Matthew D. Howland
This ancient adobe was engraved with an inscription mentioning the Mesopotamian king Yakun Diri. Researchers sampled it for study and are excited about how artifacts like this can help study Earth’s magnetic field.
Sign up for CNN’s Wonder Theory science newsletter. Explore the universe with news about interesting discoveries, scientific advances, and more.
CNN
—
Thousands of years ago, Earth’s magnetic field A significant power surge occurred in parts of the Earth, including the ancient kingdom of Mesopotamia. People at the time probably didn’t notice the fluctuations, but signs of the anomaly, including previously unknown details, were preserved in the adobe bricks they baked, new research shows. It turned out that.
When scientists recently examined bricks in Mesopotamia that date back to between 3000 B.C. and 1000 B.C. Including current Iraq Magnetic signatures from the first millennium have also been detected in parts of present-day Syria, Iran, and Turkey, indicating that bricks were fired at a time when the Earth’s magnetic field was unusually strong. A stamp on the brick with the name of a Mesopotamian king allowed researchers to see the time range of the magnetic spike.
Their discovery coincided with a known magnetic surge called the Levantine Iron Age geomagnetic anomaly, which occurred between 1050 and 550 BC.This has been previously recorded in artifacts from the Azores, Bulgaria and China, using archaeomagnetic analysis – examining the particles of archaeological objects in pottery and ceramics to gain clues about the Earth’s magnetic activity. to investigate, the scientists reported Dec. 18 in the journal Proceedings of the National Academy of Sciences.
“It’s really interesting that ancient artifacts from Mesopotamia can help explain and record important events in Earth’s history, such as fluctuations in the magnetic field,” said the study co-authors. mark altaweelProfessor of Near Eastern Archeology and Archaeological Data Science at the Institute of Archaeology, University College London.
“It shows why preserving Mesopotamia’s ancient heritage is important to science and humanity more broadly,” Altaweer told CNN in an email.
If an ancient artifact contains organic material such as bone or wood, scientists can tell how old it is through radiocarbon dating, which compares the rate of decay preserved in carbon isotopes. can.However, for inorganic artifacts such as pottery and ceramics, archaeological magnetic analysis is needed to determine their age, the study’s lead author said. Matthew HowlandAssistant Professor, Department of Anthropology, Wichita State University, Kansas.
The technique is an important complement to radiocarbon dating, Howland told CNN, because pottery is the most common type of artifact at archaeological sites around the world.
“Archaeomagnetic dating can be applied to any type of magnetically sensitive material that has been heated,” Howland said. And its usefulness extends beyond archeology.
“Geologists often use analysis of rocks to study the Earth’s magnetic field, but in more recent times, when rocks have not yet had time to form and cannot be studied, archaeological artifacts “We need to take advantage of it,” he said. . “Adobe bricks and pottery can be thought of as artificially created stones to study the Earth’s magnetic field.”
Prior to this new study, there was little precise archaeomagnetic evidence from Mesopotamian artifacts up to this time.
“Due to the lack of data, our ability to understand the state of the Earth’s magnetic field in that region was very limited,” Howland said. It also meant that archaeologists were unable to accurately calculate the ages of many sites in Mesopotamia, “a region of great importance in world archeology.”
The Earth is surrounded by the magnetosphere, an invisible magnetic bubble created by the powerful stirring of molten metal at the Earth’s core. It prevents the atmosphere from being stripped away by the solar wind blowing from the sun. The magnetosphere has always existed for billions of years, but its strength waxes and wanes over time. (Human health is not directly affected by magnetic field fluctuations. United States Geological Survey. )
Clay artefacts fired at high temperatures retain the “fingerprints” of the earth’s magnetism at the time in minerals such as iron oxide that were affected by magnetism. Obtaining that fingerprint requires a series of magnetic experiments in which the object is repeatedly heated and cooled, exposed to a magnetic field, and then removed. This process creates a series of new fingerprints that are compared to the object’s original magnetic strength.
Scientists can then match the object to specific periods of activity in the Earth’s magnetic field.
“Overall, this is an exciting study because it helps us understand how the Earth’s magnetic field is affecting us over time, and it also allows us to determine the age of artifacts that would not otherwise be possible. It also helps us make decisions,” he said. Cow S. Borulina, a postdoctoral fellow in the Department of Earth and Planetary Sciences at Johns Hopkins University. Borlina was not involved in this study, but he conducts research on ancient and modern magnetic fields and their effects on planet formation and habitability.
“Most importantly, these high-resolution records are critical to understanding how magnetic spikes at the surface relate to what’s happening inside the Earth,” Borlina said in an email. told CNN. “Especially in the outer core, where the Earth’s magnetic field originates.”
The new analysis not only fills in important data gaps, but also reveals new clues about the magnetic anomalies of the era.
Of the 32 stones the researchers sampled, five had inscriptions related to the reign of Nebuchadnezzar II between 604 and 562 BC. Measuring the magnetism of the stones showed that the magnetic field strengthened rapidly and strongly when the bricks were made. The stamp on the brick thus created a snapshot of the surge in magnetic power over just a few decades.
“The next step is to continue this research and apply it further to Mesopotamian adobe bricks to further refine the curve of Earth’s magnetic field strength produced over time,” Howland said. Ta.
“But perhaps even more interesting is that archaeologists working in the field in Iraq and Syria can examine our data and apply the same techniques to artifacts of unknown date,” he added. “This will help resolve many of the debates about the dating of kings that occur in the region.”
Mindy Weisberger is a science writer and media producer whose work has appeared in Live Science, Scientific American, and How It Works magazines.