A recent study led by Mark Altaweel of University College London reveals that ancient Mesopotamian bricks confirm a 3,000-year-old anomaly in Earth's magnetic field.
The bricks' iron oxide grains, heated during baking, recorded magnetic field changes, aiding researchers in reconstructing historical variations. The discovery holds potential for dating artifacts.
Mesopotamian Mud Bricks Reveal Ancient Earth's Magnetic Surge
Thousands of years ago, an unnoticed surge in Earth's magnetic field occurred over Mesopotamia, with preserved signs in baked mud bricks. A recent analysis of bricks dating from the third to the first millennia BC in Mesopotamia revealed magnetic signatures, indicating firing during a period of unusual magnetic strength.
Stamps with Mesopotamian kings' names provided a time range for this magnetic anomaly. The study, titled "Exploring geomagnetic variations in ancient Mesopotamia: Archaeomagnetic study of inscribed bricks from the 3rd-1st millennia BCE" published in PNAS, addresses challenges in dating cultural remains lacking organic material.
The researchers focused on 32 clay bricks from Mesopotamia, looking at iron oxide grains sensitive to the magnetic field. The distinct magnetic signature retained when heated allowed the creation of a timeline for Earth's magnetic field changes. Each brick, inscribed with a king's name, was dated using earlier findings.
By combining these dates with measured field strength, the researchers uncovered a notable magnetic anomaly, the "Levantine Iron Age geomagnetic Anomaly," between 1050 and 550 B.C. Although its cause remains unclear, evidence extends to China, Bulgaria, and the Azores.
Five samples from Nebuchadnezzar II's reign indicated dramatic shifts in Earth's magnetic field. This research, led by Lisa Tauxe of the Scripps Institution of Oceanography, offers high-resolution insights into the enigmatic geomagnetic field.
The well-dated remains of Mesopotamian cultures, particularly bricks inscribed with kings' names, provide a unique opportunity to study magnetic field changes in high time resolution, tracking shifts over several decades.
Clay Artifacts Key to Dating Historical Events
The Earth's magnetosphere, a protective magnetic shield generated by the planet's core, experiences variations in strength over time. While this phenomenon doesn't directly impact human health, it plays a crucial role in preventing the stripping away of Earth's atmosphere by solar winds.
Clay artifacts, when exposed to high temperatures, retain a "fingerprint" of Earth's magnetism, offering insights into historical magnetic states. The process involves multiple magnetic experiments, including heating and cooling, to create fingerprints that can be compared with the object's original magnetic intensity.
Through this method, scientists can link artifacts to specific periods of Earth's magnetic activity. This breakthrough helps not only in understanding the historical magnetic field but also in dating artifacts that would otherwise be challenging.
Cauê S. Borlina, a researcher specializing in ancient and modern magnetic fields, emphasizes the significance of high-resolution records in comprehending magnetic spikes on Earth's surface and their connection to processes within the planet's outer core where the magnetic field originates.
A recent study showed that the bricks served as a snapshot of a rapid and intense magnetic field strengthening during their creation. Beyond filling crucial data gaps, this research offers a method for archaeologists in Iraq and Syria to apply similar techniques to undated artifacts, potentially resolving debates about the chronological order of kings and historical events in the region.
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