Mountain and Volcano Formation

Transcription

1 Mountain and Volcano Formation

2 Essential Questions How are mountains made? How are volcanoes made? What are the different types of volcanoes?

3 How are mountains made?

4 Mountain Building & the Growth of Continents Earth Revealed Series ml?pid=318 Complete the question sheet provided 30 mins

5 Types of Mountains Fold Mountains (Folded Mountains) Fault-block Mountains (Block Mountains) Dome Mountains Volcanic Mountains Plateau Mountains

6 Fold Mountains (Folded Mountains) formed when two continental tectonic plates collide and their edges crumble to form mountains the crust is uplifted forming folds on top of the other

7 Fault-block Mountains (Block Mountains created when faults or cracks in the Earth's crust force materials or blocks of rocks upward or down block mountains break up into chunks or blocks and move either up or down usually have a steep front side and then a sloping back side

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9 Dome Mountains formed when large amounts of molten rock or magma push the earth s crust from underneath before it can erupt the source of magma goes away leaving the pushed up rock as such rock then cools and forms a mountain

10 Volcanic Mountains created when magma pushes its way from beneath the earth to the crust, and when it reaches the surface, it erupts as lava, ash, rocks and volcanic gases erupting materials build around the vent through which they erupted

11 Plateau Mountains formed by erosion large areas of high levels of flat land, over 600 meters above sea level formed due to earth s internal activity found near Fold Mountains

12 Ranges versus Belts Ranges are groups of mountain peaks or ridges that form areas bordered by valleys or rivers. Mountain belts are long chains of mountain ranges that can extend across continents or along their edges.

13 Ranges Most mountain ranges are uplifted, erode to low elevations, and are uplifted again before they become stable

14 Major Mountain Ranges Appalachian Mountains Rocky Mountains Ozark Mountains In Nova Scotia Appalachian Mountains Cape Breton Highlands Cobequid Hills

15 Mountain Ranges of Canada

16 Cape Breton Highlands an extension of the Appalachian mountain chain 'highland' or 'plateau' of ancient rock across northern Cape Breton Island, Canada comprise the northern portions of Inverness and Victoria counties Elevations average 350 metres at the edges of the plateau and rise to more than 500 metres at the centre Highest peak White Hill

17 Cobequid Hills are considered part of the Appalachians range stretches from Cape Chignecto in Cumberland County in the west through to Pictou County in the east are composed of a combination of sediments, granites, and volcanic rock all of which has been crushed and folded by continental drift the highest peaks Nuttby Mountain (360 m (1,181 ft)) Higgins Mountain (355 m (1,165 ft) Dalhousie Mountain (335 m (1,099 ft) Mt. Thom

18 Belts Typically 1000 of kilometers long and 100 kilometers across (wide) Parallel to continental coastlines The taller the mountains the younger WHY?

19 Major Mountain Belts North American Cordillera western edge of North and South America Andes South America Appalachians/Caledonides spanning continents Pyrenees Europe between France and Spain Alps - Europe Urals - Russia Himalaya Asia and includes Everest and K2

20 How are volcanoes made?

21 Volcanism Earth Revealed Series ml?pid=324 Complete the question sheet provided 30 mins

22 Parts of a volcano Vent an opening at the Earth's surface. Pipe a passageway in the volcano in which the magma rises through to the surface during an eruption Crater a bowl-shaped depression at the top of the volcano where volcanic materials like, ash, lava, and other pyroclastic materials are released Cone made of solidified lava, ashes, and cinder layers of lava, alternate with layers of ash to build the steep sided cone higher and higher.

23 Parts of a Volcano continued Magma Chamber an underground lake of hot liquid

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25 What are the different types of volcanoes?

26 Types of volcanoes Composite Volcanoes also called strato volcanoes Shield Volcanoes also called shields Cinder Cones & Spatter Cones Complex Volcanoes also called compound volcanoes

27 Composite Volcanoes Dimensions: Height as much as 8,000 feet Diameter 1000sq.km Volume 400km 3 formed by alternating layers of lava and rock fragments constructed along subduction zones are often so quiet they seem extinct form impressive, snow-capped peaks usually large and conical

28 Types of Composite volcanoes Concave Pyramidal Convex-concave Helmet-shaped Collapse caldera Nested Multiple summits Elongated along a fissure

29 Composite Volcano eruption usually erupt in an explosive way usually caused by viscous magma magma rises to the surface it clogs the craterpipe gas in the craterpipe gets locked up the pressure will increase resulting in an explosive eruption emits gases, ash, pumice, and a small amount of stiff, silica lava can have eruptions accompanied by lahars -- deadly mudflows

30 Shield Volcanoes Dimensions: Height often exceeding 1,500 to 2,000 feet Mauna Loa, the largest of the shield volcanoes its top is over 28,000 feet above the deep ocean floor Diameter ~5-6.5 km huge in size built by many layers of runny lava flows produced by hot spots which lay far away from the edges of tectonic plates

31 Shield Volcano eruption low-explosivity lava-fountaining forms cinder cones and spatter cones at the vent

32 Cinder & Spatter Cones Dimensions: Height rarely exceed 250m Diameter 500m formed above a vent formed by Strombolian eruptions usually a bowl-shaped crater at the top forming steep-sided accumulations grow up in groups they often occur on the flanks of strato volcanoes and shield volcanoes

33 Cinder Cone eruption lava flows through a single vent that is usually only up to about 1,000 feet tall lava fragments are ejected from a single vent and accumulate around the vent when they fall back to earth eruptions usually don't cause any loss of life

34 Spatter Cone eruption hot erupting lava contains just enough explosive gas to prevent the formation of a lava flow the lava is torn by expanding gases into fluid hot clots, ranging in size from 1cm to 50cm across

35 Complex Volcanoes it is because we mean the "system" of those volcanoes is not "simple" consists of a complex of two or more vents form because changes of their eruptive characteristics or the location of multiple vents in an area

36 Complex Volcano types Caldera complexes often have a large caldera with many subsidiary vents and deposits some of which could be considered "volcanoes" in their own right.

37 Complex Volcano eruption the most explosive volcanoes after an eruption, the result is a caldera (crater) caused when the area around the vent collapses

38 Three Stages of Activity Active Volcano: A volcano that is erupting. Also, a volcano that is not presently erupting, but that has erupted within historical time and is considered likely to do so in the future. Dormant Volcano: Literally, "sleeping." The term is used to describe a volcano which is presently inactive but which may erupt again. Most of the major Cascade volcanoes are believed to be dormant rather than extinct. Extinct Volcano: A volcano that is not presently erupting and is not likely to do so for a very long time in the future.