Fossils: In Time and Space
We are told by our teachers that the age of earth runs into millions of years!
How to count these years?
- It takes all the ten fingers of your hands to count for about four thousand million times to calculate the time elapsed since the life emerged for the first time on our planet!
- At the outset, how do we estimate time in geological past?
- What are the established time periods, era and epochs that divide different stages of life in the slice of time?
- What is the evidence to prove the prehistoric life on earth?
- How to count these years?
Answers to most of these questions are coded in one word, i.e. ‘FOSSIL’.
What is a fossil?
The term has a Latin origin, “fossilis” which defines
“any remains or imprint of a plant or animal that has been preserved in the earth’s crust since some past geologic or prehistoric time”.
Be it a fossilised bone or poop or frozen mammoths of Siberia, the foot prints of dinosaurs or even the impressions of prehistoric plants preserved in rocks, these diverse types of fossils are direct evidence of their existence in the past.
What an irony that life is a subject of study but death and burial supply all the data!
The prehistoric life was a base for the future prospects of survival, the proven fact since times immemorial. Wherever this evidence is recorded in the earth’s surface, presents a unique opportunity to understand the temporal and special spread of life buried in various strata across the length and breadth of globe. No other discipline can be as much unraveling as palaeontology to address the origins of life with impeccable certainty! What has lived and perished leaves behind an array of physical evidence which is like a trailer of past life, similar to an overnight experience of being in a Natural History Museum like the well-known Hollywood movie, “A Night in the Museum” part I and II ! Interestingly we find some of them sharing their relationships with those found in different continents at the same time! The separation of their ‘loved ones’ and the changing shapes of the world map are two closely related phenomena that hold keys to the global distribution of animals in prehistoric times.
Scientists have long observed that the coastlines of Africa and South America are similar, and in fact, if this jigsaw puzzle if pieced together, we find the whole world looking like a mass of several amorphous pieces of land pulled away from each other. If these pieces of land are ‘pieced together’ on paper, they would resemble the ancient supercontinent known as Pangaea. Several scientists have searched for any logical and scientific meaning behind such fragmentation of land mass and in 1912; it was Alfred Wegener (1912) who proposed the theory of continental drift. Therefore don’t get surprised to find taxon like a land reptile called Lystrosaurus which lived in Africa, Antarctica and India one and the same time! Glossopteris, fossil ferns, which were found in all the southern continents indicate that all the continents were once joined, like erstwhile neighbours!
India offers an excellent opportunity to see the relics of prehistoric animals buried in the ancient deposits. Dinosaurs have roamed the Indian soil is evident from several localities which report their nesting behaviour, clutches of eggs, a wide range of massive bones; contemporary plant life being represented by long and thick tree trunks, leaf impressions, fossil wooden logs; marine life with a variety of shells, shells as large as the size of a rhinoceros, members of star fish family; terrestrial animal world with early ancestors of pachyderms, equines, rhinos, hippos, camels, giraffe, tortoise, saber tooth large cats, ostriches etc. that roamed the North west India (stretching from Panjab of Pakistan to Himachal Pradesh and beyond in the Siwalik hills) until as recent as just two million years ago!
This panorama of life through ages represents India’s rich natural heritage, a priceless legacy and a great lesson in Life and Earth Sciences.
The animal figures painted/ engraved or etched on the walls and roofs of caves and the rock shelters are the ‘bone-less’ evidence of prehistoric fauna which is a continuum of fossil record, though documented by prehistoric man and rightly called the “Painted fossil record”. The fabled UNESCO World Heritage site of Bhimbetka in Central India is a tall evidence of the existence of diverse prehistoric mammals whose paintings are a testimony to the man-animal interaction in prehistory.
These are the significant signatures inscribed in the history of life, needing the world attention for education and environmental awareness. There are several such localities spread along the length and breadth of India that have yielded a rich fossil record ranging in age from several hundred thousand to billion years. In recognition to this treasure trove of fossil heritage, the Government of India has established several Fossil Parks that have become the ‘safe residences’ of the buried prehistoric animals and plants which stand as a tall testimony to the existence of prehistoric abode for animals that were silenced by the vagaries or caprice of nature.
Fossil Parks are part of the National Geological monuments and today’s the star attraction from the geo-tourism perspective. The Fossil Parks offer detailed history of the landscape, the evidence of life found, its significance in the context of evolution and dispersal. One gets to know the type of fauna, its life history and position in the history of animal kingdom. Most of these fossil sites were discovered during colonial times by British army engineers, geologists, surgeons and natural scientists, followed by Indian team of scientists during the past more than seven decades. The seven of the existing Fossil Parks highlight the remains of large mammals (Saketi, District Sirmeur, Himanchal Pradesh), Stromatalites (impression of one of the earliest forms of life on earth, blue-green algae, Districts of Chittorgarh and Udaipur, Rajasthan),
Asias largest Marine fossil park at Mahendragarh, Districts of Sarguja, Chhattisgarh, petrified wood (Akal, District Jaisalmer, Rajasthan), 100 million years old petrified tree trunks (Sattanur, District Perambalur, Tamil Nadu), and fossil trees (Tiruvakkarai, District Villupuram, Tamil Nadu). These Parks are under complete protection under the Govt. Act of Geological Monuments. The dinosaur fossil park at Balasinor (District Kheda, Gujarat) is a very recent addition to these existing parks highlighting the relics of dinosaurs discovered locally. This region has emerged as the richest nesting sites and yielded highest number of dinosaurian eggs belonging to the Late Cretaceous period. At least thirteen species of dinosaurs lived here for more than hundred million years until sixty-five million years of which Rajasaurus narmadaensis, and other two are the heroes of Rayioli. It is a Fossil wood of variety of plants and trees around Jaisalmer (part of the Great Thar desert of India) and marine fauna in Chhattisgarh would have been unacceptable but for the prehistoric reality that we are able to understand the dynamics and marvels of nature in the four and a half billion year’s history of earth, and life that emerged following the appearance of primordial biochemicals!
