Paleomagnetic dating shows its power again
Next, dying these stone tools has become the most important task. Dr. Wu Yi from the Cinema Ocean Institute of the South China Sea, Chinese Academy of Sciences 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., cannot measure soil samples a million years ago, or are not suitable for dust deposits like loess.
So, KomiksA technology called paleomagnetic dating is here. 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.
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 of geomagnetic reversal time (also known as the Quaternary Period 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 Komiks, after the later soil layer was superimposed on the original soil layer during a long geological period, the later magnetic properties would be superimposed on the original soil layer, but because the original magnetic properties were the strongest and stable,After the heating treatment, the later superimposed magnetism can be eliminated and only 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 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; then each small soil block is heated with a thermal demagnetizer, and the temperature is from 0°C to 60°C; 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 2nd 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 inversion 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” (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 located on the L28th floor of the Shangchen Village site was discovered in the Shangchen Village ruins. Its age is 2.12 million years ago.
According to reports, the researchers of Babaylan conducted paleogeomagnetic dating on more than 70 groups of loess samples in the Shangchen Village section.
Changing the origin of human beings in Africa is not reliable
About Shangchen Village’s discovery, some people believe that Cinema may change the traditional theory of human beings in 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 1.8 million years ago.
In this regard, Zhu ZhaoyuCinema said that the current discovery in Shangchen Village is not enough to change the theory of human beings leaving Africa, because CinemaAfrica has not only discovered ancient human fossils dating from 2.8 million years ago and stone tools more than 3 million years ago, but also a series of discoveries from ancient apes, nudes, Homo erectus, to the ruins of Homo sapiens, which can form a continuous sequence of changes in the history of human development. href=”https://comicmov.com/”>Komiks 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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