Section 2x The Eart And Plate

Question 1

Layers of the earth

Answer 1

1. The crust
2. The mantle
3. The core

Question 2

The Core

Answer 2

Consists of nickel and iron
Fluid outer core due to high temperatures
solid inner core higher temperature, solid due to high pressure, smaller than outer core

Question 3

The Mantle

Answer 3

High temps(100-3500c) , but does not melt rocks because of high pressure
Consists of magnesium, iron and silicon

Question 4

The crust

Answer 4

Oceanic
~10km
-high density basaltic rock
-Younger in age

Continental
~35 km
-low density granitic rock
Older in age

Question 5

Pangea proof

Answer 5

1. Jigsaw puzzle fit of continents
2. Alignment of geological features and similar rock types
3. Alignment of fossil finds
4. Alignment of paleo-climates
   5.earthquaks happen along plates

Question 6

Mechanism behind continental drift

Answer 6

Ridge push-Sea floor spreading
-continents are moved by the generation of new crust at the mid-oceanic ridges(where new oceanic floor is generated from rising magma)
-sometimes continents are split and rifted by the formation of spreading ridges

Plate density/slab pull
-Pull of oceanic lithosphere down into the mantle

Mantle convection
-heat derived from early earth and ongoing radioactive decay within earths mantel cause heat, causing rock to behave as viscous fluid and movement of plates

Question 7

Lithosphere and asthenosphere

Answer 7

Lithosphere
- earths rigid outer shell(crust and upper part of mantle

Asthenosphere
-weak part of upper mantle that behaves like viscous solid

Question 8

Divergent plate boundaries

Answer 8

Moving away
- mostly mid-ocean ridges(sea floor spreading)
Also found where continents break apart

Question 9

Transform plate boundaries

Answer 9

Typically connect mid-ocean ridge segments
Plates slide past r
No production/destruction of material

Question 10

Convergent plate boundaries

Answer 10

Produced by compressional forces
High frequency of earthquakes
Marked by oceanic trenches and subduction zones

Question 11

Subduction zones (ocean-continent)

Answer 11

Oceanic lithosphere descends(subducts), partial melting of the mantle rock generates magmas
Older portions of oceanic plates are returned to the mantle in these destructive plate margins
-denser oceanic slab sinks into spasthenosphere
-continental volcanic arcs are formed
-density of the melted rock is less than the surrounding rock, therefore melt rises forming a volcanic arc

Question 12

Subduction zones (ocean-ocean)

Answer 12

Older colder one subducts beneath the younger one
If plate subducts far enough into mantle it will melt, resulting magma is buoyant and floats towards the surface, pushing up the crust above it. When the magma finds a weakness in the crust it will flow out in the form of lava.
This forms volcanoes on the ocean floor floor, which if e,edge as island for a volcanic island arc

Question 13

Collisional zones (continent-continent)

Answer 13

Continued ocean spreading brings/pushes two continents together
But since less dense buoyant continental lithosphere does not subduct, a collision results
This results in uplift and thickening of continental crust=high mountains