Learning about rocks

Report by Sol and Kiki.
 
Sintra is the perfect place for Sol to learn about the rock cycle.

​As a little intro: Sintra is part of the Sintra Hills, ranging 16 kilometers from Sintra to Cabo da Roca on the Atlantic Ocean. It was known in the Ancient World as Lunae Mons (Mountain of the Moon) and was the legendary retreat of Diana the Huntress (known as Cynthia to the Romans, hence Cintra). But I digress...

We walked up along ancient footpaths on this hill (photo below) that leads to the Castle of the Moors which you can faintly make out on top:

Back to Sol and learning about the rocks here. First Sol watched a Youtube video about the rock cycle.

​Sol says:
​Today I learnt about the rock cycle. There are three main processes of the rock cycle: 
1. Melting and Cooling
2. Weather and Erosion
3. Heat and Pressure

1. Melting and Cooling in Sintra: 
I found this information on a sign on the path to the top of the hill: ​

​Geological formation of the Sintra Hills:

The origin of the hills, which were formed around 70 to 80 million years ago, was a magmatic intrusion (the cooling of the magma mass deep below the earth's surface).

The temperature and pressure conditions within the earth's crust lead to the formation of crystals that originate granite from liquid rock.

The earth's pressure, the movement of the crust and the erosion processes have later induced the emergence of the rock, forming the hills. ​

​2. Weather and Erosion:
I learnt that weather and erosion breaks down rock. I found different examples along the path. Here are some photos I took:

Biological weathering: Lichen causing erosion

Biological Weathering: Roots causing erosion

Water causing a crack and erosion over time

3. Heat and Pressure:
The final stage in the cycle is heat and pressure.
Rock deep in the ground, it becomes soft and it eventually turns into metamorphic rock.
​Metamorphic means 'change in form': these processes cause the change in the rocks. ​

Look closely: Water dripping down from rock

Sintra Rocks