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Earth’s Magnetic Field History

16 December 2020

At https://eos.org/articles/earths-magnetic-field-holds-clues-to-human-hist… … this is one of those stories about a break through that may reveal more than what was intended. It seems the fiery demise of Near Eastern towns preserved on tells, mainly consisting of mud bricks sorched and burnt by excessive heat, might become, inadvertently, a new area of research. Destruction events are actually a source of knowledge we are told, when it comes to the magnetic field. Ancient upheavals preserve information and can be used to pin down the timeline of history, especially in the Iron Age. The big problem for C14 dating methodology during the first millennium BC is the so called Hallstat Plateau. Dating Iron Age events by scientific methods is restricted and various other means are used in support of C14, such as tree rings [dendrochronology] and thermoluminence. The use of geomagnetic changes is an additional tool for archaeologists, it is hoped, but how does it work. Well, in the Iron Age, we are told, the geomagnetic field was high over a spread of 500 to 600 years. There was greater geomagnetic activity and that in itself is interesting as the magnetic poles are behaving oddly in the modern world as well. Back then, though, the magnetic field was much more intense and this is thought to be a valuable tool that will aid the dating methodologies. From a catastrophist point of view it might even be the way to open the eyes of science to some very odd things going on at that time. The full article is viewable at https://agupub.onlinelibrary.wiley.com/doi/full/10.1002/2016GL071494

Rocks and soil can contain minerals that are magnetic. When exposed to intense heat the internal magnetic signature is erased. It happens to lava during volcanic eruptions and to clay pottery when fired in a kiln. As the material cools down it takes on the characteristics of the geomagnetic field that surrounds it. As an experiment, mud bricks were measured for their magnetic direction and for the instensity of the field. Mud bricks were a common building material in the Near East throughout the Bronze and Iron ages and after being heated make a perfect medium for study, and hopefully, for the archaeologists, an ability to date Iron Age events more exactly. The destructions are of course assumed to be the result of acts of warfare, by a majority of archaeologists. Presumably, they might also throw some light on catastrophic events – not just on human beligerence. An interesting development.

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