The Lithosphere Shopping Centre

My research project is focused on the Earth’s lithosphere which is the outermost layer of the planet and consists of the crust and the upper portion of the mantle. Under the continents it extends more than 100 km deep and it is an extremely hot layer under enormously high pressure. Apparently there is no way to take a sample from that layer, we can’t dig or drill to this depth.

So why do we need to study so deeply? Diamonds. Diamonds are produced in the mantle by super-high pressure which can be reached only under the very thick continents. The more ancient the continent, the more thicker the lithosphere and the more chances to have diamonds there.

Kimberlitic pipes are carrying diamonds out from the mantle, but if we are lucky they also carry pieces of rock from deep levels of the lithosphere. Kimberlitic melt is going from the mantle through the whole lithosphere to the surface and taking samples on its way.

To understand this better imagine you are going to shopping mall to buy diamonds.

You know you can find diamonds in David Jones only and it’s the lowest level; Big W is on the highest and Target is in between them. There are two lifts but there is no information which level they will go to. What will you do? Of course, you’re going to ask people coming up by the lifts where they are coming from.

3MT_Tret

Kimberlitic pipes work as lifts in the shopping centre, providing us with the samples from each level. Generally, I’m trying to understand from which level this particular kimberlitic pipe came from and is it possible to find diamonds on that layer. Using different techniques I’m analyzing the age and composition of minerals coming up by kimberlitic pipes. And if diamonds are a girl’s best friend, then my best friends are zircons and sulfides, because due to radioactive decay of some elements in these minerals I can determine their age and as result – the age and thickness of lithosphere.

This approach of my study has already showed that in Siberia in Russia the diamond-prospective area can be extend much further than previously suggested.

Of course, diamonds are the only part of story. Careful study of minerals and rocks carried out by kimberlitic pipes can tell us a lot about the structure of the lithosphere, its evolution and relationship with geological processes and the environment.

Irina won the People’s Choice award at the 2014 3MT competition.

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