How are Headlands and bays formed?

Headlands are formed when the sea attacks a section of coast with alternating bands of hard and soft rock which outcrop at a right angle to the coastline. (see image below). Due to the different nature of rock, erosion occurs at different rates. The bands of soft rock erode more quickly than those of more resistant rock. This leaves a section of land jutting out into the sea called a headland. A headland is a cliff formed from hard rock that sticks out into the sea and is surrounded by water on three sides. The weaker bands of soft rocks next to the headland are eroded quicker thus forming inlets known as bays. A bay is a sheltered inlet of the sea where the land curves inwards, usually with a beach.

Watch this short video clip which explains how headlands and bays are formed.

Formation of caves, stacks and stumps

Along the years, the sea breaks against the cracks in the cliff face, slowly widening and eroding them until they form sea caves, of which one can see many along the coasts of the Maltese islands. Through hydraulic action and abrasion the waves containing sand and other material grind away the rocks until cracks, joints or bedding planes are enlarged and gradually become caves. The sea, laden with rock pieces, is capable of eroding and widening cracks in hard rock such as Upper and Lower Coralline Limestone. In the picture below we can see deep caves formed into the upper coralline limestone on the northern coast of Gozo.

Where there are protruding promontories or headlands, the cave sometimes erodes right through the headland and forms a small arch. A well-known arch like this, called the azure window, could be seen at Dwejra point in Gozo until it totally collapsed into the sea on 8 March 2017. Another large arch like this can be seen at Wied il-Mielaħ, limits of Għarb in Gozo too. In Malta we may find other examples such as the arch at Ras il-Ħamrija near Għar Lapsi and Blue Grotto (see image below).

The force of the sea continues to erode the headland, thus the arch gradually becomes bigger until it can no longer support the top of the arch. Finally the ceiling of the arch collapses too and only a separate rock or a stack remains off the coast. A stack is a tall column of rock. One finds such stacks at Għar Qawqla in Marsalforn, Gozo and even in Comino.

Slowly, even this separated rock will be eroded and what remains will be only a low reef at the level of the sea known as a stump.
The diagram below explains the sequence of events in the formation of the named coastal erosional features.

Watch these two short video clips explaining clearly how caves, arches stacks and stumps are formed.

You can also watch this video by clicking here.

Now work out the following tasks.

1. Look at the figure below showing how a headland is eroded by the sea.

b. Fill in the blanks with the terms used in exercise (a) to complete this paragraph on sea erosion along the coast.

On stormy days large waves wear easily weak spots like ________________ and slowly opens them wider and wider. In this way a __________________ is formed like the one we see at Għar Lapsi and many others along the coast. Where there is a piece of land jutting out into the sea, also known as a _______________ , the cave can wear right through it and an ________________ forms like that found at Għarb at the mouth of Wied il-Mielaħ. Further erosion causes the arch to collapse forming a _______________ , which is like a pillar of rock standing away from the coast. In time this will also erode and all that will remain is a _______________ at sea level.

2. Look at these pictures.

i. Identify the coastal landform in each picture.
• Picture A ________________________
• Picture B _________________________
• Picture C _________________________
• Picture D _________________________

ii. In what sequence where these features formed?
iii. In the proper sequence draw a diagram for each. Label each diagram well. Next to each diagram explain how each of these coastal landforms was formed.

Now work out the worksheet entitled Coastal Processes 4 Worksheet available in the resources section.