Andaman booklet aw.FH10 - Zoological Survey of India

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Saddle Peak in North Andaman and 642 m at Mount Thulier in Great Nicobar Island. The precipitation is slightly higher in Nicobar with an average annual rainfall of 3000 to 3500 mm. History The Andaman and Nicobar groups of islands belong to a geosynclinals basin. The sediments of this region have gradually changed their characters, according to tectonic movements, to which they have been subjected to from time to time; as such the rocks are highly folded. The six distinct geological formations consisting of various groups of rocks, from these islands were reported. These formations include Older Sedimentaries, Ophiolite Suite, Mithakhari Group, Andaman Flysch, Archipelago series and the Rutland Shell-Limestone. They represent a period of sedimentation, from Cretaceous (about 100 million years) to Sub- Recent (less than 10,000 years). The surface deposits of gravel beds and raised soil covers, on the other hand, are of very late origin, 02
i.e., Recent to Sub-Recent (i.e., less than 10,000 years). In general, it is believed, that the mountain ridges of the island were formed at the expanse of a narrow but deep oceanic furrow during Late Mesozoic Period (100 million years). The older sediments of Mesozoic formed the basement for younger deposits. The history of later deposition is that of an inconsistent basin i.e. associated with movement, volcanism and deposition, side by side with igneous intrusions. Over the older sediments, at the deeper part of the sea bottoms, there was rich accumulation of siliceous tests of radiolarians, possibly and deposition of sediments of late Cretaceous to Oligocene. During Oligocene, the islands faced a tremendous earth movement resulting in mountain ridges, although well within the sea. Some of the ridges were suited for the growth of corals and also had the rising tendency for developing the reef islands. As such, formation of Rut islands (West Coral Reef, Middle Coral Reef, Chaura Coral Reef, Sambero Channel Coral Reef, and Car Nicobar Coral Reef) in this region is attributed to these and also to the deposition of limestone. The present configuration was, however, achieved by these islands only about 26 million years ago. Two of the islands, Narcondam and barren Islands are of volcanic origin. The former is an apparently extinct volcano, while the latter is still active. Geography The Andaman group of islands is made up of North, Middle and South Andaman Islands (Table 1). The Ritchie's Archipelago is to the east of Middle Andaman and the Tarmugli group of islands lies to the southwest of South Andaman. Rutland is situated off the southern coast of South Andaman, and Little Andaman forms the southern end of the Andaman group of islands. Port Blair in South Andaman, is the capital of Andaman and Nicobar islands. The Nicobar group has twenty-four islands, which cluster into three 03
Page 1: Fauna of Protected Areas of Andaman
Page 4 and 5: CITATION Sivaperuman, C. and Raghun
Page 8 and 9: identifiable groups. Of these, only
Page 10 and 11: million) km2 (Saldanha, 1989). The
Page 12 and 13: Dermochelys coriacea, Reticulated P
Page 14 and 15: 36. Jungle Island Wildlife Sanctuar
Page 16 and 17: Fauna of Andaman and Nicobar Island
Page 18 and 19: diversity of reef fish. These brigh
Page 20 and 21: Some important animals in the prote
Page 22 and 23: Dugong Dugong dugon: The Dugong dug
Page 24 and 25: Andaman Wood Pigeon Columba palumbo
Page 26 and 27: Nicobar Scops-Owl Otus alius: The N
Page 28 and 29: Studies conducted by Zoological Sur
Page 30: Biodiversity Conservation Prioritie

Andaman booklet aw.FH10 - Zoological Survey of India

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