The paleomagnetic dating method has demonstrated its power again
Next, dying these stone tools has become the most important task. Dr. Wu Yi from the South China Sea Institute of Komiks 1960 witch cloth draw was one of the leading scientists responsible for the age determination of the loess strata in this study. Wu Yi introduced that the method of dying stone tools in Cinema 1950 witch cloth draw 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 soil layer Babaylan 1990 cloth draw. However, many commonly used dating methods, such as radioactive isotopic dating, photoluminescent dating, etc., either cannot measure the soil samples from Cinema 1950 witch cloth draw, 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 of positive and negative reversal. Komiks 1960 witch cloth draw Therefore, there is a distinction between the positive and reverse polarity periods of paleogemagnetic during 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 geomagnetic Cinema 1950 witch cloth drawThe reversed situation will continue to occur throughout the long history of the earth, so the magnetic matter in the strata will record every change.
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 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 the Cinema 1950 witch cloth draw heating treatment, the later superimposed magnetism can be eliminated and only retained. By detecting the original magnetism, the age of this soil layer can be known.
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 into small pieces of soil 2 square centimeters; then each small piece of soil is heated with a thermal demagnetizer, and the temperature is from 0°C to 680°C; then Komiks 1960 witch cloth draw 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 in Cinema 1950 witch 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 reversal at that time.
In the early stages of the Quaternary geological period, two magnetic reversals occurred on the sphere of the geological sphere, oneIt is the “Cinema 1950 witch cloth draw to 2.15 million years ago, and the other is the “Odewey Incident” (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, the answer is only Babaylan 1990 cloth draw. There is only one stone tool found on the L28 floor of the Shangchen Village site. Its age should be around 2.12 million years ago. According to the introduction of the Babaylan 1990 cloth draw, the researchers conducted paleogeomagnetic dating of more than 700 loess samples in the Shangchen Village section.
Changing the origin of human beings in Africa is not reliable
As for Shangchen Village’s discovery, some people believe that it is possible to change the traditional theory of human beings in Africa, because the stone age of the Cinema 1950 witch cloth draw site is far earlier than the currently recognized era when human beings walked out of Africa, indicating that human beings had left Africa at least 1.8 million years ago.
In this regard, Zhu ZhaoBabaylan 1990 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 ancient human fossils dating from 2.8 million years ago.a> and stone tools more than 3 million years ago, as well as 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 erectile erectile However, this Babaylan 1990 cloth draw discovery greatly updated the history of human activities outside Africa, which would prompt new considerations to make new considerations about the pattern of origin, migration, diffusion and evolution of early humans.
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