GEOLOGY- Types of Rock and Spread

Types of Rock and Spread

geology

the different types of rock that make up an area

relief

the height and shape of the land

physical landscape

the natural world

how are igneous rocks formed

from volcanic activity, and magma cools, forming igneous rocks

intrusive rock

rock that isn’t formed or seen on Earth’s surface

extrusive rock

rock is formed and seen on Earth’s surface

how is intrusive igneous rock formed

magma cools slowly underground

examples of intrusive igneous rock

granite

how is extrusive igneous rock formed

lava exploding out of volcano cools on surface

examples of extrusive igneous rock

• tuf

• obsidian

• pumice

characteristics of igneous rock

• very hard; difficult to erode

• shiny/crystally

• sometimes have gas pockets (e.g. pumice)

what is the most common type of rock on the Earth’s crust

igneous, with 95%

how are sedimentary rocks formed

• formed as small particles of sediment are deposited on bottom of land areas

• these accumulate in layers over time

• pressure from the above layers push down, forming the rock

where are sedimentary rocks usually formed

on the bottom of lakes/oceans

examples of sedimentary rocks

• limestone

• shale

• sandstone

• rock salt

• clay

• chalk

characteristics of sedimentary rocks

• layers

• often have fossils

• softer rock; breaks and erodes easily

• no holes

what are metamorphic rocks

rock that’s change into a different type of rock in extreme heat/pressure

what types of rocks usually become metamorphic

mostly sedimentary, but can be igneous too

where do other rock types change into metamorphic rock

• under the earth where pressure and temperature are high

• on the surface during tectonic activity

examples of sedimentary rock

• shale becomes slate

• sandstone becomes quartzite

• limestone becomes marble

characteristics of metamorphic rockks

• hard

• no layers/fossils

• no holes

where are igneous rocks mostly found in the UK

in north and northwest of England, and throughout Scotland and Wales; HIGHLAND AREAS

where are metamorphic rocks mostly found in the UK

in north and northwest of England, and throughout Scotland and Wales; HIGHLAND AREAS

where are sedimentary rocks mostly found

most of England, especially the south and southeast; where there’s LOWLAND

why are igneous and metamorphic rocks where the high land is

igneous and metamorphic rocks are much harder than sedimentary, and therefore erode much slower, so these rocks keep their shape and height for longer, and so make up the mountains

why are sedimentary rocks where the low land is

sedimentary rocks are much softer and erode much faster than the hard igneous and metamorphic rock, meaning its much lower as the erosion processes erode more of this rock away in the same time as eroding the igneous and metamorphic rock