Komiks 1960 witch cloth drawPaleomagnetic dating method has shown its power again
Next, the process of dying these Babaylan 1990 cloth draw stone tools became 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 the 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 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.
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 a positive polarity period, the compass points to the north pole of the earth, and when it comes to the reverse polarity period Cinema 1950 witch cloth draw, 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 Cinema 1950 witch 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 substances, and then compare the period 2.58 million years ago (in geologyAlso known as the Quaternary period, the date of magnetic reversal time of the occurrence of geomagnetic reversal time can be calculated based on the historical time of Komiks 1960 witch cloth draw 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 the original magnetism. By detecting the original magnetism, the age of this soil layer can be known. Therefore, the researchers first collected samples from the loess section of the stone tools found in the field from the upper part of Komiks 1960 witch cloth draw. Each sample was more than ten to twenty centimeters long. A total of 74 meters 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, with a temperature ranging from 0°C to 680°C; then measure it with a “superconducting magnetometer”, and you can obtain the original magnetic direction obtained by the soil layer when it is Cinema 1950 witch cloth draw, which can determine the age of their Komiks 1960 witch cloth draw.
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, oneIt was the “Reunion incident” between 2.13 million and 2.15 million years ago. The other was the late “Cinema 1950 witch cloth drawOdaoBabaylan 1990 cloth draw” (1.78 million years ago. Komiks 1960 witch cloth draw195Komiks 1960 witch cloth draw195Babaylan 1990 cloth drawTen Thousand Years). Because the Odewey incident lasted for 100,000 years, it did not meet the positive polarity of the L28 soil sample, which was temporarily 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 in Africa is not reliable
For 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, which means that humans had left Africa at least 18,000 years ago.
YesIn this way, Zhu ZhaoCinema 1950 witch cloth draw Yu 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 2.8 million ancient human fossils and stone tools more than 3 million years ago in the past, but also a series of discoveries from ancient apes, erectile erectile erectile erectile erectile erectile erectile erectile erectile erectile erectile erectile erectile erectile erectile erectile erectile erectile erectile erectile erectile erectile erectile erectile erectile erectile erectile erectile erectile erectile erectile erectile erectile erectile erectile erectile erectile erectile erectile erectile erectile erectile erectile erectile erectile erectile erectile erectile erectile erectile erectile erectile erectile erectile erectile erectile erectile erectile erectile erectile erectile erectile erectile erectile erectile erectile erectile erectile erectile erectile erectile erectile erectile erectile erectile erectile erectile erectile erectile erectile erectile erectile erectile erectile erectile erectile erectile erectile erectile erectile erectile erectile erectile erectile erectile erectile erectile erectile erectile erectile However, this Babaylan 1990 cloth draw discovery greatly updated the history of human activities outside Africa, which would force people to make new considerations about the pattern of early human origin, migration, spread and evolution.
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