Interlocking Spurs, Waterfalls & Gorges Flashcards
All 4 cards in this deck
What are interlocking spurs?
Ridges of higher land projecting into the valley from alternate sides, which the river winds around in its upper course.
What arrangement of rock types is needed for a waterfall to form?
A band of hard (resistant) rock lying over softer, less resistant rock.
What is a plunge pool?
A deep pool at the foot of a waterfall, eroded by hydraulic action and abrasion from the falling water and rocks.
What are the steps in the formation of a gorge below a waterfall?
e.g. a waterfall where hard rock lies over soft rock- The soft rock beneath is eroded, undercutting the hard rock and forming an overhang.
- The unsupported hard rock collapses into the plunge pool.
- Repeated collapse makes the waterfall retreat upstream, leaving a narrow, steep-sided gorge.