Journey To The Centre Of The Earth Video Flashcards
Geologist suspect what abit the volcanism with Hawaii volcano?
Some remarkable phenomenon that happens deep inside the planet
Mt Kilawauai Hawaii is the worlds most active what?
Volcano lol
The earths interior is what to scientists?
Inaccessible
However in a way scientists have been to the centre of the planet, how?
Probed it to the core
Iceland sits on what?
A rift where it breaks on the earths surface highlighting where two plates meet
What are the two plates in Iceland?
American and Eurasian
How much movement between these two plates in Iceland a year?
20mm
In 1960s they discovered plate tectonics, huge leap in learning about the earth. They knew plates were moving but what didn’t they know?
How they moved
How did Dan Mckenzie go about understanding how the plates moved?
Knew it wasn’t on the surface, this had been learnt about in detail
So there must be something in the mantle driving the force. This was the first place to look
Different waveforms can give information on what?
Different properties of the earth as a whole
Scientist began to develop an idea of the interior of the earth. What is the core?
An immense ball of liquid iron, as big as Mars
What is the mantle?
Outer layer, composed of solid rock
What are the plates made from?
The upper layer of the mantle with the crust thinly on top
Leaning the different layers of the earth, core, mantle, upper mantle, crust didn’t show what?
How the plates moved so new approach needed
Lurfgernt, Island in Sweden, in 1940 there was a lot of water, what happened to it?
It started slowly moving away
Andes Celsuis noticed sea falling in Sweeden, he marked in stone where the sea level was in 1731, from this they can estimate sea level drop a year, what was it?
Over 1cm a year
Scandinavia could be what?
Rising
Evidence suggest since ice melted 10,000 years ago what ha Scandinavia done?
Slowly rose out of the sea
Why has Scandinavia rose?
Huge ice sheet over scandanvia pressed it down into the mantle. Melted quickly. So crust bobbed back. But this suggests rocks of the mantle can behave as a fluid and flow
Occasionally volcanoes bring rocks bring what which are what from the mantle, this aids in research?
Small unmelted rocks
Eckus selya studies unmelted rocks, what type of rock/crystal can it bring up?
Olivine
Tiny sample of olivine put in vice called diamond anvil, to understand, to understand how pressure affects sample what does he use?
X rays
They do research to understand what about our planet?
How it’s governed by subatomic particles in mantle
The sample may remain solid in lab experiments but what happens?
Intense pressure, disrupt structure of crystals so means materials can flow
The mantle is both what?
A solid and a fluid, it’s just a question of timescale
In lab try to recreate conditions of core, use gun for this. To hit iron target, he is trying to discover how hot it is, what does he find from his gun?
Iron makes a brief flash of light, melting temperature 6200centigrade, 1000 hotter than sun. Core of earth glowing ball of hot iron, 3000km in diameter, where the heat slowly comes out into the earth
When you heat a fluid from below what happens?
It starts moving
What is convection?
Hot material comes up from bottom, rises to surface, cools comes back again. Is this happening to earth?
Name the 3 things which depend on convection happening in Earth?
Thermal properties of fluid
Viscosity of the fluid
How deep the layer is
We know how deep the mantle is from earthquake waves, we know about thermal properties from diamond anvils, good estimate of viscosity from Scandanvia from when ice cap melt. What did this mean for convection in the Earth?
It must convect, in fact very vigorously
At mid ocean ridges how does convection work?
Rises, cools makes plates. Pushes apart, sinks back into earth
Dan Mckenzie unexpectedly discovered what, by fining a fluid similar to mantles
shines light through syrup onto mantle. Shows image on screen. Shows dark light where hot is rising, white falling. And there is lots of different cells.
Analysis of fresh lava samples show what?
When it might erupt next also shows helium 3, which could mean it came from mantle rock risen rapidly deep down in the earth
Evidence that Hawaii sits above a mantle plume?
The Gawain Islands themselves form a perfectly linear chain that moves off to the northwest
The islands have been carried away by a moving plate, island burnt into a specific plate. There’s a ku wiki forming underwater at the moment. Could be start of new island?
After realising mantle plume, started to map convective circulation under plates. Red patches plume coming up, where are these plumes?
Everywhere!!!! Hahahah
Rising from interior plumes of hot rock push up from interior, 20 years ago not a possibility. Today they are what?
Vital
Lava flow Western India, formed Dechan traps. Evidence of volcanism on gigantic scale. In 1995 French physicist looked at magnetic reversals what did he suggest?
There was only 2/3 reversals in magnetic reversal. Proof that whole volcanism couldn’t last more than 1milli. Could only cause from a massive surface of a mantle plume head
Enough lava in Dechan falls to cover United States, what did French physicist believe?
Could only be result of a powerful new plume breaking crust and over the surface
Iceland shows evidence of plume, also shows what?
It changed the motion of the plates
Iceland didn’t fit into Pangea, why?
Because of the rift connected to Iceland, great mid ocean ridge where ocean basin slowly moving up. Iceland is only above the water because it’s held up by a mantle plume
About 60milli years ago scotalnd used to sit next to Greenland. Why did it move?
Volcanic plume, split the two continents an they rifted apart. Stretched crust either side, got mantle material came up either side. Rocks in Scotland an Greenland same age
The plume from Greenland Scotland may still be sitting where?
Under Iceland
When did Dechan Flows happened when, and why?
Found mammals in sediments from flows, 65milli years. Crustaceus period. Also showed extinction of dinosaurs
Dinosaurs started disappearing slowly before asteroid. This could have happened from lava flows
Basically remember that shit
