Cratons of india

Presented By Under guidance of
Pramoda G H. T. Basavarajappa
2nd semester, Geology Professor
Presentation on
“CRATONS OF INDIA”

• Introduction
• Dharwar Craton - WDC AND EDC
• Baster Craton
• Singbhum Craton
• Bundelkhand Craton
• Aravalli Craton
• Conclusion
• References
CONTENTS:

INTRODUCTION
1. Cratons are the part of the earth’s continental crust which
has attained stability and was least affected by deformation
during the later periods.
2. Cratons are generally found in the interiors of tectonic
plates.
3. They are characteristically composed ancient of
crystalline basement rock, which may be covered by
younger sedimentary rocks.
4. They have a thick crust and deep lithospheric roots that
extend as much as a few hundred kilometers into the
Earth's mantle.
5. A shield is part of the craton, where the basement rock
crops out at the surface.

There are five major cratons in India. They are;
1. BASTAR CRATON
2. DHARWAR CRATON
3. SINGHBHUM CRATON
4. ARAVALLI CRATON
5. BHUNDELKHAND CRATON
MAJOR CRATONS OF INDIA

Outline map of the shield showing the distribution of cartons

DHARWAR CRATON:-Dharwar
craton is
divided into
two tectonic
blocks in 1986
by Rogers.
1. Western
Dharwar
craton (WDC)
2. Eastern
Dharwar
craton (EDC)

WDC EDC
SCHIST BELT LARGE WITH
VOLCANICS, SUBORDINATE
SEDIMENTS.
NARROW, WITH GREENSTONE BELTS.
PILLOW BASALTS.
BASEMENT IS PENINSULAR GNEISS.
UNCONFORMITY MARKED BY
QPC.(<3000MY)
DHARWAR BATHOLITH INTRUSIVE ON
ALL SIDES .(2500-2700 MY)
OLDER SEQUENCE (SARGUR
GROUP)AS NARROW BELTS AND
ENCLAVES, ABUNDANT IN THE
SOUTH.
OLDER SEQUENCE(WARANGAL GROUP)
MOSTLY AS ENCLAVES IN THE NORTH.
INTER MEDIATE PRESSURE
METAMORPHISM.
LOW PRESSURE METAMORPHISM.
Comparison between WDC and EDC

WDC -
It occupied by vast areas of peninsular India With 2 prominent
super belts
1. Bababudan-western ghats-shimogga super belt
• This super belt spread appro.300km long & 100-150km wide.
• Schistose rocks occupying 3000km Sq. Remaining 1500km Sq.
Occupied by basement peninsular gneiss.
• Bababudan Schist belt occupies an area 2500km Sq.
• A prominent but thin horizon of quartz pebble conglomerate.
• This group dominantly made up of Metabasalt with
interbedded cross-stratified quarzitites capped by a prominent
BIF. Age is about 2700-2800MY.

• The Bastar craton (BC) is also called Bastar-Bhandara craton. It lies to
ENE of the Dharwar craton (DC), separated from the latter by the
Godavari rift. Located to the south of the Central Indian Tectonic Zone
(CITZ) the Bastar craton is limited by three prominent rifts, namely the
Godavari rift in the SW, the Narmada rift in the NW and the Mahanadi
rift in the NE.
• The Bastar craton is essentially formed of orthogneisses with enclaves of
amphibolites, vestiges of banded TTG gneisses of 3.5–3.0 Ga, and low- to
high-grade metasediments as supracrustals.
• The gneiss/migmatites and amphibolites, constituting the early crustal
component of the Bastar craton, are grouped under the Amgaon gneiss
that resembles the Peninsular Gneiss Complex of the Dharwar craton. It
craton. It ranges in composition from tonalite to adamellite. Amgaon
gneisses occur in the north of Bastar craton and south of Central Indian
Shear zone (CIS).
Facts

 In Bastar craton the gneisses are classified into 5 types.
These are: the Sukma granitic gneiss (Group 1), Barsur
migmatitic gneiss (Group 2), leucocratic granite (Group 3)
occurring as plutons with migmatitic gneiss, pegmatoidal or
very coarse granite (Group 4), and fine-grained granite
(Group 5) occurring amidst the Sukma gneisses.
 The gneisses of Groups 1 and 2 are chemically and
mineralogically similar to the Archaean TTG, while the
gneisses of Groups 3, 4 and 5 are of granitic nature.
 In the Bastar craton, three Archaean supracrustal units are
recognized. First is Sukma metamorphic suite consisting of
quartzites, metapelites, calc-silicate rocks, and BIF with
associated metabasalt and ultramafic rocks

Grey gneisses and migmatites of TTG composition are exposed in southern
Bastar and in Amgaon –Gadchiroli ares
Banded gneisses occur as large raft within the dominant granitic gneisses of the
ares
These migmatites gneisses are dated at ~3000 Ma these gneisses are affected
by the later thermal events of ~2500 Ma and ~2100 Ma
Granulite Belts
Bhopalpatnam granulite belt is about 300 km long and 30-40 km wide ,and
trends NW-SE to the north of Godavari graben.
The incipient charnockites are also reported to occur in the transitional domain
.meta-peridolites contain olivine spinel and orthopyroxene.BIF and Mg-Al
pelites are composed of orthopyroxene, sapphirine and spinel Quartzite are rich
in sillimanite .calc-silicate rocks contain wollastonite scapolite and humite
Recently reported younger age (1.6-1.9 Ga))
Gneissic Complex

• Singbhum craton is made of Archean rocks that are exposed in an
area of 4000km.Sq in jharkhand and northern parts of the Orissa
state.
• Craton borded by Chhotanagpur Gneissic complex to the north,
Eatern Ghats mobile belt to the southeast, Bastar craton to the south
west and Alluvium to the east.
• Singbhum Granite (I,II,II phases) with enclaves of (i) Older
Metamorphic Group(OMG) and Older Metamorphic Tonalite
Gneiss(OMTG).
• Iron ore group(IOG), dominantly BIF at the margins of the
Singbhum Granite.
• Volcanics or greenstone belts (Simlipal,Dhanjori,Dalma etc)
Key points

Major belts of CGGC
1. South Palamau –Gumla-Ranchi-Puruchi Belt.
2. Daltonganji-(Northern Palamau)- Hazarobagh Belt
3. North Garhwa-Chatra-Girdih-Deogarh-Dumukh Belt
4. The Bihar Mica Belt
5. Rajgir – Kharagpur Belt

Geodynamic Evolution
• Older metamorphic group which yield same age as
Metamorphic Tonalite Gneiss.
• Zircon age in politic rock of OMG suggest that sialic crust had
existed about 3.6Ga. Prior to the formation of OMG.
• Singhbhum Granite – 1 in which xenoliths of OMTG Found.
• Mesoarchean continental crust of SG-1 with enclaves OMG
and OMTG rifted and formed greenstone belt of Badamphar
group – Komatiites, pillowed tholeiitic, BIF and Fuchsite
quartzite.
• Closing of greenstone belt basins – granite intrusion (Phase 2
and 3).
• Next cycle marked by volcanic and sediment association of
2.8Ga

Bundelkhand Craton is one of the Archean cratons in the Indian shield. It is
exposed over 26,000 sq. km and is bound by the Son Narmada lineament in
the south.
Bundelkhand craton is separated from the Satpura mobile belt in the south
and the Aravalli craton in the west by the proterozoic vindhyan besin and the
northern part is overlain by the Indo-Gangetic alluvium
The main components of the craton are
1) Enclave suite of supracrustal rocks within orthogneisses.
2) Bundelkhand granite associated with quartz reefs and rare felsic
volcanic.
3) Mafic dyke swarms
Facts

1)Enclave suite of supracrustal rocks within
orthogneisses
Supracrustals
Two prominent east-west trending belts of enclave are noticed
i) Northern belt extending from karera to kabrai, kuraicha
Jhansi Mauranipur and Mahoba
ii) Southern belt from to Baraitha through Girar.
Enclave are noticed at near panna and kalinjer. These belts have a regional
trend of E-W with northerly dips.
The enclaves consist essentially of BIF with amphibolites, ultramafics and
minor quartzite, metapelite and marble.
Ultramafic rocks are mainly peridotites, dunites, pyroxenites and gabbros
closely associated with metabasic rocks and BIF.

2) Bundelkhand granite associated with quartz reefs and
rare felsic volcanic
The vast country of Bundelkhand granite represents a large plutonic
complex of batholithic dimension.
Three types Granite;
i)Coarse grained porphyritic granite.
ii)Medium grained porphyritic granite.
iii) Leucogranite,
Felsic volcanic rocks: these rocks are associated with the granites at
many places such as mahoba, bansi, and simra near prithipur they occur
as grey to pink , fine to coarse grained and porphyritic felsic rocks.

Quartz Reefs
The emplacement of NE-SW
trending giant quartz reefs along
brittle shear zones probably
marks the end stage
hydrothermal activity related to
granitic plutonism.
3) MAFIC DYKE SWARMS
A NW-SE trending swarm of Mafic
dykes is a characteristic feature of
Bundelkhand craton some of dykes
have ENE trend, like the prominent
mahoba dyke .The geometry of the
main dyke swarms is attributed to E-
W shearing stress, developed after
cratonisation.

TECTONIC EVOLUTION
• Bundelkhand and Aravalli cratons were traditionally regarded as
interlinked, with the Bearch granite of Aravalli craton being considered as the
equivalent of Bundelkhand granite.
• Geochemical and Geochronological similarities have reinforced this
comparison. The separation of two cratons with the evolution of Hindoli and
Mahakoshal belts at the cratonic margin, was followed by the evolution of
Vindhyan basin.
• Bundelkhand craton witnessed N-S compression –induced deformation ,
metamorphism and emplacement of TTG gneisses produced by the partial
melting of a garnet amphibolite parental source at 3000-3300Ma. Widespread
collision-related arc magmatism represented by bundelkhand granite
commenced probably at 2700Ma and culminated at 2500Ma.

 The region is characterized by the presence of dominantly
three types of shear zones:
E-W, NE-SW and NW-SE.
 The E-W trending, vertical shear zones constitute the subject
matter of the present study and the areas where these shear
zones are exposed have been shown.
 It may be noted that in addition to the E-W shear zones
shown in this map, there are many such shears of relatively
smaller extent that could not be shown because of the scale of
the map, however, were studied because of their typical
features, e.g. Jhankri, Kuraicha, Roni, etc.

Field photographs showing the typical occurrence of the vertical shear zones in the
Bundelkhand terrain. The rocks are mylonites. (a) Near Shivgarh, (b) At Dhaura,
(c) Near Koti, about 6 km SE of Babina, (d) North of Pura, about 5 km NW of
Sukumwa Dam.

A & B- Ultramylonite showing high degree of grain-size reduction because of dynamic
recrystallization
Cataclasite showing angular grains set in a fine grained matrix.

 It occupies NW part of Indian shield covering an area of over 1 lakh sq.km.
 It consists of Mewar craton in the east & Marwar craton in the west.
 Aravalli craton is bounded to the east by Great Boundary Fault, to the west
by sands of Thar desert, to the north by Indo-Gangetic alluvium and to the
south by Son-Narmada-Tapti lineament.
 Predominantly consists of quartzites, marbles, pelites, greywackes and
volcanocs, exposed in Aravalli-Delhi orogen.
 It is distinguished by the largest felsic volcanic province of India, 3rd in the
world (Malani Igneous Suite).
ARAVALLI CRATON

STRATIGRAPHIC CLASSIFICATION OF ARAVALLI
SUPERGROUP:
Aravalli Super Group
Champaner Group
Lunavada group
Jharol Group
Udaipur Group
Delbari Group
Delwara Group
------------Unconformity------------
Mangalwar/Sandmata Complex
Mewar Gneiss with enclaves of Jagat Group

Delmar group :has an area over 300km with an average
width of about 500m.The basement rock is orthoquartzite
which is overlain by volcanic conglomerate(volcanic unit)
Delbari group: it overlain the Delwara group consists of a
thick horizon of petromict conglomerate,pebble arkose and
feldspatic quartzite. The conglomerate has a maximum
thickness of 2500m near Dabari
Udaipur group: consist of thick accumulation of greywacke-
phyllite intercalated with chemogenic and biogenic rocks. The
greywacke-phyllite is overlain by dolomite associated with
carbonaceous phyllite and quartzite.

Jharol group: consists of thick sequence of carbonate-free
phyllite and arenite(as distal turbidites) Has an area of 200km
with a width of 40km
Lunavada group: It occupy the polygonal area in the south
of the aravalli orogen.The bulk of the group consists of
greywacke-phyllite with associated quartz arenite.The
stratigraphy of the Luna group is not clearly established.
Champaner group: occurs as rectangular outcrop and
consists of subgreywacke,siliceous phyllite,pelitic
schist,quartzite and petromict conglomerate.It is folded into
an anticlinorium plunging to the west
The stratigraphy status is unclear because it is seperated by
the main fold belt

Neoproterozoic Marwar supergroup
(500-550Ma Malani igneous Suite
(720-750Ma) Sindreth/punagarh group
(800-850Ma) Sirohi group
(900Ma) Erinpura granite
Mesoproterozoic Delhi supergroup
(1100-900Ma) South Delhi fold belt
(1600-1450Ma) North Delhi fold belt
Palaeoproterozoic Hindoli group
(1800-1700Ma) Sandmata complex
(2200-1800Ma) Aravalli Supergroup & Mineralised Basin(Rajpura-Dariba
etc)
Neoarchean
(2900-2600Ma)
Mangalwar complex with Bhilwara Group
Mesoarchean
(3300-3000Ma)
Mewar gneiss with Jagat group
TECTONIC-STRATIGRAPHIC TABLE OF EVOLUTION OF
ARAVALLI CRATON

ECONOMIC DEPOSITS:
The major economic deposits are:
Pb-Zn deposits (Zawar)
Gypsum
Marble (Macrana)
BIF
Mica (Jagat group)
Copper (Khetri )
Tungsten (Degana, Balda and Sewariya-Govindgarh areas.)

 In general, the cratons are dominated by granite and
metamorphic rocks, mainly gneisses, which imply a series of
intense mountain making episodes (deformation and
metamorphism) in the Precambrian time before the stable
conditions set in. A common feature of these cratonic regions is the
occurrence of greenstone-gneiss association, as found in other
Archaean cratons of the world.
 The Indian shield is made up of a mosaic of Precambrian
metamorphic terrains that exhibit low to high-grade crystalline
rocks in the age range of 3.6–2.6 Ga.
 Cratonic blocks are described with respect to their geology,
geochronology, and structural characteristics

Reference
• Cratons and Fold Belts of India 2009 By
Sharma Ram S Sharma.
• Geological survey India website for images
http://www.portal.gsi.gov.in/portal
• http://www.sciencedirect.com/science/article

Cratons of india

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