On this page, you will find information related to grade 7 projects that students created to learn about the Earth's Crust and to share information.

 

 

TYPES OF VOLCANOES

 

 

 

TYPE OF VOLCANO	HOW IS IT FORMED	EXAMPLES
FISSURE	When tectonic plates move apart, lava rises to fill the space.	Mid-ocean Ridges
SHIELD	A broad, shallow volcanic cone formed when running lava, which is fluid and hot, cools slowly.	Hawaiian Volcanoes
DOME	A volcano with a steep, convex slope formed by thick fast flowing lava.	Mount Lassen, Shastina
ASH-CINDER	Built up from layers of ash, cinder and lava.	Mount Zion, Moon Craters
COMPOSITE	Built up from alternate layers of ash and lava but there are small craters on the side as well as the main crater.	Mount St. Helens  Mount Hood
CALDERA	An old volcano with a large (up to 100km wide) sunken crater. There may be smaller craters in the large crater.	Yellowstone Crater lake

 

   

 

 

 

Dome Volcano

 

                

 

Mauna Loa Fissure Volcano

 

 

Cinder Cone

 

 

Mt. St. Helens (pre 1980) Composite Volcano

 

 

 

Caldera

 

The following video shows Mt. Saint Helens erupting in 1980.

 

 

 

 

Earthquakes result from a sudden release of energy when rocks under stress slide past each other along a break (fault) in the Earth's crust. There are three main types of Earthquakes. Divergent earthquakes often are accompanied by fissure volcanoes (mid ocean ridges). The recent Earthquake in Japan was a Convergent or Subduction Earthquake. The San Andreas fault in California is an example of a Transform Earthquake.

 

     

 

 

                                                                                                                              Subduction Earthquake - Juan De Fuca Plate

 

San Andreas Fault in California

                                                                                                     A famous tranform fault. 

 

 

The Ring of Fire is an area of intense volcanic and earthquake activity around the Pacific Plate. Over 75% of the world's active and dormant volcanoes are found in this area. The Ring of Fire is a subduction zone.

 

 

 

 

 

 

 

 

TYPES OF MOUNTAINS (other than volcanoes)

1. FOLDED MOUNTAINS; When two plates push together, it causes the land to bend, break and fold over time. The Canadian Rockies are an example of this type of mountain.

2. A BLOCK FAULT MOUNTAIN: When tension on the Earth's crust cause it to crack and break. One piece slides down and another rises up. this creates sharp and unusual faces on mountains such as the Teton Range. 

3. A DOME MOUNTAIN is formed when a large amount of magma pushes up on the Earth's crust without actually erupting.

Berg Lake in the Canadian Rockies, a folded mountain range. Notice the layers of rock in the mountains.  

 

 

 

The above diagram shows how block fault mountains form. Below is the Teton Mountain Range which was formed in this way.

 

The diagram below shows how dome mountains are formed.

 

Below is a dome mountain in the Catskill Range.

 

If earthquakes occur in the ocean floor, the energy released can cause a huge wave called a Tsunami. Tsunamis can also be caused by underwater volcanic eruptions, explosions and landslides.

 

 

 

The picture above shows the tsunami wave from the Indian Ocean in 2004. Notice how large the wave is compared to the highrise buildings on the shore.

 

 

 

 

 

 

 

 

A glacier is a large, long-lasting body of ice.  Glaciers form in areas where snow lasts year round (at the poles and on high mountains). Layers of snow pile up and change into ice over time. The upper layers of snow compress the lower layers. A glacier is a solid but due to its mass, it flows very slowly over the Earth. As it moves, it carves the Earth's surface forming valleys and cliffs. Glaciers scrap off the outer layers of soil and rock leaving only the bedrock beneath as in the Canadian Shield. Glaciers carry rock and debris and deposit it along the way. Where glaciers melt, they form aluvial plains (large open areas covered in gravel and boulders). The weight of large icesheets press down on continents, lowering their elevation. When the glacier melts, the continent will rise up.

 

 

 

 

The land above was scraped clean by a glacier.

 

 

 

A Hot Spring is hot water from deep in the Earth's Crust. There are two types of hotsprings: 1. Non-volcanic: In non-volcanic areas, water is geothermally heated (heated by the heat of the Earth). This water is pleasantly warm. there are hotsprings in Moose Jaw and in Banff.  2. Volcanic: In volcanic areas, such as Yellowstone Park, water is heated by magma. It these areas the water can reach the boiling point or become superheated. Sometimes the water erupts from time to time as a geyser (Old Faithful). Other times the water comes to the surface more gently as a stream or fumarole.

 

Hot springs in non-volcanic areas stay hot even in winter because they are heated by hot rocks in the Earth's Crust.

 

 Hot springs in volcanic areas are super hot all the time.

 

Sometimes they erupt as geysers as shown below.

 

 

 

A mineral is a naturally occuring chemical substance made from specific chemicals and with a definite particle structure. Examples are quartz, feldspar, and mica.

A rock is a collection of minerals bound together. Some rocks like limestone are made almost entirely of one mineral, calcite. Other rocks like granite are mostly made from two minerals, quartz and feldspar, but also contain other minerals.

 

 

 

 

Crystals are minerals that had a chance to grow into their full shape. The chemicals in a mineral determine the shape of the crystal it can become if it has enough room and time to grow. A big chunk of mineral is called a massive mineral. If it has a clear shape with easy to see sides, it is a crystal. Crystals form over millions of years deep in the earth's crust. Crystal structure influences a minerals physical properties. For example diamonds and graphite have same compostion (pure carbon) but graphite is soft while diamonds are one of the hardest minerals. This is because the carbon atoms in graphite are arranged in sheets while those in diamonds are in a definite, three dimensional structure (crystal).

 

   

 

Diamonds                                                             Graphite

 

 

 

Fossils are the remains of plants and animals or signs left by animals (footprints) that have been preserved in rock. To be fossilized, something has to be in the right place at the right time. Remains need to be covered with sediment or frozen as soon as possible after they die. Minerals slowly replace the remains as they decay in the sediment. The minerals harden, creating an impression of the plant or animal. 

 

 

        

 

Fossilized Fern                                                      Fossilized Crayfish                                                     Fossilized Footprint