Know Your Sugarloaf
In which county is the Great Sugar Loaf?
Wicklow
What sediment collected in an ancient sea at the beginning of the Sugarloaf’s rock story?
Sand.
What do we call the loose rock fragments on a mountain slope?
Scree.
In which county is the Great Sugar Loaf?
Quartzite.
Which rock changed into quartzite?
sandstone
What happens to water when it freezes inside a crack?
It expands and pushes against the sides of the crack.
Quartzite belongs to which rock group: igneous, sedimentary or metamorphic?
Metamorphic.
What TWO things changed sandstone into quartzite?
Heat and pressure.
Explain how repeated freezing and thawing can break rock apart.
Water enters cracks and freezes. Expansion widens the cracks. Repeated cycles eventually cause pieces to break off.
Someone says, “The Sugarloaf is pointed, so it must be a volcano.” Explain why this is not good evidence.
Shape alone cannot prove how a mountain formed. The Sugarloaf’s quartzite and geological history support a different explanation.
Explain how uplift and erosion helped produce the Sugarloaf landscape we see today.
Earth movements raised the rocks. Over time, less resistant surrounding rocks wore away more easily, leaving the resistant quartzite prominent.
A student says, “Quartzite is resistant, so it can never break down.” Correct the statement and give an example.
Resistant means it wears away less easily, not that it cannot break down. Freeze-thaw weathering can break quartzite into fragments.