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 sample where the stone tools are located. Komiks 1960 witch cloth drawAs long as you know the age of the soil layer, you will also know the age of the stone 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 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, so there will be differences between positive and negative polarity periods in the geological historyKomiks 1960 witch cloth draw 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 only need to measure the positive and negative situations of geomagnetic polarity recorded by magnetic substances, and then compare the date of 2.58 million years ago (also called the second in geology.The specific time of the occurrence of geomagnetic reversal time Babaylan 1990 cloth draw, as well as the historical time of each polar era, can be used to calculate the age of magnetic matter. Wu Yi explained that after a long geological period, the later soil layer will be superimposed on the original soil layer, but because the original Cinema 1950 witch cloth draw has the strongest and stable magnetic properties, so after the heat treatment, the later superimposed magnetic properties can be eliminated, retaining only the original magnetism, and by href=”https://comicmov.com/”>Cinema 1950 witch cloth drawIt turns out that by detecting magnetic properties, you 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 tool in the field. Each sample was more than ten centimeters to twenty centimeters long. In total, a total of 74 meters 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 with a thermal demagnetizer, and the temperature is from 0℃ to 680℃; 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 28th 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 reversal at that time.
In the early stages of the Quaternary geological period, two magnetic reversals occurred on the earth, one Cinema 1950 witch cloth draw is the “Reunion incident” between 2.13 million and 21 years ago. The other is the “Omire” incident that dates from 2.13 million to 21 years ago. The other is the “Omire” incident that dates from 170,000 to 1.95 million years ago. Because the Omire incident lasts for 1 years, Komiks 1960 witch cloth draw for 1 years. href=”https://comicmov.com/”>Babaylan 1990 cloth drawFor 00,000 years, it did not meet the positive polarity of the L28 soil sample, so it was denied. Therefore, there was only one answer. The stone tool found at the Shangchen Village site on the 28th floor of the Cinema 1950 witch cloth draw should be around 2.12 million years ago.
According to reports, researchers conducted paleogemagnetic dating on more than 700 sets of loess samples in the Shangchen Village section.
Changing the origin of human beings is not reliable
For the Shangchen Village, it is not reliable to change the origin of human beings. According to this, some people believe that it may change the traditional theory of human origin in Africa, because the stone age of the site is far earlier than the currently recognized era when humans walked out of Africa, which means that humans left Africa at least 1.8 million years ago.
Zhuyu Zhu said that he is currently on the Babaylan Babaylan 1990 cloth draw Chencun’s discovery is not enough to change the theory of human beings leaving Africa, because Africa has not only discovered ancient times 2.8 million years ago.ttps://comicmov.com/”>Komiks 1960 witch cloth drawhuman fossils and the stone tools dating more than 3 million years ago, as well as a series of discoveries from ancient apes, nudes, Homo erectus, to the ruins 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 humans outside Africa. The history of the existence of draw activities will prompt new considerations to the pattern of early human origin, migration, spread and evolution. Babaylan 1990 cloth draw.
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