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A Map That Fills 500 Million Years Of Missing Earth’s History

Did you know that the rate of movement of Earth’s tectonic plate is of the order of the growth of a human’s fingernail? This makes the study of their movement a very hard and tedious task. The reason for this immense slow movement is the upper layer of the mantle. Mantel is basically sludge of molten rocks and which is nearly 2,500km beneath the crust. Movements in the mantle cause movement in the plates. Scientists now use global satellite imaging to study and record the tectonic plates and their movement, respectively.

Due to obvious reasons, we were not able to do it for the movement of plates in prehistoric times. Thus, leading to complete darkness in this area of Earth’s past. We were not able to predict how life came into existence and where precisely. Until now!

The 500 Million-Year-Old Map

Scientists have developed a map of Earth from 1,000 million to 520 million years ago. This was the time when the amount of oxygen increased in the atmosphere and the flora & fauna saw a boom in their diversification. This map enabled us to fill the gap of nearly 500 million years of unaccounted history of the planet as a whole. Scientists believe this era was the time when Earth witnessed the most amount of changes in the climate. From an ‘Icy Ball’ to a hot one, Earth experienced everything. Now with this information, we are able to study the plate’s tectonic movement and also predict how this movement affected the Earth System.

Earth System is the interaction of chemistry, biology, and the physical processes that take place on the surface.



Before This Development

The reason this map is fascinating is that earlier we were only able to map till the last 200 million years. Before this, all the knowledge about tectonic movement and placement is not available. The reason for this is ‘subduction’. Subduction is the process in which the ocean floor is pulled into the deep Earth. Here they accumulate on the border of the mantle and the crust. Thus, greatly affecting the tectonic movement. Subduction only happens in the ‘subduction zone’. Also, this phenomenon causes the earlier plates inaccessible to the scientists for the study.

Methods Used To Develop The Map

However, they used alternate representations of plate margins in the geological record. They found rocks above the subduction zone. The data was collected from the locations of Madagascar, Ethiopia, and far west Brazil. This made us go back further than we ever went in terms of studying Earth.

Another method that was employed was: “palaeomagnetic measurements”. We were able to determine the latitude of the plates using rocks that are iron-bearing rocks. These freeze the magnetic field in them as they form. This could be compared to a ‘fossil compass’. And this ‘compass’ is having its needle pointed to the ground at an angle related to the latitude where it is formed. This method is applicable because of the general properties of the magnetic field of Earth. The magnetic field at the equator is almost perpendicularly out of the surface. However, this is not the case at the poles as there the field lines are perpendicularly inwards to the surface.

The Importance Of This Map

The importance of this map’s development is appreciated when we will make fact-based predictions of our history. We were never able to understand how the current climates and phenomena came to being. This is because tectonic movements govern many of the Earth’s factors.

 

This includes climate, earthquakes, topography alteration, how the water flows, the flow of rivers, the chemical composition of water bodies, the number of climates a place can experience, etc. With this map, we will be able to accurately predict all the above and more. We will be able to reason the current state of our planet and its properties with facts.

 

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