year 8 geology - rocks & minerals Flashcards
igneous rock
igneous rock is formed when magma or lava are cooled
metamorphic rock
if you put a sedimentary rock under heat and pressure
sedimentary rock
when sediments are placed under pressure or compacted
weathering
the disintegration and decomposition of rocks
physical weathering
causes rocks to disintegrate (smaller pieces)
chemical weathering
causes rock to decompose (change chemicals)
biological weathering
caused by plants and animals and its actions speed up mechanical and/or chemical weathering
exfoliation
repeated heating and cooling of rock can cause cracks to form
abrasion
the breaking away of rock by colliding particles
freeze thaw weathering
when water freezes it expands, taking up space
carbonation weathering
the mixing of water with CO2 from the air to make carbonic acid or acid rain
oxidation weathering
oxidation is a chemical reaction between some minerals in rock and the oxygen in the air (causes a colour change)
erosion
erosion is the transportation of sediments from weathering by water, wind, ice or gravity
water erosion
the transport of sediments by water from one location to another
wind erosion
the transport of sediments by wind from one location to another
ice erosion
the transport of sediments by ice from one location to another
gravity erosion
the transport of sediments by gravity from one location to another
horizontal axis
thing you change
vertical axis
thing you measure
rock cycle
volcanic eruption > igneous rock > sediment > sedimentary rock > metamorphic rock > magma
age of rock
relative age - where rock layers are compare and rocks found lower are older
actual age - using radioactive dating fossils to date rock
types of igneous rock
extrusive - forms when lava cools in the surface of the earth
intrusive - forms when below the surface of the earth
