geology (rocks) Flashcards
what are the 3 types of rock?
sedimentary, metamorphic and igneous
how is sedimentary rock formed?
sedimentary rock is formed from layers of sediment being compressed in layers over a long time
what are some characteristics of sedimentary rock?
in layers, may contain fossils, brittle, hard
what are some examples of sedimentary rock?
chalk, sandstone, limestone and clay
how is metamorphic rock formed?
metamorphic rock is formed when a rock changes due to exposure to high temperature and or pressure
what are some characteristics of metamorphic rocks?
resistant, hard, dense, may contain crystals
what are some examples of metamorphic rock?
slate and marble
how is igneous rock formed?
volcanic activity, lava either cools down, forming extrusive rock, or magma cools down and divides inside the earth’s surface forming intrusive rock
what are some examples of igneous rock?
obsidian, granite, basalt
what are some characteristics of igneous rock?
resistant, may contain crystals, shiny, hard
name 2 features of upland landscapes
tors and limestone pavements
how are tors formed?
a dome of magma cools and contracts, forming granite and joints. these joints are prone to freeze thaw weathering, which causes fragments of rock to detach. then, as the rock becomes exposed to the surface over time, erosion and mass movement processes like slumping remove the weak, broken down rock and they are transported elsewhere. this leaves behind the larger, stronger rock standing, called a tor which will continuously change due to weathering (e.g freeze thaw)
how are limestone pavements formed?
limestone is made up of many joints, and as rainwater passes through these joints there is a chemical reaction which enlarges the joints, creating large gaps in the rock called grykes, and the blocks of rock left in between are called clients
what is a feature of a lowland landscape?
escarpments
how are escarpments formed?
earth movements created a large dome of chalk, but over time water eroded away the chalk, revealing the clay and sandstone beneath. this erosion left behind 2 escarpments - the North and South Downs
