Geography · Ch 2 — Structure and Physiography
The Islands
The Islands
The photograph is a bird’s-eye view of a small tropical island, likely one of the coral atolls of Lakshadweep or a low-lying island of the Andaman–Nicobar group. The island is densely covered with vegetation, giving it a dark, forested appearance that stands out sharply against the surrounding sea. Around its edge runs a bright, narrow band of white sand — the beach — which forms a clean fringe between the green interior and the water. Beyond that, the sea surrounds the island on all sides, completing the classic image of an isolated landmass rising from the ocean.
What makes the image instructive is not any single feature but the whole arrangement: a small patch of land, ringed by sand, set in an expanse of water. That layout is exactly what the chapter’s text describes for India’s two island groups. The Andaman and Nicobar islands are believed to be the elevated portions of submarine mountains, so their relief tends to be more rugged, with peaks like Saddle Peak (738 m) and Mount Thuiller (642 m). The Lakshadweep group, by contrast, is built entirely of coral deposits, so its islands are low, flat, and typically ringed by the kind of sandy beach the photograph shows. The image thus captures the shared visual signature of both groups — a forested core, a sandy rim, and the sea closing in — while the text explains the different geological stories behind that similar appearance. …
India has two major island groups, and they sit in two different seas. One group lies in the Bay of Bengal, the other in the Arabian Sea. They differ sharply in origin, size, and character — the eastern group is largely mountainous and partly volcanic, while the western group is built entirely of coral.
The Bay of Bengal Islands: Andaman and Nicobar
The Bay of Bengal group consists of about 572 islands and islets. They lie roughly between 6°N–14°N latitude and 92°E–94°E longitude. Within this group, two principal clusters of islets are recognised: the Ritchie's Archipelago and the Labrynth Island.
The entire group is divided into two broad categories — the Andaman Islands in the north and the Nicobar Islands in the south. These two are separated by a water body called the Ten Degree Channel.
These islands are believed to be the elevated portions of submarine mountains. However, some of the smaller islands are volcanic in origin. Barren Island, the only active volcano in India, is located here in the Andaman and Nicobar group.
Some important mountain peaks in these islands are:
| Peak | Location | Height |
|---|---|---|
| Saddle Peak | North Andaman | 738 m |
| Mount Diavolo | Middle Andaman | 515 m |
| Mount Koyob | South Andaman | 460 m |
| Mount Thuiller | Great Nicobar | 642 m |
The coastline of these islands has coral deposits and beautiful beaches. The islands receive convectional rainfall and support an equatorial type of vegetation.
On 26 December 2004, the Andaman and Nicobar Islands experienced one of the most devastating natural calamities — the Indian Ocean tsunami, triggered by an undersea earthquake. The same calamity severely affected coastal areas of Tamil Nadu, Sri Lanka, Indonesia, Thailand, and the Maldives. Its major consequence was widespread destruction of life and property, with coastal settlements washed away and thousands of people killed.
The Arabian Sea Islands: Lakshadweep and Minicoy
The islands of the Arabian Sea include Lakshadweep and Minicoy. They are scattered between 8°N–12°N latitude and 71°E–74°E longitude, lying at a distance of 220 km to 440 km off the Kerala coast.
The entire island group is built of coral deposits. There are approximately 36 islands, of which only 11 are inhabited. Minicoy is the largest island, with an area of 453 sq. km. …
The Andaman and Nicobar Islands, though mostly low-lying, are believed to be an elevated portion of submarine mountains and carry several named peaks: Saddle peak (North Andaman) - 738 m. Mount Diavolo (Middle Andaman) - 515 m. Mount Koyob (South Andaman) - …