WESTERN DHARWAR CRATON
SARGUR SCHIST BELT
HOLE NARASIPURA SCHIST BELT
CHARNOCKITES OF WDC
YOUNGER GRANITES OF WDC
ECONOMIC IMPORTANCE OF WDC
The Archaean Dharwar craton covers an area of 4.5 lakh sq km
is bounded in the south by the pan pacific Pandyan mobile
belt (pmb)and to the north the Deccan traps underline and
fringed by the Proterozoic (Purana) Kaladgi and Bhima basin.
Towards the east boundary is given by the Eastern Ghat mobile
belt and towards the west it is bounded by the Arabian sea which
separates India from Madagascar.
The Dharwar craton is one of the best studied terrain of
peninsular India and its renowned for its greenstone schist belt
,grey gneisses charnockites and younger granites.
The craton is divided in to two tectonic blocks by
Swami Nath (1976 ) et al, they are western and
Renamed respectively as the Western Dharwar
Craton (WDC) and Eastern Dharwar Craton (EDC)
by Rogers (1986)
5. WESTERN DHARWAR CRATON
Western Dharwar Craton is occupied by vast area of
Two prominent super belts are seen;
1. Bababudhan-Western ghats-shimoga and
belonging to the Dharwar Supergroup
Southern part –narrow linear schist belts belonging to
the older Sargur group , like Holenarsipur , Nuggihalli,
The younger granites like Chitradurga , Hosadurga,
Arsikere occur as isolated pluton in the gneissic country
8. The Gorur gneiss is the oldest gneiss and it consists
of trondhjemitic gneiss with associated tonalites and
granodiorites , U-Pb in zircon – 3500-3600 Ma
(SHRIMP- Sensitive High Resolution Ion MicroProbe)
It consist of oligoclase,
subordinate microcline, quartz
and biotite or hornblende
Geochemical studies indicate
that the gneisses are high –silica,
low –alumina trondhjemites
enriched in REE
Gorur gneiss are found at
Gundalpet and other places
9. Sargur group
It occurs as linear Mafic- Ultra mafic belts
Group of enclaves scattered throughout the
Rock types –ultra mafic ,mafic intrusive complex,
chert, BIF, garnet- biotite schist, sillimanite gneiss,
11. BABABUDAN GROUP
It overlies the Sargur group of rocks in the stratigraphic column.
It consists of four formations: Kalasapura formation, Allampura
formation, Santaveri formation and Mullaingiri formation.
The major rock types are metabasalts, BIF, gabbro, ultramafic
schists, phyllites, quartzites, conglomerate.
13. SCHIST BELTS
Sargur Schist Belt
Holenarasipura schist belt
Nuggihalli schist belt
Bababudan schist belt
Western schist belt
14. Sargur Schist Belt
It is a zone of schist enclaves and narrow bands near Sargur
town , situated 40km south west of Mysore city.
The zone of enclaves extends from near Mysore to Kerala ,and
up to Nanjangud in the east
Fresh outcrops of various lithologies were best exposed in the
canals of Kabini river near Sargur, and hence the name of Sargur
Rock types –Fuchsite quartzite, metapelites, carbonates and
calc-silicate rocks etc
Mafic – ultra mafic rocks form one of the major components of
Sargur Schist Belt
Mafic rocks are more abundant than ultra mafic rocks, and are
associated with iron formations.
The ultra mafic rocks are essentially serpentinites and tremolite
– actinolite-anthophyllite-chlorite schists
The earliest recognizable structure in the narrow belts of
Sargur group is widespread schistosity parallel to the bedding,
intrafolial folds and migmatic banding
Second phase of deformation has given rise to upright , tight to
Third deformational phase has refolded the folds of second
The Sargur schist belt of WDC consist of several other minor
.Manantavadi(Wayanad )schist belt
.Kasargod schist belt
17. Holenarasipura schist belt
It is a trident shaped schist belt
The trident shape of the schist belt is due to the
deflection of schist's around bosses of
The Sargur and Dharwar succession are not well
exposed but deformed and metamorphosed
together during later Dharwar orogeny
19. Other major schist belts of WDC are as follows
Nuggihalli Schist belt- altered dunite ,tremolite-
Melukote and Nagamangala belt
Western Ghat belt
Chitradurga schist belt
20. Charnockite of WDC
They are associated with PGC, continue upto Moyar
Bhavani shear zone
It shows spectacular transformation from the TTG
suite of peninsular gneiss are seen all along the
amphibolite granulite facies boundary from Manglore
and Coorg in the west to the Nanjangud in the east.
21. Younger granite in WDC
There are five types of granites found in
22. Other intrusion in WDC
Thagaduru layered basic intrusion
Kunduru betta ring intrusion
23. 08/12/17 23
Western Dharwar Craton (WDC) Eastern Dharwar Craton (EDC)
1. Dharwar schist belts – large, with
volcanics, subordinate sediments.
2. Peninsular gneiss, (>3000 Ma)
basement having angular
unconformity with the Dharwar
marked by QPC. Basement gneiss
inliers within schist belts.
3. Three fold succesion of
II. Shelf facies at the margin and
homotaxial pillowed basalt BIF in
III. Greywackes- BIF-volcanics
4. Older sequence (Sargur group) as
narrow belts and enclaves
abundant in the south.
5. Intermediate pressure (Kyanite-
sillimanite type) metamorphism.
1. Dharwar greenstone belts- narrow
with dominant pillowed basalts.
2. Dharwar batholith (2500-2700 Ma)
intrusive on all sides. Diapiric
gneiss domes common.
3. Three fold succession of
I.Rare shelf sediments disrupted
into screens at the belt margins
II. Pillowed volcanics,
III. Felsic volcanics,
4. Older sequence ( Warangal group)
mostly as enclaves in the north
east and Salem group in the south
5. Low pressure ( Andalusite-
sillimanite type) metamorphism.
Western Dharwar Craton is bounded to the east by the Eastern Dharwar
Craton, to the west by the Arabian Sea, and to the south by a transition
into the so-called ‘‘Southern Granulite Terrane.” The remaining
boundary to the north is buried under younger sediments and the
Cretaceous Deccan Traps.
The division between the Western and Eastern Dharwar Cratons is
based on the nature and abundance of greenstones, as well as the age
of surrounding basement and degree of regional metamorphism.
The WDC shows an increase in regional metamorphic grade from
greenschist to amphibolite facies in the north and granulite facies in the
The metamorphic grade increase corresponds to a paleopressure
increase from 3 to 4 kbar in the amphibolite facies to as much as 9–10
kbar (35 km paleodepth) in the highestgrade granulite-transition zone
along the southern margin of the craton.
The Dharwar supracrustal rocks uncomformably overlie widespread
gneiss-migmatite of the Peninsular Gneissic Complex (3.0–3.3 Ga) that
encloses the Sargur schist belts08/12/17
Radhakrishna, B.P., Naqvi, S.M., (1986). Precambrian continental crust of India and
its evolution. 94, 145–166.
Ramakrishnan .M and Vaidyanadhan R (2010).Geology of India, Geol.Soc.Ind., v.1,