Waterfall Formation Flashcards

Questions and Answers

Where do waterfalls form?

The upper course

Where do waterfalls form (site)?

Waterfalls form in upper course areas where there is an increase in vertical erosion, where there is a layer of cap rock overlaying a softer, less resistant rock.

What physical processes undercut hard rock?

Over time hydraulic action and abrasion erode soft rock more quickly, undercutting hard rock.

What happens when hard rock is left overhanging?

The hard rock is left overhanging and because it isn't supported, it eventually collapses. Signup and view all the answers

How is the plunge pool eroded?

The fallen rocks crash into the plunge pool and so the process of hydraulic action and corrasion works to further erode the plunge pool. Signup and view all the answers

Why does a waterfall move upstream?

This process is repeated and the waterfall moves upstream. Signup and view all the answers

How is a steep-sided gorge formed?

A steep-sided gorge is formed as the process of undercutting is repeated and the waterfall retreats. Signup and view all the answers

Explain how waterfalls form:

Waterfalls form in upper course areas where there is an increase in vertical erosion and there is a layer of cap rock overlaying a softer, less resistant rock. Over time hydraulic action and abrasion erode soft rock more quickly, undercutting hard rock. The hard rock is left overhanging and because it isn't supported, it eventually collapses. The fallen rocks crash into the plunge pool, allowing hydraulic action and corrasion to further erode the plunge pool. This process is repeated, and the waterfall moves upstream, leading to the formation of a steep-sided gorge. Signup and view all the answers

Study Notes

Waterfall Formation Overview

Waterfalls typically form in the upper course of rivers.
They occur where vertical erosion increases, particularly where hard, resistant cap rock overlays softer rock.

Erosion Processes

Hydraulic action and abrasion are two key processes that undercut hard rock.
Soft rock erodes more rapidly, leading to undercutting of the harder layer.

Overhanging Rock Collapse

As undercutting progresses, the hard rock may become overhanging.
Lack of support eventually leads to the collapse of the overhanging hard rock.

Plunge Pool Erosion

When rocks fall into the plunge pool, they create more erosion through hydraulic action and corrasion.
This ongoing process enhances the depth and shape of the plunge pool.

Upstream Movement of Waterfall

As the waterfall continues to erode the surrounding landscape, it gradually migrates upstream.
The repeated erosion and collapse process causes this retreat of the waterfall.

Formation of Steep-Sided Gorges

A steep-sided gorge forms as the waterfall retreats due to continually repeated undercutting.
This geological feature showcases the effects of persistent erosion over time.

Example of Waterfalls

Angel Falls in Venezuela serves as a notable example of waterfall formation, illustrating the principles discussed.

Description

Test your knowledge on how waterfalls are formed with these flashcards. Each card explores the processes and locations where waterfalls typically occur. Perfect for students studying geology or physical geography.