Active learning ideas
Metamorphism is the study of transformation. This topic examines how existing rocks change in response to heat and pressure without melting. Students differentiate between contact metamorphism, driven by the heat of igneous intrusions, and regional metamorphism, driven by the immense pressure and heat of mountain-building events. This is a critical component of the OCR Geology specification, requiring a deep understanding of solid-state recrystallisation.
Activity 01
Using layers of different coloured plasticine and glitter, students apply heat (warmth from hands) and directed pressure to model foliation. They observe how 'minerals' (glitter) align perpendicular to the pressure, mimicking the formation of slate and schist.
What are the primary agents of metamorphism?
Activity 02
Students examine a map of an igneous intrusion and rock samples from different distances. They must arrange the samples in order of increasing metamorphic grade and explain the changes in crystal size and mineralogy.
How does regional metamorphism differ from contact metamorphism?
Activity 03
Students are given a list of metamorphic rocks and a list of protoliths (parent rocks). They must pair them up (e.g., Limestone to Marble) and explain what physical changes occurred during the transformation.
What causes foliation in metamorphic rocks?
A few notes on teaching this unit
Watch Out for These Misconceptions
Metamorphism involves melting the rock.
If a rock melts, it becomes igneous. Metamorphism happens entirely in the solid state. Using the analogy of 'toasting bread' (changing texture/chemistry without turning it into liquid) helps clarify this boundary.
Pressure always creates foliation.
Foliation only occurs if there is directed pressure and the rock contains platy minerals like mica. Marble and quartzite are non-foliated because their minerals (calcite/quartz) are equidimensional. A collaborative investigation into mineral shapes helps surface this error.
Methods used in this brief
Mineral Identification and Properties
Develop practical skills in identifying common rock-forming minerals using diagnostic physical properties. Students will investigate hardness, cleavage, lustre, and specific gravity.
8 methodologies
Igneous Processes and Rocks
Examine the formation of igneous rocks from magma and lava, focusing on cooling rates and crystal size. Classify igneous rocks based on their mineral composition and texture.
8 methodologies
Sedimentary Environments
Trace the journey of sediments from weathering and erosion to transport, deposition, and lithification. Analyse sedimentary structures to interpret past depositional environments.
8 methodologies