thesis describes host rock petrology, mineralization structures
& textures, and genesis of four fluorspar deposits / prospects
of Rajasthan, viz., Mando-Ki-Pal, Chowkri-Chhapoli,
Jhalara and Asind.
the Mando-Ki-Pal area the country rocks are migmatites with
occasional bands of muscovite-kyanite-schist. Lower Proterozoic
Aravalli quartzite surrounds the migmatites of Precambrian Banded
Gneissic Complex (BGC). This study has shown that the
host rocks of fluorspar are not cherts and cherty limestone,
as hither-to-considered, but are silicified cataclastic rocks.
They include proto- to ultramylonite, blastomylonite, and gangmylonite.
Consequently, the genetic model for the deposit will be different
and its resource evaluation will have to be modified.
and purple fluorite, calcite ((mangeneferous at places, displaying
red fluorescence) and quartz, are the main vein minerals,
which display characteristic cavity: filling structures, viz.,
fissure filling, joint filling, fracture filling, symmetrical
crustification, cockade structure, segmented veins, breccia
filling and brecciated veins etc. Grains of pyrite, chalcopyrite,
galena, and sphalerite are rarely present. Green fluorite and
Mn-calcite display fluorescence. Epimorphs of calcite in gangmylonite
is also common. Silicification and chloritization of the host
rocks is observed. At Kaila persistent stratabound veins
of brownish / grayish fluorite occur in quartzite. Jhalara is
an extension of Mando-Ki-Pal area and the mineralization is
very poor, occurring in migmatites, pegmatite and quartzite.
This area was abandoned after prospecting.
Chowkri the fluorspar occurs in tonalite boss intruding the
Middle Proterozoic Ajabgarh garnet-biotite schist. While
at the adjoining Chhapoli the fluorspar is confined to Ajabgarh
feldspathic quartzite. Green & purple fluorite in both these
areas occur as large, color-zoned octahedral crystals. Calcite
and quartz are associated with fluorite. Secondary neodigenite
and hydrous iron oxide are found in few sections. Mineral,
zoning is noticed at Chowkri area. Fluorite, calcite, quartz
occur in the central part while apatite, quartz form the outer
zone. The hydrothermal mineralization has brought about
kaolinization and hematitization of the host rocks. Ilmenite
and magnetite is associated with hornblendite reefs in the area.
Asind the fluorspar veins occur in migmatites of Banded Gneissic
Complex; amphibolite, pegmatite, aplite, epidosite, unakite
are also present. Epidotization of vein wall in migmatite
is characteristic features observed in the area. Associated
minerals are quartz and rarely calcite. Here too the mineralization
is poor and the area was discarded after prospecting.
fluorspar mineralization in these areas is diplogenetic formed
by low temperature hydrothermal solution related to migmatization
at Mando-Ki-Pal, Jhalara, Asind and tonalite-granite at Chowkri-Chhapoli.
Fluorine bearing solutions leached calcium front the country
rocks and deposited fluorspar in the available cavities (fissures,
fractures, joint planes, pore spaces, etc.). Since cavity
filling in non-calcareous rocks is predominant and replacement
poor, therefore, the deposits are of poor economic significance.
Investigation of the Karara Fluorspar Deposit, District
of the Ph. D. thesis of Dr. R. S. Dashora
Thesis submitted on 29.04.1981 to the University of Rajasthan.
Supervisor:Dr. P. S. Ranawat
rocks around Karara (Rajasthan) belong to the late Proterozoic
Malani suite of volcanic rocks and a range of pyroclastic
rocks represented by: volcanic breccias, lapilli tuffs,
and welded tuffs including ignimbrites and extrusive basalt,
andesite, trachyte, dacite and rhyolite. S-pole diagrams
of joint planes show a peripheral spread of the sub-maxima,
which is typical of central type of volcanic activity. Field
and remote sensing studies in this desert region conclusively
prove that the area represents a volcanic vent that had
witnessed repeated volcanic-activity of violent nature.
mineralization at Karara is widely distributed in the pyroclastic
rocks and is confined along fissures and joints. Minor
quantity of ore occurs in vesicles, shrinkage cracks and related
vugs. The mineralization is essentially fluorspar-quartz-barite
type. Fluorites in the area are fine-grained, coarse grained
and columnar. Barite occurs in coarse columnar form and the
quartz in crystallized or granular. Characteristic cavity
filling structures and textures are crustification, cocked structure,
banded, segmentation, breccia filling and brecciated ores.
Replacement is rarely seen but wall rock alteration as kaolinization
structure and fluid inclusion study of fluorite and associated
barite, quartz and calcite reveal three distinct stages of mineralization:
Stage-I is represented by- crystallized (cubo-octahedron
phantom crystal with in cubic crystal ) / coarse granular
fluorite + acicular / crystallized barite + quartz + calcite;
During the Stage-II - columnar fluorite + columnar barite +
quartz + calcite / siderite formed. Stage-III is represented
by- fine-grained fluorite + fine grained quartz + pyrite (rare).
Two- phase primary aqueous fluid inclusions having a high degree-of-fill
are present in fluorite, barite and quartz of Stage-I. Th
= 120°-240°C. Biphase fluid inclusions with more than 98% degree-of-fill
or monophase (liquid only) inclusions occur in minerals of Stage-II,
T = 80°-110°C, Fluorspar of Stage-III is fine grained and shows
few monophase fluid inclusions. Leachate analysis shows that
the fluid in inclusions is of very low salinity, being nearly
mineralization is attributed to low temperature volcanogenic
hydrothermal solutions. The veins were formed after volcanic
activity had shattered the host rocks and provided channel ways
for movement of mineralizing fluids. During the first
stage of mineralization slow nucleation of fluorite occurred
from fluids having high oxidation potential and low fluorine
concentration. Subsequently, fluorine concentration increased
but crystallization was still slow (Stage-II). In final stage
(stage-III) high concentration of fluorine and rapid nucleation
is evident in reduced oxygen regime.
INCLUSION STUDIES OF FLUORITE AND ASSOCIATED MINERALS
FROM CHOWKRI-CHHAPOLI AND MANDO-KI-PAL AREAS, RAJASTHAN
of the Ph. D. thesis of Dr. R. L. Somani
Thesis submitted on 12.01.1987 to the University of Rajasthan.
Supervisor:Dr. P. S. Ranawat
thesis embodies a detailed fluid inclusion and rare earth element
(REE) study of Chowkri -Chhapoli and Mando-Ki-Pal fluorspar
deposits of Rajasthan.
Chowkri the fluorspar mineralization occurs in the post-Delhi
tonalite, reef quartz and hornblendite. At Chhapoli, on the
other hand, the fluorspar mineralization is hosted in feldspathic
quartzite (Ajabgarh Group of Delhi Supergroup). At both
the localities the fluorite occurs as large color-zoned octahedral
crystals, a comparatively rare habit of fluorite crystallization.
Coarse granular fluorite is also present. Associated minerals
are quartz, calcite, apatite, galena, and pyrite. Quartz
occurs as granular (reef quartz, quartz-I) and twined crystallized
(quartz-II). Hornblendite contains magnetite and ilmenite.
Wall rock alteration as hematitization of tonalite and kaolnization
of feldspathic quartzite is conspicuous.
contains primary aqueous fluid inclusions having faceted cavities
usually of tetrahedral shape. Another characteristic feature
is rare occurrence of secondary inclusions in fluorite.
The phases present are - an aqueous phase, vapor bubble and
occasionally a halite daughter mineral. Two-phase (liquid
+ vapor) and three-phase (liquid + vapor + halite) fluid inclusions
have been observed in the same polished plate. Cryometric
study has shown that the fluids in inclusions contain CaCl2
and NaCl and the bulk fluid salinity in most of the fluorite
crystals is nearly 26 ± 5 Eq. Wt % NaCl. This just-saturated
critical salinity is responsible for occurrence of two-phase
and three-phase fluid inclusion in the same plate. In some of
the two phase FIs the halite nucleates during freezing runs,
which homogenizes ~10 0 C! The general range
of salinity of fluid in inclusions, taken as a whole for the
entire area, however, ranges from 31 to 3.4 Eq. Wt. % NaCl.
The CaCl / NaCl ratio is fairly high (9: 1) based on the freezing
study the fluid inclusion have been classified in to three types.
Temperature of homogenization ranges from 200° to 130°C.
Mando-Ki-Pal the fluorspar mineralization can broadly be classified
into two types.
One is that which occurs in mylonite and granitic gneisses of
basement complex (Bhilwara Supergroup). The mineralization
displays fracture filling, joint filling, crustification, cockade
structure etc. minerals present are-Green fluorite, purple fluorite, calcite, quartz
with rare presence of galena, sphalerite, pyrite, pyrolusite.
minerals contain two-phase aqueous inclusions having high degree-of-fill.
They are of irregular shapes and have wider range of size.
Microthermometry data indicates presence of salts other than
NaCl in the fluids, salinity of which range from 14 to 22 Eq.
Wt. % NaCl in fluorite; in quartz and calcite it ranges from
10 - 19 Eq. Wt. % NaCl. The temperatures of homogenization range
from 102° - 168°C for fluorite; 93° to 134°C for quartz; and
112° to 135°C for calcite. All the minerals contain large
number of pseudosecondary and secondary inclusions.
Another type of fluorspar mineralization is the one that occurs
as persistent stratabound veins in quartzite in Kaila and Nawagaon
Blocks. Fluorite is milky white or light brown in color
and occurs as fine granular aggregate of fluorite and quartz.
Both these minerals contain CO2, CO2-H2O
and rarely CH4 inclusions. Cryometric data indicate
that CH4 density is about 0.24 g/cc. Density
for the CO2 inclusions ranges from 1.10 to 0.6 g/cc
although density of 0.8 to 0.7 g/cc is more common. The
aqueous FIs have salinity of 4 - 9 Eq. Wt. % NaCl.
Rarely, a halite daughter crystal has also been observed in
some of the fluid inclusions, indicating that the solutions
were saturated with respect to NaCl. The temperature of homogenization
for the H2O - CO2 type inclusions has
a range of 185° to 360°C with maximum values lying between 220°
In Chowkri-Chhapoli, the mineralization fluids are possibly
genetically related to Chhapoli Granite and Salwari Tonalite.
In Mando-Ki-Pal region the quartzite-hosted mineralization appears
to be metamorphosed while the mylonite and migmatite hosted
mineralization is cavity filling hydrothermal type that deposited
at fairly low temperatures and pressure.
The REE data for 20 samples of fluorite are plotted on Tb/Ca
Vs. Tb/La diagram (Möller et al., 1976) and they fall in
the “hydrothermal” field.
The thesis has seven chapters covering text in 144 pages and
having 17 plates, 20 tables, 43 figures and bibliography of
largest resources of anthophyllite occur within the ultramafic
rocks exposed to the West of Udaipur, Rajasthan. The ultramafic
rocks constitute a linear belt designated as Jharol-West belt
that extends for a strike length of about 25 km in NNE - SSW direction
with maximum width of nearly 2 km. The ultramafic bodies
occur as intrusives within tile rocks of Jharol Group of Aravalli
Supergroup and exhibits concordant relationship with them.
The original nature of the ultramafic rocks is difficult to ascertain
since they have undergone high degree of steatitization and anthophyllitization.
Quartz-mica schist, quartzite, few bands of impure marble along
with isolated outcrops of amphibolite and pegmatite mainly represent
the Aravalli metasediments of the area.
GEOLOGY OF AMPHIBOLE ASBESTOS DEPOSITS OF JHAROL AREA, RAJASTHAN
of the Ph. D. thesis of Dr. M. S. Shekhwat
Thesis submitted on 29.04.1987 to the University of Rajasthan.
Supervisor:Dr. P. S. Ranawat
The anthophyllite deposits occur as lensoidal bodies of varying
dimensions. They show a characteristic set of lithological
zoning where a zone of phlogopite separates the ore-bodies from
enclosing quartz-mica schist. Anthophyllite occur as parallel,
triangular or radiating aggregates of acicles/fibers. Minerals
occurring in association with anthophyllite are talc + antigorite
+ chlorite + biotite + phlogopite + magnetite + ilmenite + olivine
± tremolite ± quartz ± calcite.
on geochemistry and field relationship it is concluded that
the ultramafic rocks of the area are product of peridotitic
magma (Orogenic "root-zone"), Iherzolite sub-type, which was
emplaced in subsolidus state though of fractures developed in
the crust during the Aravalli orogeny where the Aravalli sediments
were suffering, folding. Lensoidal shape of the ore-bodies
was developed due to pinch-and-swell structure due to ductile
deformation after their emplacement. XRD & chemical
study proved that the asbestos of the area is anthophyllite
that is Mg-rich variety of ortho-amphibole.
is product of metamorphism of the ultramafic rocks in amphibolite
facies. Based on minerals association and fluid inclusion
study carried out on some of the co-genetic transparent minerals,
it has been concluded that the rocks of the area were subjected
to pressure of about 4.50 ± 0.20 kb. and temperature of about
670 ± 20°C. It is also concluded that metamorphic fluids
were H2O + CO2 type with variable CH4
content from margin to core of the ore-bodies. Retrograde
metamorphism in the form of' steatitization of anthophyllite
is observed specially in the northern part of the belt.
deposits of the area are being developed by small-scale, manual,
opencast methods of' mining. The resource produced from tile
area is being processed within the state for its industrial
use. Anthophyllite of the area has much higher tensile strength
(40,000 - 45,000 psi) compared to values reported for anthophyllite
from other areas of world (< 4260 psi). It also has
good values of cement absorption capacity, resistance to acids
and alkalis, wet volume (buoyancy), surface area. Therefore,
the resource is extensively utilized in a number of industries
and hence, it has significant contribution in the development
of economy of the nation.
OF SCHEELITE BEARING SKARNS AND ASSOCIATED ROCKS OF KARARAVAV,
DISTRICT PALI, RAJASTHAN
of the Ph. D. thesis of Dr. B. S. Rathore
Thesis submitted on 20.02.1991 to the University of Rajasthan.
Supervisor:Dr. P. S. Ranawat
scheelite skarn prospect of Kararavav (SW Rajasthan) belongs
to Middle Proterozoic Kumbhalgarh Group of Delhi Supergroup.
The principal rocks of the area are granite, skarn, calc-silicate,
amphibolite and impure limestone. The general strike direction
of metasedimentary litho units is N20° W to N35° W and dips
are moderately steep ranging from 60° to 75° towards NE.
The granite-limestone contact is marked by the development of
skarn rocks where zonal pattern from limestone to intrusive
is represented successively by limestone, calc-silicate, skarn,
types of granites are occurring in the area. One is grayish
to pink hornblende granite and other is gray biotite granite.
These scheelite skarn generating granitoids have been geo-chemically
studied to decipher I, S, A or M-type characteristics.
most important litho units of the area are skarn and calc-silicate
that have been differentiated texturally and by the fact that
skarn displays characteristic metasomatic zoning in terms of
dominant mineral assemblages due to addition of material from
on field relation, petrography and mineral chemistry, it is
inferred that impure limestone was subjected to high-grade regional
metamorphism and subsequent metasomatism to generate calc-silicate
and skarn rocks of the area under the influence of magmatic
activity of skarn forming fluids and chemical controls on scheelite
deposition in metasomatized facies conditions are broadly reviewed
and it is concluded that scheelite was precipitated between
the zone where in-flowing W-rich boiling solutions became fairly
Ca-rich for the solubility product of scheelite to be exceeded
and the zone where W is being extracted from the out-flowing
fluids due to scheelite deposition. The concentration
of Ca ion in the under-saturated solution was raised with the
interaction of calcium rich rocks (e.g., limestone).
estimate of P, T, X C02 and F02 conditions
for the scheelite bearing host rocks (skarn and calc-silicate)
has been made from coexisting stable phase equilibrium of mineral
assemblages In the multi-component systems and from the fluid
inclusion study of various calcio-silicate minerals.
mineral stability fields have been utilized to ascertain P-T
conditions of skarn and calc-silicate rocks. Various calcio-silicate
viz., scheelite, vesuvianite, clinozoisite, garnet quartz and calcite, contain
mostly H2O + CO2 type and multiphase fluid
inclusions. Microthermometric data indicates low XCO2
content of boiling fluids that had temperature fluid activity
occurred in the rocks as indicated by low temperature secondary
IMPLICATIONS OF RAMPURA-AGUCHA LEAD-ZINC DEPOSITS RAJASTHAN,
WITH REFERENCE TO EVALUATION OF EXPLORATION DATA
of the Ph. D. thesis of Dr. N. K. Sharma
Thesis submitted on 24.02.1994 to the University of Rajasthan.
Supervisor:Dr. P. S. Ranawat
Precambrian formations of south-central Rajasthan host a unique
lead-zinc deposit near Rampura-Agucha. The deposit owes
economic significance due to presence of 39.2 MT proved, 13.8
MT probable and 10.7 MT possible reserves of ore having an average
grade of 13.6% Zn and 1.9% Pb. This deposit has aggrandized
the national resources by 16.6%. Its geological importance rests
with the fact that the ore is hosted in highly metamorphosed
Precambrian rocks having significant silicate, sulfide and oxide
principal rocks in area are para-gneiss (Agucha Gneiss), calc-silicate,
impure marble, amphibolite, mylonite and pegmatite. The general
strike direction of metasedimentary lithounits and mineralization
is NNE-SSW to NE - SW and the dips are moderately steep ranging
from 60° to 75° towards SE. The ore-body extends for a
strike length of 1.6 kilometer in a long linear wedge-shaped
depression. The average width is 60 meters and it persists
up to 380 meters below the surface. The surface manifestation
of ore-body is demarcated by multicolored, patchy oxidized exposures.
mineralization in characterized by the diagnostic sulfide assemblage
sphalerite (ferroan) + pyrrhotite + galena + graphite + marcasite
with sporadic occurrence of chalcopyrite and arsenopyrite.
X-ray diffraction study has confirmed the existence of tetrahedrite,
stephanite, smithsonite, cerrusite, zincite and anglesite.
Microprobe study has revealed the presence of breithauptite
(NiSb), gudumndite (FeSbS), ulmanite (NiSbS), tetrahedrite,
pyrargyrite (Ag3SbS3), stephanite (Ag5SbS4).
Miargyrite (Ag2SbS4), rutile, gahnite
on field relations, petrography and petrochemistry, it is inferred
that the Agucha Gneiss is the product of regional metamorphism
of marine sediments of pelitic to graywacke composition.
Petrographic study under transmitted and incident light has
proved that the silicates and sulfides have involved in high-grade
regional metamorphism; cataclastic textures superimposed on
the recrystallization textures are also prominently present.
The textural evidence is consistent with and reinforces interpretation
of ore as stratiform metamorphosed type of mineralization.
mineral stability fields have been utilized to ascertain the
P-T conditions of metamorphism of ore bearing rocks. It
has been observed that the ore bearing sediments were metamorphosed
under P-T conditions of upper amphibolite facies (6.5 ± 0.8
Kb, 680° ± 30°C). Common occurrence of migmatites
and hydrous minerals and poor development of hypersthene in
the rocks of the area indicates that during metamorphism PH2O
was equal to PTotal. The presence of sphalerite +
pyrrhotite + pyrite assemblage has been used for the geobarometric
the basis of field evidence, petrography, petrochemistry and
nature of mineralization, it is concluded that the Rampura-Agucha
lead-zinc deposit represents a synsedimentary-metamorphosed
type of deposit. Tectonic activities and major orogenic
cycles (Aravalli and Delhi) brought about characteristic changes
in the synsedimentary ore body into high grade metamorphosed
(mobilized and remobilized) massive sulfide deposit, recrystallization
and redistribution of chemical components were promoted by regional
metamorphism under high P-T conditions, Dynamic metamorphism
followed regional metamorphism which produced coherent finely
granulated ore containing rounded porphyroclasts of host rock
and those of pyrite (ball texture).
lead-lead isotope data (207 Pb vs. 206 Pb
/ 204 Pb and 208 Pb / 204 Pb
vs. 206 Pb / 204 Pb) indicates an age
of recrystallized galena ca 1.8 Ga. The metamorphism and
remobilization of the massive lead-zinc deposit of Rampura-Agucha,
has been eventuated near pre-Delhi geological cycle. The
sulfur isotope composition of 13 S (sphalerite) depicts
the range +7 to + 10.3, indicates the source of sulfur for the
present area was either seawater or leached tholeiitic basalt,
carbon isotope reveals the range of - 24 to 29%0.