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This is geology B with all of us
trampled. 

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When plate tectonics was first 
discovered some parts of the 

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planet quickly fell into place 
as textbook examples of plate, 

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tectonics in action. 
The best examples where the 

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oceanic plates of the Atlantic, 
and the Pacific with their rigid

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plates, forming at mid-ocean 
spreading ridges, and being 

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consumed at subduction zones, 
But other parts of the world 

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were not so easily. 
Understood notably the 

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Mediterranean. 
Laurence Olivier is a professor 

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at The Institute of Earth 
Sciences at the sorbonne 

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University. 
He's interested in the processes

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that drive the motion of the 
plates, as well as the motion in

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the mantle below them, a field 
called Geo Dynamics. 

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He has unravelled, the 
geological history of the 

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Mediterranean, which to put it 
mildly is not quite as simple as

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that of the Atlantic and the 
Pacific. 

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Let me suggest upfront that for 
this podcast in particular, it 

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would be helpful to look at the 
illustrations of a geology, by 

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its website long. 
As you leave. 

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A welcome to Georgie B in the 
introduction. 

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I said that the Mediterranean is
not a normal ocean, but before 

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we talk about the Mediterranean,
what do we mean? 

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When we talk about normal ocean,
the best example would be the 

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Atlantic Ocean open between the 
Erasure. 

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AA on the Eastern side and North
America on the Northern side or 

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Africa versus South America. 
So it's open, starting with the 

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rift within our continent. 
Continental crust is thin and 

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then it's replaced by oceanic 
crust. 

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And from there on the two 
continents, they move away from 

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each other and large ocean is 
Progressive reform during 100 or

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200 million years. 
That's the case of the Atlantic 

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Ocean. 
So the bottom of the ocean is 

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everywhere. 
Oceanic crust made of mainly 

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basic rocks, like Basalt or 
Gabriel's Mediterranean is very 

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different from that used to be a
very large ocean, it had a 

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compression or history that that
modified it quite significantly.

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So overall the crust of say the 
Atlantic is extending taking up 

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more space, on the surface of 
the Earth, but as you alluded to

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the overall context of the 
Mediterranean tells us right 

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away that something quite 
different must be happening. 

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Okay. 
And that's because we know that 

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Africa is moving northwards and 
colliding with Europe, which 

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should in fact be reducing the 
space available between the two.

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So there's a kind of paradox 
here. 

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There is a paradox if you think 
of the Mediterranean as a normal

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ocean, but actually since the 
late Cretaceous say, around 84 

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million years ago, the 
Mediterranean has been shrinking

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because Africa has been 
converging with respect. 

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Eurasia moving northward with 
respect to Europe and this 

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convergence is accommodated 
within several subduction zones 

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where the African lithosphere is
diving into the mantle 

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underneath Europe and these 
abductions subduction zone, they

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have a special behavior 
actually, not that special 

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because it's quite frequently, 
the surface of the Earth. 

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The fact that the subduction 
zone itself is the trench. 

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If you like where exactly the 
place, where the subducting 

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lithosphere A sphere is 
disappearing into the mantle is 

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retreating. 
What I mean by retreating is 

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that the trench is moving away 
from the continent under which 

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the lithosphere is subducting. 
And this causes extension within

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a very wide domain that is 
shrinking. 

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So Africa gets closer to Europe.
And in the middle bits of Europe

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are moving away from Europe by 
this process that we call a 

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stab. 
So the slab is the lithosphere, 

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the rigid plate that rise over 
The Mantel. 

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And by Retreat, you mean that 
the place where the slabs? 

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Adducts, the hinge is moving 
backwards, what makes a slab 

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Retreat. 
So the idea is quite simple. 

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Let's imagine that. 
You have in your hand, a piece 

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of paper and you hold it with 
your right hand and then you you

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fold the piece of paper with 
your left hand and you pull it. 

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Downward and you will see the 
hinge of that sheet of paper. 

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Moving closer to your right hand
and this is exactly what 

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happens. 
They are in the Mediterranean, 

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the hinge is the trench. 
Most trenches are the deepest 

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part of the earth underneath the
ocean. 

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This is the trench. 
This is the hinge of that big 

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fold and the subducting 
lithosphere sinks into the 

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mantle under its own weight. 
Just like the sheet of paper 

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that you are pulling downward. 
So the hinge retreats Respect to

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the upper plate and this leads 
to extension India for played. 

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Oh, I see. 
So, as the hinge moves back, it 

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creates more space in front of 
the hinge, which creates an 

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extensional environment, just in
front of the retreating slab. 

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Yes. 
Exactly. 

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So as that slab sinks down into 
the mantle. 

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Does it have an effect on the 
mantle? 

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Presumably the mantle has to 
make way for the slab. 

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Yes of course is a very 
important Part of the subduction

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Dynamics because the slav is 
diving into the mantle sinking 

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into the mantle under its own 
weight. 

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And you can even imagine 
subduction without convergence 

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of the big plates at the 
boundary of your system. 

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So there is this component of 
subduction which is due only to 

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the weight of the slab. 
And there is another component 

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of subduction, which is due to 
convergence in the total amount 

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of Seduction is Convergence, 
plus slab, Retreat, so the 

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mantle Is underneath, of course,
will be strongly affected by 

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sinking of the mantle and by 
slab Retreat. 

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Imagine that you have your hand 
in the water and you move it 

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toward you, the water above your
hand, or below your hand. 

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With, of course, follow the 
displacement of your hand and 

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this is exactly what happens in 
the mantle. 

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And we can see this flow in the 
mantle using the tools of 

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seismology and especially what 
is called a seismic an isotropy 

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which It shows the orientation 
of minerals in the mantle and 

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disorientation depends upon this
flow. 

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So you see that the flow is 
parallel to the direction of 

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retreat that you reconstruct 
from geological evidence. 

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Just to explain that seismic and
isotropy, refers to seismic, 

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waves, such as those that are 
caused by earthquakes, whose 

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speed varies depending on what 
direction, they're traveling in.

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We expect this to happen when 
crystals in the mantle are lined

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up as Results of motion such as 
the motion induced by a sinking 

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slab. 
So we see the mantle flow moving

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with this lab in front of and 
behind the slab. 

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What happens at the edges of the
slab? 

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That's a good question, exactly.
As when you move your hand in 

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the water, the base of Mount on 
the door, just above or below. 

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Your hand will follow exactly 
the motion of your hand, but we 

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are in an incompressible fluid. 
So as soon as you move a piece 

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of the mantle somewhere, you 
have to move it to create will 

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create Eight movement somewhere 
else. 

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And in that case, the motion of 
your hand will push the 

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mentality's below toward you 
then. 

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And then on either side of your 
hand, the water will return 

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making some sort of cells 
rotating cells with an axis of 

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rotation. 
That would be vertical at would 

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call the toroidal flow at the 
edges of each piece of slab. 

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So we have natural flow 
following the slab, in the 

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middle of the slab. 
And at the edges are And of 

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Eddie as you might see next to a
paddle moving through water and 

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that's called toroidal flow. 
Perhaps we should mention that. 

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It's moving much, much slower of
the order of centimeters a year 

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though that certainly adds up 
over millions of years. 

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Exactly. 
Does this flow exert an 

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influence on the overriding 
lithosphere? 

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In fact, we have shown recently 
that the overriding little 

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sphere and this is Mental Floss,
strongly coupled. 

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We know from the And of safe, 
make an isotropy that gives you 

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the flow in the mantle and the 
direction of extension that has 

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been recorded by Roxy the crust.
So the direction of extension 

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that you can see when you walk 
in the field. 

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For instance, we know that these
directions are very often 

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parallel and numerical models 
also show that this coupling is 

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efficient and so it's flow of 
the mount or underneath the 

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crust is one very efficient 
driver of the deformation in the

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cross. 
So, the discuss is And it is 

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also very strongly affected by 
the mantle flowing underneath. 

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It is sheared actually by the 
mantle flowing underneath and 

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this explains a lot of the 
features we see in the extending

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crossed in the Aegean or indeed 
you're tearing and see for 

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instance in the Mediterranean 
region. 

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Is there a specific example 
where we can see the effect on 

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the lithosphere of the toroidal 
mantle flow going around? 

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The edge of a sinking slab? 
There is one very good example. 

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That is the Eastern 
Mediterranean, if you look at 

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the GPS videos, Citi Field which
is the the active motion 

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recorded by space geodesy. 
So the GPS satellite 

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constellation, you see that the 
main body of Anatolia. 

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Anatolia is the plate that 
covers most of turkey is 

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rotating counterclockwise about 
a rotation pole. 

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That would be somewhere in the 
Eastern Mediterranean, say north

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of see knife and this system is 
rotating further to the east. 

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Arabia is Moving toward the 
North and the Northwest. 

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And so there is rotating 
Anatolia and if you go further 

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to the west and to the South 
West, you have, then the motion 

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of the Aegean Sea of Crete 
toward the southwest. 

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And this draws an overall very 
large tidal flow with a rotation

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about a pole in the Eastern 
Mediterranean, hmm, geometry, 

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seems quite complicated. 
I was sort of naively 

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visualizing a wide plate 
subducting along a trench 

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running roughly parallel to the 
northern coast of Africa. 

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Had they're in fact being such a
large plate and did it then 

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break up. 
Yes. 

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Actually it all starts with the 
initial configuration of Africa 

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when it collided with Eurasia in
the Jurassic, there was a sort 

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of promontory sticking out of 
Africa toward the north. 

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That we now called apulia or 
Adria, sometimes presented as a 

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micro content and this because 
Collided first with Europe way 

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before the main body of Africa. 
So, we had that time, we had 

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this Promontory of Africa, 
colliding, with Europe and this 

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started to form the Alps and the
competence. 

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And then on the other side, we 
had the oceanic subduction of 

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the tethys, ocean to the East, 
and to the West. 

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So already the subduction zone 
were divided into Bart, the 

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Eastern subduction zone and the 
Western subduction zone, but it 

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was not yet the Mediterranean it
was still open. 

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Open toward the East and open to
our the west and then some 35. 

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30 million years ago, we had 
this Collision in the east, at 

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the longitude of Iran. 
And then the Zagros range 

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started to form and later 
further to the north, the 

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caucuses sensual. 
So the ocean was was somehow 

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locked in the East and the same 
thing happened in the west at 

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the longitude of Morocco and 
Spain. 

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So we had these two oceanic 
space subducting Underneath 

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Europe and separated by this 
Continental Promontory that we 

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call that Puglia, okay? 
To summarize in the Jurassic 

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about 150 million years ago, a 
former Promontory of Africa, 

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called apulia collided, with 
Europe, the Collision of two 

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continental plates, creates 
mountains. 

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And, in this case, the Collision
started to form the Alps and the

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carpathians, meanwhile on either
side of this Collision, the 

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Duction of the tethys. 
Ocean under Europe. 

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Continued toward the north. 
This carried on until about 30 

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million years ago when two more 
collisions took place, one to 

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the east around, present-day, 
Iran, and one in the west around

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Morocco and Spain. 
Yes, exactly. 

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In this very dramatic 
consequence because of the 

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Collision in the East and the 
West Northwood motion of Africa,

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was considerably Sloan and this 
make the subduction Ray, Didn't 

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change completely because the 
seduction could not swallow 

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Africa at the same velocity 
because Africa, didn't move 

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northward at the same velocity. 
As, before subduction started to

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00:13:14,500 --> 00:13:18,800
retreat in the East and side and
on the western side as well. 

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00:13:19,300 --> 00:13:22,200
So, because if you return to my 
comparison, with a sheet of 

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paper, if you don't have this 
convergence, the only way for 

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the oceanic lithosphere to sink 
into the mantle at the same 

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velocity, because The engine is 
there. 

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It's the weight of the syncing 
data sphere. 

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You have this slab Retreat that 
increases the rate of 

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subduction, despite the slower 
convergence, and this 30 35 

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million euros. 
It's really the birth date of 

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the Mediterranean. 
When this peculiar way, of 

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subduction started to proceed. 
And during that process, the 

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subducting slab was torn in 
several bar. 

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And these slabs got very narrow,
sometimes like below. 

228
00:14:01,100 --> 00:14:06,000
Ria Alba load, jibril dark 
toward the west, the narrower, 

229
00:14:06,000 --> 00:14:09,800
the slab, the faster, the 
retreat can imagine that it's 

230
00:14:09,800 --> 00:14:13,700
easier to move your hand in the 
water and to move a very large 

231
00:14:13,800 --> 00:14:16,900
Board of wood for instance 
because of the resistance of the

232
00:14:16,900 --> 00:14:19,500
fluid. 
So there are several different 

233
00:14:19,500 --> 00:14:23,300
processes that you mentioned, 
there is slab Retreat. 

234
00:14:23,700 --> 00:14:29,500
There's mantle flow and slab 
breakup or tearing How do we 

235
00:14:29,500 --> 00:14:31,900
know these things are actually 
happening? 

236
00:14:32,300 --> 00:14:36,300
So you know, they are happening 
because of to well three main 

237
00:14:36,300 --> 00:14:39,400
reasons. 
The first one is the techniques.

238
00:14:39,400 --> 00:14:43,500
We have to unravel the geometry 
of the the slabs that depth and 

239
00:14:43,500 --> 00:14:45,400
this comes from seismic 
tomography. 

240
00:14:45,600 --> 00:14:50,400
Make tomography is somehow 
analogous to echography when we 

241
00:14:50,400 --> 00:14:53,000
want to see what's inside the 
human body. 

242
00:14:53,000 --> 00:14:57,300
Except instead of using acoustic
waves, we use face make waves. 

243
00:14:57,600 --> 00:15:00,900
We have 3D models of what's 
going on in depth. 

244
00:15:00,900 --> 00:15:04,600
So the geometry of stop where 
they are straight, where they 

245
00:15:04,600 --> 00:15:09,300
are curved, when there are 
detached tone and so on and the 

246
00:15:09,300 --> 00:15:12,800
geometry can be quite complex. 
Then we have the geological 

247
00:15:12,800 --> 00:15:17,000
record in the geological record 
shows very clearly that the arcs

248
00:15:17,000 --> 00:15:21,500
like the Hellenic Arc or the 
collaboration Arcadian Arc and 

249
00:15:21,500 --> 00:15:25,200
so on are moving away from from 
Eurasia. 

250
00:15:25,600 --> 00:15:29,900
And we know the rates of this 
motion, then Can reconstructed 

251
00:15:29,900 --> 00:15:33,900
quite precisely independently of
any other data set. 

252
00:15:34,600 --> 00:15:38,500
And finally we have numerical 
models and especially now 3D 

253
00:15:38,500 --> 00:15:42,900
numerical model with rather high
resolution where you can put all

254
00:15:42,900 --> 00:15:45,600
the material, you need the 
lithosphere, the mentor, the 

255
00:15:45,600 --> 00:15:49,300
asthenosphere and so on and you 
can calculate the displacement 

256
00:15:49,300 --> 00:15:51,300
and the forces and the thermal 
Evolution. 

257
00:15:51,300 --> 00:15:54,600
And you see that this process is
feasible. 

258
00:15:54,600 --> 00:15:58,700
First an inevitable s it 
correlates very well with what 

259
00:15:58,800 --> 00:16:05,000
You see in nature, you mentioned
arcs, an arc is a curved chain 

260
00:16:05,000 --> 00:16:08,900
of volcanic activity, that we 
usually see on the plate that 

261
00:16:08,900 --> 00:16:12,500
overrides a subduction zone, 
typically a few hundred 

262
00:16:12,500 --> 00:16:15,900
kilometers from the trench and 
parallel to it. 

263
00:16:16,500 --> 00:16:20,500
And if a slab is retreating the 
active parts of the arc will 

264
00:16:20,500 --> 00:16:23,100
move in step with the retreating
slab. 

265
00:16:24,400 --> 00:16:27,700
So, to take the Hellenic Arc, 
for example, which includes 

266
00:16:27,700 --> 00:16:31,300
dormant volcanoes as well as 
active ones, like, Santorini 

267
00:16:32,200 --> 00:16:35,900
it's created by the Hellenic 
subduction zone to its South, 

268
00:16:36,000 --> 00:16:39,600
which is just North of Libya, 
which is subducting under the 

269
00:16:39,600 --> 00:16:42,900
Aegean Sea. 
And as it Retreats southwards 

270
00:16:42,900 --> 00:16:46,500
towards Africa, the volcanic 
activity of the Hellenic Arc 

271
00:16:46,500 --> 00:16:50,600
moves South with it. 
And that is in fact what we can 

272
00:16:50,600 --> 00:16:53,300
see in the geological record. 
Yes, exactly. 

273
00:16:53,800 --> 00:16:56,500
Okay. 
So I'd like to ask about some of

274
00:16:56,500 --> 00:16:59,100
the geological events that many 
of us know about. 

275
00:16:59,600 --> 00:17:02,300
Let's start with the strong 
earthquakes in the apennines 

276
00:17:02,300 --> 00:17:06,099
such as the lethal one in. 
L'aquila in 2009. 

277
00:17:06,400 --> 00:17:09,800
The earthquakes in the 
Mediterranean they are related 

278
00:17:09,800 --> 00:17:13,000
to several different processes, 
some of the earthquakes, they 

279
00:17:13,000 --> 00:17:14,800
are related directly to 
subduction. 

280
00:17:14,800 --> 00:17:18,400
We do create or below the 
Adriatic Sea or not. 

281
00:17:18,500 --> 00:17:21,000
Along the northern coast of 
Africa, you have plenty of 

282
00:17:21,000 --> 00:17:25,800
earthquakes that are caused by 
convergence and compression, but

283
00:17:25,800 --> 00:17:28,400
you also have extension 
realistic waves in the back Arc 

284
00:17:28,400 --> 00:17:31,900
region in the apennines. 
Yes, we have destructive 

285
00:17:32,000 --> 00:17:34,600
earthquakes every 10 years or 
so. 

286
00:17:35,100 --> 00:17:38,400
And these are earthquakes happen
within the other nines, which is

287
00:17:38,400 --> 00:17:41,100
the backbone range of an 
insular, Italy. 

288
00:17:41,700 --> 00:17:45,400
And these earthquakes are simply
the consequence of slab Retreat 

289
00:17:45,400 --> 00:17:49,300
and the mountain belt that is 
formed during your Sometimes is 

290
00:17:49,300 --> 00:17:52,700
presently collapsing. 
And if you look at the map of 

291
00:17:52,700 --> 00:17:55,600
the earthquakes in that region, 
you will see a concentration of 

292
00:17:55,700 --> 00:17:57,800
earthquakes, shallow 
earthquakes. 

293
00:17:57,900 --> 00:18:01,400
When I say, shallow is shallower
than 10, 15 km all. 

294
00:18:01,400 --> 00:18:04,500
Along the backbone of Italy. 
And these words correctly are 

295
00:18:04,500 --> 00:18:08,000
all extensional and their 
related to normal folk 

296
00:18:08,000 --> 00:18:12,500
extensional thoughts, that move 
rather continuously, and from 

297
00:18:12,500 --> 00:18:17,200
time to time, you have a 
magnitude 6.5 7 earthquake. 

298
00:18:17,600 --> 00:18:19,700
And as these are Earthquakes are
quite shallow. 

299
00:18:19,700 --> 00:18:23,100
They can be rather destructive, 
like it was the case in in 

300
00:18:23,100 --> 00:18:26,000
l'aquila, as you mentioned. 
Yes they are really a 

301
00:18:26,000 --> 00:18:28,300
consequence of laboratory T, 
those Quakes. 

302
00:18:29,100 --> 00:18:32,700
So as you mentioned earlier 
because the lithospheric slab is

303
00:18:32,700 --> 00:18:37,200
retreating as its abducts, the 
overriding plate in front of it,

304
00:18:37,600 --> 00:18:41,500
has to fill the space being 
created by the retreat, which 

305
00:18:41,600 --> 00:18:46,000
causes it to stretch and hence 
the extensional nature of the 

306
00:18:46,000 --> 00:18:49,500
earthquakes you mentioned. 
I want to ask about another 

307
00:18:49,500 --> 00:18:53,300
geological event that many of us
know about, which is the 

308
00:18:53,300 --> 00:18:58,000
explosive eruption of Santorini 
in 1600 BC that may have 

309
00:18:58,000 --> 00:18:59,300
destroyed the minoan 
civilization. 

310
00:18:59,300 --> 00:19:04,600
It is possible that the minoan 
civilization being already 

311
00:19:04,600 --> 00:19:07,600
severely damaged by a series of 
earthquakes. 

312
00:19:07,600 --> 00:19:12,100
This is not sure at all, but it 
seems that when the minoan 

313
00:19:12,100 --> 00:19:15,700
eruption the big eruption of 
Santorini had to endure minoan 

314
00:19:15,700 --> 00:19:18,100
civilization was already in a 
bad shape. 

315
00:19:18,400 --> 00:19:22,300
And there was not so many people
left on the island at that time.

316
00:19:22,700 --> 00:19:27,300
Also, there were apparently 
series of earthquakes that were 

317
00:19:27,400 --> 00:19:31,400
signaling, that something weird 
and dangerous was going to 

318
00:19:31,400 --> 00:19:34,900
happen at the difference. 
With what we see in Pompeii in 

319
00:19:34,900 --> 00:19:39,400
Italy, there was no discovery of
bodies within the volcanic 

320
00:19:39,400 --> 00:19:43,400
ashes, so probably the people 
living on Santorini had left 

321
00:19:43,400 --> 00:19:46,300
already. 
But this eruption at the 

322
00:19:46,300 --> 00:19:49,200
consequences, all around the 
Mediterranean, Ukrainian with a 

323
00:19:49,200 --> 00:19:53,100
probable tsunamis and as far as 
Egypt. 

324
00:19:53,600 --> 00:19:56,100
Okay, let's talk about the 
volcanism in the central 

325
00:19:56,100 --> 00:20:00,100
Mediterranean such as Mount Etna
in Sicily and Vesuvius near 

326
00:20:00,100 --> 00:20:05,700
Naples that destroyed Pompeii in
79 ad and the aeolian islands. 

327
00:20:05,700 --> 00:20:09,300
Just north of Sicily. 
Why do we have volcanism today? 

328
00:20:09,300 --> 00:20:13,200
Just concentrated in those 
specific locations in general. 

329
00:20:13,200 --> 00:20:17,600
First the subduction related 
volcanism is due to the 

330
00:20:17,600 --> 00:20:21,500
injection Of water into the 
mantle, by the subduction zone, 

331
00:20:22,000 --> 00:20:26,300
let me explain the subducting 
lithosphere carries sediments. 

332
00:20:26,400 --> 00:20:29,800
They contain a lot of water and 
also the upper part of the 

333
00:20:29,800 --> 00:20:32,100
oceanic crust underneath the 
sediments and the upper part of 

334
00:20:32,100 --> 00:20:36,700
the mantle and contain a lot of 
water when these rocks, go down 

335
00:20:36,700 --> 00:20:42,100
in depth of the subduction zone,
reaching 100 or 130 km. 

336
00:20:42,300 --> 00:20:46,200
The pressure increases 
drastically and this increase of

337
00:20:46,200 --> 00:20:50,500
the pressure will sort of 
Squeeze the Rocks like a sponge 

338
00:20:50,600 --> 00:20:54,000
and water will be invade the 
mantle below the overriding 

339
00:20:54,000 --> 00:20:58,200
lithosphere and this will lower 
the melting temperature of the 

340
00:20:58,300 --> 00:21:02,900
mantle rocks, and produce 
Magma's these magma, that will 

341
00:21:02,900 --> 00:21:06,300
then accumulate below the 
lithosphere. 

342
00:21:06,300 --> 00:21:10,600
And then they will go up inside 
Doritos fear, and, and then 

343
00:21:10,600 --> 00:21:15,700
quickly and up to the surface. 
So, that's the general cause of 

344
00:21:15,700 --> 00:21:18,300
subduction related for Canada 
men because there is Out of 

345
00:21:18,300 --> 00:21:20,500
water in these volcanic rocks, 
T. 

346
00:21:20,500 --> 00:21:24,800
There is a lot of fluids and lot
of pressure accumulated below 

347
00:21:24,800 --> 00:21:27,900
the crust and this will lead to 
very explosive eruptions. 

348
00:21:28,700 --> 00:21:31,700
Then there is a precise location
of these volcanoes. 

349
00:21:32,400 --> 00:21:36,700
So they can be like just a line 
like in the end is for instance,

350
00:21:36,700 --> 00:21:40,500
a line above the subduction zone
and this is quite simple. 

351
00:21:40,900 --> 00:21:44,300
But then when the slab is 
retreating and when the slab is 

352
00:21:44,300 --> 00:21:49,200
torn in several narrow pieces, 
the mantle fluid depth will be 

353
00:21:49,200 --> 00:21:51,600
more complex. 
As we said, we store it all flow

354
00:21:51,600 --> 00:21:57,300
and so on and we'll have sort of
Windows opened by these tears in

355
00:21:57,300 --> 00:22:00,700
the slab. 
The magma will come up more 

356
00:22:00,700 --> 00:22:04,500
easily through those windows and
you will see, for instance, in 

357
00:22:04,500 --> 00:22:08,800
the Southeast entire agency, 
north of Sicily, you will see 

358
00:22:08,800 --> 00:22:11,600
narrow bands of volcanic 
material. 

359
00:22:11,900 --> 00:22:16,000
Some of them are aligned like 
the aeolian islands like 

360
00:22:16,000 --> 00:22:20,200
Stromboli and would Cano and Is 
volcanoes. 

361
00:22:20,200 --> 00:22:23,200
Others are not visible at the 
surface. 

362
00:22:23,200 --> 00:22:26,800
There are only found at the 
seafloor and they are found with

363
00:22:26,800 --> 00:22:31,500
the geophysical exploration and 
probably one of the most 

364
00:22:31,500 --> 00:22:34,700
spectacular example of this 
volcanism related to a slab 

365
00:22:34,700 --> 00:22:38,800
tearing is Mount Etna. 
It's probably located about just

366
00:22:38,800 --> 00:22:43,000
above one of those tears. 
In the slab do there is still a 

367
00:22:43,000 --> 00:22:46,300
lot of work to head over to 
really prove this but yes, there

368
00:22:46,300 --> 00:22:50,200
is a strong impact of The 
tearing of the slab on the 

369
00:22:50,200 --> 00:22:54,300
distribution and the evolution 
of volcanism in the areas that's

370
00:22:54,300 --> 00:22:58,800
fascinating, that slab tears 
serve to produce the window that

371
00:22:58,800 --> 00:23:01,100
shapes. 
The volcanism above the gap, 

372
00:23:02,100 --> 00:23:05,700
What is the long-term future of 
the Mediterranean inevitably? 

373
00:23:05,700 --> 00:23:09,700
The matron will disappear caught
between the huge bodies of 

374
00:23:09,700 --> 00:23:13,700
Africa and Eurasia. 
And so the snow lotions that has

375
00:23:13,700 --> 00:23:17,600
been formed during the cenozoic,
these backup base, since we were

376
00:23:17,700 --> 00:23:21,400
mentioning together with the old
ocean across that is in the 

377
00:23:21,400 --> 00:23:25,300
eastern Mediterranean and even 
the old oceanic crust also, that

378
00:23:25,300 --> 00:23:27,800
was formed in the Cretaceous in 
the Black Sea. 

379
00:23:27,900 --> 00:23:32,200
All those bits of ocean will 
disappear and be some Police 

380
00:23:32,200 --> 00:23:36,500
abducted, and some of these 
rocks will be integrated into 

381
00:23:36,500 --> 00:23:40,400
the future mountain belt. 
That will be forming there. 

382
00:23:40,400 --> 00:23:44,900
So, the geologist of the future 
within, I don't know, 20, 30 

383
00:23:44,900 --> 00:23:47,800
million years, they would have a
very hard job making. 

384
00:23:47,800 --> 00:23:52,200
The difference between these 
poly Oceanic domains, they will 

385
00:23:52,200 --> 00:23:57,500
have very different ages from 
200 million euros, 230 million 

386
00:23:57,500 --> 00:24:00,500
years only. 
And this makes our job at the 

387
00:24:00,500 --> 00:24:03,700
present very difficult when When
we interpret, very old mountain 

388
00:24:03,700 --> 00:24:06,800
belts like the various compared 
to other caledonians Caledonian 

389
00:24:06,800 --> 00:24:10,600
because we don't know exactly 
the geometry of the system 

390
00:24:10,800 --> 00:24:13,900
before the complete collision 
was achieved. 

391
00:24:14,500 --> 00:24:17,700
So we hope that future geologist
will be able to dig up the 

392
00:24:17,700 --> 00:24:20,400
papers. 
You and others are writing today

393
00:24:20,400 --> 00:24:22,600
in order to find out what 
actually happened. 

394
00:24:23,100 --> 00:24:26,000
What are the main puzzles about 
the geology of the Mediterranean

395
00:24:26,000 --> 00:24:28,800
that remain? 
Well, or a few questions? 

396
00:24:28,900 --> 00:24:31,800
Why did in the first place? 
Suction. 

397
00:24:32,300 --> 00:24:37,200
That's a big question. 
We know that somehow the motion 

398
00:24:37,200 --> 00:24:39,400
or relative motion of Africa and
Eurasia. 

399
00:24:39,400 --> 00:24:43,600
I've changed some 84 million 
years ago, but it's a question 

400
00:24:43,600 --> 00:24:47,100
of hand. 
An egg did the motion of Africa 

401
00:24:47,100 --> 00:24:51,000
changed because of subduction 
initiated in the 30s, Ocean or 

402
00:24:51,000 --> 00:24:54,100
is it the other way around? 
The seduction is created because

403
00:24:54,400 --> 00:24:57,600
the emotion of Africa will 
achieve to arrange your change. 

404
00:24:57,600 --> 00:25:01,700
So we don't really know why 
subduction initiated in general.

405
00:25:01,900 --> 00:25:03,800
Oh then this is a very important
question. 

406
00:25:03,800 --> 00:25:07,600
Not only in the Mediterranean 
but all over the world and then 

407
00:25:07,600 --> 00:25:10,700
there are several. 
Other questions may be smaller 

408
00:25:10,700 --> 00:25:14,800
scale, but quite as important, 
in terms of our society, is the 

409
00:25:14,800 --> 00:25:16,900
concentration of mineral 
resources. 

410
00:25:17,400 --> 00:25:21,700
We pretty well know that now 
that the concentration of gold 

411
00:25:21,700 --> 00:25:26,600
of iron of copper, and all these
minerals that are very useful 

412
00:25:26,600 --> 00:25:30,400
for our Economic Development, 
these concentrations are 

413
00:25:30,400 --> 00:25:33,600
intimately related to You're a 
large-scale geodynamic 

414
00:25:33,600 --> 00:25:36,200
Evolution. 
This has been known for quite a 

415
00:25:36,200 --> 00:25:39,500
long time, right? 
After the Advent of plate 

416
00:25:39,500 --> 00:25:42,000
tectonics. 
But with the tools we have now 

417
00:25:42,000 --> 00:25:44,900
we can reconstruct very 
precisely the evolution of 

418
00:25:44,900 --> 00:25:48,900
Continental margins plate, 
boundaries and evolution through

419
00:25:48,900 --> 00:25:51,900
time. 
We can model them numerically 

420
00:25:51,900 --> 00:25:54,900
and can play with all the 
parameters, the velocities, the 

421
00:25:54,900 --> 00:26:00,300
temperature, Etc, the nature of 
rocks, and can then study the 

422
00:26:00,300 --> 00:26:03,700
processes that lead to To the 
concentration of mineral 

423
00:26:03,700 --> 00:26:07,800
resources but also the 
concentration of heat geothermal

424
00:26:07,800 --> 00:26:13,000
energy, is one very nice leader,
toward a Greener energy in the 

425
00:26:13,000 --> 00:26:16,500
future. 
And if we understand better, why

426
00:26:16,500 --> 00:26:20,600
heat is concentrated in that 
place or this place will be much

427
00:26:20,600 --> 00:26:25,400
easier for prospecting for 
geothermal fields and the same 

428
00:26:25,400 --> 00:26:29,700
for mineral resources to better.
We know the processes that lead 

429
00:26:29,700 --> 00:26:31,700
to the concentration, the 
easier. 

430
00:26:31,900 --> 00:26:36,500
It's to find new resources. 
For my last question, I'd like 

431
00:26:36,500 --> 00:26:38,800
to ask you about your current 
research. 

432
00:26:39,000 --> 00:26:42,600
There is one. 
Very exciting question, which is

433
00:26:42,600 --> 00:26:47,200
the vertical motion of the floor
of the Mediterranean Sea through

434
00:26:47,200 --> 00:26:50,700
time, and not only the material 
and see that all the countries 

435
00:26:50,700 --> 00:26:54,500
that are around Venice, for 
instance, and the periodic 

436
00:26:54,500 --> 00:26:58,200
flooding of Kansas on Marco with
seawater. 

437
00:26:58,700 --> 00:27:03,800
This is due to external 
processes climate and tides. 

438
00:27:04,100 --> 00:27:08,300
And And so on, but it's also due
to the fact that Venice is 

439
00:27:08,300 --> 00:27:12,400
slowly subsiding, and it is 
subsiding because it is within a

440
00:27:12,400 --> 00:27:15,500
crust that is loaded with the 
apps actually within the weight 

441
00:27:15,500 --> 00:27:19,300
of the arms. 
So, one important question is to

442
00:27:19,400 --> 00:27:25,500
disentangle the effect of sea 
level rise, and with respect to 

443
00:27:25,500 --> 00:27:29,600
the part due to internal 
Dynamics, the mental Dynamics, I

444
00:27:29,600 --> 00:27:33,600
was talking about. 
So with this complex, Joe 

445
00:27:33,600 --> 00:27:36,800
dynamic, Next of the 
Mediterranean but it's true for 

446
00:27:36,800 --> 00:27:40,200
other places in the world, just 
concentrate it in a small area 

447
00:27:40,200 --> 00:27:42,300
here. 
In the Mediterranean Joe 

448
00:27:42,300 --> 00:27:46,600
Dynamics leads to subsidence, 
Joe Dynamics leads to uplift and

449
00:27:46,600 --> 00:27:50,400
you can have a place in one 
place and subsidence, 200 

450
00:27:50,400 --> 00:27:54,700
kilometers from there, and if 
you are not able to deconvolute 

451
00:27:54,700 --> 00:27:59,700
the signal and say which part is
due to internal Dynamics and 

452
00:27:59,700 --> 00:28:03,900
which part is due to externally 
driven processes like climate 

453
00:28:04,100 --> 00:28:06,500
you, Cannot understand the 
system, and you cannot predict 

454
00:28:06,500 --> 00:28:09,500
anything and it's a very 
different topic. 

455
00:28:09,500 --> 00:28:12,900
But we are also working with 
archaeologist in the island of 

456
00:28:12,900 --> 00:28:14,700
delos. 
Where we have this huge 

457
00:28:14,700 --> 00:28:18,400
Sanctuary, they're the largest 
archaeological site of Greece, 

458
00:28:18,700 --> 00:28:21,700
and on this tiny Island, 
hundreds of temples. 

459
00:28:21,700 --> 00:28:23,800
And these temples are made of 
marble. 

460
00:28:24,000 --> 00:28:27,100
And there are very few marbles 
on the island that is made 

461
00:28:27,100 --> 00:28:31,100
mostly of granite and gneiss. 
So the idea is to find where 

462
00:28:31,100 --> 00:28:34,300
these marbles come from in order
to reconstruct. 

463
00:28:34,400 --> 00:28:39,300
Strictly commercial system at 
that time and where the Rocks 

464
00:28:39,300 --> 00:28:42,600
were coming from. 
This is also quite exciting at 

465
00:28:42,600 --> 00:28:46,600
the interface between geology 
and archaeology and the only 

466
00:28:46,600 --> 00:28:48,700
show, leave a thank you very 
much. 

467
00:28:48,800 --> 00:28:52,600
Well, thank you very much for 
inviting me for more about 

468
00:28:52,600 --> 00:28:56,000
geology, b, as well as pictures 
and diagrams that illustrate. 

469
00:28:56,000 --> 00:28:59,200
This podcast, you can go to 
geology B.com