Paleomagnetic dating shows its power again
Next, dying these stone tools has become the most important task. Cinema 1950 witch cloth draw
South China Sea Institute of Chinese Academy of SciencesBabaylan 1990 cloth drawDr. Wu Yi from the Institute of Foreign Studies of the United States 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 know the age of the stone tools found in the Komiks 1960 witch cloth draw 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 technology called paleomagnetic measurement of the Babaylan 1990 cloth draw 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 and negative 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, so the magnetic matter in the formation will record every change.
Because Cinema 1950 witch cloth draw, geologists only need to measure the positive and negative polarity of the geomagnetic recorded by magnetic substances, and then compare the positive and negative polarity of 2.58 million years ago (also known as the Quaternary Period in geologyref=”https://comicmov.com/”>Komiks 1960 witch cloth draw)Cinema 1950 witch cloth drawThe specific time of the geomagnetic reversal time occurs, and the historical time of each polar era of Cinema 1950 witch cloth drawThe age of magnetic matter can be calculated. Wu Yi explained that during a long geological period, after the later soil layer was superimposed on the original soil layer of Komiks 1960 witch cloth draw, the later magnetic properties would be superimposed on the original soil layer of Babaylan 1990 cloth draw onto the original soil layer of Babaylan 1990 cloth draw, but because the original magnetic properties were the strongest and stable, after heating treatment, the later magnetic properties could be superimposed on Komiks 1960 witch The cloth draw‘s nature fades away, retaining only the original magnetism. By detecting the original magnetism, you can know the age of this soil layer. Therefore, the researchers first collected samples from top to bottom on the loess section of the Babaylan 1990 cloth draw 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 lab and carefully cut each large sample Komiks 1960 witchThe cloth draw is opened and made into small soil blocks of 2 square centimeters; then each Komiks 1960 witch cloth draw is first heated by a thermal demagnetizer, and the temperature is from 0℃ to 680℃; then measured 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 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 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). Since the Oduwee incident lasted for 100,000 years, it was denied that it did not meet the positive polarity of the L28 soil sample for a short period of time. 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
As for Shangchen Village, Babaylan 1990 cloth draw, some people believe that Komiks 1960 witch cloth draw may change the traditional theory of human beings’ origin of Africa. Babaylan 1990 cloth draw because the stone age of this site was far earlier than the time when human beings walked out of Africa, it means 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. Cinema 1950 witch cloth drawBecause Africa has not only discovered ancient human fossils dating 2.8 million years ago and more than 3 million times ago.A>The stone tools of a year ago, Cinema 1950 witch cloth draw, and 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 erectile erectile erectile erectile erectile erectile erectile erectile erectile erectile erectile erectile erectile erectile erectile erectile erectile erectile erectile However, this discovery greatly updates 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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