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Driest Place On Earth Has Not Seen Rainfall In 14 Million Years

by hridika ahire

Driest Place On Earth Has Not Seen Rainfall In 14 Million Years

April 18, 2021

McMurdo Dry Valleys located in Antarctica is the driest place in the world. The valley is located in the middle of Antarctica, but its surface is completely bare and snow-free. It is not covered with snow and has no terrestrial vegetation. Scientists say the area of McMurdo Dry Valleys resembles the environment of Mars.

We know that the topography and climate changes of any place depend on the geographical position of the place. The weather of any area can change from hour to hour, month-to-month, and even year-to-year. A region’s weather pattern which is tracked for the last 30 years is considered its climate. Some parts of the world have a tropical wet climate where it is hot and rainy almost every day. Others have a polar climate which means they are always cold and snow-covered most of the year.

Many other climates contribute to Earth’s biodiversity and geological heritage. A climate system is made of five major components: the atmosphere, the hydrosphere, the cryosphere, the land surface, and the biosphere. The composition and movement of gases that surround the Earth have the capacity of changing greatly and are influenced by natural and man-made factors. Therefore, you can see that the deserts are always dry and hot whereas, forests are cold and rainy.

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Friis Hills

The Desert is a barren area of landscape and you can experience little precipitation. The living conditions, therefore, are hostile for plants and animals. About one-third of the total land surface of Earth is arid or semi-arid and includes polar regions as well, where little precipitation occurs and they are sometimes known as polar deserts or “cold deserts”

One type of cold desert is the Antarctica region since it very dry and has not received rainfall in 14 million years. The driest place of Earth is without a doubt, the Friis Hills. Friis Hills are a cluster of ice-free hills in Antarctica. It extends for 11kms and rises to 1,750 meters on the side of the Taylor Glacier in Victoria Land, Antarctica. It is one of the “Dry Valleys” which lay to the west of McMurdo Sound.

Friis Hills

Dry Valleys

The McMurdo Dry Valleys are a row of snow-free valleys in Antarctica and are located within Victoria Land. These dry valleys experience extremely low humidity and due to the mountains, that surround them, the flow of ice from the nearby glaciers is restricted. It is one of the world’s most extreme deserts and a saline lake called Lake Vida and the Onyx river which is a meltwater stream and the longest river in Antarctica.

Fossils show that when the climate of Earth was warmer, more than 14 million years ago, tundra mosses and a lake were once a part of the flat-topped hills. The valleys are known as Dry Valleys because they have extremely low humidity and no snow. Since the mountains are so high that they block the seaward-flowing ice of the East Antarctic Ice Sheet from reaching the Ross Sea, the area experiences dryness. That is why there is no measurable rain or snow in this area, although if the winds are strong enough, some snow drifts in from the nearby hills.

Search for Beryllium-10

In order to study the region and to find out the ancient rainfall amounts, a graduate student from the University of Pennsylvania named Rachel Valletta started looking for traces of beryllium-10 in the lake sediments on the Friis Hills. Beryllium-10 is a radioactive isotope of beryllium. It is formed in the atmosphere of Earth mainly due to cosmic ray spallation of nitrogen and oxygen.

Cosmic ray spallation is also known as the x-process which is a set of naturally occurring nuclear reactions which cause nucleosynthesis. Nucleosynthesis is the process of creating new atomic nuclei from pre-existing nucleons and nuclei. It takes place due to the formation of chemical elements from the impact of cosmic rays on an object. When the cosmic rays collide with the matter, a large number of nucleons are released from the matter that was hit.

Using Beryllium-10

SinceBerrylium-10 decays on a predictable time scale, it becomes easier for geochemists to estimate the age of the sediments containing the isotope. This is why Valletta tested the lake sediments for meteoric beryllium-10 isotopes that are created in Earth’s atmosphere and are carried down to the surface by means of rainfall. She measured it in intervals from the surface down to 60 centimeters below ground. It was found that at the deepest level, the isotope was undetectable. This means the beryllium-10 which would be present if there was any rainfall even millions of years ago, had completely decayed away and no water had trickled into the ground to replace it.

Valletta told LiveScience that, “We would have expected greater concentrations of beryllium had there been water flowing over the surface. Concentrations this low do indeed support the fact that there has been no surface water present. Other evidence that proves that the hills have not experienced any rainfall in millions of years is the ash layers that had no chemical weathering caused by water. Valletta says that she will continue using beryllium-10 data to track the erosion rates at Friis Hills.

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