Archaeologists have made a remarkable discovery – ancient Mesopotamian bricks made over 3000 years ago contain evidence of a mysterious event that caused abnormalities in Earth’s magnetic field for a period of time. Analysis of the magnetic properties preserved in these inscribed bricks has unveiled crucial insights into our planet’s deep past.
Overview of Findings
The study published in Proceedings of the National Academy of Sciences analyzed 37 inscribed bricks excavated from multiple archaeological sites across Mesopotamia, the region between the Tigris and Euphrates rivers in modern day Iraq.
Using a quantum diamond microscope, researchers identified unusual levels of magnetic minerals in the fabric of bricks made during the Neo-Assyrian Empire between 900 BC to 600 BC. The higher concentration and alignment of magnetic particles indicates the strength of Earth’s magnetic field increased significantly during that period.
Lead author Dr. Jonathan Friedman from Tel Aviv University explains:
“We found that the strength of the magnetic field almost doubled over a period of 200 years. It’s an abnormal phenomenon we can’t explain with our current understanding of Earth’s magnetic fields.”
Significance for Archaeomagnetic Dating
The ability to accurately date archaeological artifacts and sites is crucial for piecing together human history. Archaeomagnetic dating measures subtle changes in Earth’s magnetic field over time that get imprinted in baked clay like bricks when they are manufactured.
This newly identified anomaly will greatly improve the dating precision of Mesopotamian artifacts in museum collections from this era:
Time Period Dating Precision Before Dating Precision After
Bronze Age ± 120 years ± 35 years
Iron Age ± 100 years ± 30 years
Study co-author Professor Erez Ben-Yosef emphasizes how integrating geomagnetic science creates a positive feedback loop, enriching both disciplines:
“Archaeology provides long-term geomagnetic data while geomagnetism supplies archaeologists with a precise dating reference. Accuracy has increased by an order of magnitude.”
Theories on What Caused This Ancient Magnetic Anomaly
Earth generates its magnetic field from the spinning, convecting liquid iron alloy at our planet’s outer core over 3000 km below the surface. Minor fluctuations in magnetic intensity naturally occur due to dynamic flows in the molten outer core.
But this newly found spike between 1000 BC and 600 BC far exceeds normal variation. Researchers speculate 3 hypotheses that may account for the abnormal strengthening event:
Solar storm: A massive burst of solar wind disrupted Earth’s magnetosphere. Further modeling is needed on how much solar wind energy would be required to effect changes deep underground.
Meteor impact: A large iron-heavy meteor plowed into Earth’s crust and momentarily magnetized the upper mantle rocks. However the temporary spike would be expected to gradually weaken, not remain elevated for 200 years.
Exotic inner core formation: Crystallization of the metallic inner core released heat that strongly drove outer core convection currents for centuries. But little evidence exists to support the timing of this proposed event.
Overall the origins of this 900-600 BC geomagnetic jerk remain mysterious for now. More interdisciplinary investigation blending archaeology, geophysics, space science and planetary dynamics is warranted to unravel this ancient magnetic puzzle.
What’s Next For This Research
The research team has already scanned over 100 Mesopotamian bricks in museum collections across Europe and the Middle East, but many more await analysis. Taylor University geophysicist Dr. Matthew Jalbert who contributed modeling work to the study says:
“Expanding the dataset to include other archaeological artifacts over a wider geographic area would allow us to really trace the timing and contours of this anomaly. Integrating more evidence helps determine whether this was a global or localized event in Earth’s past.”
Broader sampling can clarify the spatial extent, duration and intensity profile of the abnormal field strength occurrence. It may also detect any precursor build-up or aftermath decline effects.resolution phenomenon or if secondary processes are amplifying the signal.
Fine-grained temporally sequential samples could also reveal whether the strengthened state was gradual over 200 years – or whether it was a sudden high-
Additionally, the researchers suggest exploring objects magnetized through lightning strikes or volcanic lava flows to exclude if alternative magnetizing factors were at play. Ruling out these variables bolsters the case for a bonafide geomagnetic jerk event.
For now, the 3000-year old Mesopotamian bricks have presented the first tangible evidence of an unaccounted for magnetic anomaly in Earth’s history. One that may harbour valuable lessons about the dynamics and secrets of the spheres embedded deep within our planet.
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