Carnosaurs were large predatory dinosaurs and Sauropods were long-necked, herbivorous dinosaurs and were notable for the enormous sizes they could grow up to.
The geological sites of Ariyalur are known to be a treasure trove of dinosaur remains, but it is the first time that hundreds of nests embedded with hundreds of clusters of dinosaur eggs have been unearthed in the district.
The work was carried out by the researchers of Periyar University.
Ever since a British couple Mrs. and Mr. Wine collected 32 boxes of “strange stone” objects in 1843, the Ariyalur region has drawn geologists from across the world for its rich fossil presence and diversity.
According to the researchers, eggs may not have hatched due to the Deccan volcanic eruptions or the seasonal flooding. “We suspect the extinction of dinosaurs were triggered by the Deccan volcano as the red bole bed formed by the volcanic ashes cap the eggs,” say the researchers.
It is estimated that originally the Deccan flows may have covered an area in excess of 2 million sq km with a total volume of 2 million cubic km. Deccan volcanism may have released into the atmosphere gases which had been locked up in the bosom of the earth. Thus huge quantities of sulfur dioxide, hydrogen chloride, nitrogen oxide, carbon dioxide and other similar gases may have been injected into the atmosphere. These gases could combine with steam from the volcanoes, resulting into the lethal mixture known as ‘acid rain’.
Scientists now believe that the Deccan volcanics may not have been directly responsible for the demise of the dinosaurs and other organisms, but they must have had a slow but sure influence on deterioration of the ecosystem over a 2 to 3 million-year period, leading to the disruption of the food-web. Atmospheric pollution would have been further aggravated by the fact that the volcanic ash would have been injected into the atmosphere, leading to the formation of a dark cloud, blocking sunlight.
The volcanic activity of the Deccan between 68 and 65 million years ago was one of the most stupendous eruptions that the Earth has witnessed. It was second only to the Permian-Triassic volcanic eruptions of Siberia when again over 80 percent of the land and sea animals perished dramatically in a short period of time.
Evidence of dinosaurs in India.
Finding dinosaur bones, or dinosaur eggs for that matter, in India is not a difficult task, but one must know where to look. The record of dinosaurs in India spreads from the Late Triassic to the end of the Cretaceous (i.e. from about 225 to 65 million years ago), but the most common finds are in the Jurassic and the Cretaceous.
In order to help the young collector find the localities where dinosaurs remains can be located, India has been divided into the following geographic sectors:
1.Western sector comprising the states of Rajasthan and Gujarat.
2.Central sector comprising the states of MP and Maharashtra.
3.Southern states comprising the states of Andhra Pradesh, Tamil Nadu and Karnataka.
The oldest and the best known locality of the central region is, of course, the Bara Simla Hill in the Cantonment area of Jabalpur from where the first reports of dinosaur bones were made by William Sleeman. Other sites in the region are related mainly to dinosaur eggs and nests. These include several sites near the town of Dohad, and the region between Jobat and Bagh.
The best studied dinosaurs come from the Southern sector is the Pranhita-Godavari valley running north westwards and south eastwards.
Near the village of Maleri in the Godavari basin, fossils of some of the earliest dinosaurs (Triassic) known to science have been reported.
Recently some people have claimed to identify the foot prints of Dinosaurs in coalfield area of North Karanpura area some 50 kms from Ranchi in Jharkhand State of India. But the findings still wait for the scientific approval.
India has a special place in the studies of dinosaur eggs. The largest Cretaceous nesting sites for dinosaurs anywhere in the world lies in Central India, extending from Kutch in the west to Nagpur in the east, and then further southwards to Adilabad district, north of Hyderabad.