Vanadium Bearing Titaniferous Magnetite Ore Bodies of Ganjang ...

26 JOURNAL ABHISHEK GEOLOGICAL SAHA AND SOCIETY OTHERS OF INDIA
Vol.76, July 2010, pp.26-32
Vanadium Bearing Titaniferous Magnetite Ore Bodies of Ganjang,
Karbi-Anglong District, Northeastern India
ABHISHEK SAHA 1 , SOHINI GANGULY 1 , JYOTISANKAR RAY 1 and AVIK DHANG 2
1 Department of Geology, University of Calcutta, 35, Ballygunge Circular Road, Kolkata 700 019, India
2 Aurum S.P.R.L., 59, Avenue Colnol Muzemba, Lubumbashi, Democratic Republic of Congo
Email: jsray65@hotmail.com
Abstract: A new occurrence of (syenite-hosted) Vanadium bearing titaniferous magnetite ore body has been reported
from Ganjang (26°09'35" N: 93°20' E), Karbi-Anglong, Northeastern India. The magnetite ore bodies have lumpy and
sporadic occurrences within the host syenite pluton intrusive into gneissic country rocks. Ore microscopic studies reveal
that magnetite is often associated with haematite and ilmenite depicting different textural patterns. Critical consideration
of several elemental patterns suggests magmatic differentiation to be main ore-forming process. The ore body is suggested
to have been formed as late stage segregation from a differentiating alkaline magma in a fluid enriched milieu.
Keywords: Vanadium bearing titaniferous magnetite, Karbi-Anglong, Widmanstatten texture, Magmatic differentiation,
Northeastern India.
INTRODUCTION
The emplacement of alkaline-carbonatite magmas in
relatively stable, intracratonic platforms is facilitated by
lithospheric uparching, crustal thinning followed by
fracturing and rifting caused by the impact of an incubating
mantle plume onto the base of continental lithosphere
(Woolley, 1989). A wide range of ore-forming processes are
known to be related to the mechanism of intracontinental
rifting and the resulting alkaline-carbonatite magmatism
(Piranjo, 2007).The various processes of magmatic
differentiation operating in a fluid enriched environment,
sometimes aided by metasomatic effects on the parent melt,
favour intrusions of alkaline-mafic-ultramafic rocks and
carbonatites. This is accompanied by late stage enrichment
of elements like Ti, V, Fe, Mn, Zr, Ni, Co, Cr, Cu etc. in the
residual or immiscible liquid fraction (Krishnamurthy et al.
2000; Krishnamurthy, 2007). Economic minerals are known
to occur in alkaline igneous rocks and associated
carbonatites as they are enriched in elements like Ti, V, Fe,
Mn, Zr, Pb, Ni, Mo, Co, Cr, Cu, Th, Au, Ag and PGE. Titanium,
Vanadium and Fe oxides are generally derived from magmas
that are richer in Fe, Ca and alkali. Economically important,
orthomagmatic, vanadium bearing titaniferous magnetite
ores are formed by late stage segregation from volatile rich,
differentiated alkaline magmas triggered by episodic
increases in fO 2
(Piranjo, 2007). The present article reports
for the first time the occurrence of orthomagmatic vanadium
bearing titaniferous magnetite ore body from Ganjang (26°09'
35"N: 93°20'E), Karbi-Anglong, Northeastern India,
supported by petrograhic and geochemical data. Available
literatures (Kumar et al. 1989; Hoda et al. 1997) on this body
are preliminary in nature and describe it as apatite-magnetiteperovskite
(AMP) rock.
GEOLOGICAL SET UP AND MODE OF
OCCURRENCE
The presently investigated vanadium bearing
titaniferous magnetite ore bodies occur within the
Samchampi-Samteran ultramafic-mafic-alkaline-carbonatite
complex of Northeastern India (Kumar et al. 1989; Nag et al.
1999). The Samchampi-Samteran complex occurs as a near
circular, stock like intrusion emplaced into the Precambrian
gneissic rocks of Mikir Hills, in the Karbi-Anglong district
of Assam (Kumar et al. 1989; Nag et al.1999; Srivastava and
Sinha, 2004; Srivastava and Sinha, 2007). This lineament
controlled emplacement is a part of ultramafic-mafic-alkalinecarbonatite
magmatism of Shillong Plateau, representing
latest differentiation phases of Sylhet Trap basalts in
Northeastern India (Coffin et al. 2002; Kent et al. 2002). The
oval shaped syenite body with arcuate ijolite-melteigite suite
of rocks occurs as a discrete plug like pluton within the
Precambrian basement gneisses. The ijolite-melteigite suite
of rocks also shows occasional presence of inliers of alkali
0016-7622/2010-76-1-26/$ 1.00 © GEOL. SOC. JOUR.GEOL.SOC.INDIA, VOL.76,JULY2010

VANADIUM BEARING TITANIFEROUS MAGNETITE ORE BODIES OF GANJANG, NE INDIA 27
36
28
20
12
N
72 80 88 96
ARABIAN
SEA
DELHI
INDIAN OCEAN
I N D E X
KOLKATA
0 600 Km
SCALE
STUDY AREA
BAY OF
BENGAL
72 80 88 96
26°13´30´´ + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + +
+ + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + +
+ + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + +
N
1 Km + +
36
+ + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + +
+ + + +
Samchampi
+ + + + + + + + + + + + + + + + + + + + + + + + + +
+ + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + +
+ + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + +
28
+ + + + + + + + + + + + + + + + + + + + + + + + + + +
+ + + + + + + + + + + + + + + + + + + + +
+ + + + + + + + + + + +
20
+ + + + + + + + + +
+ + + + + + + + + +
+ + + + + + + + +
12
+ + + + + + + +
+ + + + + + +
+ + + + + +
+ + + + +
+ + + + +
+ + + + +
+ + Samteran + + +
+ + + + + + + +
+ + + + + + + + +
+ + + + + + + + + +
+ + + + + + + + + + + +
+ + + + + + + + + + + +
+ + + + + + + + + + + +
+ + + + + + + + + + + + + +
+ + + + + + + + + + + + + + +
+ + + + + + + + + + + + + + + +
+ + + + + + + + + + + + + + + + +
+ + + + + + + + + + + + + + + + + + + + + +
+ + + + + + + + + + + + + + +
Ganjang
+ + + + + + + + + + + + +
+ + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + +
26°09´15´´
93°14´ 93°27´20´´
+ + + Precambrian Granite gneiss
+ + + with minor occurrences of
migmatite
Alkali Gabbro
Nepheline syenite
dykes
66°
75°
52°
Syenite bodies
Alkali pyroxenite
63°
Foliation plane in Granite Gneiss
Vanadium bearing
TitaniferousMagnetite
ore bodies
Ijolite-Melteigite
suite
Brecciated rock
Carbonatite
Fig.1. Geological map of the study area. Inset map shows the location of study area in the map of India.
pyroxenite and alkali gabbro. Younger intrusives marked by
carbonatite and nepheline syenite traverse the pluton (Fig.1).
The vanadium bearing titaniferous magnetite ore bodies
have lumpy and sporadic occurrences and are distributed
at and around Ganjang (26°09'35"N: 93°20' E) being hosted
in syenite pluton (Fig.1). The vanadium bearing titaniferous
magnetite ore is hard, massive, deep brown in colour with a
very high specific gravity. Ore microscopic study of the
polished sections of the representative samples reveals that
these rocks are dominantly composed of magnetite with
subordinate amount of haematite and ilmenite. Pronounced
effect of martitization is also evident in magnetite (Fig.2).
Ilmenite occurs as exsolution lenses in close association
with haematite (Fig.3). Widmanstatten (Box-work type)
Mar
M
Fig.2. Photomicrograph showing pronounced effects of
martitization (Mar) in Magnetite (M).
Fig.3. Photomicrograph depicting exsolution lenses of ilmenite (I)
occuring in close association with haematite (H).
JOUR.GEOL.SOC.INDIA, VOL.76,JULY2010

28 ABHISHEK SAHA AND OTHERS
Fig.4. Photomicrograph depicting Widmanstatten (Box-work
type) textural pattern in martitized magnetite.
textural pattern has also been observed in martitized grains
(Fig.4).
CHEMISTRY
In order to decipher the pattern of elemental zonation
and chemical variations within vanadium bearing titaniferous
magnetite ore bodies, several constituent elements were
analysed from representative grid samples using hand-held
XRF XLt Niton (Model No. XLt 592 KVw). The analyses
were performed at Aurum S.P.R.L. Laboratory, Lubumbashi,
Democratic Republic of Congo. The details of analytical
procedure and accuracy are given in Acharya et al.(2006).
The analytical data (Table 1) reveal that this ore body is
predominantly composed of FeO (FeO (t) content ranging
from 82.97 to 94.94 wt. %), followed by TiO 2
(4.38 to 13.73
wt. %) and V 2
O 5
(0.07 to 2.14 wt. %) which justifies its
vanadium bearing titaniferous nature. Among trace
elements, the vanadium bearing titaniferous magnetite ore
body is characterized by consistent and appreciable
concentrations of Co (264-1765 ppm), Cr (86-1546 ppm), Ni
(68-238 ppm), Cu (164-629 ppm), Zn (373-1161 ppm) and Zr
(337-4542 ppm) with lesser amounts of As, Pt, Nb, Pd and
Ag. The Zr concentrations of the vanadium bearing
titaniferous magnetite ore body are found to vary from 337
ppm. (in the margin) to 4542 ppm (in the core). The
combination of high charge and comparatively high radius
(0.79 Å) compels Zr not to enter into the common rock
forming minerals to any degree but helps Zr to be enriched
into later differentiates (Mason and Moore, 1985). This
Table 1. Chemical analysis of Vanadium bearing titaniferous magnetite ore body
Major oxides (wt %)
Specimen no. SAJ 75 SAJ 72 SAJ 77 SAJ 70 SAJ 61 SAJ 65 SAJ 67
FeO(t) 94.73 94.66 82.97 89.82 89.94 93.11 94.94
TiO 2
4.38 4.43 13.73 9.24 8.75 6.36 4.59
V 2
O 5
* 0.61 0.58 2.14 0.67 0.90 0.30 0.07
MnO 0.29 0.34 1.17 0.38 0.41 0.24 0.40
FeO** 60.95 60.91 53.38 57.80 57.87 59.91 61.09
Fe 2
O 3
** 37.53 37.50 32.87 35.59 35.63 36.89 37.62
Trace elements (ppm)
Specimen no. SAJ 75 SAJ 72 SAJ 77 SAJ 70 SAJ 61 SAJ 65 SAJ 67
Location of samples
Margin Core Margin
in the ore body
Pd 35 0 18 19 0 12 11
Ag 47 96 0 68 99 0 22
Mo 0 0 9 48 9 0 0
Nb 12 0 712 1101 838 12 68
Zr 381 337 - 4125 4542 423 362
Bi 0 0 0 125 164 0 0
Au 0 0 18 0 0 25 0
Pt 36 0 27 0 0 59 0
As 36 96 36 29 58 0 34
W 60 217 91 164 0 0 137
Zn 570 482 1161 561 769 373 713
Cu 617 361 244 164 239 629 271
Ni 238 169 100 68 103 194 -
Co 1119 1614 264 - 922 1048 1765
Cr 216 - 173 1546 532 86 485
V 3420 3252 11989 3736 5056 1675 375
*V 2
O 5
recalculated from V content in ppm; ** FeO/Fe 2
O 3
recalculated values
JOUR.GEOL.SOC.INDIA, VOL.76,JULY2010

100
VANADIUM BEARING TITANIFEROUS MAGNETITE ORE BODIES OF GANJANG, NE INDIA 29
93°19´
26°10´50´´
N
93°21´30´´
93°19´
26°10´50´´
N
381
337
194
194
4125
423
238
169
103
362
103
169
238
4542
4125
100
381
337
423
423
337
362
68
103
362
381
INDEX
238
169
194
INDEX
26°09´30´´
(a)
Ganjang
Vanadium bearing Titani-
-ferous Magnetite ore
bodies
Syenite
26°09´30´´
(b)
Ganjang
Vanadium bearing Tiatani-
-ferous ore bodies
Syenite
26°10´50´´
93°19´ 93°21´30´´
N
93°19´
26°10´50´´
N
325
3420
325
3252
3252
5056
1675
3736
5056
3736
11
11989
264
5056
922
1675
3420
1614
1765
1048
1119
INDEX
3736
3420
3252
1675
325
INDEX
26°09´30´´
(c)
Ganjang
Vanadium bearing Titani-
-ferous Magnetite ore
bodies
Syenite
26°09´30´´
(d)
Ganjang
Vanadium bearing Titani-
-ferous Magnetite ore
bodies
Syenite
Fig.5. Contour maps showing (a) variation of Zr concentration in Vanadium bearing Titaniferous Magnetite ore body (from Ganjang).
Bolder dotted line represents the margin of the investigated body. Figs.5 (b), (c) and (d) denotes contour-patterns for Ni, Co and
V respectively in the ore body.
JOUR.GEOL.SOC.INDIA, VOL.76,JULY2010

30 ABHISHEK SAHA AND OTHERS
feature of progressive enhancement of Zr from margin to
core has been nicely depicted in Fig.5a. This behaviour
clearly suggests that Zr gets enriched from margin to core
of the Vanadium bearing titaniferous magnetite ore body
concomitant to the advent of differentiation. Among the
Mg, Fe and coherent heavy trace elements, the sequence of
entry into crystal lattice is as follows: Mg, Ni, Co, Fe 2+ on
the basis of ionic charges, radii and electronegativity
principles (Ringwood, 1955; Taylor, 1965). The Ni content
of the Vanadium bearing titaniferous magnetite ore body is
found to range from 68 ppm to 238 ppm against 110 ppm of
the world average of ultramafic rocks (Goles, 1967). Figure
5b shows that Ni content of the Vanadium bearing
titaniferous magnetite ore body gradually falls from 238 ppm
(in the margin) to 68 ppm (in the core) again attesting to
normal differentiation of the parent melt. Figure 5c shows
that Co depicts systematic fall from 1765 ppm in the margin
to 264 ppm in the core. The elemental variation pattern for
cobalt is therefore found to be similar to that observed for
nickel. Since Co proxies for Mg during magmatic
fractionation (Mason, 1966, p.136), the fall of cobalt
concentration from margin to core of the ore body suggests
progressive magmatic differentiation. The V concentration
in the vanadium bearing titaniferous magnetite ore body
has been depicted in Fig.5d which clearly shows extreme
vanadium enrichment (11989 ppm) towards the core part of
the ore body while in the marginal part vanadium content
falls down to 325 ppm which again suggests normal magmatic
differentiation trend. Logarithmic elemental concentration
patterns of Zr, Ni, Co and V within the investigated ore
body (margin-core-margin) have been shown in Fig.6 to
depict the spatial variation of these elements.
log of elemental concentration in ppm
100000
10000
1000
100
10
Ni
V
Co
Zr
Margin of the
investigated body
Core of the investigated body
varying degrees of oxygen fugacity as documented by
presence of carbonatite with variable proportions of apatite
and opaque minerals. Vanadium bearing titaniferous
magnetite ore bodies have been described from different
parts of the Indian shield viz. Kumhardubi, Singhbhum
(Banerjee, 1984), Nausahi, Orissa (Chakraborty et al. 1988),
Masanikere, Shimoga, Karnataka (Govindaiah et al.1989) and
Kurihundi, Sargur, Karnataka (Vidyashankar and Govindaiah,
2009). In most of the cases, such ore bodies are related to
primary magmatic crystallization involving cumulus,
adcumulus and postcumulus mechanisms. Nevertheless,
report on syenite-hosted Vanadium bearing titaniferous
V
Ni
Co
Zr
Margin of the
investigated body
Fig.6. Logarithmic elemental concentrations for Ni, V, Co and Zr
in the Ganjang ore body (margin – core – margin).
FeO(t)
FeO (t)
DISCUSSION
Alkaline-carbonatite magmatism and associated
Vanadium bearing titaniferous magnetite mineralization can
be attributed to a complex interplay of several tectonomagmatic
processes (Gaspar and Wyllie, 1983; Piranjo, 2007;
Reguir et al. 2008). The occurrence and geological
relationships of Ganjang vanadium bearing titaniferous
magnetite ores indicate that their genesis is intimately
related to fractional crystallization processes that were
responsible for the formation of their silicate host rocks as it
has been documented from Bushveld Complex (Reynolds,
1985). The elemental concentration patterns and overall
chemical features suggest that the Ganjang Vanadiumtitanium-magnetite
mineralization has resulted due to late
stage segregations from a differentiating alkaline magma in
a fluid enriched milieu controlled by metasomatism and
TiO2 2
MnO
Fig.7. Plots of investigated samples (open square) from Ganjang
in FeO (t) -TiO 2
-MnO triangular diagram. Shaded area
demarcates field for vanadium bearing titaniferous magnetite
ore body from Singbhum region, Eastern India (Banerjee,
1984; Saha, 1994)
JOUR.GEOL.SOC.INDIA, VOL.76,JULY2010

VANADIUM BEARING TITANIFEROUS MAGNETITE ORE BODIES OF GANJANG, NE INDIA 31
Table 2. Electron probe analysis of magnetite (major), ilmenite
(minor) phases of Kumhardubi ore, Singhbhum (after
Banerjee, 1984)
Sample no. 53 54 50
Phase Mt Mt Il Mt Il
MgO 0.24 0.4 0.19 0.41 0.86
Al 2
O 3
2.62 3.75 1.63 1.6 1.43
TiO 2
5.76 10.26 25.72 12.85 28.48
V 2
O 5
1.54 1.18 1.31 1.71 1.81
MnO 0.007 0.12 0.12 0.13 0.11
FeO(t) 90.21 80.85 67.85 80.13 63.7
Total 100.38 96.56 96.82 96.83 96.39
Mt: Magnetite, Il: Ilmenite
magnetite ore body from Indian shield is rather rare. As
FeO (t) ,TiO 2
and MnO are dominant constituents of vanadium
bearing titaniferous magnetite ore bodies of Ganjang, an
attempt has been made to compare its chemistry with that of
vanadium bearing titaniferous magnetite ore body of
Kumhardubi, Singhbhum (Banerjee, 1984; Saha, 1994, pp.219-
221) on compositional-basis (Table 2). The data plots for
Ganjang clearly occupy the field demarcated by vanadium
bearing titaniferous magnetite body of Singhbhum in FeO (t)
- TiO 2
– MnO diagram (Fig.7). The vanadium and titanium
concentrations of the investigated magnetite ore body (V 2
O 5
:
0.07-2.14 wt. % and TiO 2
: 4.38-13.73 wt%) seem to be quite
encouraging considering the economic prospects (see
Mohanty et al. 1999; Devaraju et al. 2009) and hence, this
ore body may be explored by suitable organizations at an
early date.
Acknowledgements: The authors thank Dr. M.
Angamuthu (IAS), Mr. Pradip Singner and Mr. Har Singh
Kro for providing ample administrative and logistic support
for carrying out the present field investigation in the remote
part of Karbi-Anglong. The authors are also thankful to Dr.
Shyamal Sengupta for some stimulating discussion on
geology of Samchampi-Samteran Complex. JR thanks the
University Grants Commission, New Delhi for financial
support in form of a major research project {Sanction No:
34-51/2008(SR)}. The Head, Department of Geology,
University of Calcutta and authorities of Aurum, S.R.P.L.,
Lubumbashi, DRC provided necessary laboratory facilities.
The authors gratefully acknowledge an anonymous reviewer
for constructive comments and suggestions.
References
ACHARYA, A., RAY, S., CHAUDHURI, B.K., BASU, S.K., BHADURI, S.K.
and SANYAL, A.K. (2006) Proterozoic Rock suites along South
Purulia Shear Zone, Eastern India: evidence for rift-related
settings. Jour. Geol. Soc. India, v.68,no.6,pp.1069-1087.
BANERJEE, P.K. (1984) On some geochemical features of the
vanadiferous magnetite deposits of Kumhardubi and Betjharan,
Mayurbhanj district, Orissa. Chem. Geol., v.43, pp.257-269.
CHAKRABORTY, K.L., ROY, J. and MAZUMDAR, T. (1988) Structures
and textures of vanadium-bearing titaniferous magnetite ores
and their interpretation. Jour. Geol. Soc. India, v.31, pp.305-
313.
COFFIN, M.F., PRINGLE, M.G., DUNCAN, R. A., GLADEZENKO, T.P.,
STOREY, M., MILLAR, R.D. and GAHAGAN, L.A. (2002) Kerguelen
hotspot magma output since 130 Ma. Jour. Petrol., v.43,
pp.1121-1139.
DEVARAJU, T.C., VILJOEN, R.P., SAWKAR, R.H. and SUDHAKARA, T.L.
(2009) Mafic and Ultramafic Magmatism and Associated
Mineralization in the Dharwar Craton, Southern India. Jour.
Geol. Soc. India, v.73, pp.73-100.
GASPAR, J.C. and WYLLIE, P.J. (1983) Magnetite in the carbonatite
from the Jacupiranga Complex, Brazil. Amer. Mineral., v.68,
pp.195-213.
GOLES, G.G. (1967) Trace elements in Ultramafic rocks. In:
P.J.Wyllie (Ed.), Ultramafic and related rocks. John Wiley and
Sons. Inc., pp.352-362.
GOVINDAIAH, S., PATHAN, A.M. and NAGANNA, C. (1989) Textural
features of V-Ti magnetite deposits of area around Masanikere,
Shimoga greenstone belt, India. Jour. Indian Acad. Geosci.,
v.32, pp.1-14.
HODA, S.Q., RAWAT, T.P.S., KRISHNAMURTHY, P. and DWIVEDY, K.K.
(1997) Geology and the Economic Resources of the Samchampi
Alkaline Carbonatite Complex, Mikir Hills, Assam, India.
Explo. Res. At. Min., v.10, pp.79-86.
KENT, R.W., PRINGLE, M.S., MULLER, R.D., SAUNDERS, A.W. and
GHOSH, N.C. (2002) 40 Ar/ 39 Ar geochronology of the Rajmahal
basalts, India, and their relationship to the Kerguelen Plateau.
Jour. Petrol., v.43, pp.1141-1153.
KRISHNAMURTHY, P., HODA, S.Q., SINHA, R.P., BANERJEE, D.C. and
DWIVEDY, K.K. (2000) Economic aspects of carbonatites of
India. Jour. Asian Earth Sci., v.18, no.2, pp.229-235.
KRISHNAMURTHY, P. (2007) Basalts and Carbonatites: Some
Petrological Perspectives and Integrated Studies in the 21 st
Century In: J. Ray and C. Bhattacharyya (Ed.), Igneous
Petrology: 21 st century perspective. Allied Publ., New Delhi,
pp.165-181.
KUMAR, D., MAMALLAN, R., SARAVANAN, B., JAIN, S.K. and
KRISHNAMURTHY, P. (1989) Petrology and geochemistry of the
Samchampi alkaline carbonatite complex, Mikir hills, Assam,
India. Explo. Res. for Atomic Minerals, v.2, pp.183-199.
MASON, B. (1966) Principles of Geochemistry. John Wiley, New
York, 136p.
MASON, B. and MOORE, C.B. (1985) Principles of Geochemistry.
Wiley Eastern, New Delhi, 350p.
MOHANTY, J.K., KHAOASH, S., SINGH, S.K., SAHOO, P.K. and PAUL,
JOUR.GEOL.SOC.INDIA, VOL.76,JULY2010

32 ABHISHEK SAHA AND OTHERS
A.K. (1999) Characterisation and utilisation of vanadiumbearing
titaniferous magnetite of Boula-Nausahi igneous
complex, Orissa, India. Scan. Jour. Metal., v.28(6), pp.254-259.
NAG, S., SENGUPTA, S. K., GAUR, R. K. and ABSAR, A. (1999) Alkaline
rocks of Samchampi-Samteran, District Karbi Anglong, Assam,
India. Proc. Indian Acad. Sci. (Earth Planet. Sci.), v.108, pp.33-
48.
PIRANJO, F. (2007) Mantle plumes, associated intraplate tectonomagmatic
process and ore systems. Episodes, v.30(1), pp.6-19.
REGUIR, E.P., CHAKHMOURADIAN, A.R., HALDEN, N.M. and YANG, P.
(2008) Early Magmatic and Reaction-Induced Trends in
Magnetite from the Carbonatites of Keriwasi, Tanzania.
Canadian Mineral., v.46,pp.879-900.
REYNOLDS, I.M. (1985) The nature and origin of titaniferous
magnetite-rich layers in the upper zone of the Bushveld
Complex; a review and synthesis. Econ. Geol., v.80, no.4,
pp.1089-1108.
RINGWOOD, A.E. (1955) The principles governing trace element
distribution during magmatic crystallisation. Pt. I. Influence of
electronegativity . Geochem. Cosmochem. Acta, v.7(3-4),
pp.189-202.
SAHA, A.K. (1994) Crustal Evolution of Singhbhum-North Orissa,
Eastern India. Mem. Geol. Soc. India, no.27, 341p.
SRIVASTAVA, R.K. and SINHA, A.K. (2004) Geochemistry of Early
Cretaceous Alkaline Ultramafic-Mafic complex from Jasra,
Karbi Anglong, Shillong Plateau, Northeastern India. Gondwana
Res., v.7, no.2, pp.549-561.
SRIVASTAVA, R.K. and SINHA, A.K. (2007) Petrogenesis of the Early
Cretaceous Ultramafic–Mafic-Alkaline-Carbonatite Igneous
complexes from the Shillong Plateau, NE India In: J. Ray and
C. Bhattacharyya (Ed.), Igneous Petrology: 21 st century
perspective. Allied Publ., New Delhi, pp.143-164.
TAYLOR, S.R. (1965) The application of trace element data to
problems in petrology In: L.H.Arhens (Ed.), Physics and
Chemistry of the Earth. Pergamon Press., v.6, pp.133-213.
VIDYASHANKAR, H.V. and GOVINDAIAH, S. (2009) Ore Petrology of
the V-Ti Magnetite (Lodestone) Layers of the Kurihundi Area
of Sargur Schist Belt, Dharwar Craton. Jour. Geol. Soc. India,
v.74, pp.58-68.
WOOLLEY, A.R. (1989) The spatial and temporal distribution of
carbonatite In: K. Bell (Ed.), Carbonatite genesis and evolution.
Unwin Hyman, London, pp.15-37.
(Received: 20 July 2009; Revised form accepted: 22 December 2009)
JOUR.GEOL.SOC.INDIA, VOL.76,JULY2010