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Click here to return to the Earth Systems Revision Page HOTSPOTS AND VOLCANIC ACTIVITY Start by having a look at this excellent animation on hotspot formation (link from Wycombe High School) What are Hotspots? These are jets of plumes of hot solid material rising from the mantle. REMEMBER - hotspot currents are fixed within the mantle - i.e. they are stationary - as the overlying lithosphere gradually moves over the top of the hot spot, a trail of volcanoes and volcanic islands is gradually left behind. 
| What processes result in Hot-Spot Activity?
- Hot spots provide localised intensive heat sources (mantle plumes) - which partly melt the overlying plate, creating a continuous magma source;
- Magma is lighter than the solid lithosphere and rises up, erupting at the surface;
- Where crust is thin above a hot spot, this provides further opportunity for magma to escape as volcanic eruption;
- Lava builds up over time, eventually creating an island, above the present sea-level.
As plate movement gradually carries an active volcano away from the hot spot it becomes inactive as it looses its magma source and a new volcano will be formed above the hot spot. EXAMPLES: 1. HAWAIIAN ISLANDS (series of volcanic islands) - in middle of Pacific Plate 2. YELLOWSTONE NATIONAL PARK - USA - hotspot located in interior of a continental plate (North American Plate) |
See also the following links / resources...
Try some of the following links to check your understanding of hotspots: Hotspots - Mantle Thermal Plumes - a good article from the USGS A good article looking at how Hotspots can be used as a reference point for calculating plate motion. Hotspots (ThinkQuest site) Hotspots - a good overview from the Plate Tectonics Site |
