CH1 PLATE TECTONICS

Question 1

HOW OLD IS EARTH

Answer 1

roughly 4.6 billion years old

Question 2

WHAT IS INNER CORE

Answer 2

1,200km thick and makes up centre of earth. Its 6,000°C, Solid due to intense pressure. made of 90per cent iron and small amounts of nickel and sulfur

Question 3

DESCRIBE OUTER CORE

Answer 3

2,200km thick , surrounds inner core , Roughly 4,000°C. Made of molten iron and nickel

Question 4

DESCRIBE Mantle

Answer 4

2,900km thick, middle layer of earth. makes up 75% of the earths volume , its divided in 3 sections

Question 5

NAME EACH 3 Mantle sections

Answer 5

Lower Mantle, Asthenosphere, Lithosphere

Question 6

DESCRIBE LOWER MANTLE

Answer 6

Made up of molten magma(liquid Rock) as magma becomes hot, it rises upwards towards the surface . As it rises, it cools and eventually sinks downwards again this creates thermal convection currents are responsible for endogenic forces

Question 7

WHAT IS ASTHENOSPHERE

Answer 7

its the name given to a 100-200km thick section of Mantle that’s made of semi-molten rock. as its partially melted, asthenosphere allow solid rock above to slide on it

Question 8

WHAT IS ENDOGENIC FORCES

Answer 8

forces from within the Earth that cause the crust to move vertically and horizontally.Convection currents are mainly responsible for endogenic forces

Question 9

WHAT IS LITHOSPHERE

Answer 9

Solid upper Mantle sits on the (A) , this and crust combined is known as LITHOSPHERE

Question 10

DESCRIBE LITHOSPHERE

Answer 10

varies 50km to 200km in thickness , its broken in several sections called plates. these plates slide on top of asthenosphere.

Question 11

WHAT IS MOHO LINE

Answer 11

The boundary that divides the solid upper Mantle and earths crust

Question 12

WHAT IS CRUST

Answer 12

Outer layer of earth . made up of solid rock, divided 2 parts

Question 13

continental crust

Answer 13

averages 45km in thickness , makes up continents of world , the rocks that form it are light (e.g granite) Rocks like G are Rich in SIlica and ALumina ,

Question 14

WHAT IS OCEANIC CRUST

Answer 14

thinner than C.C average 8km thickness , rocks that form O.C are heavy (eg basalt) rocks such as basalt made up of SIlica and MAgnesium

Question 15

WHAT ARE THE 4 PLATE TECTONICS THEORY

Answer 15

1Continental drift 2Thermal convention current 3Sea floor spreading 4 Subduction

Question 17

What is continental drift

Answer 17

Theory by Alfred wegener-all earth landmass was once connected (pangaea)

Question 18

What is seafloor spreading

Answer 18

Sea floor spreading is when new oceanic crust forms at mid-ocean ridges and moves away, driving the movement of Earth’s lithosphere.

Question 19

What is subduction

Answer 19

The sinking of the edge of an oceanic plate into the mantle where it melts at a depth of 100km