I’ll have to read the article, but I’m guessing it has to do with the increase in radiation from the sun affecting the tree’s growth and hence the width of the rings. Not sure if more radiation would cause the tree to grow faster or slower. (Faster???)
Lava flows will show the changes in the alignment of the iron, and ancient campfires will also show the changes as the rocks around the campfire will heat up and the iron molecules will warm up and align to magnetic north, and then when the rocks cool they will be frozen in that alignment.
What I am REALLY curious about is - what the heck are they doing there? From the little photo it looks like a HUGE expanse has been excavated - and at a depth to 27 feet? I suppose a mine of some sort? I think bauxite mines can be like this.
Now to go read the article and see how far off I am!
As soon as I saw that the link was to Newsweek (that’s still around!?) I knew it wouldn’t be much help. Other than to say they discovered it while expanding a geothermal energy facility.
Hmmm - don’t let the greenies see this photo. They’ll want to shut down geothermal energy too after seeing all that barren dirt.
Lol—in true FReeper fashion!