Consider the following statements. 1. The landforms of chalk are rath...
Landforms of Chalk: Characteristics and Features
Chalk is a soft, white, porous sedimentary rock composed of the mineral calcite. It is formed from the remains of microscopic planktonic algae and foraminifera that lived in the warm, shallow seas of the Cretaceous period. The landforms of chalk are rather different from those of other limestones due to their unique characteristics and features.
Statement 1: The landforms of chalk are rather different from those of other limestones.
- Chalk is a soft, porous rock that weathers easily and is susceptible to erosion by water, wind, and ice.
- Chalk is usually found in the form of a plateau or escarpment, with steep, white cliffs facing the sea and gentle slopes inland.
- Chalk forms distinctive landforms such as caves, arches, stacks, and blowholes due to its solubility in rainwater and the erosive power of the sea.
Statement 2: There is little or no surface drainage and valleys which once contained rivers are now dry.
- Chalk is a porous rock that allows rainwater to soak through quickly, rather than forming surface runoff.
- As a result, there is little or no surface drainage on chalk landscapes, and river valleys that once contained water are now dry.
- This has led to the formation of dry valleys or coombes, which are steep-sided, narrow valleys with a flat floor that may contain a small stream or pool.
Statement 3: These are often called coombes.
- Coombes are a characteristic feature of chalk landscapes, but they can also be found on other types of rock.
- The word "coombe" comes from the Old English word "cumb", which means "valley" or "hollow".
- Coombes are often used for grazing animals or for growing crops such as wheat or barley.
Conclusion
All three statements are correct. The unique characteristics of chalk, such as its solubility, porosity, and susceptibility to erosion, have led to the formation of distinctive landforms and features, including dry valleys or coombes. These features are characteristic of chalk landscapes and have important ecological and agricultural significance.
Consider the following statements. 1. The landforms of chalk are rath...
- The landforms of chalk are rather different from those of other limestones.
- There is little or no surface drainage, and valleys which once contained rivers are now dry.
- These are often called coombes. The chalk forms low rounded hills in southern and southeastern England, where they are called downs and in northern France.
- The chalk is covered with short turf, and in places with woodland, and is used for pasture and sometimes for arable farming.
- Because of the friable nature of the rock, swallow-holes and underground cave networks do not generally develop.