Soil formation Flashcards
Describe Igneous rocks
Magma is liquid rock found under the earth’s crust. Magma is called Lava above ground. When it cools it hardens to from rocks. When it cools it also forms crystals from minerals. It forms small crystals if it cools quickly and large crystals it cools slowly
What are the three most common crystals in Igneous rocks?
Quartz, Feldspar and Mica
Is Quartz alkaline or acidic?
Acidic
Is feldspar alkaline or acidic?
Alkaline
Describe Granite
Granite is formed when magma cools in the earths crust. Granite contains a lot of Quartz and is therefore acidic. Soils formed from it are also acidic
Describe Basalt
Basalt is formed when lava cools. It os less acidic than granite as it contains less Quartz. It contains feldspar,making it fine grained and smooth. It’s soils take a similar form.
Describe sedimentary rocks
Over millions of years, layers of sediment deposit on the bottom of seas and lakes. These layers built up and compacted slowly. As they compacted, the solidified to form sedimentary rocks.
Mineral sediments are made up of different sizes, the largest being Quartz (sand) and the smaller particles being clay (weathered igneous rocks). Sedimentary rocks are also made up of animal fossils
Describe Sandstone
Acidic and made from sand
Describe Shale
Weakly acidic and made from clay
Describe Limestone
Alkaline and made from fossils and shells
Describe metamorphic rocks
Metamorphic rocks are formed from either igneous or sedimentary rocks. Heat or pressure changes the rock and its mineral content.
Describe Marble
Formed from limestone
Describe Slate
Formed from Shale
Describe Gneiss
Formed from Granite
Describe Quartzite
Formed from Sandstone
What is the difference between physical and chemical weathering?
Physical weather involves the breakdown of rocks into sediments and Chemical weather brings a chemical change during the decomposition process.
What are the main methods of Physical weather
Heating and Cooling
Freeze-Thaw action
Activity of roots
Grinding action
What are the three main rock types?
Igneous
Sedimentary rocks
Metamorphic
What are the main methods of chemical weathering? Explain each.
Hydrolysis
Oxidation
Hydration
Solution and Carbonation
What are the five factors that effect soil formation? Explain each
Parent material Climate Living organisms Topography Time
Describe how bogs are formed.
Organic parent material consists of dead partially decomposed organic matter. This can build up in wet/waterlogged/lake conditions. In these conditions oxygen isn’t present and so decomposition does not fully take place. Peat forms from this. Peat is the main material in bogs
Name the three types of bogs found in Ireland. Explain their formation
Basin bogs
Flat bogs(fens)
Blanket bogs
