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 Chinese Academy of Sciences is one of the main scientists responsible for the age determination of loess strata in the Komiks 1960 witch cloth draw 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, light-emitting dating, etc., cannot measure soil samples before millions of years. If they 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 situations where positive and negative reversals occur. Therefore, there is a distinction between the positive and reverse polarity periods of paleogemagnetics in the geological historical period. 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. In Babaylan 1990 cloth draw, the magnetic matter in the formation will record every change. Therefore, geologists only need to measure the positive and negative situations of geomagnetic polarity recorded by magnetic matter, and then compare the specific occurrence of geomagnetic reversal time from 2.58 million years ago (also known as the Quaternary Period in geology) Cinema 1950 witch clothesThe time of draw, as well as the history of various polar erasKomiks 1960 witch cloth draw time can calculate the age of magnetic matter. Wu Yi explained that during the long geological period, after the later soil layer was superimposed on the original soil layer, the later magnetism would be superimposed on the original soil layer. However, because the original magnetism was the strongest and stable, the later magnetism could be eliminated after heating treatment, and only the original magnetism could be retained, and the original magnetism could be preserved. href=”https://comicmov.com/”>Babaylan 1990 cloth drawMagnetic detection, Komiks 1960 witch cloth draw can tell the age of this soil layer.
Therefore, 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 centimeters 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 and make it into small soil blocks of 2 square centimeters square; then each small soil block is heated with a thermal demagnetizer, and the temperature is from 0℃ to 680℃; then measure it with a “superconductive magnetometer”, and the original magnetic direction obtained by the soil layer at that time can be obtained, which can determine their age.
Scientists found that the bottom 28th layer of loess (L28) showed a short positive polarityBabaylan 1990 cloth draw, 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 field at that time.Sexual inversion.
In the early stages of the fourth Cinema 1950 witch cloth draw periodKomiks 1960 witch cloth draw, two magnetic reversals occurred on the earth. One was the “Reunion incident” between 2.13 million and 2.15 million years agoCinema 1950 witch cloth draw, and the other was the “Odewey incident” that was laterBabaylan 1990 cloth draw (dating from 1.78 million to 19Komiks 1960 witch cloth draw50,000 years). Since the Oduwee incident lasted for 100,000 years, it did not meet the positive polarity of the L28 layer soil sample, which was briefly encountered. Therefore, there is only one answer to Komiks 1960 witch cloth draw. The stone tool found on the L28th floor of the Shangchen Village site should be between 2.12 million years ago.
According to reports, researchers conducted paleogeomagnetic dating on more than 700 sets of loess samples in the Shangchen Village section.
Carrying the origin of human beings in Africa is not reliable
According to Shangchen Village’s discovery, some people believe that it is possible to change the traditional theory of human beings’ origin of Africa, because the stone age of the site was far earlier than the time when humans walked out of Africa, Cinema 1950 witch cloth draw shows 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 dating from 2.8 million years ago and 300 dating from now onThe stone tools from thousands of years ago also have a series of discoveries from ancient apes, talented people, Homo erectus, to the site of Homo sapiens, Cinema 1950 witch cloth draw, which can form a continuous sequence of changes in the history of human development. The Babaylan 1990 cloth draw, and other regions outside Africa do 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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