In this unit we will be learning all about rocks. How were the rocks in Malta made? Are the rocks we have in Malta all the same? What are quarries? What happens with a quarry one all the rock is taken out? Get ready for one interesting topic!
The lessons covered in this unit are: 1. Sedimentary rocks 2. Types of rock in Malta 3. Describing rocks 4. Benefits of quarries 5. Problems of quarries 6. Quarrying sustainably |
1. SEDIMENTARY ROCKS
🡺 I can describe in simple terms the processes involved in the
formation of sedimentary rocks and fossils. 🡺 I can conduct a simple experiment to build a sedimentary block of rock, including seashells. Our rocks formed under the sea, from material that was carried from rivers and placed at the bottom of the sea. In the past, rivers in Europe were larger and they emptied into the Mediterranean Sea. Layer upon layers of sediment such as pebbles, sand, rocks and mud, started to form at the bottom of this sea. Many animals, such as snails, sea urchins and fish lived in this sediment. When they died, they would be covered by sediment that was brought by the rivers. After many years, under its own weight this material merged and hardened, forming rocks, which we now call sedimentary rocks. During this time, there were strong earthquakes, much stronger than today’s. Because of this, the continent of Africa started moving towards the continent of Europe. The sedimentary layers found at the bottom of the sea started to bend and compress. Some of them were pushed to the surface of the water and formed the Maltese Islands. Maltese rocks have many fossils inside them. Fossils are the shapes of plants and animals which are found embedded in rocks. They tell us the plants and animals that lived and died over 200 million years ago when the rocks were just mud and sand. Over the years, sediment turned into hard rock, but the shapes of plants and animals have remained clear enough for us to see. Fossils are very important because they provide us with pre-historic evidence. Fossils are part of our natural heritage and are protected by law. You are advised not to extract fossils since this may cause permanent and irreparable damage to our natural heritage. |
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Geo-check!
1. Explain why Maltese rocks have fossils inside them.
2. Why are fossils important? What do they tell us? 3. Match these statements about sedimentary rocks below.
____ made up of layers. ____ hardened because of the pressure and its own weight. ____ 30 million years ago. ____because the continents of Europe and Africa moved towards each other. ____ sediment such as rocks, sand and mud. ____ is called Sedimentary rocks. 4. Write down the names of the fossils under the photos on the right. [Hint: All of these were animals. Some of these animals still exist.] |
TYPES OF ROCK IN MALTA
🡺 I can draw and label a diagram showing the local geological sequence of rock strata in the Maltese Islands.
In the Maltese Islands, we have five types of rock. All these rocks are sedimentary rocks. The bottom most layer is called Lower Coralline Limestone. This was the first one to form at the bottom of the sea, around 30 million years ago. The diagram here shows the five different layers of rocks in Malta. Each of these layers have different colours, texture, hardness and thickness. |
Geo-check!
1. The five layers of rock are written below. Match the rock layers names in Maltese to the table below.
[ Ramli / Franka / Qawwi t’isfel / Qawwi ta fuq /Tafli ]
2. Draw a diagram of the layers of rock and label each layer in English. 3. Which layer of rock is the oldest one? Why? 4. Which layer of rock is the youngest one? Why? 5. On the photo here, label the different rock layers. |
3. DESCRIBING ROCKS
🡺 I can recognise the five main rock types of the Maltese Islands, with the use of rock samples and imagery.
🡺 I can describe the main characteristics (permeability, resistance and colour) and uses of the five main types of rock found in the Maltese Islands.
The following are rocks found in the Maltese islands. As you can see, each rock has different colours, quality, uses and locations.
🡺 I can describe the main characteristics (permeability, resistance and colour) and uses of the five main types of rock found in the Maltese Islands.
The following are rocks found in the Maltese islands. As you can see, each rock has different colours, quality, uses and locations.
UPPER CORALLINE LIMESTONE
Colour: Pale grey or white Quality: Very hard and withstands large forces. Uses: Tarmac and concrete. Location: Hilltops and plateaus on the East of Malta: Rabat, Dingli Fact: Can be polished to look like marble (Gozo Marble) |
GREENSAND
Colour: Greenish yellow. Quality: Breaks easily. Uses: Rubble walls. Location: It is a very thin layer: Dingli and slopes near Ramla l-Hamra. Fact: It preserves fossils very well. |
BLUE CLAY
Colour: Grey when dry. Dark blue when wet. Quality: Soft when wet. Uses: Was used for pottery in the past. Location: On hillsides: Ghajn Tuffieha Fact: It does not let water pass through (impermeable). |
GLOBIGERINA LIMESTONE
Colour: Whitish yellow. Quality: Soft, but hard enough to be used for building. Uses: Building blocks. Location: Central and South Malta: Siggiewi and Qrendi Fact: It covers around 70% of Malta |
LOWER CORALLINE LIMESTONE
Colour: Whitish grey. Quality: Very hard rock. Uses: Breakwaters, facades of buildings and concrete. Location: Cliffs in the South of Malta: Dingli and Ta’ Cenc. Fact: Was formed 30 million years ago in shallow waters. |
Geo-check!
1. Write down the names of the rocks that match these descriptions.
- The youngest Maltese rock.
- The oldest Maltese rock.
- Seen on hillsides, at 450 angles.
- Can be seen on cliff sides.
- The thinnest layer of Maltese rock.
- An impermeable Maltese rock.
- The crumbliest layer of Maltese rock.
- Covers most of Malta.
- This rock is mainly found on the Eastern parts of Malta and Gozo.
- Rocks were formed under the sea as sedimentary rocks.
- Used to build most buildings in Malta.
- Was used to make pottery.
- The thickest layer of Maltese rock.
- The third layer of rock.
4. BENEFITS OF QUARRIES
🡺 I can explain the benefits of quarries.
When people landed on Malta for the first time around 7000 years ago, they found the island full of rock that is easy to cut and be worked on. Since then, rocks around Malta have been used for many reasons. Quarrying for rocks is still an important job in Malta. Here are some reasons why:
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5. PROBLEMS OF QUARRIES
🡺 I can explain the problems of quarries.
Although quarrying has many benefits, many rocks are being wasted and thrown away in our landfills. In fact, industrial waste coming from the construction industry adds up to almost 80% of all the waste Malta produces. Malta throws away around 1.3 million tonnes of stone waste every year. This means that almost half of the rocks that are cut from our quarries is being wasted. Recently, studies have shown that if we keep quarrying rock at the rate we are now, in less than 300 years we won’t have any more Globigerina and in 100 years we won’t have any more Coralline Limestone to quarry anymore. Quarries are often associated with many problems. Here are just a few of them.
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Geo-check!
2. During a public meeting where people could express their opinion about stone waste, a number of people and organisations attended. Who do you think said the following statements? Explain their reasoning.
Building contractor / Environmentalist / Residents / The government
a. We need to urgently limit the use of Limestone. The quarries are making a negative impact on our country’s natural environment.
b. If we stop the quarry workers, I will have to fire many workers – builders, tile layers, and others.
c. If the industrial waste is dumped into old, empty quarries we will be reducing the abmout of rocks sent to the landfill. At the same time, we’ll have more jobs.
d. The mountain of industrial waste sent to the landfill is influencing our health negatively. The landfill is also a huge eyesore.
Building contractor / Environmentalist / Residents / The government
a. We need to urgently limit the use of Limestone. The quarries are making a negative impact on our country’s natural environment.
b. If we stop the quarry workers, I will have to fire many workers – builders, tile layers, and others.
c. If the industrial waste is dumped into old, empty quarries we will be reducing the abmout of rocks sent to the landfill. At the same time, we’ll have more jobs.
d. The mountain of industrial waste sent to the landfill is influencing our health negatively. The landfill is also a huge eyesore.
6. QUARRYING SUSTAINABLY
🡺 I can list some ways of quarrying in a sustainable way.
The management of quarries can be encouraged to be more sustainable during and after quarrying. The quarrying company is expected to restore or improve the quarry site after they have extracted the rock. Measures can be put in place to enable this to happen in a more sustainable way. Quarry restoration can take place. Areas that have already been quarried can be restored while works go on in other areas of the quarry. Reducing the use of rocks
Engineered landfills
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Geo-check!
Look up “quarry restoration” on the internet. Find ONE case study of a quarry that has been restored. Some examples are given below.
Print the article / website and bring it to school. Please print back to front. No colour is needed.
You will complete a task for which you will be asked the following details:
Examples:
Print the article / website and bring it to school. Please print back to front. No colour is needed.
You will complete a task for which you will be asked the following details:
- Where the quarry is located (country).
- A photo of the quarry.
- What the quarry was used for before restoration.
- How the quarry has been restored.
- When the restoration happened. (Date)
Examples:
- Limestone Heritage, Malta
- Soft Stone Quarry no 44, Malta
- Holme Park Quarry, UK
- Stoney Cove Quarry, UK
- Cotswold Water Park, UK
- Dinmor Parc Quarry, Wales
- The Eden Project Clay Pit, UK
- Serra da Arrabida Naural Park, Portugal