Paleomagnetic dating shows its power again
Next, dying these stone tools has become the most important task. Dr. Wu Yi from the Nanhai Ocean Institute of Cinema 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 strata samples where the stone tools are located. As long as Komiks knows the age of the soil layer, then Cinema will 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 the soil samples from millions of years ago, or are not suitable for dust deposits such as loess.
So, a technology called paleomagnetic dating was shown 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 where positive and negative reversals occur. 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 not be available in the long history of the earth.The interruption occurs, so the magnetic material in the formation will record each 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. Babaylan
Wu Yi explained that during a long geological period, after the later soil layer was superimposed on the original soil layer, the later magnetism would be superimposed on the original soil layer. However, since the original magnetism was the strongest and stable, after heating treatment, the later superimposed magnetism could 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 the loess section of the stone tool from top to Babaylan 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 into small soil blocks of 2 square centimeters; then each small soil block is heated first with a thermal demagnetizer, and the temperature is from 0℃ to 680℃; then use a “superconductive magnetometer” to obtain the original magnetic direction obtained by the soil layer at that time, 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 be in the “Cinema 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 years ago to 1.95 million years ago). Since the Oduwee incident lasted for 100,000 years,href=”https://comicmov.com/”>Komiks does not meet the positive polarity of the L28 layer soil sample, which is briefly occurring, and is therefore denied. Therefore, there is only one answer. The stone tools found on the L28th floor of the Shangchen Village site should be 212 thousands of 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’s discovery, some people believe that it may 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 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, because Africa has not only discovered ancient human fossils dating from 280 years ago and stone tools dating from Cinema more than 3 million years ago, but also established people from ancient apes, talented people, and direct people. href=”https://comicmov.com/”>Babaylan, a series of discoveries to the Homo sapiens site can form a continuous sequence of changes in the history of human development, and other regions outside Africa do not have such continuity. 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.
1 2