Identify weathering, erosion, deposition, burial, metamorphism and melting in a rock cycle.
Method and worked examples
Weathering breaks down or alters rock in place. Erosion transports material; deposition leaves it behind. Burial can lead to compaction and cementation. Heat and pressure can produce metamorphism; melting produces magma; cooling produces igneous rock. Uplift and removal of overlying material can expose buried rock.
The rock cycle has multiple pathways, not one compulsory sequence. Any exposed rock can weather, and igneous rock can become metamorphic without a sedimentary stage. Timescales vary: some lava cools quickly, while deep burial and mountain building often take much longer. In fixed-rate questions, multiply the stated rate by the stated time rather than assuming a universal geological speed.
Example 1
Rain alters a rock in place; a stream later carries fragments away. Name the two processes in order.
Weathering acts in place; erosion transports material.
Example 2
Can granite become metamorphic rock without first forming sandstone?
Yes. Heat and pressure can metamorphose existing granite directly, without a sedimentary stage.
Watch out:Different pathways are possible. The next stage depends on the processes and conditions acting on that rock.
Rock-cycle pathways and timescales | Year 8 Science | Ascent Arcade