topic 1: rocks Flashcards
How are sedimentary rocks formed?
Through recycled bits of other rocks.
How are metamorphic rocks formed?
Through heat and pressure, though no (full) melting occurs.
How are igneous rocks formed?
Through the cooling and re-crystallisation of rocks magma.
Name a feature of sedimentary rocks.
Rounded grains.
Name a feature of metamorphic rocks.
Foliated crystals.
Name a feature of igneous rocks.
Randomly orientated crystals.
What are the main diagnostics when describing texture of a rock?
Size, shape and sorting,.
What words are used to describe the size of particles?
Large/coarse, medium and small/fine.
What words are used to describe the shape of particles?
Rounded or angular (for grains). Regular shapes with straight edges (crystals).
What words are used to describe particle sorting?
Well sorted (all same size) or poorly sorted (lots of different sizes).
What other features can be described for texture?
Fossils, minerals within the rock, distinctive colour, layering or foliation, feel of the rock, pore spaces or gas bubbles.
What are examples of sedimentary rocks?
Conglomerate, shale, coal and limestone.
What are examples of metamorphic rocks?
Slate and marble.
What are examples of igneous rocks?
Gabbro and granite.
