8 117.3 151.0 181.8508.3
Rb 56.3 49.6 65.5 92.8 21.2 31.3 1.91.83.539.42.23.01.42.83.0 1.9 1.6 22.422.5
Ga 19.2 22.0 18.6 23.6 22.2 24.0 29.9 30.2 25.1 24.8 27.0 24.0 29.7 28.3 28.6 27.9 27.0 22.921.6
Zn(b) 80 110 91 126 95 113 4682 113118101165132 5778 111 100 129107
Hf 16 13 9 10 10 17 14 16 14 12 16 15 26 18 19 18 16 13 10
W 1.0 1.7 0.7 b.d.l. b.d.l. 0.9 b.d.l.b.d.l.b.d.l. 0.5 b.d.l. 0.5b.d.l. 0.50.8 b.d.l. b.d.l. b.d.l.0.5
Copyright © 2012 SciRes. IJG
A. P. KOUSKE ET AL.
270
Continued
Th 12.3 6.7 6.5 5.9 5.7 12.3 10.110.614.010.68.2 6.918.410.1 10.2 9.8 8.5 5.66.2
U 4.2 1.2 2.4 2.6 2.0 5.1 20.518.311.314.9651.1627.988.9188.8 176.0 119.5 513.8 536.0147.5
Li (b) b.d.l. b.d.l. 29 26 11 b.d.l. b.d.l.b.d.l.b.d.l. 299 b.d.l. 10 b.d.l. 2 2 6 9 13
V 8.3 b.d.l. 44.9 33.8 29.2 b.d.l. 6.25.3b.d.l. 38.313.57.210.9 b.d.l. 5.3 6.4 9.0 34.833.7
Pb (b) 13 15 12 15 15 10 6 8 13 1211555 22 18 20 20 16 5222
Rare earth
elements (ppm)
La 198.4 68.6 49.2 42.7 49.1 173.2 148.4 149.9 213.186.5107.8 139.2 237.7 184.6 184.5 184.6 160.9 28.858.6
Ce 408.1 150.1 103.9 98.6 100.7 369.9 316.8 313.9 443.0 176.4 223.2 279.7 488.3 348.0 360.6 373.1 321.2 62.9118.7
Pr 46.8 18.2 12.2 12.5 11.3 40.5 37.0 36.7 48.8 20.1 26.9 21.6 53.2 41.1 41.2 42.0 35.8 7.913.8
Nd 173.2 71.5 47.4 50.3 40.8 149.6 137.1 134.3 177.973.0103.1 105.7 191.3 150.7 149.8 153.7 131.2 33.552.1
Sm 26.2 13.8 8.7 11.6 8.2 22.8 20.419.825.711.118.418.326.320.1 20.3 22.2 19.6 7.29.4
Eu 0.3 1.0 0.9 0.9 0.9 0.2 0.4 0.4 0.2 0.9 1.7 1.0 0.3 0.2 0.2 0.3 0.2 0.91.4
Gd 19.6 12.4 8.1 11.4 8.1 16.7 13.813.618.4 8.8 17.213.419.514.2 14.4 17.2 15.0 7.08.5
Tb 2.0 1.7 1.1 1.8 1.2 1.7 1.5 1.5 1.7 1.0 2.3 1.2 2.0 1.2 1.2 1.8 1.6 1.11.1
Dy 9.3 9.5 6.3 10.9 7.0 7.2 6.9 7.1 7.3 5.512.510.78.9 4.6 4.8 8.7 7.4 6.76.7
Ho 1.6 1.7 1.2 2.1 1.4 1.2 1.2 1.3 1.1 1.1 2.2 2.0 1.6 0.8 0.9 1.5 1.3 1.31.4
Er 4.5 4.8 3.6 6.2 4.0 3.6 3.2 3.5 3.3 3.2 5.9 5.8 4.9 2.5 2.8 4.4 3.7 4.03.9
Tm 0.6 0.6 0.5 0.9 0.6 0.5 0.4 0.5 0.4 0.4 0.7 0.4 0.7 0.3 0.4 0.6 0.5 0.60.6
Yb 4.0 4.1 3.5 5.4 3.9 3.7 2.9 3.1 3.2 2.9 4.6 4.6 4.9 2.2 2.7 4.1 3.6 4.04.0
Lu 0.7 0.6 0.6 0.8 0.6 0.7 0.5 0.5 0.6 0.5 0.7 0.8 0.9 0.4 0.5 0.7 0.7 0.70.6
REE 895.25 358.73 247.22 255.87 237.72 791.33 690.69 686.05 944.90 391.23 527.04 604.331040.
44 770.91 784.23 814.82 702.63 166.71280.50
LREE 852.95 323.19 222.32 216.61 210.94 756.17 660.22 655.00 908.81 367.96 481.01 565.56 997.20 744.72 756.57 775.88 668.87 141.35253.87
HREE 42.29 35.54 24.90 39.26 26.79 35.16 30.48 31.05 36.09 23.26 46.03 38.77 43.24 26.19 27.66 38.95 33.76 25.3626.63
LREE/HREE 20.17 9.09 8.93 5.52 7.87 21.51 21.66 21.09 25.18 15.82 10.45 14.59 23.06 28.44 27.35 19.92 19.81 5.579.53
KIT1-1, KIT3-3, KS5-4, KS4-3, KS4-3, KS4-4, KS5-3, KS2-1, KS3-1, KS7-1, KS8-1, KS8-2, KS10, KS11-2 (equigranular granite); KS17-2, KS17-3 (porphy-
ritic granite); KS9-1, KS22, KS12-2, KS23 (faults rocks). (b) Elements measured by ICP-AES.
Copyright © 2012 SciRes. IJG
A. P. KOUSKE ET AL. 271
Figure 12. (a) Total alkali-silica (TAS) diagram [38] for chemical classification and nomenclature of the Kitongo granitoids;
(b) K2O vs. SiO2 diagram [39] illustrating the spread of the Kitongo granitoids from tholeiitic to shoshonitic series , see the
text for more explanations; (c) AFM diagram of Kitongo granitoids [40]; (d) Shand’s molar parameters Al2O3/(CaO+Na2O+
K2O) versus Al2O3/(Na2O+K2O) [A/CNK vs. A/NK] of Kitongo granitoids [41].
Figure 13. Harker variation diagrams of selected SiO2 vs. major oxides for Kitongo granitoids. Symbols are the same as in
Figure 12.
Copyright © 2012 SciRes. IJG
A. P. KOUSKE ET AL.
Copyright © 2012 SciRes. IJG
272
Figure 14. (a) R1-R2 multicationic [43] diagram showing various tectonic fields [44]; (b) Ta-Yb discriminant diagram show-
ing tectonic settings of Kitongo granitoids [45]. Symbols are the same as in Figure 12.
5.2. Trace Elements porphyritic granites) of the Kitongo U occurrence show
enrichment (237.7 to 1040.4 ppm; average 673.7 ppm).
The granites exhibit similar REE, LREE and HREE dis-
tribution patterns, high LREE abundances and compara-
tively low HREE abundances. In addition chondrite-nor-
malized REE patterns (Figure 15(a)) for these granites
are characterized by moderate fractionation of LREE to
HREE with (La/Lu)N and (Ce/Yb)N values ranging from
5.84 to 43.53 and 4.75 to 40.27, respectively (La/Sm)N
ratios of 2.32 to 5.78. The chondrite- normalized REE
patterns for the fault rocks (Figure 15(b)) are character-
ized by moderate fractionation of LREE to HREE with
(La/Lu)N and (Ce/Yb)N values ranging from 4.43 to 19.48
and 4.05 to 15.98, respectively. Both the granites and the
fault rocks of the Kitongo area have strong negative Eu
anomalies (Figures 15(a) and (b)) but this is more pro-
nounced in the granite (Eu/Eu* = 0.03 to 0.33) as com-
pared to the fault rocks (Eu/Eu* =0.28 to 0.48). The
negative Eu anomaly in the granites typically suggests
feldspar fractionation or indicates separation of melt
from a plagioclase-rich source.
The U content of the equigranular granite reaches a ma-
ximum value of 651 ppm while the Th concentration is
low (18 ppm). The HFSE show moderate to high enrich-
ment in the granites (Ce up to 488 ppm), Zr (1189 ppm),
Y (59.9 ppm), Nb (173.9 ppm), Pb (115 ppm) while the
transition elements exhibit moderate enrichment (Zn: 46
- 165 ppm; Ga: 19 - 30 ppm). Amongst the large ion li-
thophile elements (LILE), Rb (1.4 - 92.8 ppm) Sr (13.4 -
267.1 ppm) and Ba (22.6 - 562.8 ppm) show moderate to
high abundances. Predominance of Sr over Rb is indi-
cated by low Rb/Sr ratio (average 0.31) which is more
akin to a mantle source, while Rb/Ba and Sr/Ba ratios are
0.14 and 1.48, respectively. The fault rocks show differ-
ent trace element characteristics when compared to the
fresh granite (Table 1). Uranium concentration here ranges
from 2.4 to 536 ppm while Th values range from 5.6 to
10.6 ppm. The subduction-related arc magmatism is in-
dicated by Yb and Ta plot [45] where all of the study
rocks spread in fields of volcanic arc granite (VAG) and
within plate granite (WPG), except for the microgranite
that falls in the field of syn-collisional granite (syn-CO-
LG) (Figure 14(b)). 6. Hydrothermal Alteration
The hydrothermal alterations experienced by the host gra-
nite and associated fault rocks such as albitization, haema-
tit iza tio n and uranium mineralization are discernable from
the whole rock geochemical data. The alteration of K-feld-
spar to albite is evidenced by a sharp decrease in K con-
5.3. Rare Earth Elements
With regards to REE geochemistry, all the samples have
moderate to high LREE contents and comparatively low
content of HREE. The REE data for granites (equi- and
A. P. KOUSKE ET AL. 273
centration (from ~5.32 wt% in the fresh rock to ~0.08
wt% in the ore zone granite, and from 2.4 wt% in the
fresh rock to ~0.5 wt% in the mineralized fault rock) and
by corresponding increase in Na (from ~4.33 wt% to
10.92 wt% in the fresh granite and from ~5.58 wt% to
9.75 wt% in fault rocks (Table 1, Figure 16(a)). The
decrease of K is probably enhanced by the chloritization
of biotite although the amount of biotite in the fresh
rocks is relatively small. Fe and Mg vary slightly from
~3.10 wt% to ~5.07 wt% and ~0.02 wt% to ~0.16 wt%,
respectively, from fresh granite to ore zone granite, and
from ~3.81 wt% to 4.99 wt% and ~0.98 to ~0.96 wt%
respectively from the barren to the mineralized fault rock.
Al increases (from ~13.16 wt% in unaltered granite to
approx. 18.17 in mineralized granite) and (from ~14.63
wt% to ~17.37 wt% respectively from barren to miner-
alized fault rocks). P2O5 slightly increase (from ~0.04
wt% to 0.55 wt% from barren to mineralized granite
zone) and (from ~0.17 wt% to ~0.25 wt% respectively
in barren and mineralized fault rocks. The increase of
P2O5 in ore zones signifies that apatite continued to form
during the main ore stage. Formation of calcite is reflected
by increased Ca contents (from average ~0.34 wt%
Figure 15. (a) Chondrite-normalized REE patterns of Ki-
tongo granite; (b) Chondrite-normalized REE patterns of
faults rocks. Normalized values [46].
Figure 16. Whole rock geochemistry of granitoids from Ki-
tongo uranium occurrence, with K, Ca, and U plotted as
function of degree of albitization (expressed as K – (Na +
Ca). (a)-(c) mineral change: A = unaltered rocks; B = al-
tered and weakly mineralized rocks; C = highly altered and
mineralized rocks, formation of U-mineral. The evolution
tr end i s highlighted by arrowed hyperbole cur ve. The ellipse
shows the positive correlation between albitization and U-
mineralization.
to average ~1.6 wt% with few samples of up to 6.5 wt%
(Figure 16(a)). The granite host rock U concentrations
vary from 1.2 to 5.1 ppm (Table 1) with an average of
2.99 ppm, approximately equal to those in typical granite
which contains ~3.2 ppm [47] and therefore are not U
fertile granite. The formation of U minerals is reflected
by the increase in U concentration from an average of
~3.40 ppm to ~651 ppm in ore zones (Table 1 and Figure
Copyright © 2012 SciRes. IJG
A. P. KOUSKE ET AL.
274
16(c)). Figure 16(c) shows that the main U-ore stage is
directly related to albitization as an increase in U con-
tent positively correlates with the decrease in K. The
increase of Ca contents follows almost a similar pattern
to that of U, increasing slightly during albitization and
correlating positively with albitization expressed as K –
(Na + Ca) more at low K concentrations (Figure 16(b)).
Considering the evolution of K, Na and Ca concentra-
tions (Figure 16), it appears that Na was continuously
added to the system, whereas Ca increased only after
initial albitization was almost complete although some
samples show increasing Ca before this stage. K, Rb,
Nb, Ba and Si seem to be the only elements removed
from the system whereas Pb, Zn, Ga, Hf, Sr, Fe, Al, P
and Zr were added during alteration and mineralization
in addition to U, Na and Ca (Table 1).
Variation in Th/U ratios (0.01 - 5.64 and 0.01 - 2.72)
with lower average values (1.26 and 0.87) respectively in
granite and fault rock as compared to global Th/U ratio
of 3.8 [48,49] suggests U mobilization in the system lead-
ing to either selective enrichment or depletion. Figure 17
however suggests that there is no increase of Th contents
with the increase of U. Thus all the recorded radiometric
anomalies are due to uranium.
7. Discussion
7.1. Petrology and Rock Classification
Pluton margins are likely to be broadly schistose or my-
lonitic in plutons emplaced diapirically when the body
was more than 70% crystallized notably along zones of
ductile shear [50]. The syn- to late-tectonic Kogué mas-
sif in this study is a diapir whose emplacement was fa-
vored by the density contrast between the massif and the
country rock under greenschist facies metamorphic con-
ditions [36]. The detailed field mapping presented here
Figure 17. Whole rock Th and U concentration of grani-
toids from Kitongo uranium occurrence. No increase of Th
contents is observed with the increase of U.
shows that the lithology at the Kitongo U occurrence com-
prised granodiorite, granite locally associated with mafic
dikes and fault rocks made up of a mélange of two dis-
tinct rock types: the metamorphic rocks of the Poli Group
and the Kogué granite.
The Kitongo granitoids belong to the tholeiite to sho-
shonite series exhibiting low to high K/Rb ratios respect-
tively. It is proposed that the magma which gave rise to
the tholeiittic series, came from an intermediate differen-
tiating magma. The probable explanation for the tholeii-
tic character of some samples of both granite and fault
rocks is hydrothermal alteration that lowered the K con-
tent of the rocks. I-type granites are metaluminous to weak-
ly peraluminous (ASI between 0.99 and 1.8) and com-
monly contain biotite, hornblende and titanium [51]. The
weakly aluminous and peralkaline Kitongo granitoids have
clear I-type characteristics. Further, these rocks were ge-
nerated at a collisional tectonic environment involving
lower crustal-upper mantle source material, which under-
went fractional crystallization as evidence by anthipathe-
tic relationship of SiO2 with CaO, FeOt, MgO and Al2O3
and sympathetic relationship between K2O and Na2O.
7.2. Trace and Rare Earth Elements
In the Yb and Ta plot [45], the studied rocks spread in
fields of volcanic arc granite (VAG) and within plate gra-
nite (WPG), except for the microgranite that falls in the
field of syn-collisional granite (syn-COLG). This overlap
sample data set in VAG and WPG fields is perhaps pro-
duced by both the differentiation trend and/or character-
istics of the source rocks [52]. The REE data for granites
(equi- and porphyritic granites) of the Kitongo U occur-
rence show an enrichment (237.7 to 1040.4 ppm; average
673.7 ppm) compared to the average global REE content
of about 250 ppm for granites in general [53]. Note that
the sum of REE in acid and intermediate rocks ranges
from 220 - 350 ppm [54] and their abundance in the upper
crust is 156 ppm [48]. The REE enrichment in the Ki-
tongo granite is similar to the REE enrichment in the
granite rocks of Ado-Ekiti-Akure area, SW Nigeria [55]
and the Pan-African granites of Obudu Plateau South-
eastern Nigeria [56] but more than four times higher than
those for the No. 302 uranium deposit in Northern Guang-
dong, South China [57] and more than four to five times
lower than those of the granitoids of the Kinwat Crystal-
line Inlier, Nanded and Yeotmal Districts Maharashtra
[58]. In addition, the granites at Kitongo show LREE-en-
richment compared to the composition of the average
upper crust. LREE-enrichment is common in calc-alka-
line rocks [59,60]. Eu depletion depicted by a strong Eu-
anomaly in both mineralized and barren granitoids and
the fault rocks suggests that these rocks have experienced
feldspar differentiation.
Copyright © 2012 SciRes. IJG
A. P. KOUSKE ET AL. 275
7.3. Structure and Structural Control on
U Mineralization
The internal fabric of the pluton is linked to both magma-
tic features developed during emplacement and deforma-
tion [61-66]. The strong foliation recorded within the fault
rocks and the Poli Group strikes N050-080E and dipping
70˚SE (Figure 6 and Figure 7(c)) to vertical. The latter
deformation is compatible with the sinistral and dextral
strike-slip fault of the D2 deformation phase defined wi-
thin the regional structures of the northern CAFB in Ca-
meroon [11,67]. Mineral lineation has N050-070E direc-
tion and plunge values 65˚ SE and the preferred orient-
tation of xenoliths (N050-066 SE with dip 65˚SE) are
both parallel to the PSF, the foliation in the fault rocks as
well as the extension direction. The pitch of the lineation
and sense of foliation dip show that sinistral movement
in Kitongo SZ includes a reverse component that indica-
tes oblique ascent of the Kogué granite northwestward
during syntectonic emplacement ; this fact is evidenced
on Figure 7(c).
Within strike-slip fault systems, synthetic (P) and an-
tithetic (R’) faults commonly intersect at high angles for-
ming a rhomb-shaped fault network [68]. The bulk per-
meability structure and strength of a fault zone are con-
trolled by preexisting and newly developed structures,
the regional and local stress state, fault-zone geometry,
and changes in lithology resulting from the coupling of
mechanical, thermal, uid ow, and reactive geochemi-
cal processes [69]. Fluid ow in fault zones can control
the location, emplacement, and evolution of economic
mineral deposits and geothermal systems [70-73]. Further-
more, many hydrothermal deposits within metallogenic
belts are linearly distributed, as best illustrated by those
around the Pacific Rim [74]. The Kitongo fault zone con-
sists in a conjugate fault system overprinting the earlier
ENE-WSW-trending SZ referred to as the PSF and along
which mylonites are the major observed features. The Rie-
del fault system defines an extension direction parallel to
the PSF (ENE-WSW). This fault architecture is compati-
ble with the NW-SE stress direction controlling the
nearby “Vallée des Roniers” dextral SZ (VRSZ) directed
E-W and its N110 synthetic across the Kogué granite.
From the Riedel model (Figure 4) and the occurrences of
dextral kinematic markers in the PSF, this ductile fault
could have been reactivated and operated as the VRSZ
synthetic P fault during dextral evolution. Tectonic reac-
tivation plays a significant role in the mineralization pro-
cess by providing channel-ways coeval with block move-
ments on deep faults/fractures which sustain hydrother-
mal circulation system [68]. Fault intersections over the
margin of the Kitongo granite yielded to high-permeabi-
lity channels having trapped the uranium mineralizing
fluids, and the horizontal section of the distribution of
mineralized shoots conforms to the final stage of anoma-
lous structures of geochemical fields of hydrothermal ore
deposition [75], where hydrothermal alteration led to zo-
ning marked by alternation of variably alterated granites
surrounding the mineralized core zones. The spotted U-
mineralization mapped here occurs at fault intersections
between the Riedel fault system and the SZ and parallel
to it, reflecting the deep traces of the Kitongo strike-slip
faults [74].
7.4. Relationship between Albitization and
Uranium Mineralization and Type of U
Mineralization
The relationship between the main alteration event and
the uranium mineralization can be used for defining the
genetic type of uranium occurrence [76]. Syn-ore zircon
precipitated simultaneously with newly formed albite,
which would suggest an immediate relationship between
albitization and uranium mineralization [77]. The main
uranium mineralization in similar deposits is often not
related to the main albitization event but clearly removed
in time from it [76]. However, the observations presented
above differ from these interpretations. Field surveys ha-
ve revealed a two-stage albitization over the Kitongo ura-
nium occurrence. The second albitization event overprint-
ing the first one was more effective at faults intersections.
The whole rock geochemistry indicates that albitization
was contemporaneous with uranium mineralization posi-
tively correlated. Albitization evidenced by the formation
of albite, decrease of K within the U-bearing lithologies
(granite and fault rocks 5.32 - 0.08 wt% and 2.4 - 0.5 wt%
respectively) and increase of Na (4.33 - 10.92 wt% and
5.58 - 9.75 wt% respectively in granite and the fault
rocks, Table 1, Figure 16) is followed by the formation
of calcite. The latter increases slightly during albitization
from 0.34 up to 6.5 wt% and positively correlates with
albitization mostly where albitization was intense (Figure
16). The main uranium mineralization is thus related to
the second albitization event that has overprinted the first
albitization phase at fault intersections. This mineralizing
event is probably associated in time with the calcite- ura-
nium stage and it is characterized by locally abundant U,
Pb, Zn, and Ga enrichment. Albitization promoted sub-
sequent fluid circulation (for the main stage U minerali-
zation) by creating a more brittle and permeable rock
assemblage. The high U contents in the host rocks are not
the main factor controlling the intensity of uranium min-
eralization. Whether the granite is associated with miner-
alization or not and form lean ores or high-grade ores
was determined by the degree of uranium mobilization.
Hydrothermal activity remobilizes fixed U into fluid phase
[57] and eventually transports it to favourable sites where
ore precipitation is then accompanied by intense altera-
tion processes. The early stage altered hydrothermal fluid
Copyright © 2012 SciRes. IJG
A. P. KOUSKE ET AL.
276
is an omen for large-scale mineralization; it can not only
change the state of U and cause the mobile U increase,
but also provide a partial uranium source [78]. Thus, the
Kitongo U occurrence can be classified as Na-metasoma-
tism related, in agreement with [76,77].
8. Conclusions
The following conclusions can be drawn.
It has not been possible to carry out surface radiometry
on the whole prospect due to vertical cliff-faces and thick
overburden masking the most important parts of the area.
The main rock types at the prospected area comprise:
the metavolcanic and metasedimentary unit, the fault rocks
unit, the granodioritic unit and the granitic unit; U occur-
rence is hosted by granitic rocks that include interleaved
sequence of metasedimentary and metavolcanic rocks of
the collectively termed Poli Group.
Uranium shoots at the Kitongo area are controlled by
ENE-WSW-trending strike-slip faults. However miner-
alization does not occur uniformly along this fault. The
most important segments hosting uranium shoots in the
area are those intersecting with late Pan-African Riedel
fault system.
The Kitongo U occurrence in northern Cameroon is
Na metasomatism-related and characterized by local al-
bitization of the host rock granite (U content up to 651.5
ppm) that is part of the Kogué batholith and the and my-
lonitic fault rocks (0.22% U3O8) following the shear zone.
In addition, all the recorded radiometric anomalies are
due to uranium.
The main uranium mineralization is related to the sec-
ond albitization event that has overprinted the first al-
bitization phase at fault intersections with SZ. This min-
eralizing event is probably associated in time with the
calcite-uranium stage. However, the importance of the
albitization to the mineralization event, in genetic terms,
may be in its role as potential source for uranium. Ura-
nium concentration in unaltered rocks at Kitongo is lo-
wer, thus it is possible that the late magmatic fluids re-
sponsible for albitization also mobilized U as well as hy-
drothermal activity remobilizing fixed U and making it
available for later deposition. Thus, the uranium miner-
alization is post magmatic and related to hydrothermal
activities and faulting events.
The identification of favorable ore hosting segments
within strike-slip faults has great implication for explora-
tion strategies.
9. Acknowledgements
This study is part of a PhD thesis by Arnaud Patrice
KOUSKE at the University of Yaoundé I, Cameroon.
This work could not have been completed without the as-
sistance of Mega Uranium Cameroon PLC. The authors
are thankful to Mr. Marius Van Niekerk for kind accep-
tance to carry out field work on Mega U concessions in
northern Cameroon, and financial support for geochemi-
cal analysis. The authors are grateful to all the Mega U
staff for constant encouragements. They are also grateful
to Mega U’ President, Mr. Stewart Taylor for kind per-
mission to publish materials in this paper.
REFERENCES
[1] R. G. Skirrow, S. Jaireth, D. L. Huston, E. N. Bastrakov,
A. Schofield, S. E. Van der Wielen and A. C. Barnicoat,
“Uranium Mineral Systems, Processes, Exploration Crite-
ria and a New Deposit Framework,” Geoscience Au s tralia
Record, 2009/20, 2009.
[2] J. R. Faul, “Emerging Demand from Emerging Markets -
A Trader’s Perspective,” NEI, International Uranium Fuel
Seminar Savannah, 2010.
[3] W. Zittle, L. Bölkow and J. Schindler, “Uranium Re-
sources and Nuclear Energy,” Energy Watch Group Re-
port, EWG No.1, 2006.
http://www.energywatchgroup.com/fileadmin/global/pdf/
EWG_Report_Uranium_3-12-2006ms.pdf
[4] International Atomic Energy Agency, “Integrated Nuclear
Fuel Cycle Information System (iNFCIS),” IAEA, Vi-
enna. http://www-nfcis.iaea.org/
[5] V. Thoste, “Mineral Exploration in North Cameroon,
Region of Poli,” Final Report, Federal Republic of Ger-
many, Number of Project 80.2273.3, 1985.
[6] International Atomic Energy Agency, “World Distribu-
tion of Uranium Deposits (UDEPO) with Uranium De-
posit Classification,” IAEA, Vienna, IAEA-TECDOC-
1629, 2009, p. 12.
[7] M. Lassere, “Cameroun Mise en Evidence Radiométrique
de Deux Séries d’Embréchites au Sein de la Zone Mobile
de l’Afrique Centrale,” 10ème Colloque de Géologie Afr-
icaine, Montpellier, 25-27 Avril 1979, p. 59.
[8] M. Lassere and D. Soba, “Migmatisation d’Age Pan-
africain au Sein des Formations Camerounaises App-
artenant à la Zone Mobile de l’Afrique Centrale,” Compte
Rendu Sommaire Société Géologique de France, Vol. 2,
1979, pp. 64-69.
[9] B. Bessoles and R. Trompette, “Géologie de l’Afrique, la
Chaîne Panafricaine, Zone Mobile d’Afrique Centrale
(Partie Sud et Zone Mobile Soudanaise),” Mémoires du
Bureau de Recherches Géologiques et Minières, Vol. 92,
1980.
[10] P. Affaton, M. A. Rahaman, R. Trompette and J. Sougy,
“The Dahomeyide Orogen, Tectonothermal Evolution and
Relationships with the Volta Basin,” In: R. D. Dallmeyer
and J. P. Lécorché, Eds., The West African Orogens and
Circum-Atlantic Correlatives, Springer-Verlag, Berlin,
1991, pp. 107-122.
[11] V. Ngako, P. Affaton and E. Njonfang, “Pan-African
Tectonics in the Northern Cameroon, Implication for the
History of Western Gondwana,” Gondwana Research,
Vol. 14, No. 3, 2008, pp. 509-522.
Copyright © 2012 SciRes. IJG
A. P. KOUSKE ET AL. 277
doi:10.1016/j.gr.2008.02.002
[12] D. Küster and J. P. Liégeois, “Sr, Nd Isotopes and Geo-
chemistry of the Bayuda Desert High-Grade Metamorphic
Basement (Sudan), an Early Pan-African Oceanic Con-
vergent Margin, Not the Edge of the East Saharan Ghost
Craton?” Precambrian Research, Vol. 109, No. 1-2, 2001,
pp. 1-23. doi:10.1016/S0301-9268(00)00147-9
[13] V. Ngako, “Les Deformations Continentales Panafricaines
en Afrique Centrale, Résultat d’un Poinçonnement de Type
Himalayen,” Thèse de Doctorat d’Etat, Université de
Yaoundé I, Yaoundé, 1999.
[14] S. F. Toteu, “Geochemical Characterization of the main
Petrographical and Structural Units of Northern Camer-
oon, Implication for Panafrican Evolution,” Journal of
African Earth Sciences, Vol. 10, No. 4, 1990, pp. 615-624.
doi:10.1016/0899-5362(90)90028-D
[15] J. Penaye, A. Kröner, S. F. Toteu, W. R. Van Schmus and
J. C. Doumnang, “Evolution of the Mayo Kebbi Region
as Revealed by Zircon Dating: An Early (ca. 740 Ma)
Pan-African Magmatic Arc in Southwestern Chad,”
Journal of African Earth Sciences, Vol. 44, No. 4-5, 2006,
pp. 530-542. doi:10.1016/j.jafrearsci.2005.11.018
[16] S. F. Toteu, J. Penaye, E. Deloule, W. R. Van Schmus
and R. Tchameni, “Diachronous Evolution of Volcano-
Sedimentary Basins North of the Congo Craton, Insights
from U-Pb Ion Microprobe Dating of Zircons from the
Poli, Lom and Yaounde´ Groups (Cameroon),” Journal of
African Earth Sciences, Vol. 44, No. 4-5, 2006, pp. 428-
442. doi:10.1016/j.jafrearsci.2005.11.011
[17] W. R. Fitches, A. C. Ajibade, I. G. Egbuniwe, R. W. Holt
and J. B. Wright, “Late Proterozoic Schist Belts and Plu-
tonism in NW Nigeria,” Journal of the Geological Society,
Vol. 142, No. 2, 1985, p. 319.
doi:10.1144/gsjgs.142.2.0319
[18] R. Caby, “The Pan-African Belt of West Africa from the
Saharan Desert, the Gulf of Benin,” In: J. P. Schaer and J.
Rodgers, Eds, Antonony of Mountain Ranges, Princeton
Univeristy Press, Princeton, 1987.
[19] R. Caby, “Les Terrains Précambrien du Bénin, Nigéria et
Nord-Est Brésil et les Connections Sud-Atlantiques au
Protérozoïque Supérieur,” International Meeting on Pro-
terozoic Geology and Tectonics of High-Grade Terrains,
Ile-Ife, Nigeria, Program and Lecture Series, 1988.
[20] S. F. Toteu, A. Michard, J. M. Bertrand and G. Rocci,
“U-Pb Dating of Precambrian Rocks from Northern Cam-
eroon, Orogenic Evolution and Chronology of the Pan-
African Belt of Central Africa,” Precambrian Research,
Vol. 37, No. 1, 1987, pp. 71-87.
doi:10.1016/0301-9268(87)90040-4
[21] S. F. Toteu, J. Macaudière, J. M. Bertrand and D. Dautel,
“Metamorphism Zircon from North Cameroon, Implica-
tions for the Pan-African Evolution of Central Africa,”
Geologishe Rundschau, Vol. 79, No. 3, 1990, pp. 777-788.
doi:10.1007/BF01879214
[22] C. Castaing, C. Triboulet, J. L. Feybesse and P. Chèvre-
mont, “Tectonometamorphism Evolution of Ghana, Togo
and Benin in the Light of the Pan-African Brasiliano
Orogeny,” Tectonophysics, Vol. 218, No. 4, 1993, pp.
323-342. doi:10.1016/0040-1951(93)90322-B
[23] C. Castaing , J. L. Feybesse, D. Thiéblemont, C. Triboulet
and P. Chèvremont, “Palaeogeographical Reconstitutions
of the Pan-African/Brasiliano Orogen, Closure of an Oce-
anic Domain or Intracontinental Convergence between
Major Blocks?” Precambrian Research, Vol. 69, 1994,
pp. 327-344. doi:10.1016/0301-9268(94)90095-7
[24] R. Trompette, “Geology of Western Gondwana (2000 -
500 Ma), PanAfrican-Brasiliano Aggregation of South
America and Africa,” A. A. Balkema Press, Rotterdam,
1994.
[25] J. L. Poidevin, “La Tectonique Panafricaine à la Bordure
Nord du Craton Congolais, l’Orogenèse des ‘Ouban-
guides’,”12th Colloque on African Geology, Bruxelles,
1983, p. 75.
[26] P. Jegouzo, “Evolution Structurale du Sud-ouest Came-
roun durant l’Orogénèse Panafricaine, Associations de
Tectoniques Cisaillantes et Chevauchante,” Colloq ue CNRS,
Chevauchement et Défor m at i o n, Toulouse, 1984, p. 23.
[27] J. P. Nzenti, P. Barbey, P. Jegouzo and C. Moreau, “Un
Nouvel Exemple de Ceinture Granulitique dans une Chaine
Proterozoïque de Collision, Les Migmatites Yaoundé au
Cameroun,” Comptes Rendus Académie Sciences Paris,
Vol. 299, 1984, pp. 1197-1199.
[28] C. Pin and J. L. Poidevin, “U-Pb Zircon Evidence for a
Pan-African Granulite Facies Metamorphism in the Cen-
tral African Republic. A New Interpretation of the High-
Grade Series of the Northern Border of the Congo Cra-
ton,” Precambrian Research, Vol. 36, No. 3-4, 1987, pp.
303-312. doi:10.1016/0301-9268(87)90027-1
[29] S. F. Toteu, W. R. Van Schmus, J. Penaye and A. Mich-
ard, “New U-Pb and Sm-Nd Data from North-Central
Cameroon and Its Bearing on the Pre-Pan-African History
of Central Africa,” Precambrian Research, Vol. 108, No.
1-2, 2001, pp. 45-73.
doi:10.1016/S0301-9268(00)00149-2
[30] Y. H. Poudjom-Djomani, J. M. Nnange, M. Diament, C. J.
Ebinger and D. J. Fairhead, “Effective Elastic Thickness
and Crustal Thickness Variations in West Central Africa
Inferred from Gravity,” Journal of Geophysical Research,
Vol. 100, No. B11, 1995, pp. 22047-22070.
doi:10.1029/95JB01149
[31] U. O. Njel, “Paléogéographie d’un Segment de l’Oro-
genèse Panafricaine, la Ceinture Volcano-Sédimentaire de
Poli (Nord Cameroun),” Compte Rendu de lAcadémie
des Sciences, Vol. 30, 1986, pp. 1737-1742.
[32] Y. Le Fur, “Les Indices de Cuivre du Groupe Volcano
Sédimentaire de Poli (Cameroun),”Bulletin du BRGM,
Vol. 6, 1971, pp. 79-91.
[33] S. F. Toteu, J. F. Dumont, J. Bassahak and J. Penaye,
“Complexe de Base et Séries Intermediaires Dans la Zone
Mobile Panafricaine de Poli au Cameroun,” Comptes
Rendus de lAcadémies des Sciences, Vol. 299, 1984, pp.
561-564.
[34] P. Pinna, J. Y. Calvez, A. Abessolo, J. M. Angel, T.
Mekoulou-Mekoulou, G. Mananga and Y. Vernhet, “Neo-
proterozoic Events in the Tcholliré Area, Pan african
Crustal Growth and Geodynamics in Central-Northern
Cameroon (Adamawa and North Provinces),” Journal of
Copyright © 2012 SciRes. IJG
A. P. KOUSKE ET AL.
278
African Earth Sciences, Vol. 18, No. 4, 1994, pp. 347-353.
doi:10.1016/0899-5362(94)90074-4
[35] J. Penaye, “Pétrologie et Structure des Ensembles Méta-
morphiques au Sud Est de Poli (North Cameroon),”
Unpublished Doctoral Thesis, University of Nancy (INPL),
France, 1988.
[36] J. Bassahak, “Le Complexe Plutonique de Kogué (poli,
nord cameroun). Petrologie-Geochimie-Petrologie Struct-
urale; sa Place dans la Chaine Panafricaine au Nord Cam-
eroun,” Thèse de Doctorat University Nancy I, 1988.
[37] R. E. Wilson, “Basic Wrench Tectonic,” American Asso-
ciation of Petroleum Geologists Bulletin, Vol. 57, 1973,
pp. 74-96.
[38] K. G. Cox, J. D. Bell and R. J. Pankhurst, “The Interpre-
tation of Igneous Rocks,” Allen and Unwin, London,
1979.
[39] A. Peccerillo and S. R. Taylor, “Geochemistry of Eocene
Calc-Alkaline Volcanic Rocks from the Kastamonu Area,
Northern Turkey,” Contributions to Mineralogy and Pe-
trology, Vol. 58, No. 1, 1976, pp. 63-81.
doi:10.1007/BF00384745
[40] T. N. Irvine and W. R. A. Baragar, “A Guide to the
Chemical Classification of the Common Volcanic Rocks,”
Canadian Journal of Earth Sciences, Vol. 8, No. 5, 1971,
pp. 523-548. doi:10.1139/e71-055
[41] P. D. Maniar and P. M. Piccoli, “Tectonic Discrimination
of Granitoids,” Geological Society of America Bulletin,
Vol. 101, No. 5, 1989, pp. 635-643.
doi:10.1130/0016-7606(1989)101<0635:TDOG>2.3.CO;
2
[42] S. J. Shand, “Eruptive Rocks, Their Genesis, Composi-
tion, Classification, and Their Relation to Ore-Deposits
with a Chapter on Meteorite,” John Wiley & Sons, New
York, 1943.
[43] H. De La Roche, J. Leterrier, C. P. Grande and M. Mar-
chal, “A Classification of Volcanic and Plutonic Rocks
Using R1-R2 Diagrams and Major Element Analyses its
Relationships and Current Nomenclature,” Chemical Ge-
ology, Vol. 29, No. 1-4, 1980, pp. 183-210.
doi:10.1016/0009-2541(80)90020-0
[44] R. A. Batchelor and P. Bowden, “Petrogenetic Interpreta-
tion of Granitoid Rocks Series Using Multicationic Pa-
rameters,” Chemical Geology, Vol. 48, No. 1-4, 1985, pp.
43-55. doi:10.1016/0009-2541(85)90034-8
[45] J. A. Pearce, N. B. W. Harris and A. G. Tindle, “Trace
Element Discrimination Diagrams for the Tectonic Inter-
pretation of Granitic Rocks,” Journal of Petroleum, Vol.
25, No. 4, 1984, pp. 956-983.
[46] W. Boynton, “Cosmochemistry of the Rare Earth Ele-
ments, Meteorite Studies,” In: P. Henderson, Ed., Rare
Earth Element Geochemistry, Elsevier, 1984, pp. 63-114.
[47] F. J. Flanagan, “1972 Compilation of Data on USGS
Standards,” In: F. J. Flanagan, Ed., Descriptions and
Analyses of Eight New USGS Rock Standards, USGS Pro-
fessional Paper 840, 1976, pp. 131-183.
[48] S. R. Taylor and S. M. Mclennan, “The Continental Crust,
Its Composition and Evolution,” Blackwell, Oxford,
1985.
[49] W. R. Van Schmuss, “Natural Radioactivity of the Crust
and Mantle Global Earth Physics—A Handbook on Phy-
sical Constants,” American Geophysical Union Reference
Shelf, Vol. 1, 1995, pp. 283-291.
[50] J. C. Soula, “Characteristic and Mode of Emplacement of
Gneiss Domes and Plutonic Domes in Central Eastern
Pyrenees,” Journal of Structural Geology, Vol. 4, No. 3,
1982, pp. 313-342. doi:10.1016/0191-8141(82)90017-7
[51] B. W. Chappell and A. J. R. White, “I- and S-Type Gran-
ites in the Lachlan Fold Belt,” Transactions Royal Society
of Edinburgh Earth Sciences, Vol. 83, 1992, pp. 1-26.
[52] H.-J. Förster, G. Tischendorf and R. B. Trumbull, “An
Evaluation of the Rb vs. (Y+Nb) Discrimination Diagram
Toinfer Tectonic Setting of Silicic Igneous Rocks” Lithos,
Vol. 40, No. 2-4, 1997, pp. 261-293.
doi:10.1016/S0024-4937(97)00032-7
[53] R. Emmermann, L. Daieva and J. Schneider, “Petrologic
Significance of Rare Earth Distribution in Granites,”
Contributions to Mineralogy and Petrology, Vol. 52, No.
4, 1975, pp. 267-283. doi:10.1007/BF00401457
[54] L. A. Haskin and R. A. Schmitt, “Rare-Earth Distribu-
tions” In: P. H. Abelson, Ed., Researches in Geochemis-
try, John Wiley and Sons, Inc., New York, Vol. 2, 1967,
pp. 235-258.
[55] V. O. Olarewaju, “REE in the Charnockitic and Associ-
ated Granitic Rocks of Ado Ekiti-Akure, SW Nigeria,” In:
P.O. Oluyide et al., Eds., Precambrian Geology of Nige-
ria, Geological Survey of Nigeria Publication, Kaduna,
1988, pp. 231-239.
[56] V. U. Ukaegbu and F. T. Beka, “Rare Earth Elements as
Source Indicators of Pan African Granites from Obudu
Plateau, Southern Nigeria,” Chinese Journal of Geo-
chemistry, Vol. 27, No. 2, 2008, pp. 130-134.
doi:10.1007/s11631-008-0130-2
[57] G. Zhang, R. Hu, X. Bi, H. Feng, P. Shang and J. Tian,
“REE Geochemical Characteristics of the No. 302 Ura-
nium Deposit in Northern Guangdong, South China,” Chi-
nese Journal of Geochemistry, Vol. 26, No. 4, 2006, pp.
425-433. doi:10.1007/s11631-007-0425-8
[58] R. Banerjee and K. Shivkumar, “Geochemistry and
Petrogenesis of Radioactive Palaeoproterazoic Granitoids
of Kinwat Inlier, Nanded and Yeotmal Districts Ma-
harashtra,” Journal of the Geological Society of India,
Vol. 75, No. 4, 2010, pp. 596-617.
doi:10.1007/s12594-010-0054-4
[59] R. K. O’Nions and R. J. Pankhurst, “Rare-Earth Element
Distribution in Archaean Gneisses and Anorthosites,
Godthab Area, West Greenland,” Earth and Planetary
Science Letters, Vol. 22, 1974, pp. 328-338.
[60] P. O. Okeke and M. A. Meju, “Chemical Evidence for the
Sedimentary Origin of Igarra Supracrustral Rocks in the
Southwestern Nigeria Basement Complex,” Nigeria Jour-
nal of Mining and Geology, Vol. 22, No. 2, 1985, pp.
97-104.
[61] R. Balk, “Structural Behavior of Igneous Rocks,” Mem-
oire (SAUS) Geological Society of America, Vol. 1, 1937,
pp. 291-302.
Copyright © 2012 SciRes. IJG
A. P. KOUSKE ET AL.
Copyright © 2012 SciRes. IJG
279
[62] G. Courrioux, “Etude d’une Evolution Magmatique et
Structural dans le Contexte d’une Zone de Cisaillement
Ductile Active, Exemple du Linéament Granitique Her-
cynien de Puentedeume (Gallice, Espagne),” Thèse 3e
cycle, University Nancy I, 1984.
[63] S. C. Paterson and O. T. Tobisch, “Using Pluton Ages to
Date Regional Deformation Problems with Commonly
Used Criteria,” Geology, Vol. 16, No. 12, 1989, pp. 1108-
1111.
doi:10.1130/0091-7613(1988)016<1108:UPATDR>2.3.C
O;2
[64] J. L. Lagarde, “Granites Tardi Carbonifères et Défor-
mation Crustale, l’Exemple de la Meseta Marocaine,”
Thèse Docteur ès Science, Rennes, 1987.
[65] J. L. Lagarde, S. Ait Omar and B. Roddaz, “Structural
Characteristics of Plutons Emplaced during Weak Re-
gional Deformation, Example from Late Carboniferous
Plutons Morocco,” Journal of Structural Geology, Vol.
12, No. 7, 1990, pp. 805-821.
doi:10.1016/0191-8141(90)90056-5
[66] D. Gasquet, “Genèse d’un Pluton Composite Tardi-
Hercynien, le Massif de Tichka, Haut Atlas Occidental
(Maroc),” Thèse Docteur ès Science, Université Henri
Poincaré, 1991.
[67] J. P. Nzenti, V. Ngako, R. Kambou, J. Bassahak and U. O.
Njel, “Structures Régionales de la Chaîne Panafricaine du
Nord-Cameroun,”Comptes Rendus de lAcadémie des
Sciences, Vol. 315, 1992, pp. 209-215.
[68] J. Li, M. Zhou, X. Li, Z. Fu and Z. Li, “Structural Control
on Uranium Mineralization in South China, Implication
for Fluid Flow in Continental Strike Slip Faults,” Science
in China, Vol. 45, No. 9, 2002, pp. 851-864.
[69] J. S. Caine, R. L. Bruhn and C. B. Forster, “Internal
Structure, Fault Rocks, and Inferences Regarding Defor-
mation, Fluid Flow, and Mineralization in the Seis-
mogenic Stillwater Normal Fault, DixieValley, Nevada,”
Journal of Structural Geology, Vol. 32, No. 11, 2010, pp.
1576-1589. doi:10.1016/j.jsg.2010.03.004
[70] W. H. Newhouse, “Ore Deposits as Related to Structural
Features,” Hafner Publishing Co., New York, London,
1942, p. 280
[71] S. F. Cox, M. A. Knackstedt and J. Braun, “Principles of
Structural Control on Permeability and Fluid Flow in
Hydrothermal Systems,” Reviews in Economic Geology,
Vol. 14, 2001, pp. 1-24.
[72] R. H. Sibson, “Seismogenic Framework for Hydrothermal
Transport and Ore Deposition,” Reviews in Economic
Geology, Vol. 14, 2001, pp. 25-50.
[73] S. Micklethwaite, “Mechanisms of Faulting and Ferme-
ability Enhancement during Epithermal Mineralization,
Cracow Goldeld, Australia,” Journal of Structural Ge-
ology, Vol. 31, No. 3, 2009, pp. 288-300.
doi:10.1016/j.jsg.2008.11.016
[74] N. C. White, M. J. Leake and S. N. McCaughey, “Epi-
thermal Gold Deposits of the Southeastern Pacific,” Jour-
nal of Geochemical Exploration, Vol. 54, No. 2, 1995, pp.
87-136. doi:10.1016/0375-6742(95)00027-6
[75] V. G. Voroshilov, “Anomalous Structures of Geoche-
mical Fields of Hydrothermal Gold Deposits, Formation
Mechanism Methods of Geometrization, Typical Models,
and Forecasting of Ore Mineralization,” Geology of Ore
Deposits, Vol. 51, No. 1, 2009, pp. 3-19.
doi:10.1134/S1075701509010012
[76] P. Alexandre, “Mineralogy and Geochemistry of Sodium
Metasomatism-Related Uranium Occurrence of Aricheng
South, Guyana,” Mineralium Deposita, Vol. 45, No. 4,
2010, pp. 351-367. doi:10.1007/s00126-010-0278-7
[77] S. Cinelu and M. Cuney, “Sodic Metasomatism and U-Zr
Mineralization, a Model Based on the Kurupung Batho-
lith (Guyana),” Geochim Cosmochim Acta, Vol. 70, No.
18, 2006, A103.
[78] B. T. Zhang, J. Wu, Z. Qiu and Y. Liu, “On the Relation-
ship between Hydrothermal Alteration and Uranium En-
richement,” Geological Review, Vol. 38, 1990, pp. 238-
245.