Our Earth - A Never Ending Story

Pandit Nehru, former PM of India, had said: “Our Earth is like an open book . It keeps a record of everything that has happened in the past.” The language for reading this book is rooted in Geology, Paleontology, Petrology, Stratigraphy and Geography. In short, say Earth Science. But, an open book has only two pages open. The rest are closed. One has to make determined effort to turn over the pages to know more about the past.

The beginning - as we know it

Millions of years ago, there was only one supercontinent. We call it PANGAEA. The rest of the earth was covered with fresh water. Sea became saline much later, when various salts were carried by rivers and dumped into the sea. It took millions of years for sea water to turn saline. Salinity is still increasing. The atmosphere of Pangaea had no oxygen. Gradually, after vegetation came into existence, oxygen arrived. The earliest rocks show no oxidation because there was no oxygen. Oxygen gradually increased through photosynthesis, so did fauna and flora (animal and plant life). Thus, the evolutionary process started.

Tectonic (underground) forces broke Pangaea into two land masses—Ankara Land (northern continents having Europe, Asia and North America) and Gondwana Land (Southern continent having South America, Africa, India, Australia and Antarctica). In between Ankara Land and Gondwana Land, there was Tathus Sea. Ankara Land, after millions of years, broke up into North America, Europe and Asia. Gondwana Land broke up into South America, Africa, India, Australia and Antarctica. This movement is called “continental drift.” This theory was first propounded by Wagner. It was fully accepted when Geologists and Petrologists found rocks proving Wagner’s theory.

Formation of mountains

Continental drift never stopped. It is a continuous process. The earth crust, including ocean floors, is made up of 12 big and 8 small plates. All these plates are floating on a very thick liquid called Magma. Magma is made of molten rocks. Due to earth movements and convection currents in the magma, floating masses (Or plates) keep them moving. India is moving North-North East direction. Indian plate pushed up the Tathus Sea floor and sea floor buckled up to form the HIMALAYAS. The Himalayas are still rising. In the last 100 years, it rose by about 30 feet. They will go on rising as long as the Indian Plate is pressing into the Asian Plate. Africa is shifting in north east direction. The two Americas are drifting westward. Pacific Ocean is shrinking and Atlantic is widening. A day will come, after hundreds of centuries, when Atlantic shall be bigger than Pacific.

The most spectacular movement is of India. Millions of years ago, India was on South Pole. It moved northward, came to a handshake distance from Africa. It then drifted North – North East and embraced the Asian plate. Before hitting the Asian plate it lifted and buckled up the floor of Tathus Sea. Plenty of fossils of sea creatures are found in Himalayas. On the contrary, no fossils are found in the Aravali mountains. Aravallis were formed when there was no life on Earth. Deccan Plateau also cannot yield any fossils because it was made of volcanic lava. It is very interesting to note that, age wise, Aravallis are the world’s oldest mountains and Himalayas the youngest. Himalayas are only about 80 million years old. The residual part of Tathus sea is still seen as Mediterranean sea, Caspian sea and Aral sea.

Wherever there is a crack in the earth crust, magma comes up in the form of volcanic eruptions and oozes lava. Lava solidifies into igneous rocks. There are volcanoes all around the Pacific Ocean shores in Asia, North America and South America. Joints of two plates are not true joints. There are gaps at several places giving rising to several volcanoes. The chain of volcanoes around the Pacific is called, ‘THE RING OF FIRE’.

Impact of the glacial and inter-glacial periods

Shore lines keep changing when the volume of water increases or decreases in oceans and seas. During glacial ages( ice ages) huge quantities of water was trapped in mountain glaciers and in the polar ice caps. Sea level reduced by several meters during inter glacial period (warmer period) glaciers reduced and receded, ice caps shortened and sea level increased by several meters. Since about 20,000 years we are passing through and inter glacial period. Ten or Fifteen thousand years hence next glacial age will come and sea level, will considerably reduce. Generally, The Earth has been experiencing glacial, inter glacial cycle of Thirty Five thousand years. It corresponds with the increasing and decreasing of solar heat in a cycle of about Thirty Five thousand years. During ice ages, the barring strait disappeared and Alaska joined Asia, Lanka joined India and many east indies island join up to make land route from India to Australia. Siberian people of yellow race walked to North America (USA and Canada) via Alaska. They were called Red Indians in U.S.A. and Canada. According to some anthropologists Australian aborigines had walked from India to Australia same with Maori New Zealanders. According to Hindu mythology, Lord Rama and his army had walked from India to Ceylon when sea level was much lower.

Scientists have discovered a lot about Earth, and a lot is to be discovered. Wait on for many surprises.

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This Article was Sent to Us from our Indian reader,  previously he has written
Mating Pattern seen in Indian Tribes ,
Why the weathermen shouldn't be blamed for incorrect predictions? and
What information do Fossils provide ?

Our team wants to thank him for his contributions to this site.