DECCAN TRAPS

 

A view of the Ajanta Caves excavated in the gorge wall of the Waghur/Waghora River. The caves, listed as a World Heritage Site, are excavated in compound lava flows. The Buddhist cave monuments date from 2nd century BCE to 6th century CE 

(Photo courtesy of Francesca Lugeri)

At the end of the Cretaceous, the western part of peninsular India underwent numerous volcanic eruptions that resulted in the formation of the Deccan Traps. A total of 48 lava flows have been identified within the Deccan Traps, with a maximum thickness of about 2.5 km on the western side of the plateau near Mumbai. The Deccan Traps are spread over half a million square kilometers in the west-central parts of India, and they occupy huge areas of the states of Maharashtra and Karnataka. India also has the longest lava flows known to be preserved. They are estimated to be 1500 km long and drain out into the Gulf of Bengal near Rajahmundry in Karnataka.

Many archaeological monuments like the Buddhist, Hindu, and Jain temples of Ajanta, Ellora, and Elephanta are the oldest in-situ basalt cave temples, dating back to the second century. They also have the oldest known cave paintings on the Indian subcontinent. However, this title could be snatched by the recent discoveries in Mangar Bani, near the outskirts of Delhi.

At least 4 of the UNESCO World Heritage Sites in India, like the Ajanta, Ellora, and Elephanta cave temples, and the Chhatrapati Shivaji Maharaj Terminus (formerly Victoria Terminus), is made of this basalt.

Deccan basalts are in high demand worldwide and are mined for a variety of purposes including masonry stone, road metal, and as a raw material for corrosion-resistant basaltic pipes and basalt wool.

Quarrying of Deccan basalt is done in the western Deccan Plateau region, especially around Navi Mumbai, Aurangabad, Jalgaon, Nashik, and Kolhapur.

Basalt is a dark-colored, fine-grained, extrusive igneous rock (i.e., the molten rock or lava cooled on the surface) 

Basalt flows cover about 70% of the Earth’s surface and huge areas of terrestrial planets.

They come from the mantle. When rocks melt under pressure and temperature, they then make their way up to the surface via ducts and feed fissure volcanoes on the surface.

Future studies could gather more evidence about the environmental conditions that led to the mass extinction of non-avian dinosaurs and gigantic reptiles. 

The massive Deccan volcanic mountain ranges of the Western Ghats (east of Mumbai) reach up to a height of 3500 m and consist entirely of layered lava flows. (photo courtesy of G. Keller)

RAMGARH CRATER

source - Google Earth

At Ramgarh, a quiet village in Rajasthan, a 4 km hole is punched into the ground. It is a circular impact crater rising abruptly (the wall is about a km high) in the plain area surrounded by vast agricultural fields.

This structure was first noticed in 1869. Since then, it has been studied by geologists and confirmed to be a meteorite impact crater later.

Apart from some temples, there are two water bodies present within the crater filled with rainwater. Migratory birds have been observed here. This area is considered a potential Geological Heritage Site in India as it is archaeologically, biodiversity-wise, and geologically important.

Coordinates—25°20'8.90"N, 76°36'23.70"E

 

ICHTHYOSAUR FOSSIL SITE IN THE CAUVERY BASIN

Ichthyosaurus were marine reptiles with a dolphin like appearance which lived in the oceans of the Mesozoic Era (251 million to 65.5 million years ago ) & had eyes the size of a football, fossil evidences show it gave birth to live young.

Dinosaur Eggs have been found in Ariyalur since 1860s

In India fossils of these marine reptiles are found in Gujarat and Tamil Nadu.
Karai Badlands are one of the most fossil rich localities in south India, the area is barren and heavily eroded by intense rainfall and supports little vegetation.

In the past higher sea levels created a shallow sea here which began to expand into an Ocean as India, Australia and Antarctica began separating 137–132 million years ago, after the break-up of super-continent Pangea

Location — 12° 56′ 15.64″ N, 79° 18′ 58.82″ E. (Perambalur, Tamil Nadu, India)

The Geological Survey of India has identified this area as a potential National Geological Monument.
The Karai Badlands yield abundant fossils of brachiopods, belemnites, bryozoans, corals, algae, bivalves, cephalopods, gastropods, foraminifers, calcareous sponges, sharks & marine reptiles.

a: Oyster shells inside the body chamber of an Ammonite
b: Debris of Pycnodonte vesiculosa
c: Rhynchostreon shells
d: Pycnodonte vesicularis

Some well known finds from this area are listed below -

➢ In 1989, Palaeontologists of GSI found fragmentary remains of the pelvis, vertebrae and the 2-metre-long shin bone of a giant Sauropod (Titanosaur) in Tiruchirapalli district & named it Bruhathkayosaurus, estimates put it at 34 metres long, 85 to 139 tonnes in weight

➢ In 2011,conical teeth of Ichthyosaurus were found, later a Vertebra of an Ichthyosaurus was discovered in 2015 by students

➢ In 2013, tooth of a small crocodile (Simosuchus) were found, it was the size of a Dog & ate shoots, leaves & insects

Vertebra discovered in 2015

 

Listen to podcasts on this topic  -

How India's fossil treasures are turning to dust (Nature India Podcast)

Desi Stones & Bones