Basics
What is the definition of a rock?
A natural, solid, cohesive aggregate of one or more minerals.
What are igneous rocks formed of?
They are formed from molten material that has cooled and solidified.
What are sedimentary rocks?
Rocks that form due to compaction and cementation of sediments
What is a metamorphic rock?
A rock formed by the alteration of a preexisting rock due to the effects of pressure, high temperature, and/or a chemical change
What is the rock cycle?
Rocks in the Earth’s crust are continuously being formed, broken down, and then re-formed
What are the major rock types?
Igneous, sedimentary, and metamorphic.
The first rocks ever formed on earth were igneaous rocks. True or False?
True. The first rocks on Earth were formed as the outer crust slowly solidified billions of years ago
What are rock strata?
Sediments are often deposited in horizontal layers, called strata.
What is the "parent rock"?
The original rock before metamorphism takes place.
A rock changes over time between igneous, sedimentary, and metamorphic forms. True or false?
True. That's the rock cycle.
What is coal made of?
Coal is formed from the lithified remains of ancient plants.
What are the 2 criteria used to classify igneous rocks?
Texture (size of grains) and mineral composition (types of mineral).
Where in the US can you find great examples of sedimentary rocks?
For example on the Colorado Plateau, an area with many National Parks.
Metamorphism can change both the texture (crystal size) and the mineral composition of the parent rock. True or false?
True.
What is rock erosion?
The process of rock eroding or being eroded (diminished) by wind, water, or other natural agents.
What are the remains or traces of an ancient organism preserved in a rock called?
Fossils
Does an igneous rock light in color usually have a high silica content or a low silica content?
A high silica content.
What are the 2 main types of sediments?
Detrital (fragments of existing rocks) and chemical (dissolved minerals).
What is the "parent rock" for marble?
Limestone.
How does metamorphic rock turn into igneous rock?
First it melts into magma (inside the earth), which then cools and solidifies into igneaous rock.
What is magma?
Molten rock material inside the earth. When magma reaches the surface it's called lava.
A very common igneous rock with a high silica content that is also used for counter tops?
Granit
Alabama has lots of Limestone. What kind of rock is limestone?
A chemical sedimentary rock.
How does igneous rock become sedimentary rock?
Igneous rock weathers and erodes, then its sediments are compacted and cemented over time until they are compressed into sedimentary rock.