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 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 the 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, Cinema light luminescence dating, etc., either cannot measure soil samples millions of years ago, 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 where positive and negative reversals occur. Therefore, there is a distinction between the positive and reverse polarity periods of paleogemagnetics in the geological historical period. When it is in a positive polarity period, the compass points to the north pole of the earth, and when it comes to the anti-polarity period, the compass points to the south pole of the earth.
This kind of geomagnetic inversion of Komiks will continue to occur throughout the long history of the earth, so the magnetic matter in the strata will record every change. Therefore, geologists only need to measure the positive and negative situations of geomagnetic polarity recorded by magnetic substances, and then compare the specific time when the time occurs in reversed, as well as the historical time of the Babaylan era during the period of 2.58 million years ago (also known as the Quaternary period in geology) and the historical time of the Babaylan era in each polarity., you can calculate the age of magnetic matter. 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 heating treatment, the later superimposed magnetism can be eliminated, and only the original magnetism of Cinema can be retained. By detecting the original magnetism, we can know the age of this soil layer. Therefore, the researcher first collected samples from top to bottom of the loess section of the stone tools at the field site. 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 laboratory, carefully cut each large sample and make small soil blocks of 2 square centimeters square; then each small soil block is heated first with a Cinema thermal demagnetizer, with a temperature ranging from 0°C to 680°C; then use a “superconductive magnetometer” for measurement, and the original magnetic direction obtained by the Babaylan layer at that time can be obtained, which can determine their age.
Scientists found that the bottom 28th layer of yellow Komiks soil (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 yellow soil 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” (1.78 million to 1.95 million years ago). Because the Oduwee incident lasted for 100,000 yearsIt is not consistent with the positive polarity of the L28 layer soil sample for a short time, so it was 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.
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 Komiks is currently in the Shangchen Village. Babaylan is still insufficient 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 and stone tools dating from more than 3 million years ago, but also ancient apes, talented people, href=”https://comicmov.com/”>CinemaThe series of discoveries from Homo erectus to the site of Homo sapiens 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 on the pattern of early human origin, migration, and expansion of Komiks.
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