Rocks and Geological Time
National Curriculum:
- Understand, through the use of detailed place-based exemplars at a variety of scales, the key processes in physical geography relating to rocks and geological timescales (KS3 subject knowledge in red).
GCSE specification:
AQA:
- Simplified geological time scale. The position of granite, Carboniferous limestone and chalk and clay within this framework.
- Characteristics and formation of igneous, sedimentary and metamorphic rocks. The location of these in the UK. The links between different categories – the rock cycle.
- Granite; chalk and clay and Carboniferous limestone provide resources to extract, land to farm on and unique scenery for tourism
- Demand for resources has led to quarrying. This is an important issue and has led to conflict and debate. A case study of a quarry – its location, economic, social and environmental advantages and disadvantages.
- Impact of quarrying on the environment can be reduced by careful, sustainable management. A case study of a quarry – and the attempts made to manage the extraction and use of the land during extraction and/or after the resource is exhausted. To include strategies used during extraction and restoration following extraction – use for farming, recreation and tourism.
- Satellite images – impacts of quarrying (GCSE subject knowledge in green).
- Understand, through the use of detailed place-based exemplars at a variety of scales, the key processes in physical geography relating to rocks and geological timescales (KS3 subject knowledge in red).
GCSE specification:
AQA:
- Simplified geological time scale. The position of granite, Carboniferous limestone and chalk and clay within this framework.
- Characteristics and formation of igneous, sedimentary and metamorphic rocks. The location of these in the UK. The links between different categories – the rock cycle.
- Granite; chalk and clay and Carboniferous limestone provide resources to extract, land to farm on and unique scenery for tourism
- Demand for resources has led to quarrying. This is an important issue and has led to conflict and debate. A case study of a quarry – its location, economic, social and environmental advantages and disadvantages.
- Impact of quarrying on the environment can be reduced by careful, sustainable management. A case study of a quarry – and the attempts made to manage the extraction and use of the land during extraction and/or after the resource is exhausted. To include strategies used during extraction and restoration following extraction – use for farming, recreation and tourism.
- Satellite images – impacts of quarrying (GCSE subject knowledge in green).
Subject knowledge:
There are three types of rock and they all depend on how the rock was formed:
Igneous Rocks:
These are formed when molten rock (magma) from the mantle (inside the earth) cools and solidifies. When magma erupts it cools and forms volcanic landforms known as extrusive rocks. If it cools inside the earth it forms intrusive rock. Examples of igneous rocks includes granite and basalt.
Sedimentary Rocks:
These rocks formed from fragments of other rocks or the remains of living things that have been compressed into rocks. The process of compaction is called lithification. Examples of sedimentary rocks include sandstone, chalk and limestone.
Metamorphic Rock:
These are existing rocks (sedimentary and igneous rocks) that have been changed by intense heat and pressure to form new rocks. The new rocks are harder and more compact that the original rocks. Metamorphic rocks can be created when tectonic plates collide, rocks are changed by the massive heat and pressure that builds up. Examples of how metamorphic rocks can form include limestone becoming marble and sandstone becoming quartize.
This is a key part of KS3 geography and it is also crucial for GCSE students to have a solid understanding as well.
There are three types of rock and they all depend on how the rock was formed:
Igneous Rocks:
These are formed when molten rock (magma) from the mantle (inside the earth) cools and solidifies. When magma erupts it cools and forms volcanic landforms known as extrusive rocks. If it cools inside the earth it forms intrusive rock. Examples of igneous rocks includes granite and basalt.
Sedimentary Rocks:
These rocks formed from fragments of other rocks or the remains of living things that have been compressed into rocks. The process of compaction is called lithification. Examples of sedimentary rocks include sandstone, chalk and limestone.
Metamorphic Rock:
These are existing rocks (sedimentary and igneous rocks) that have been changed by intense heat and pressure to form new rocks. The new rocks are harder and more compact that the original rocks. Metamorphic rocks can be created when tectonic plates collide, rocks are changed by the massive heat and pressure that builds up. Examples of how metamorphic rocks can form include limestone becoming marble and sandstone becoming quartize.
This is a key part of KS3 geography and it is also crucial for GCSE students to have a solid understanding as well.
Rock cycle:
The rock cycle shows how igneous, sedimentary and metamorphic rocks are formed, and how one type is changed into another. 1) Weathering of all three rock types creates loose sediment 2) This makes it easier for erosion to occur 3) The sediment is transported away (e.g. by rivers) and deposited in the sea bed. 4) Sediment is compacted on the sea bed through lithification to form sedimentary rocks. 5) Heat and pressure (e.g. from overlying layers of rock) can change any rock type to new metamorphic rock 6) Melting of any rock type (e.g. in the mantle) creates magma. When magma cools, igneous rocks are formed. Again, this is a key part of KS3 geography and it is also crucial for GCSE students to have a solid understanding as well. |
Geological timescale-
The earth is estimated to be 4,6 billion years old and life is thought to have become dominant on Earth 542 million years ago. While time is often measured in hours and minutes, to geologists, time relating to rocks is measured in 100s and 1000s of years. This time is divided into eras and periods which is the formation of the geological timescale (see diagram below) which relates to events, such as mountain building, atmospheric changes or widespread sea level change, that have happened in the Earth's history. For example, tropical weather in the UK formed coal and limestone which is known as the Carboniferous Period. The most recent period is known as the Quaternary period in which the Ice Age occurred.
The earth is estimated to be 4,6 billion years old and life is thought to have become dominant on Earth 542 million years ago. While time is often measured in hours and minutes, to geologists, time relating to rocks is measured in 100s and 1000s of years. This time is divided into eras and periods which is the formation of the geological timescale (see diagram below) which relates to events, such as mountain building, atmospheric changes or widespread sea level change, that have happened in the Earth's history. For example, tropical weather in the UK formed coal and limestone which is known as the Carboniferous Period. The most recent period is known as the Quaternary period in which the Ice Age occurred.
It's not important for GCSE to remember exact periods of time but it is important to understand the size of the geological time period. Here is an overall summary. This could also be used for KS3 as they are required to have a basic understanding of the rock cycle but not as detailed as GCSE level.
Important rocks and their time period:
Granite: Permian Period. It is a hard, igneous rock, made up of quartz, feldspar and mica.
Carboniferous Limestone: Carboniferous period. It is a sedimentary rock made of calcium carbonate. It reacts with the acids in rainwater and dissolves to form distinctive scenery such as limestone pavement, caves and gorges.
Chalk: Cretaceous period. It is also a sedimentary rock made of calcium carbonate. It is porous, so water can penetrate it. It is eroded by solution.
Clay: Jurassic, Cretaceous and Tertiary periods. It is a sedimentary rock made of tiny particles of weathered rocks and minerals.
Granite: Permian Period. It is a hard, igneous rock, made up of quartz, feldspar and mica.
Carboniferous Limestone: Carboniferous period. It is a sedimentary rock made of calcium carbonate. It reacts with the acids in rainwater and dissolves to form distinctive scenery such as limestone pavement, caves and gorges.
Chalk: Cretaceous period. It is also a sedimentary rock made of calcium carbonate. It is porous, so water can penetrate it. It is eroded by solution.
Clay: Jurassic, Cretaceous and Tertiary periods. It is a sedimentary rock made of tiny particles of weathered rocks and minerals.
The geology of an area is one of the key factors influencing the shape of the landscape:
- Strong rocks tend to produce highland areas, whereas weaker rocks tend to form lowlands.
- Whether rock allow water to pass through them tells you whether they are permeable or impermeable. Water will pass through permeable rocks however water cannot pass through impermeable rocks.
- The permeability of rocks will determine how wet or dry the surface of a landscape is. Limestone is a permeable rock that tends to form dry uplands areas with few streams and thin soils. Clay is an impermeable rock that tends to produce wet lowland areas.
- Strong rocks tend to produce highland areas, whereas weaker rocks tend to form lowlands.
- Whether rock allow water to pass through them tells you whether they are permeable or impermeable. Water will pass through permeable rocks however water cannot pass through impermeable rocks.
- The permeability of rocks will determine how wet or dry the surface of a landscape is. Limestone is a permeable rock that tends to form dry uplands areas with few streams and thin soils. Clay is an impermeable rock that tends to produce wet lowland areas.
Rock types in Britain:
There is a wide variety of rock types and geological formations in the British Isles. The type of underlying rock in a particular area determines the region's physical appearance, as well as its economic activities.
There is a wide variety of rock types and geological formations in the British Isles. The type of underlying rock in a particular area determines the region's physical appearance, as well as its economic activities.
Dartmoor: Granite:
Dartmoor is a National Park and is the top of an exposed batholith. There are over 150 rock outcrops called tors, formed by a combination of freeze-thaw weathering and hydrolysis. It also contains areas of standing water and peat bogs, due to the combination of high rainfall and impermeable rock. V-shaped river valleys formed by the numerous surface streams. Valley sides are steep due to the resistant nature of the granite. The land is at a higher altitude than the surrounding area due to the resistant nature of the granite. Most of the large settlements - eg Tavistock, and Ashburton - are found near the outskirts of Dartmoor. The area is a popular tourist location. The map to the right shows the location of Dartmoor in the South West of England. |
Human activity:
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Problems:
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Yorkshire dales: Limestone
One of the largest areas of limestone in the UK is found in the Yorkshire Dales National Park, near Malham and Ingleton. Limestone is a sedimentary rock made of calcium carbonate. It dissolves slowly in carbonic acid (carbon dioxide and rainwater) creating a range of distinctive landforms. The structure of limestone is like building blocks, with joints (vertical) and bedding planes (horizontal) separating the blocks. Most weathering takes place between the blocks where the acidic rainwater can penetrate: limestone is a pervious rock. Due to the pervious nature of the rock, drainage is usually underground and can only be seen where the limestone meets an area of impermeable rock. This process can be seen in the appearance of natural springs and is known as resurgence.
Some landforms include: Gorges. If the roof of an underground cave system collapses due to extensive limestone solution, it leaves a stream flowing at the base of a deep narrow valley Caves. These are found when a stream flowing down a swallow hole has dissolved a large area underground. Deposits of limestone hanging down from the ceiling are called stalactites; those found rising from the floor of a cave are called stalagmites. |
Human activity:
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Problems:
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South Downs: Chalk
The South Downs is an AONB (area of outstanding natural beauty). Chalk is a sedimentary rock made of calcium carbonate. It is porous and allows water to penetrate into the rock. For this reason, surface streams (winterbournes) are only visible when the rock is saturated. Dry valleys are a common feature. These were eroded by fast-flowing surface streams towards the end of the last Ice Age. Where the chalk (permeable) meets an impermeable rock (frequently clay) springs form and can be seen when rivers begin to flow at the surface. Chalk is eroded by solution. Soils are thin which means vegetation is mainly grasses. Chalk forms gentle hills inland (eg the South Downs in southern England) and steep cliffs at the coast (eg the Seven Sisters in Sussex). Chalk escarpments have a gentle slope (or dip) on one side and a steeper slope (or scarp) on the other. Chalk beds are good natural aquifers (underground areas that allow storage of water due to the porous nature of the rock).
The South Downs is an AONB (area of outstanding natural beauty). Chalk is a sedimentary rock made of calcium carbonate. It is porous and allows water to penetrate into the rock. For this reason, surface streams (winterbournes) are only visible when the rock is saturated. Dry valleys are a common feature. These were eroded by fast-flowing surface streams towards the end of the last Ice Age. Where the chalk (permeable) meets an impermeable rock (frequently clay) springs form and can be seen when rivers begin to flow at the surface. Chalk is eroded by solution. Soils are thin which means vegetation is mainly grasses. Chalk forms gentle hills inland (eg the South Downs in southern England) and steep cliffs at the coast (eg the Seven Sisters in Sussex). Chalk escarpments have a gentle slope (or dip) on one side and a steeper slope (or scarp) on the other. Chalk beds are good natural aquifers (underground areas that allow storage of water due to the porous nature of the rock).
Human Activity:
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Clay
Clay is a sedimentary rock made of tiny particles which come from the weathering of other rocks and minerals. The particles can be transported by rivers or ice and then deposited. Clay vales are frequently found at the foot of chalk escarpments, eg in the South Downs of Southern England. Clay collapses easily when wet (slumping) and forms gentle landscapes, which are frequently waterlogged. It is impermeable and is characterised by having many surface streams. Clay is high in nutrients and is not eroded easily.
Human activity:
Clay is a sedimentary rock made of tiny particles which come from the weathering of other rocks and minerals. The particles can be transported by rivers or ice and then deposited. Clay vales are frequently found at the foot of chalk escarpments, eg in the South Downs of Southern England. Clay collapses easily when wet (slumping) and forms gentle landscapes, which are frequently waterlogged. It is impermeable and is characterised by having many surface streams. Clay is high in nutrients and is not eroded easily.
Human activity:
- Quarrying. Clay is used to make pots and bricks, and in the manufacturing of paper.
- Farming. The main land use is farming due to clay's high nutrient content and the characteristically flat landscape, making it accessible to farm machinery. The land is used for arable farming, market gardening and dairy farming.
Quarrying:
Quarrying was first used by early settlers in Britain for building stone and extracting metals for weapons, and continues as a primary industry that involves the extraction of rocks such as limestone and slate.
There are many conflicted views associated with quarrying:
Quarrying was first used by early settlers in Britain for building stone and extracting metals for weapons, and continues as a primary industry that involves the extraction of rocks such as limestone and slate.
There are many conflicted views associated with quarrying:
Advantages:
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Disadvantages:
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Case studies:
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 in other areas of the quarry. Holme Park: Holme Park quarry is a limestone quarry that has been quarried for over 50 years. Holme is a village and civil parish in the South Lakeland district of Cumbria, England. Within and close to the area there are sites of special scientific interest. Areas of limestone pavement have been left. One forms an island in the centre of the quarry. The other is found to the south west. This retains some of the habitatfor the wildlife. The quarry management team worked with the county council and the local community to retain and restore areas within the quarry. Community access was increased, so that the people could learn more about the wildlife and geology of the area. (The map to the right shows the location of the quarry and its surrounding settlements) |
Teaching and Pedagogy:
KS3 Class:
Aim: To introduce the rock cycle
Objectives:
a) To be able to understand and remember the qualities of the 3 rock types.
b) To be able to create and label a diagram of the rock cycle
c) To be able to explain how igneous, metamorphic and sedimentary rocks can be changed in the rock cycle.
Starter activity:
KS3 Class:
Aim: To introduce the rock cycle
Objectives:
a) To be able to understand and remember the qualities of the 3 rock types.
b) To be able to create and label a diagram of the rock cycle
c) To be able to explain how igneous, metamorphic and sedimentary rocks can be changed in the rock cycle.
Starter activity:
Main activity:
The main activity will require an introduction by the teacher of what the rock cycle is. This can be done trough a powerpoint activity or through the use of a video such as the one to the right. Students should write notes as the watch the video to help complete a handout of the rock cycle. Students should use the information from the youtube video (and extra textbooks if they require them) to create a comic strip of how a rock can be changed into all 3 rock types. |
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Plenary:
On the board there should be a blank diagram of the rock cycle. Choosing certain students, they should fill out the blank diagram on the board.
Resources:
- Powerpoint
- Video
- Starter/main activity handouts
- Coloured pens
On the board there should be a blank diagram of the rock cycle. Choosing certain students, they should fill out the blank diagram on the board.
Resources:
- Powerpoint
- Video
- Starter/main activity handouts
- Coloured pens
GCSE Class
Aim: To develop an understanding of geological time
Objectives:
a) To be able to understand the length of geological time
b) To be able to outline particular periods within the timescale.
c) To be able to explain where granite, limestone, clay and chalk are positioned in the geological time period.
Starter:
Create a spider diagram including everything you already know about geological time and rocks. This could include any information you have learned previously in geography or science, including: rock types, names of rocks, properties of rocks etc.
Main activity: (tables of 4 needed)
Teacher led demonstration of the size of geological time. This website shows a way of actively demonstrating the scale of the time period and also a way of recording it. However, a way of transforming this into a geography lesson would be to add in the different climates and features at each period as well as where the key rocks are located.
a) Individually create a profile on your given geological time period using the textbook and the internet. Include factors such as what the climate was like, what rocks were created, whether there was any life at this time etc. (15 minutes).
b) Once this is complete, teach the person next to you about your time period and identify 3 similarities and differences between the time periods.
c) After this, you must swap time periods with the person next to you and teach the person sat opposite you about the time period you have just found out about. The teachers will have 1 minute to teach their time periods to the other pupil. The pupils will write notes on what is being taught to them.
d) Pupils will return to their initial partner to share information about the new time period they have found out about. Students will now have information about all 4 time periods where granite, limestone, clay and chalk are positioned.
Plenary:
On a post-it note, list 3 things your partner has learned today.
Homework:
Answer the following exam question: "Contrast the position of 2 rocks on the geological timescale" (6 marks)
Resources:
- Laptops/iPads/Computer room/books (dependent on school resources)
- Powerpoint
- Rope for active demonstration of geological time
- Activity sheet for prompts if students require extra help
Aim: To develop an understanding of geological time
Objectives:
a) To be able to understand the length of geological time
b) To be able to outline particular periods within the timescale.
c) To be able to explain where granite, limestone, clay and chalk are positioned in the geological time period.
Starter:
Create a spider diagram including everything you already know about geological time and rocks. This could include any information you have learned previously in geography or science, including: rock types, names of rocks, properties of rocks etc.
Main activity: (tables of 4 needed)
Teacher led demonstration of the size of geological time. This website shows a way of actively demonstrating the scale of the time period and also a way of recording it. However, a way of transforming this into a geography lesson would be to add in the different climates and features at each period as well as where the key rocks are located.
a) Individually create a profile on your given geological time period using the textbook and the internet. Include factors such as what the climate was like, what rocks were created, whether there was any life at this time etc. (15 minutes).
b) Once this is complete, teach the person next to you about your time period and identify 3 similarities and differences between the time periods.
c) After this, you must swap time periods with the person next to you and teach the person sat opposite you about the time period you have just found out about. The teachers will have 1 minute to teach their time periods to the other pupil. The pupils will write notes on what is being taught to them.
d) Pupils will return to their initial partner to share information about the new time period they have found out about. Students will now have information about all 4 time periods where granite, limestone, clay and chalk are positioned.
Plenary:
On a post-it note, list 3 things your partner has learned today.
Homework:
Answer the following exam question: "Contrast the position of 2 rocks on the geological timescale" (6 marks)
Resources:
- Laptops/iPads/Computer room/books (dependent on school resources)
- Powerpoint
- Rope for active demonstration of geological time
- Activity sheet for prompts if students require extra help
Exam questions:
Higher: (a) Contrast the position of granite and chalk on the geological time timescale (4 marks). (b) Outline the characteristics of Carboniferous limestone (6 marks) Foundation: (a) Are the following statements true or false? (3 marks) Chalk was formed during the Cretaceous Period. Granite is older than chalk. A period is longer than an era. (b) Outline the characteristics of Carboniferous limestone (6 marks) |
Higher: (a) Outline two main characteristics of Igneous rocks (4 marks). (b) Describe the processes which lead to the formation of Sedimentary rocks (6 marks). Foundation: (a) Write the correct rock type next to the following statements (4 marks): Limestone and Clay are examples of this rock ________________ This rock type forms when magma cools ________________ Heat and pressure have changed these rocks ________________ This rock type forms in layers ________________ (b) Describe the processes which lead to the formation of Sedimentary rocks (6 marks). |