The geological , mineralogical and petrological studies of holenarsipura schistbelt, southern india

1. YUVARAJA COLLEGE
(An Autonomous Constituent college)
Department of Earth Science and Resource
Management
Project report on
THE GEOLOGICAL , MINERALOGICAL AND
PETROLOGICAL STUDIES OF HOLENARSIPURA
SCHISTBELT, SOUTHERN INDIA.

2. A Project report submitted by
PRAMODA G
YB120112
(Final year B.Sc student (CBEr)), Yuvaraja’s college,
Mysuru
Under guidance of
Dr. M. P. Dharmesh
Lecturer, Dept of Earth Science and Resource
Management
Yuvaraja’s college, Mysuru

3. GEOLOGICAL FILED WORK
Geology is a field science. Without sustained
filed work, no theoretical aspect of geology can
be taught and no geological and mineral
exploration or research can be carried out.
Fieldwork is an important part of Geology as it
provides many of the data on which our
knowledge of the Earth and its evolution along
with that of life through time.

4. GEOLOGICAL HISTORY OF KARNATAKA
The geological history of Karnataka is confined two
oldest eras that is Archean and Proterozoic. Major part
of state consists of Archean rocks.
A substantial part of north Karnataka is covered by
Decan trap, representing of phenomenal outburst of
volcanic activity at the dawn of Cenozoic era.
The oldest rocks dated so far in Karnataka are a group
of grey gneisses giving and age ranging from 3400 –
3000 million years. Since these gneisses contain
enclaves of deformed and metamorphosed amphibolitic
and granulitic grade rocks, the existence of an older
group of sediments and associated igneous intrusive

5. GEOLOGY FIELD CARRIED AROUND
YENNEHOLERANGA-BETTA
The Holenarasipur greenstone belt of southern India
is well known for a variety of mineral deposits such as
chromite, asbestos, magnesite, corundum, Kyanite,
Staurolite,Beryl, feldspar, muscovite, quartz, graphite
and iron ore, so it is called as “Natural mineralogical
museum of Karnataka” and it is also known as
“Veritable geological museum’, “Petrological
paradise” it is titled so because this region is known
for ‘nine metamorphic minerals.

7. GEOLOGY
The contact between the Bababudan and the Sargur
Groups of rocks can be seen in the Holenarasipur
belt. The northern part of the belt, lying to the north
of the Hemavathi River, is classified as Bababudan
Group while the southern N-S striking limb, lying
to the south of the River, is classified as part of the
Sargur Group.
The southern N-S striking 20 km long limb of
the belt is made up of an association of
ultramafic-mafic and meta-sedimentary rocks.

8. • The rocks strikes N-S and dips 45°-70°
east. Holenarasipura schist belt is Trident in
shape.
• The belt extends maximum length of 65KM
from Doddagudda to Yedegondahalli with a
wide range of 0.5KM to 3KM and belt covers
an area of 250Sq.Km in which
Yenneholerangana Betta is a small hillock
which is named after the God Rangaswamy.
•The southern terrain is high grade
metamorphic terrain, northern part is
metamorphosed.

9. Amphibolite Sample
•The Amphibolites occurs as linear bands
occupying the hill top and most part of
the hill. The dip and strike of
the amphibolites are measure with the
help of clinometer whose dip east 31 W
strike is N6E-S84W.
•Minerlogically it is made up of green hornblende and
grey plagioclase minerals aligned parallel to the plane
of schistosity.
•These amphibolites belong to Sargur group and
these forms a part of intrusive ultramafic complexes

10. CHLORITE SCHIST:
•It is a low grade metamorphic rock. It
exhibits well developed schistose
texture, the grains are aligned parallel
to the schistose. It is a green colour
with distinct cleavage and low
hardness.
•It occurs in the form of linear and thin linear lenses occupying
the lower flanks of Yenneholerangana Betta. This linear and
parallel bands show variable dips, their trend in NNE-SSE and
are soft meta-sedimentary rocks. They have been subjected to
low grade green schist metamorphism. Along with Chlorine,
Granetiferrous chlorite-schist are seen and collected small grain
of Garnet are seen whose size is0.2cm and less that

11. GARNET
•In the study area the garnet clearly
shows Cubic or Dodecahedron shape
and cleavage is perfect.
•Luster is vitreous in nature.
•Some of the weathering rocks have
been observed in the study area.
CALCITE
Calcite is a common formed of
sedimentary rocks, limestone in
particular, much of which is formed
from the shells of dead marine
organisms. Approximately 10% of
sedimentary rock is limestone. Calcite
is the primary mineral in metamorphic
marble.

12. ASBESTOS
Asbestos is one of the important economical mineral along
with carbonates which are derived form the Serpentine bodies in the
form of Calcite. It has Rhombohedral cleavage which is distinct in
the crystals and exhibits low hardness i.e. it can be easily scratched
by pen knife and it exhibits sub-vitreous luster.
The asbestos are derived from the
alteration of amphibolites these is low
grade products which exhibits fibrous
habit & fibers are long fine flexible and
easily separable color variation from
white to wooden brown the fibrous
asbestos are found in between serpentine
and trimolite actinolite schists these
formed due to the metamorphism of ultra-
amafic rocks.

13. STAUROLITE
A special property of Staurolite is that
often occurs twinned in a
characteristic cross-shape called
penetration similar to quartz, with the
twinning displaying optical
continuity.
It can be identified in metamorphic rocks by its swish
cheese appearance and often mantled porphoryblastic
character to prism of 3-4cm long it exhibits dark brown to
black color well developed crystals.
Staurolite occurs in the form of anhedral crystals ranging
from small crystals of Staurolites were collected.

14. KYANITE
• Kyanite-Staurolite-Biotite-
Muscovite schist are described as
metaphillites.
These metaphillites are easily
weathered so they occupy low
mound of undulated area.
• These are exposed to surface in channel cutting area
of NNE at Yenneholerangana Betta in filed it is seen
that extensive invention of quartz veins in an important
feature of this schist which helps to the concentration of
bladed.
•It exhibits varying hardness and cleavages. They are
distinct and it exhibits vitreous to pearly luster. The
samples were collected near channel cutting.

15. Talc-calcite rock is formed
from Serpentine with
subordinated Treolite,
Actinolite, Anthophyllite,
chlorite and Calcite.
Along with this is a specimen is collected near
the dyke such as formation is seen around the
dyke such formations is seen around the dyke
for several meters. It might have formed due to
the hydrothermal alteration of feldspar to Mica.

16. VISIT TO ULTR-MAFIC AND MAFIC REGION
Ultra-mafic occupy a linear zone along the western
margin of the schist belt. It occurs as numerous bands
closely altering with chlorite schist, around
Yenneholerangana Betta, particularly on northern flanks
and towards east of the Yenneholleranaga Betta in
Hemavathi canal sections.
Some weathered Serpentines were seen in the valley
region towards the east Yenneholleranaga Betta. It
occurs as broadly lenticular bodies standing out as bold
mass in the hills and as a resistant out crops in plain
regions.

17. GRADE OF METAMORPHISM
LOW GRADE MEDIUM GRADE HIGH GRADE
QUARTZ
FELDSPARS
MUSCOVITE
HORNBLENDE
PYROXENE
CHLORITE
BIOTITE
GARNET
STAROLITE
KAYANITE
SILLIMANITE

18. The group members with mentor Dr. M P Dharmesh

19. Presented by
Prmoda G
Dept. Earth Science and Resource
Management
Yuvaraja’s College, Mysuru