4.1 Geology And Uk Flashcards
(18 cards)
Igneous rocks are
The earths oldest rocks, formed from lavas and deep magmas. They were once molten, then cooled and crystallised. Most igneous rocks are resistant to erosion
Examples of igneous x3
Granite, basalt, Andesite
Igneous rocks location in UK
North of the Tees-Exe line in the uplands
Igneous rocks approx age
Around 3.5 billion years old
Sedimentary approx age
Around 73 million years old
Sedimentary definition
Formed from sediments eroded and deposited by rivers, the sea or on the sea bed. Some are resistant for example limestone while others crumble easily.
Sedimentary examples
Chalk, limestone, clay.
Sedimentary location
Lowland, south of the tees-exe line
Metamorphic definition
Sedimentary rocks that are heated and compressed during igneous activity. Heating and compression harden them and make them resistant - shale becomes slate and limestone becomes marble
Metamorphic location
Upland, north of the tees-exe lone
Metamorphic examples
Schist, slates
Metamorphic rock approx age
1.8 billion years
Difference between igneous and metamorphic
The main difference is that the crystals in an igneous rock is shaped as it crystallized from a melt. The structures in a metamorphic rock are earlier strucures (crystals, sedimentary fragments, etc.) that have been deformed or recrystallized due to heat or pressure, or some chemical change
Granite
it is formed from magma that cools and solidifies after a volcanic eruption. Granite rocks were formed when pockets of magma cooled below the Earth’s surface, with the overall process taking longer than for many other igneous rocks.
Carboniferous limestone
Formed from sediments eroded and deposited by rivers, the sea or on the sea bed. Some are resistant for example limestone while others crumble easily.
Chalk formation
Chalk is formed from lime mud, which accumulates on the sea floor which is then transformed into rock by geological processes.
Slate formation
Slate is a low grade metamorphic rock that is generally formed by metamorphosis of mudstone or shale, under relatively low pressure and temperature conditions.
Glacial deposition
A glacier’s weight, combined with its gradual movement, can drastically reshape the landscape over hundreds or even thousands of years. The ice erodes the land surface and carries the broken rocks and soil debris far from their original places, resulting in some interesting glacial landforms.
