Igneous & Metamorphic Rocks
Molten rock below the surface is called this, and once it reaches the surface it is called this.
Magma, then lava
Sedimentary rocks often form in layers called this, and may contain these preserved remains of ancient life.
Strata, and fossils
Rocks are made up of these natural, crystalline building blocks.
Minerals
Name Earth's four layers in order, from the surface to the centre.
Crust, mantle, outer core, inner core
Name the three types of plate boundary and how the plates move at each.
Convergent (towards each other), divergent (away from each other), transform (past each other)
What does the word metamorphic mean, and what two things cause a rock to become metamorphic?
It means to change form. Heat and pressure cause it
Name the process that squeezes sediments together and the process that glues them together.
Compaction squeezes them together. Cementation glues them together (minerals fill the gaps)
What scale is used to measure the hardness of minerals, and what is the approximate hardness of a mineral that can only be scratched by diamond?
The Mohs scale. About 9
Which layer is made of liquid iron and nickel and produces Earth's magnetic field?
The outer core
At this type of boundary new crust forms as magma rises, a process called seafloor spreading.
A divergent boundary (such as a mid-ocean ridge)
Granite and basalt are both igneous rocks. Which one is intrusive, which one has large crystals, and why?
Granite is intrusive and has large crystals because it cooled slowly underground. Basalt is extrusive and has small crystals because it cooled quickly at the surface
Put these steps of sedimentary rock formation in order: compaction and cementation, deposition, weathering, erosion and transport.
Weathering, erosion and transport, deposition, then compaction and cementation
Name the rock cycle process that brings buried rock back to the surface, and what causes it.
Uplift, caused by the movement of tectonic plates
Name the scientist who proposed continental drift, the supercontinent he named, and why his theory was rejected.
Alfred Wegener. Pangaea. He could not explain what force moved the continents
The San Andreas Fault is an example of which type of boundary, and what hazard does it cause?
A transform boundary. It causes earthquakes when built-up pressure suddenly releases
What is the difference between foliated and non-foliated metamorphic rocks? Give an example of each.
Foliated rocks have layers or bands (for example gneiss or slate). Non-foliated rocks have randomly arranged crystals (for example marble)
Classify each as clastic, chemical or biological: sandstone, rock salt, coal.
Sandstone: clastic (fragments of rock).
Rock salt: chemical (minerals crystallise as water evaporates).
Coal: biological (ancient plant remains)
Explain how the location of a resource decides whether it is mined by open-cut mining, quarrying or underground mining.
Open-cut mining is used when the resource is close to the surface. Quarrying is surface mining for large amounts of rock such as granite. Underground mining is used when the resource is deep, using tunnels and shafts
Give two pieces of evidence that support continental drift.
Matching fossils on separated continents (for example Mesosaurus or Glossopteris), continents that fit together like a jigsaw, matching rocks and mountain ranges, or coal deposits showing land has moved from the equator
Describe what happens when
(a) an oceanic plate meets a continental plate and
(b) two continental plates collide.
(a) The denser oceanic plate sinks under the continental plate (subduction), forming a trench and volcanoes, as with the Andes.
(b) Neither plate sinks because both are thick and buoyant, so the crust buckles upward to form mountains, as with the Himalayas
Explain why metamorphic rocks are usually harder and denser than sedimentary rocks, and why the parent rock does not melt.
Pressure pushes particles closer together and removes gaps. The rock stays solid because the heat is not enough to melt it. If it melted, it would form an igneous rock instead
State the Law of Superposition and explain how it helps scientists compare the ages of fossils.
In undisturbed layers the oldest strata are at the bottom and the youngest are at the top. Fossils in lower layers are older than fossils in higher layers. This gives relative age, not exact age
Trace a piece of granite through the rock cycle, using at least four steps and naming each process.
Example: granite is weathered into sediment, eroded and deposited, then compaction and cementation form sedimentary rock. Heat and pressure change it to metamorphic rock, melting makes magma, and cooling and solidifying forms a new igneous rock
Explain how the lithosphere and asthenosphere allow tectonic plates to move.
The lithosphere (crust and rigid upper mantle) is broken into plates. The asthenosphere below is softer, hot rock that flows very slowly, so the rigid plates move over it
Explain slab pull and name two other things that drive plate movement.
Slab pull: cold, dense oceanic crust sinks at a subduction zone and pulls the rest of the plate behind it. Others: convection currents in the mantle, ridge push, trench suction