Paleomagnetic dating shows its power again
Next, the process of termination of 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 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, then Babaylan 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 are not suitable for dust deposits such as loess.
So, a technology called paleomagnetic dating is now showing its power here at Komiks. It turns out that in the geological historical period, the magnetic polarity of the earth is not fixed and reversed, so there will be a situation where the positive and negative reversals occur. Therefore, there is a distinction between the positive and negative 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 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, as long as geological workers measure 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), as well as the historical time of each polar era, they 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 magnetic properties will be superimposed on the original soil layer. However, since the original magnetic properties are the strongest and stable, after heating treatment, the later superimposed magnetic properties can be eliminated, retaining only the original magnetic properties, and by the original magnetic propertiesBy testing, you can know the age of this soil layer.
Therefore, the researchers first collected samples from top to bottom of the loess profile 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 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 Cinema0℃Komiks to 680℃Cinema; then Babaylan to 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 28th layer of loess (L28) showed a short positive polarity, and this soil layer should have been in the “Rose Mountain 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 earth. One was the “Reunion Incident” between 2.13 million and 2.15 million today, and the other was the “Odewey Incident” (1.78 million to 1.95 million today). 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 found on the L28th floor of the Shangchen Village site should be 2.12 million years ago.
Babaylan According to reports, the research is Cinema personnel conducted paleogemagnetic dating on several groups of loess samples in Shangchen Village.
Cinema said it was not reliable. Regarding Shangchen Village’s discovery, some people believe that it may change the Babaylan theory of human origin in Africa, because The stone instruments of this site are far earlier than the time when humans walked out of Africa, which means that humans left Africa at least long ago.
Zhuyu said that the current discovery in Shangchen Village is not enough to change the theory of humans leaving Africa, because Africa has not only discovered ancient humans 2.8 million years ago. href=”https://comicmov.com/”>Cinemafossils and stone tools more than 3 million years ago, as well as a series of discoveries from ancient apes, nudes, Homo erectus, to Homo sapiens sites, 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 of Africa, which will prompt people to make new considerations about the pattern of early human origin, migration, diffusion and evolution. Cinema
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