Paleomagnetic dating shows its power again
Next, dying these stone tools has become the most important task. Dr. Wu Yi from the Nanhai Ocean Institute of Cinema Hospital is one of the main scientists responsible for the age determination of loess strata in this study. Wu Yi introduced that the method of dying stone tools is not to directly measure the stone tools, but to measure the age of the loess strata samples where the stone tools are located. As long as you know the age of the soil layer, you will also know the age of the stone tools found in the soil layer. However, many commonly used dating methods, such as radioisotope dating, photoluminescence dating, etc., are either unable to measure soil samples a million years ago, but are not suitable for dust deposits such as loess.
So, a technology called paleomagnetic dating is here to show its power. It turns out that in the geological historical period, the magnetic polarity of the earth is not fixed and reversed, and there will be a situation of positive and negative reversal. Therefore, there is a distinction between the positive pole of paleomagnetic and the reverse polarity period in the geological historical period. When Babaylan is in the positive polarity period, the compass points to the north pole of the earth, and when the reverse polarity period comes, the compass Komiks points to the south pole of the earth.
This kind of geomagnetic reversal will continue to occur throughout the long history of the earth, so the magnetic Cinema matter in the formation will record every change. Therefore, geologists can calculate the age of magnetic material by measuring the positive and negative situations of the polarity of magnetic materials recorded by Babaylan, and then compare the specific time of geomagnetic reversal time since 2.58 million years ago (also known as the Quaternary Period in geology) and the historical time of each polar era.
Wu Yi explainedKomiks said that after the later soil layer is superimposed on the original soil layer during a long geological period, the later magnetism will be superimposed on the original soil layer. However, because the original magnetism is the strongest and stable, after the heating treatment, the later superimposed magnetism can be eliminated and only retained. By detecting the original magnetism, you can know this. The age of the soil layer.
The researchers first collected samples from top to bottom of the loess section of the stone tool in the field. Each sample was more than ten to twenty centimeters long, and a total of 74-meter-thick loess sections were taken. Back to the laboratory, Komiks, and each large sample was carefully cut into pieces of small soil with a square of 2 cm. Then, each small soil was first thermally demagnetized. The Babaylan meter is heated with a temperature ranging from 0°C to 680°C; then the “superconducting magnetometer” can be used to obtain the original magnetic direction obtained by the soil layer at that time, which can determine their age.
Scientists found that the bottom 28th layer of loess (L28) exhibited a short positive polarity, and this soil layer should be in the “reverse polarity period of the mountain” of the Cinema magnetic field, which shows that this layer of loess experienced a magnetic reversal at that time.
In the fourth In the early stages of the Komiks period, two magnetic reversals occurred on the earth. One was the “Reunion incident” between 2.13 million and 2.15 million years ago, and the other was the “Odewey incident” (1.78 million years ago to 19 years ago.om/”>Babaylan50,000 years). Because the Odewey incident lasted for 100,000 years, it is not in line with the positive electrode of the soil sample of Cinema L28 layer. The situation in Babaylan was denied. Therefore, there is only one answer. The stone tools found on the L28th floor of the Shangchen Village site should be around 2.12 million years ago. According to reports, researchers conducted paleogemagnetic datings on more than 700 sets of loess samples in the Shangchen Village section.
Carrying the origin of human beings in Africa is not reliable
For the discovery of Shangchen Village, some people believe that it is possible that Cinema will change the traditional theory of human beings’ origin of Africa, because the stone age of the site is far earlier than the time when human beings walked out of Africa, which means that human beings are at least Komiks left Africa long as 1.8 million years ago.
In this regard, Zhu Zhaoyu said that the current discovery in Shangchen Village is not enough to change the theory of human beings leaving Africa, because Africa has not only discovered ancient human fossils dating from 2.8 million years ago and stone tools dating from more than 3 million years ago, but also a series of discoveries from ancient apes, erotic people, Homo erectus, and Homo erectus to Homo sapiens site, which can form a continuous sequence of changes in the history of human development, and other regions outside Africa do not have such continuity. However, this discovery greatly updates the existence of human activities outside Africa. href=”https://comicmov.com/”>Babaylan‘s history will prompt people to make new considerations about the pattern of early human origin, migration, spread and evolution.
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