Polar Regions - An Archives of Antarctic Paleoclimate and Paleoenvironment Since the Antarctic ice sheet is hundreds to thousands of meters thick and the climate is extremely cold, there is no melting during the ice formation process. Therefore, glaciologists are studying Antarctica.

When studying the age of continental ice sheets and the historical process of their formation, the method of drilling ice core samples was used to determine the age and formation process of glaciers.

They found that from the ice core samples of glaciers, they could not only determine the age of the glacier and its formation process, but also obtain the temperature and precipitation data of the corresponding historical era, as well as the content of atmospheric chemical components such as carbon dioxide in the corresponding era, opening up a way to restore ancient times.

New paths to climate and paleoenvironment.

Records show that ice core samples obtained from the Antarctic continental ice sheet have so far exceeded 2,000 meters, and have obtained paleoclimate and paleoenvironmental data from 150,000 years ago.

How to obtain paleoclimate and paleoenvironment data from ice cores?

First, let’s talk about how to obtain ice age information.

The Antarctic ice sheet is formed by the weight of the snow itself and is called gravity ice.

In the Antarctic region, due to the low temperature, the snow does not melt. Each year, the snow accumulates to form layers of sediments. Year after year, layers of ice gradually form from the bottom to the top. The older they go up, the younger they become.

In winter, the temperature is low, and the snow particles are fine and dense; in summer, the temperature is high, and the snow particles are thick and loose; therefore, the ice layers formed by snow in winter and summer have significant differences in bedding structure, just like the annual rings of a tree trunk.

Intuitive methods can identify only about 90 meters of ice, representing nearly 500 years of ice deposition.

To determine the age of ice at depths above 100 meters, oxygen isotope methods must be used.

The so-called isotopes of oxygen are oxygen atoms that belong to the same oxygen element (O) but have different mass numbers. For example, 160, 170 and 180 are the three isotopes of oxygen.

The number in the upper left corner of the oxygen element symbol is its mass number. Obviously, the mass of 180 is greater than 160. 180 is not easy to evaporate, but 160 is easy to evaporate.

Therefore, when the temperature is high in summer, the 160 contained in the water decreases, so the value of 180/160 increases; when the temperature is low in winter, the value of 180/160 decreases.

Based on this, the age of the ice layer can be determined by measuring the changes in the 180/160 value of each ice layer in the ice core. Each fluctuation in the ratio is one year.

With the ice age data of the ice layer, and further determining the temperature and precipitation of each ice age, we have the most basic data of historical climate.

In principle, the annual precipitation can be determined based on the thickness of the ice layer in each year.

The condition is that ice core data from areas with very low wind speeds must be selected to eliminate the influence of wind and snow.

For example, in the inland areas of Antarctica, ice core data are ideal due to low wind speed.

The method of using ice cores to extract ancient temperature data can be carried out through the following methods.

First, the temperature at a certain point on the modern Antarctic ice sheet and the 180/160 value in the snowfall at the corresponding time were actually measured to obtain a curve of the relationship between the temperature and the 180/160 value in the Antarctic region; then, the 180/160 value in the ice layer in a certain year in the past was obtained.

By comparing the /160 value with the above curve, you can know the temperature that year.

Former Soviet scientists used this method to measure ice core samples from 0 to 2,038 meters at the East Antarctic Station, and extracted data on global temperature changes over the past 150,000 years.

Methods for obtaining paleoenvironmental data may vary depending on the chemical composition of the atmosphere.

The close relationship between carbon dioxide and climate has long attracted world attention.

Therefore, the issue of obtaining historical carbon dioxide data was first put on the agenda.

As snow accumulates and squeezes into ice in the Antarctic region, polynya cavities are always left, preserving the air of the year.

When analyzing ice core samples, the carbon dioxide content can be measured by analyzing the atmospheric chemical composition of oxygen bubbles trapped in the ice core.

With the above prerequisites for determining ice age, the historical evolution data of carbon dioxide can be obtained.

According to the same method, historical data of gases such as methane and nitrogen can also be analyzed.

Historical information on the composition of various other elements can also be analyzed from ice core samples, such as sulfur, arsenic, fluorine, potassium... These are important basis for studying environmental changes.

Similar to the idea of ??drilling ice core samples to analyze paleoclimate and paleoenvironment data, drilling cores from lake bottom sediments in the Antarctic region can also obtain historical data on paleoclimate and paleoenvironment.

Antarctic Natural Environment Antarctica is located around the South Pole. It is a continent covered with ice and snow, and is dotted with islands around it.

The area of ??Antarctica, including the Antarctic continent and its islands, is approximately 14 million square kilometers, accounting for 10% of the world's land area. It is equivalent to the combined area of ??the United States and Mexico, 1.45 times the land area of ??China, and the largest land area of ??Australia.

Twice the area, it is the fifth continent in the world.

Antarctica is surrounded by the stormy and ice-prone Southern Ocean, which is an extension of the Atlantic, Pacific and Indian Oceans. It covers an area of ??about 38 million square kilometers. For the convenience of research, it is called the fifth largest ocean in the world.

Antarctica is the closest to South America, separated by the Drake Strait, which is only 970 kilometers away.

It is about 3,500 kilometers away from Australia; about 4,000 kilometers away from Africa; and about 12,000 kilometers away from Beijing, China.

Antarctica was formed by the separation and disintegration of Gondwana. It is the highest continent in the world, with an average altitude of 2,350 meters.