Rocks never forget!

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Figure1. Elephant rock, Castelsardo, Sardinia, Italy (picture by Vid Pogačnik)

Did you know that some rocks can have an incredible “magnetic memory”? The age of rocks can vary from seconds to billions of years, and besides their sometimes very old age they store information that is useful to reconstruct the history of our Planet.

We commonly use the word “memory” referring to our computer storage capacity or our own ability to remember. Rocks store information, but unlike us they are able to do it over longer periods of time. The oldest memory we have is limited to what humankind experienced but some rocks are much older than humans. Therefore it is really important to be able to extract their memories in order to better understand what we didn’t experience ourselves.  

This “magnetic memory” relates to certain minerals in rocks (e.g. magnetite, hematite) able to record the direction and the intensity of the Earth’s magnetic field when they form.

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Up and down! What?

What happens when magnetic reversals occur? This is what I asked my professor during my first year at university when he mentioned the “reversals of the Earth’s magnetic field” and I remember that joking he answered: we will be “up and down”!

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Figure 1: Cartoon of a man being up and down.

Well, this would be an interesting experience but instead of us, our compass needle is reversing! This may sound boring but there is a lot more around this phenomenon. No human on Earth has experienced a magnetic reversal as we are too young for that (the latest one occurred 780,000 years ago); however there is evidence that it happened many times in the Earth’s history. Its discovery has played a major role in the development of Earth Science. Continue reading

“Geology isn’t a real science!”

Dr. Sheldon Cooper, physicist, from “The Big Bang Theory”, and his strange relationship with geology! (still image from “The Big Bang Theory”)
Dr. Sheldon Cooper, physicist, from “The Big Bang Theory”, and his strange relationship with geology! (Still image from “The Big Bang Theory”)

Some of you probably know “The Big Bang Theory” sitcom and if not I strongly suggest it. One of the characters in this funny American sitcom is a physicist and he firmly believes that geology cannot be considered as a real science. This is a pretty strong statement and it makes us think …..So let’s borrow this exclamation “Geology isn’t a real science!” and reflect about what geology is.

You probably know the stereotype of a geologist: shorts with a thousand pockets, a hammer, a compass and a magnifying glass. But what is this sort of David Attenborough looking for? Continue reading