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The Geology of Kerala Region:

•

Kerala is a south-west coastal strip of about 500 km long andaverage width of less than 0 km!

• "t has # distinct geomorphologic units such as $% coastal lands &%

mid lands and #%'igh land! The coastal lands and of coastal

alluvium( mid lands and highlands are consisting of )aterite soil

underlain by hard laterites! The hard rock( mainly gneisses for the

basement!

• The generali*ed geological cross-section +,-% .irection is as

follows:

Arabian sea

Westernghats

Highlands

Midlands

W E

Coastal alluvium & lateritic soil

sedimentary rocks

Tertiary

Metamorphic rocks

/rchaen

Laterites

leistocene

Doleritic intrusions

)ower tertiary

Coastal alluvium & lateritic soilRecent

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• The oldest rock in erala terrain is the metamorphic rocks o! Archaen

system" The rocks in this system are hondolite #$illimanite garnet

gneiss% and Charnockite #Hypersthene granulite%" All other rocks are

younger and uncon!ormably overlying this rock ith varying

thickness or absence"

• Teritiary rocks overlie the Archaen gneiss at the coastal region o! !rom

arkali up to Chertahalai having a thickness o! more than '(((m at

certain locations" They are comprised o! alternating layers o!

sandstones) limestones and shales" $taratigraphically they are knon

as Warkali series) *uilon series and +aikom series"

• ,oth Archaen gneiss and Tertiary rocks are criss-crossed by doleritic

intrusions having the geological age o! .aleocene to Eocene"

• The Lateritic rocks o! midland and highland are o! .leistocene age

and it is !ormed !rom the in-situ leaching o! the underlying gneissic

rocks"

• The coastal alluvium is o! recent origin hich is !ound all along the

coasts"

• The laterite soil cover is generally seen on top o! lateritic hori/on are

generally o! transported ones and occasional insitu origin"

ngineering and economic importance of rocks and overburden of

Kerala 1tate!

• hondalite and Charnockites are very good !oundation rocks and also

very good as stones !or masonry constructions

• The tertiary rocks especially sandstones are good engineering material

and all these hori/ons are having good groundater potential"

• The laterite is a good engineering material hich is very good as a!oundation rock) can be cut as bricks hich are good !or construction"

The lateritic hori/ons can have stable vertical cuts !or roads and

0uarrying purposes unlike other overburdens"

• The coastal alluvium is rich in placer deposits o! illmanite and

mona/ite) hich are the only ma1or mineral resources o! erala"

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