Rocks Flashcards
What is the approximate diameter of the Earth?
12,000 km
What is the name of the outer layer of the Earth?
The crust
What is the approximate depth of the Earth’s outer layer (Crust)?
10 - 70 km
What is being described here:
Below the Earth’s crust is a layer of rock that makes up 80% of the planet’s volume, it flows slowly like liquid.
Mantle
What is the approximate temperature of the partially melted mantle
3000 ‘c
What is the centre of the Earth called?
The core
What is the centre of the Earth made of?
metals
What is the approximate temperature of the Core?
6000’c
Are the minerals that occur naturally in the Earth’s crust elements or compounds?
Both
What do we commonly call the mixtures of these minerals in the Earth’s crust?
Rocks
Name the top 5, most common occuring, elements in the Earth’s crust
Oxygen (47%), Silicon (28%), Aluminium (8%), Iron (5%), Calcium (3.5%)
Fill in the missing words:
The Earth’s ______ is cracked into large pieces called _______ Plates. These float on the _______, moving due to __________ in the mantle. They usually move very _______. only a few ____ each year. When they move more suddenly, they create ________. _________ and _________ often occur where two plates meet.
The Earth’s CRUST is cracked into large pieces called TECTONIC Plates. These float on the MANTLE, moving due to CONVECTION in the mantle. They usually move very SLOWLY. only a few CENTIMETRES each year. When they move more suddenly, they can create EARTHQUAKES. EARTHQUAKES and VOLCANOS often occur where two plates meet.
Weathering breaks all types of rocks into small pieces called?
Sediments
Does weathering occur quickly or over a long period of time?
Long period of time
What are the three types of weathering?
physical, chemical, biological
What is Erosion?
the movement of the broken pieces of rock to a new location.
What is the common name of the type of weathering described below:
Water repeatedly freezes in cracks and spaces inside rocks. When the water freezes it expands, when the water thaws it contracts. The repeated change in forces results in cracks widening and eventually pieces of rock break off.
Freeze Thaw Weathering
Name two types of physical weathering
Freeze Thaw and Onion Skin
Describe Onion Skin weathering.
During the day, the hot sun heats the surface of the rock and it expands. At night the temperature reduces and the surface cools and contracts. The repetition of heating and cooling, expansion and contraction, over long periods of time cause cracks to form in the surface and the outer layer eventually falls off.
Name a source of chemical weathering.
Acid Rain
Fill in the missing words:
Man-made pollution causes _______ gases to be released into the _________. These gases travel upwards and combine with water droplets in the air. The water droplets cool and condense to form __________ which is released onto the rocks below and causes __________ weathering.
Man-made pollution causes ACIDIC gases to be released into the ATMOSPHERE. These gases travel upwards and combine with water droplets in the air. The water droplets cool and condense to form ACID RAIN which is released onto the rocks below and causes CHEMICAL weathering.
What is biological weathering?
Weathering caused by plants and animals.
Give an example of how trees can cause biological weathering
The trees roots gradually enter small cracks in the rock. As the roots grow they prise apart the rock causing more and larger cracks.
Why do Bacteria, Algae & lichens cause biological weathering.
Bacteria, algae and lichens can produce chemical which break down the rock surface. They do this to release the nutrients in the rock.
Why do some small animals bore into rock, by scraping or secreting chemicals?
To create holes for protection.
How are extrusive igneous rocks formed?
Magma flows out of a volcano to become lava, the lava cools quickly on the Earth’s surface forming extrusive igneous rocks.
Why do extrusive igneous rocks have small, fine grains?
Due to rapid cooling
Give 2 examples of extrusive igneous rocks
Basalt, Obsidian, Pumice
How are Intrusive Igneous Rocks formed?
Magma is trapped in the earth’s crust (often surrounded by sedimentary rock), the magma cools very slowly in the crust forming Intrusive Igneous Rock.
Does intrusive igneous rock have small fine grains, or large coarse grains? Any why?
Large, course grains due to slow cooling.
Give an example of an intrusive igneous rock
Diorite, Granite
Fill in the missing words:
Sedimentary rocks have ______. Each ______ is a different type of rock. Each layer is called a ______. Each layer is made up of separate grains of older rock. Sedimentary rocks are usually _________, ____ and can be scratched _______.
Sedimentary rocks have LAYERS. Each LAYER is a different type of rock. Each layer is called a STRATA. Each layer is made up of separate grains of older rock. Sedimentary rocks are usually POROUS, SOFT and can be scratched EASILY.
This statement describes the formation of what type of rock:
Rocks are weathered. The eroded sediments end up in water and begin to settle (sedimentation or deposition). Further layers are deposited and press down on the layers below. Salt crystals glue the layers together.
Sedimentary rocks
In the formation of sedimentary rocks what is the name of the process of layers pressing down on lower layers?
Compaction
Fill in the missing words:
Sedimentary rock layers may contain dead _____ and ______, that were trapped during their formation.
Sedimentary rock layers may contain dead PLANTS and ANIMALS, that were trapped during their formation.
what is the name of the process of salt crystals gluing together layers of sedimentary rocks?
Cementation
Name two means of weathered rock being eroded.
Water, wind, gravity, glaciers, animals
In sedimentary rock are the bottom or top layers the oldest?
bottom
Describe what is formed in sedimentary rock when a skeleton is trapped in a sediment layer and compacted?
Fossils
What word means to change form and is related to the name of a type of rock
Metamorphism
What 2 things change sedimentary or igneous rocks into metamorphic rocks?
Intense heat and pressure
How do sedimentary or igneous rocks become buried and changed into metapmorphic rocks?
The earth moves, rocks become buried and are heated and squeezed.
Fill in the missing words about the metamorphic process:
The rocks ___ ____ melt, however the chemicals (_______) inside them _______.
The rocks DO NOT melt, however the chemicals (MINERALS) inside them CHANGE.
Where are metamorphic rocks usually formed?
In the upper mantle
Are metamorphic rocks usually harder or softer than sedimentary and igneous rocks
usually harder than sedimentary, softer than igneous
Do metamorphic rocks contain crystals & grains
they may contain small crystals and grains clumped together
Do metamorphic rocks have layers
they may contain thin layers, if the original rock was sedimentary
Sandstone is sedimentary rock, what metamorphic rock would it form
Quartzite
What metamorphic rock is formed from Granite (Igneous rock)?
Gneiss
Marble is a metamorphic rock formed from what sedimentary type of rock?
chalk (limestone)
What type of sedimentary rock can form metamorphic rocks slate and schist?
Shale
