117
3
The Geosphere
Answer key
Analyse
24.
Compare the igneous and metamorphic rock
processes. What conditions are needed for a rock to
transform into metamorphic rock and not igneous
when subjected to high temperatures?
Igneous rocks are formedwhenmagma (meltedminerals) rises
to the surface, and as it cools it becomes solid. Metamorphic
rocks are rocks that change into a different type of rock when
exposed to pressure and high temperature.
Understand
25.
Listen, look at the rock cycle and say true or false.
Audio script and answer:
a) The rock cycle is a series of processes that a rock goes
through. (True)
b) The processes happen very quickly. (False)
c) Not all rocks can undergo the processes. (False)
d) If the rocks melt, magma will form. (True)
26.
In which layer of the geosphere does the rock cycle
take place? Which rocks form at the deepest level?
In the Earth’s crust, the most superficial layer, where materials
are solidified, thus forming rocks. At the deepest level, we
find plutonic igneous rocks and metamorphic rocks because
those depend on high pressure and high temperature, very
common in deepest areas.
Analyse
27.
Explain which types of rock can transform into igneous
rocks.
An igneous rock or magmatic rock can transform into any
types of rocks:
– Sedimentary rock: if it is subjected to the following
agents of the external geological processes: weathering,
erosion, transportation, sedimentation or deposit of
those fragments and diagenesis or transformation in a
sedimentary rock.
– Magmatic rock: if it is subjected to high temperatures
that provoke a fusion and again another transformation
into magma. When magma solidifies, a new igneous
rock is formed.
– Metamorphic rock: if it is subjected to high pressure/
temperature (metamorphism), without melting it but
transforming it into a different rock.
