Paleomagnetic dating shows its power again
Next, dying these stone tools has become the most important task. Dr. Wu Yi from the South China Sea Ocean Institute of Cinema 1950 witch cloth draw 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 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 Babaylan 1990 cloth draw is 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 the positive and negative reversal will occur. Therefore, there is a distinction between the positive and negative periods of paleomagnetic periods 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 comes to the reverse polarity period, the compass points to the south pole of the earth.
Cinema 1950 witch cloth drawBabaylan 1990 cloth draw
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 in Komiks 1960 witch cloth draw.
Cinema 1950 witch cloth draw<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 Quaternary Period in geology) and the historical time of each polar era. Wu Yi explained that after a long geological period, after the later soil layer was superimposed on the original soil layer, the later magnetism of Babaylan 1990 cloth draw will be superimposed on the original soil layer. However, because the original magnetism is the strongest and stable, the later magnetism of Babaylan 1990 cloth draw can be eliminated after heating treatment, and only retain the original magnetism can be retained. 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 tool from top to bottom in the field. Each sample was more than ten to twenty centimeters long, and a total of 74 meters of thickness was taken. Return to the laboratory, carefully cut each large sample of Cinema 1950 witch cloth draw and make it into small pieces of soil in 2 square centimeters; then each piece of soil is heated with a thermal demagnetizer, and the temperature is from 0°C to 680°C; then measure it with a “superconductive magnetometer”, and the original magnetic direction obtained by the soil layer at that time can be obtained. This can determine their age.
Scientists found that the bottom 28th layer of loess (L28) showed a short positive polarity, and this soil layer should be in the “Songshan reverse polarity period” of the geomagnetic field, which shows that this layer of loessAt that time, I experienced a magnetic reversal.
In the early stages of the Quaternary period of Cinema 1950 witch cloth draw, 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 “OdeweyBabaylan 1990 cloth draw” (1.78 million to 1.95 million years ago) Cinema 1950 witch cloth draw. Since the Odewey incident lasted for 100,000 years, it did not meet the situation of positive polarity of the 28-layer soil sample, which was briefly present, 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.
Komiks 1960 witch cloth draw According to reports, the researchers conducted paleogeomagnetic dating samples of more than 700 groups of loess in the Shangchen Village section.
Komiks 1960 witch cloth drawThe theory of changing the origin of human beings in Africa is not reliable
For the discovery of Shangchen Village, some people believe that it is possible to 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, which means that human beings had left Africa at least 1.8 million years ago.
YesZhu Zhaoyu said that the current discovery in Shangchen Village is not enough to change the theory of human beings leaving Africa, because Africa not only discovers ancient human fossils dating from 2.8 million years ago and Komiks 1960 witch cloth draw stone tools, but also a series of discoveries from ancient apes, nudes, Homo erectus, and Homo erectus to Homo sapiens sites, which can form a continuous sequence of changes in the history of human development, but other regions outside Africa do not have this. Draw like 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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