OCR A-Level Geology sedimentary and metamorphic processes overview quiz quiz

Weathering removes and transports the material, while erosion breaks the rock down in place

They both mean exactly the same thing and the terms are fully interchangeable

Erosion only ever happens by chemical attack and never involves any physical transport

Weathering breaks rock down in place; erosion removes and transports the material

Hydrolysis

Freeze-thaw

Exfoliation

Abrasion

The energy level of the final depositional environment where the grains settled

The transport distance (abrasion smooths grains over distance)

The absolute age of the rock in millions of years since deposition

The chemical composition of the cement that binds the grains together

Weathering and erosion

Melting and crystallisation

Compaction and cementation

Foliation and metamorphism

Angular breccia

Quartz sandstone

Fine mudstone

Conglomerate

Biogenic (biochemical) or chemical, by origin

As a clastic rock, classified purely by its grain size

As an igneous rock, classified by its total silica content

As a metamorphic rock, classified by its metamorphic grade

Regional metamorphism

Contact (thermal) metamorphism

Dynamic metamorphism

All metamorphism produces foliation

Confining pressure acting equally in every direction at once

Rapid cooling of the rock from a high temperature

Directed pressure that aligns platy minerals

Cementation of the grains by precipitated silica

Gneiss, schist, phyllite, slate

Schist, slate, gneiss, phyllite

Phyllite, slate, gneiss, schist

Slate, phyllite, schist, gneiss

Sillimanite

Chlorite

Garnet

All indicate the same grade

Crystallisation of a cooling magma or lava

Metamorphism (heat and pressure, solid state)

Lithification by compaction and cementation

Weathering and erosion at the Earth's surface

Only weathering acting at the Earth's surface, with no internal heat energy involved

Only the action of the wind moving loose sediment across the land surface

Plate tectonics, providing the energy and settings (subduction, collision, uplift)

Radioactive decay acting entirely on its own, with no plate tectonics at all

It is a fixed one-way loop that always runs in a single direction with no shortcuts

Igneous rocks can never under any circumstances be turned into metamorphic rocks

Sedimentary rocks are unable to melt and so can never become igneous rocks

Any rock type can be converted into any other, given the right processes

Ice (a glacier)

A fast-flowing river

Strong desert wind

Gentle beach waves