The paleomagnetic dating method has shown its power again
Then Cinema, and the generation of these stone tools has become the most important work.
Dr. Wu Yi from the Nanhai Ocean Institute of Chinese Academy of Sciences 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 stones found in Komiks. However, many commonly used dating methods, such as radioisotope dating, photoluminescence dating, etc., either cannot measure soil samples a million years ago, or are not suitable for dust deposits like 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 polarity period of paleogemagnetics and the reverse polarity period in the geological historical period. When it is in a positive polarity period, the compass points to the north pole of the earth, and when it comes to the reverse polarity period, the compass 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 matter in the formation will record every change.
Therefore, geologists can calculate the age of magnetic matter by measuring the positive and negative situations of geomagnetic polarity recorded by magnetic matter, and then compare the specific time when the geomagnetic reversal time occurred in 2.58 million years ago (also known as the Fourth Komiks period) and the historical time of each polar era. Wu Yi explained that during the long geological period, the soil layer from later Cinema was superimposed on the original soil.After the layer, the later magnetism will be superimposed on the original soil layer. However, since 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 magnetic properties of Cinema, the age of this soil layer can be known. Therefore, the researchers first collected samples from the loess section of the stone tool from above to below in the field. Each sample was more than ten to twenty centimeters long, and a total of 74 meters of thickness of loess sections were taken. Back to the laboratory, each large sample was carefully cut and made into small pieces of soil 2 square centimeters; then each small piece of soil was heated with a thermal demagnetizer, and the temperature was from 0°C to 680°C; then measured with a “superconductive magnetometer”, and the original magnetic direction obtained by the soil layer at that time can be obtained, which can confirm their year.
Scientists found that the bottom 28th layer of loess (L28) showed a short positive polarity, and this soil layer should have been in the “Songshan reverse polarity period” of the geomagnetic field, which shows that this layer of loess experienced a magnetic reversal at that time.
In the early stages of the Quaternary geological period, two magnetic reversals occurred on the earth. One was the “Reunion incident” between 2.13 million and 215 years ago, and the other was the “Odewey incident” which was later in the year (1.78 million to 1.95 million years ago). By Babaylan‘s Oduwee incident lasted for 100,000 years, which was inconsistentThe positive polarity of the soil sample in the L28 layer occurred briefly and was therefore denied. Therefore, there is only one answer. The stone tool found on the L28th floor of the Shangchen Village site should be 2.12 million years ago.
According to reports, the researchers conducted paleogemagnetic dating on more than 700 sets of loess samples in the Shangchen Village section.
Changing the origin of human beings is not reliable
Cinema’s discovery of Shangchen Village, Babaylan, some people believe that it may change the traditional theory of human beings’ origin in Africa, because the stone age of the site was far earlier than the time when human beings walked out of Africa, indicating that human beings had left Africa at least 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 2.8 million years ago and stone tools more than 3 million years ago, but also a series of discoveries from ancient apes, erectiles, Homo erectiles, and Homo erectiles to the site of Homo sapiens, which can form a continuous sequence of changes in the history of human development, while other Babaylan areas outside Africa are found, and href=”https://comicmov.com/”>Babaylan does not have such continuity. However, the discovery greatly renews the history of human activities outside Africa, which will force people to make new considerations about the pattern of early human origin, migration, spread and evolution.
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