Bundelkhand craton

2.  INTRODUCTION
 Bundelkhand craton
 Main components of the craton
 i. Supracrustls & Gneisses
 ii. Bundelkhand Granite
 and Quartz reefs
 iii. Mafic dyke swarms
 Tectonic evolution
 Shear zones
 Conclusion
 Reference

3. It is that part of the earths continental crust which has attained
stability and was least affected by deformation during the later
periods.
There are five cratons in the Indian shield .
They are :
1) Dharwar Craton
2) Bastar Craton
3) Singhbhum Craton
4) Bundelkhand Craton
5) Aravalli craton
what is a Craton?

5. Bundelkhand craton named for the fifteenth century
kingdom of Bundelkhand is a triangular region having semi-
circular sides and 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
• It located between lat. 240 30' N and 260 30' N and long.
770 30' E and 810 50'E
.

8. 1) Enclave suite of supracrustal rocks within orthogneisses.
2) Bundelkhand granite associated with quartz reefs and
rare felsic volcanic.
3) Mafic dyke swarms

9. 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.
otherlinear 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.

10. Cont……
They form melanosomes of migmatites and occur as
discrete patches in granites as near Jhansi and karera.
 Metabasic rocks are the most abundant among the enclaves
in the southern and northern belts. They range in composition
from schistose metabasalts to low grade amphibolites some of
which show primary volcanic structures.
 Banded Iron Formation is the most conspicuous in the
enclave suite and is widespread around Girar and Baraitha.
• Carbonate rocks and quartzite's also occur as scattered lens
and bands.
• Metapelites are rather rare, and when present consist of
garnet, biotite and sillimanite.

11. • Grey and pink banded (stromatic) to streaky gneisses
occur as slivers, rafts and narrow belt within vast areas of
younger Bundelkhand granite. In the stromatic gneisses,
biotite and hornblende bearing granodiorite melanosomes
occur as bandeds or rafts in leucosomes.
• A basic enclave in the gneiss at mahoba also gave an age of
3250 Ma
• The oldest gneissic component; kuraicha 3.29 Ga
• The youngest gneissic component; Panchwara 2.5 Ga

12. The vast country of Bundelkhand granite represents a larg
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.

14. The emplacement
of NE-SW trending giant
quartz reefs along brittle
shear zones probably
marks the end stage
hydrothermal activity
related to granitic
plutonism.

15. 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.

16. • 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.

17. 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.

19. 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.

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

21. • 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, the Great Boundary Fault in the west, and probably the Lesser
Himalaya in the north.
• The eastern, western, and southern margins of the Bundelkhand craton
are covered by the Proterozoic Vindhyan Supergroup and the northern part is
overlain by the Indo- Gangetic alluvium.
The main components of the cratons are -
i. Enclave suite of supracrustal rocks within orthogneisses.
ii. Bundelkhand granite with associated quartz reefs and rare felsic
volcanic.
iii.Mafic dyke swarms.
Three types of shear zones are noticed in Bundelkhand Craton
i. E-W shear zone
ii. NE-SW shear zone
iii. NW-SE shear zone

22. Geology of India by M.Ramakrishnan and
R. Vaidyanathan. Published: 2008
pg:149-260
 WEB:
www.Google.com
www.Wikipedia.com
www.Geology.com