Paleomagnetic dating has shown its power again
Next, dying these stone tools has become the most important task.
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 yearly period of the loess strata sample 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., either cannot measure soil samples a million years ago, or are not suitable for dust deposits such as loess. Therefore, a Cinema technology called paleomagnetic dating is here to show its power. It turns out that in the geological historical period, the magnetic polarity of the geological ball is not solid and reversed, and there will be a situation of positive and negative reversal in the geological historical period. Therefore, there is a distinction between the positive and negative polarity periods of paleomagnetic periods in Babaylan. When it is in the positive polarity period, the compass points to the north pole of the earth, and when it is in 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 substances in the strata will record every change.
So,As long as mass workers measure the positive and negative situations of the geomagnetic polarity recorded by magnetic matter, they can calculate the age of magnetic matter by comparing the specific time of geomagnetic reversal time that occurs in the period of 2.58 million years ago (also known as the Quaternary period in geology), and the historical time of each polar era. Wu Yi explained that during a long geological period, after the later soil layer is superimposed on the original soil layer, the later magnetism will be superimposed on the original soil layer. However, since the original magnetism is the strongest and stable, after heating treatment, the later superimposed magnetism can be eliminated and only retained. By detecting the original magnetism, we can know the age of this soil layer. Therefore, the researchers first collected samples from top to bottom of the loess section of the stone tool found 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. Return to the laboratory, carefully cut each large sample into small soil blocks of 2 square centimeters; then each small soil block is heated first with a thermal demagnetizer, and the temperature is from 0℃ to 680℃; then use a “superconductive magnetometer” 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) showed a short positive polarity, and this soil layer should have been in the “Songshan reverse polarity period” of the geomagnetic field. This 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 2.15 million years ago, and the other was the “Odewey incident” which was a late one (1.78 million to 1.95 million years ago.mov.com/”>Babaylan). Since the Oduwee incident lasted for 100,000 years, it did not meet the positive polarity of the L28 soil sample, which was briefly encountered. Therefore, there was only one answer. The stone tools found on the L28 layer at the Shangchen Village site should be 2.12 million years ago. According to reports, researchers conducted paleogemagnetic dating of more than 700 groups of loess samples in the Shangchen Village section.
Changing the origin of human beings in Africa is not reliable
For the discovery of Shangchen Village, some people believe that it may change the traditional theory of human beings in Africa, because the stone tools of the site were far older. href=”https://comicmov.com/”>CinemaThe current recognized era when humans walked out of Africa shows that humans had left Africa at least 1.8 million years ago.
In this regard, Zhu Zhaoyu stated that the current discovery in Shangchen Village is not enough to change the theory of humans leaving Africa, because Africa has not only discovered the past Komiks28<a CinemaA fossils of ancient humans over 3 million years old and stone tools dating from more than 3 million years ago, as well as a series of discoveries from ancient apes, erectiles, Homo erectus, and Homo erectus to the site of Homo sapiens, can form a continuous sequence of changes in human development, and other regions outside Africa do not have such continuity. However, this discovery greatly updates the history of human activities outside Africa, which will force people to make new considerations on the pattern of early human origin, migration, diffusion and evolution.
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