DEFINITION OF INDIA’S EASTERN AND WESTERN GHATS

Two converging mountain ranges that run along the east and west coasts of

southern India and form the east and west boundaries of the

Deccan plateau. The two ranges are joined by the Nilgiri

Hills in the south, and the highest point in the ranges is Anai

Mudi with an elevation of 8,841 feet (2,697 m). The eastern

Ghats have an average elevation of 2,000 feet (600 m) and

generally lie at 50 to 150 miles (80–240 km) from the Coromandel

coastline but locally reach the coast forming steep

coastal cliffs. The Eastern Ghats are crossed by the Godavari,

Krishna, and Kaveri Rivers and are covered by many hardwood

trees. The Western Ghats extend along the Malabar

coast from the Tapi River to Cape Comorin at the southern

tip of India and are generally very close to the coastline. Elevations

in the northern part of the Western Ghats reach

4,000 feet (1,200 m) and 8,652 feet (2,637 m) at Doda Beta

in the south. The western side of the Western Ghats receive

heavy monsoonal rainfalls, but the eastern side of the Western

Ghats is generally dry.

Geologically, the Western Ghats extend from the Deccan

flood basalt plateau in the north to the Precambrian basement

shield, including the Dharwar craton, in the south. Isotopic

ages of gneisses and greenstone belts in the Dharwar

craton range from 2.6 billion to 3.4 billion years old. The

Dharwar craton is well known for gold deposits associated

with greenstone belts and banded iron formations, with the

most well-known greenstone belt being the Chitradurga.

The Dharwar craton is divided into eastern and western

parts by the elongate north-northwest-striking 2.6-billionyear-

old Closepet granite, probably of Andean arc affinity.

Late Proterozoic metamorphism, locally to granulite grade

and including large areas of charnockites, affects much of

the southern part of peninsular India. Rocks of the Dharwar

craton are overlain by Paleozoic sedimentary deposits of

Gondwanan affinity. The Deccan flood basalts erupted at

the end of the Cretaceous and overlie Gondwana and continental

margin sequences that began developing with the

breakup of Gondwana. The Eastern Ghats are entirely within

the Precambrian basement rocks of the Indian subcontinent

and the Aravalli craton in the north. The Aravalli

craton is somewhat younger than the Dharwar craton, with

isotopic ages falling in the range of 3.0 billion years to 450

million years.

See also CRATONS; FLOOD BASALT; GONDWANA; GREENSTONE

BELTS.

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