Geography - Rocks 🌑 Flashcards
What is a rock?
A rock is a mixture of natural compounds called minerals.
What is a mineral?
A mineral is a natural compound found in rock. All rocks are made up of minerals.
What are the 3 different types of rocks?
Igneous, Sedimentary, and Metamorphic
The word “Igneous” comes from the ____ word ____, which means ____
The word “Igneous” comes from the latin word ignis, which means fire.
What are igneous rocks?
Rocks that form from the cooling or solidification of magma or lava
What are the two types of Igneous rocks?
Intrusive and extrusive.
What Classifies an Igneous rock as “Intrusive”?
Magma cools slowly, and large crystals form. This is because they are formed inside a volcano, where it takes longer to cool.
What Classifies an Igneous rock as “Extrusive”?
The lava cools quickly, the crystals are small or not visible, and they may be vesicular (having air bubbles). Also, they can have a glassy surface (obsidian). This is because they are formed outside a volcano, where they can cool in seconds.
What is the difference between magma and lava?
Lava is outside a volcano, and magma is inside.
What are sedimentary rocks?
Rocks generally formed from the compaction and cementation of sediments.
What are the two types of Sedimentary rocks?
Clastic and Organic/Crystalline
What classifies a Sedimentary rock as “Clastic”?
They are made of compacted sediments, and are classified by size.
What classifies a Sedimentary rock as “Organic” and “Crystalline”?
“Crystalline” rocks are made of precipitates and evaporates. Organic sedimentary rocks are made of biological matter.
What is a sediment?
Sediments are fragments of rocks that have been broken down as a result of weathering
Sediments are classified according to their size. What order are they classified in?
Clay, Silt, Sand, Pebble, Cobble, Boulder
What are evaporites and precipitates?
When things such as sea water evaporate to form rock salt. Precipitates are the opposite. (A chemical process)
How are sedimentary rocks formed?
1) Eroded rocks end up in the water and begin to settle (sedimentation).
2) As time goes on, more layers pile up and press down the lower rocks (compaction)
3) More layers (strata) and further compaction forces water out of the layers.
4) Salt crystals glue the strata together (cementation)
What is another word for layers in a sedimentary rock?
Strata
What are metamorphic rocks?
Rocks that are changed as a result to intense heat and/or pressure.
What are the two ways metamorphic rocks are formed?
Contact metamorphism and Regional metamorphism.
What is contact metamorphism?
When rocks are changed due to intense heat.
What is regional metamorphism?
When rocks are changed due to pressure.
What is the rock cycle?
The process of how rocks change from type to type. I recommend to study the diagram separately.
What is soil?
Soil is a mixture of clay, sand and rotting vegetation.
How is clay and sand formed?
Clay and sand is formed when rock is broken down by chemical weathering.
What are the layers of soil in the soil profile (from top to bottom)?
Humus, Topsoil, Subsoil, Weathered Rock, Bedrock.
What is humus?
Humus is a thin layer of vegetation such as grass and leaves. The nutrients in it return to the soil.
What is topsoil?
Topsoil is a layer that is rich in humus and the minerals from rock. It is good for growing crops.
The plants take in nutrients like potassium, silicon, phosphorus and calcium which came from the rock, as well as nitrogen which bacteria in the soil fix from the air.
What is subsoil?
Subsoil is a layer that has very little humus but is rich in minerals. Tree roots reach this layer.
What is weathered rock?
Weathered rock is rock that has been broken into chunks already. There are few signs of life in this layer.
What is bedrock?
Bedrock is solid rock that has not been weathered yet.
What are nutrients?
Nutrients are substances that plants must take in to grow and be healthy.
