Edexcel GCSE Geography A (1GA0) — The Physical Environment
A simple line drawn across a map can completely change the geographical features you expect to see. The Tees-Exe Line is an imaginary boundary stretching from northeast England to southwest England, dividing the UK into the mountainous, upland North and West, and the flatter, lowland South and East.
You can snap a piece of chalk easily, but try breaking a chunk of granite with your bare hands. Geology directly controls the relief of a landscape. The Edexcel specification strictly requires you to describe rocks as either resistant or less resistant to erosion, rather than "hard" or "soft".
More resistant rocks (like igneous granite and metamorphic slate) are very difficult to erode. Consequently, they remain high above the surrounding land, forming rugged upland areas like the Lake District. Less resistant sedimentary rocks (like clay and sand) are easily eroded, creating lower, flatter landscapes known as vales or plains.
The lithology of rock also affects drainage. Permeable rocks like chalk allow water to pass through, creating dry valleys. In contrast, impermeable rocks like granite or clay do not allow infiltration, leading to boggy upland landscapes or extensive surface river networks.
Fire and magma shape the UK's landscape from deep underground, even where no volcanoes exist today. An igneous intrusion occurs when magma is forced into the Earth's crust but cools and solidifies before reaching the surface. Because intrusive rocks are significantly more resistant to erosion than the surrounding country rock, they are left behind as prominent high-relief features once the softer rock erodes away.
The intense heat from an intrusion bakes the surrounding rock, creating a resistant metamorphic aureole that adds further complexity to upland landscapes.
Imagine a layered cake pushed upward from the middle and then sliced evenly across the top. This process creates scarp and vale topography, which forms when alternating layers of resistant and less resistant rock are exposed to erosion.
Resistant layers (like chalk or limestone) form a steep ridge called an escarpment. An escarpment consists of a steep scarp slope and a gentler dip slope. Meanwhile, the less resistant layers (like clay) are eroded away to form wide, flat valleys called vales. The Weald in southeast England is a prime example of an eroded anticline (a dome-shaped rock fold), where the outer resistant chalk forms the North and South Downs, and the less resistant inner clay core forms the flat Low Weald.
To construct a geological cross-section, you must first draw a transect line (e.g., from point A to B) across the map. Lay the straight edge of a piece of paper along this line. Mark a dash on the paper every time a contour line crosses it, recording the height. Plot these dashes onto graph paper with a vertical scale (metres) and a horizontal scale (distance) to reveal the landscape's profile.
Once constructed, use a 4-step process to link geology to relief:
Finding a specific location or interpreting a landscape anywhere in the country requires a methodical approach. Ordnance Survey (OS) maps use a standard grid system where the blue squares always represent exactly 1 km² of land. To fully interpret an OS map and recognise physical and human features, follow this step-by-step sequential process:
Step 1: Check the Scale and Grid. Confirm if the map is 1:25,000 (high detail, 4 cm = 1 km) or 1:50,000 (less detail, 2 cm = 1 km). Locate your general area using a 4-figure grid reference (e.g., 17 51), reading the Easting (vertical grid lines increasing left to right) before the Northing (horizontal grid lines increasing bottom to top). Pinpoint specific features using a 6-figure grid reference (e.g., 174 518).
Step 2: Analyse the Relief (Height and Shape). Look at the contour lines. Closely packed contour lines indicate a steep slope, while widely spaced lines show a gentle slope. If contour lines form a "V" shape pointing uphill (towards higher numbers), it indicates a V-shaped valley. If the "V" shape points downhill, it represents a spur. Exact heights are marked by spot heights (a black dot with a number) or triangulation pillars (a small blue triangle).
Step 3: Identify Physical Features using Symbols. Scan for vegetation and water features. Spot coniferous trees (triangular icons) or non-coniferous trees (rounded icons) over green tints. Locate low-lying wet areas like The Fens using marshland symbols (horizontal blue tufts). Follow solid blue lines to trace river routes.
Step 4: Identify Human Features and Transport. Find major transport links: motorways (thick blue lines), A-roads (green or red), and railways (black lines with cross-bars). Look for tourist or public symbols like viewpoints (blue stars), places of worship, or campsites.
Step 5: Determine Settlement Patterns. Observe how buildings (black squares/blocks) are arranged to deduce the settlement type:
Students frequently use the terms 'hard' and 'soft' rock. The Edexcel mark scheme requires you to use 'resistant' and 'less resistant' to secure marks.
Confusing spurs and valleys on an OS map. Remember: if the 'V' shape of the contour lines points uphill (towards the peak), it is a valley. If it points downhill, it is a spur.
In 'Explain' questions about geology and relief, you must explicitly link the property (e.g., highly resistant rock) to the topographical outcome (e.g., survives erosion to form a steep upland escarpment).
When describing the course of a river or the location of a feature in an exam, always use specific compass directions and provide 4- or 6-figure grid references as evidence.
Always check the key of the OS map provided in the exam to confirm whether it is a 1:25,000 or 1:50,000 scale map before attempting any distance calculations.
When constructing a cross-section, accurately mark every contour crossing on your paper strip to ensure your plotted profile correctly represents the steepness of the relief.
Tees-Exe Line
An imaginary boundary stretching from northeast England to southwest England, broadly dividing the UK into upland North/West and lowland South/East.
drainage basin
The area of land drained by a main river and all its tributaries.
Geology
The types of rock that make up the land and their physical structure, including strata, folding, and faulting.
relief
The height, shape, and steepness of the land's surface.
resistant
A term used to describe harder rocks (like granite or slate) that are difficult for wind, water, or ice to erode.
lithology
The physical characteristics of a rock, such as its mineral composition, hardness, and permeability.
intrusion
Igneous rock that has solidified from magma below the Earth's surface before it could erupt.
country rock
The pre-existing rock that an igneous intrusion is forced into.
Batholiths
Massive, deep-seated igneous intrusions that often form large, rugged upland areas.
Sills
Horizontal sheets of magma intruded between existing rock layers.
Dykes
Vertical or near-vertical sheets of magma that cut across rock strata.
metamorphic aureole
A zone of rock that has been altered by the extreme heat surrounding an igneous intrusion.
escarpment
A long ridge or steep slope consisting of a steep scarp slope and a gentle dip slope, typical of chalk landscapes.
scarp slope
The steep slope where a resistant rock layer has been eroded at its edge.
dip slope
The gentle slope that follows the natural angle of the dipping rock strata.
vales
Wide, flat valleys formed by the erosion of less resistant rock layers like clay.
anticline
An upward-curving, dome-like fold in rock layers (strata) which can erode to form scarp and vale topography.
cross-section
A diagram showing a vertical slice through the landscape or the Earth's crust to reveal relief and geology.
transect
A straight line drawn across a map or landscape along which observations or height measurements are taken.
Easting
The vertical grid lines on an OS map that increase in value from West to East (read first).
Northing
The horizontal grid lines on an OS map that increase in value from South to North (read second).
contour line
An isoline drawn on a map connecting points of equal height above sea level.
spur
A finger of high land extending out from a main hill or ridge, identified by V-shaped contours pointing downhill.
Nucleated settlement
A pattern where buildings are clustered closely together, often around a central feature like a church or bridge.
Linear settlement
A pattern where buildings are arranged in a long line, typically following a transport route or valley floor.
Dispersed settlement
A pattern where individual buildings are scattered across a wide area with no obvious centre.
Put your knowledge into practice — try past paper questions for Geography A
Tees-Exe Line
An imaginary boundary stretching from northeast England to southwest England, broadly dividing the UK into upland North/West and lowland South/East.
drainage basin
The area of land drained by a main river and all its tributaries.
Geology
The types of rock that make up the land and their physical structure, including strata, folding, and faulting.
relief
The height, shape, and steepness of the land's surface.
resistant
A term used to describe harder rocks (like granite or slate) that are difficult for wind, water, or ice to erode.
lithology
The physical characteristics of a rock, such as its mineral composition, hardness, and permeability.
intrusion
Igneous rock that has solidified from magma below the Earth's surface before it could erupt.
country rock
The pre-existing rock that an igneous intrusion is forced into.
Batholiths
Massive, deep-seated igneous intrusions that often form large, rugged upland areas.
Sills
Horizontal sheets of magma intruded between existing rock layers.
Dykes
Vertical or near-vertical sheets of magma that cut across rock strata.
metamorphic aureole
A zone of rock that has been altered by the extreme heat surrounding an igneous intrusion.
escarpment
A long ridge or steep slope consisting of a steep scarp slope and a gentle dip slope, typical of chalk landscapes.
scarp slope
The steep slope where a resistant rock layer has been eroded at its edge.
dip slope
The gentle slope that follows the natural angle of the dipping rock strata.
vales
Wide, flat valleys formed by the erosion of less resistant rock layers like clay.
anticline
An upward-curving, dome-like fold in rock layers (strata) which can erode to form scarp and vale topography.
cross-section
A diagram showing a vertical slice through the landscape or the Earth's crust to reveal relief and geology.
transect
A straight line drawn across a map or landscape along which observations or height measurements are taken.
Easting
The vertical grid lines on an OS map that increase in value from West to East (read first).
Northing
The horizontal grid lines on an OS map that increase in value from South to North (read second).
contour line
An isoline drawn on a map connecting points of equal height above sea level.
spur
A finger of high land extending out from a main hill or ridge, identified by V-shaped contours pointing downhill.
Nucleated settlement
A pattern where buildings are clustered closely together, often around a central feature like a church or bridge.
Linear settlement
A pattern where buildings are arranged in a long line, typically following a transport route or valley floor.
Dispersed settlement
A pattern where individual buildings are scattered across a wide area with no obvious centre.
