Examkin

Question

Difficulty: MediumLandform Evolution by Running Water and Underground Water

Match each landform created by running water or groundwater processes with its correct defining characteristic.

  • PoljeA large, flat-bottomed depression formed by the solution and collapse of limestone caverns
  • Plunge poolA deep basin excavated at the base of a waterfall by hydraulic action and eddying currents
  • Braided channelA wide, shallow river network created by heavy sediment deposition forming mid-channel bars
  • StalagmiteA calcite pillar growing upwards from a cave floor due to dripping mineralized water

Answer

Polje matches with the large flat-bottomed depression in limestone regions; Plunge pool matches with the deep basin at the base of a waterfall; Braided channel matches with the wide, shallow river network with mid-channel bars; Stalagmite matches with the calcite pillar growing upwards from a cave floor.
Each feature is correctly matched to its formation mechanism: a polje is a large solution depression in karst topography; a plunge pool is carved at a waterfall base by turbulent water action; a braided channel is formed by sediment deposition splitting river flow; and a stalagmite is an upward-growing cave deposit of calcium carbonate.

Step-by-Step Solution

1
Identify the karst surface feature formed by massive solution and cavern collapse.
Polje matches the description of a large flat-bottomed depression in limestone landforms.
Poljes represent an advanced stage of karst landform evolution where subterranean rivers and solution hollows coalesce into a wide flat plain.
2
Analyze the upper-course fluvial feature located beneath vertical drops in water channels.
Plunge pool matches the deep basin formed at the base of a waterfall.
Hydraulic action and abrasion by swirling sediments rapidly deepen the channel floor directly below waterfalls.
3
Classify the depositional fluvial channel form containing mid-stream islands or bars.
Braided channel matches the shallow network created by heavy sediment deposition.
When stream energy drops relative to its heavy sediment load, channels split and recombine around sediment bars.
4
Determine the subterranean dripstone feature that builds upward from cave floors.
Stalagmite matches the upward-growing calcite pillar.
Dripping water loses carbon dioxide upon entering the cavern atmosphere, precipitating calcium carbonate on the floor beneath the drip point.

Key Concept

Classification of Fluvial and Karst Geomorphic Features
Estimated Time:1m 30s
Rate this question

Topics

Landform Evolution by Running Water and Underground Water

More questions from this topic