Geological Changes Flashcards
Define weathering.
The process of wearing or being worn by long exposure to the atmosphere.
Distinguish between, physical, chemical and biological
weathering and give examples of each.
Freeze-thaw weathering
Freeze-thaw weathering occurs when rocks areporous(contain holes) orpermeable(allow water to pass through).
1. Water enters cracks in the rock.
2. When temperatures drop, the water freezes and expands causing the crack to widen.
3. The ice melts and water makes its way deeper into the cracks.
4. The process repeats itself until the rock splits entirely.
Biological weathering
Plants and animals can also have an effect on rocks. Roots burrow down, weakening the structure of the rock until it breaks away.
1. Plant roots can get into small cracks in the rock.
2. As the roots grow, the cracks become larger.
3. This causes small pieces of rock to break away.
Chemical weathering
Rainwater and seawater can be a weak acid. If a coastline is made up of rocks such as limestone or chalk, over time they can become dissolved by the acid in the water.
Describe the formation and give examples of the three
types of rocks, Igneous, Sedimentary and Metamorphic.
Igneous rocks form from cooled magma or lava. Examples include granite and basalt. Sedimentary rocks are formed from the accumulation and compression of sediments. Examples include sandstone and limestone. Metamorphic rocks are formed from the alteration of existing rocks due to heat and pressure. Examples include marble and slate.
Understand the basic structure of soil in so far as it
includes particles of different sizes and the importance of
a mixture of large and small particles.
Soil consists of particles of different sizes: sand, silt, and clay. A mixture of these particle sizes is important for soil fertility, drainage, and aeration.
What is humus and what is its role in soil.
Humus is decayed organic matter in soil. Its role is to improve soil structure, fertility, and water retention, while also providing nutrients for plant growth.
Describe the properties of Sandy soils.
Sandy soils have large particles, drain quickly, and have low nutrient retention.
Describe the properties of Clay soils.
Clay soils have small particles, retain water well, but drain slowly. They are often nutrient-rich but can be prone to compaction.
Describe the properties of Loam soils.
Loam soils are a balanced mix of sand, silt, and clay. They have good drainage, retain moisture well, and are nutrient-rich, making them ideal for plant growth.
