CH1 PLATE TECTONICS Flashcards
HOW OLD IS EARTH
roughly 4.6 billion years old
WHAT IS INNER CORE
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
DESCRIBE OUTER CORE
2,200km thick , surrounds inner core , Roughly 4,000°C. Made of molten iron and nickel
DESCRIBE Mantle
2,900km thick, middle layer of earth. makes up 75% of the earths volume , its divided in 3 sections
NAME EACH 3 Mantle sections
Lower Mantle, Asthenosphere, Lithosphere
DESCRIBE LOWER MANTLE
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
WHAT IS ASTHENOSPHERE
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
WHAT IS ENDOGENIC FORCES
forces from within the Earth that cause the crust to move vertically and horizontally.Convection currents are mainly responsible for endogenic forces
WHAT IS LITHOSPHERE
Solid upper Mantle sits on the (A) , this and crust combined is known as LITHOSPHERE
DESCRIBE LITHOSPHERE
varies 50km to 200km in thickness , its broken in several sections called plates. these plates slide on top of asthenosphere.
WHAT IS MOHO LINE
The boundary that divides the solid upper Mantle and earths crust
WHAT IS CRUST
Outer layer of earth . made up of solid rock, divided 2 parts
continental crust
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 ,
WHAT IS OCEANIC CRUST
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
WHAT ARE THE 4 PLATE TECTONICS THEORY
1Continental drift 2Thermal convention current 3Sea floor spreading 4 Subduction
