3,000-year-old Mesopotamian bricks unlock secrets of Earth's magnetic anomalies

The study, results of which were published in the scientific journal "Proceedings of the National Academy of Sciences", employed a technique called archaeomagnetism. This method uses various artefacts to provide information about the past condition of Earth's magnetic field.

The research team is optimistic about the broader adoption of this method in the future. They anticipate it will not only enhance our knowledge about Earth's magnetic field history but also aid in more accurate dating of artefacts. In certain instances, for example, with bricks or ceramics, traditional methods like radiocarbon dating may not always produce reliable results.

The scientists explored the enigmatic magnetic signatures within iron oxide particles originating from 32 bricks excavated at various archaeological sites across Mesopotamia (which corresponds to modern-day Iraq). Each brick was inscribed with the names of kings, helping to estimate the time of their creation. When combined with the archaeomagnetic technique, this information facilitated the construction of a historical map tracing changes in the Earth's magnetic field.

As per Earth.com, the study led by Prof. Matthew Howland confirmed the presence of anomalies in the Earth's magnetic field in the Middle East between 1050 and 550 BC. During this time, the magnetic field around what corresponds to modern Iraq was exceptionally robust. What led to this is still unknown, though evidence of such an anomaly was earlier discovered in regions like China, Bulgaria, and the Azores. Notably, evidence from the southern part of the Middle East was sparse. The team additionally discovered that the Earth's magnetic field experienced a significant shift within a relatively brief period between 604 and 562 BC, suggesting that abrupt, intense fluctuations in its strength are possible.