Question

Use the space below to describe hot spots. What are they? Where do they occur? What are examples of them we have on earth today?
What are they?
Where do they occur?
Examples:

Answer 1

What are hotspots?
- Hotspots are locations where hot, buoyant rock rises from deep in the mantle (often described as mantle plumes) and melts as it nears the surface, producing volcanic activity that is largely independent of plate-boundary processes.
- They commonly produce long-lived, supply-rich volcanism: large shield volcanoes, chains of islands and seamounts, or extensive flood-basalt eruptions.
- Hotspot volcanism often has distinctive geochemistry (ocean-island basalts, OIB) and can produce very large igneous provinces when plume activity is strong.

Where do they occur?
- Typically beneath tectonic plates far from plate boundaries (intraplate settings), but they can also interact with mid-ocean ridges or rift zones.
- Because the tectonic plate moves over a relatively stationary hotspot, hotspots commonly produce linear chains of volcanoes and seamounts that show an age progression away from the currently active center.
- Hotspots can occur under oceans or continents; the character of eruptions differs (fluid basaltic shield volcanoes in oceans, sometimes explosive rhyolitic/caldera volcanism on continents).

Examples on Earth today (with short notes)
- Hawaiian–Emperor chain (Pacific Ocean): Classic oceanic hotspot producing the active Hawaiian Islands (e.g., Kīlauea, Mauna Loa) and an age-progressive chain of older seamounts.
- Yellowstone (North America): Continental hotspot beneath Yellowstone National Park; produces large silicic caldera eruptions, geothermal features, and a track of volcanic centers that get older to the west.
- Iceland: A hotspot beneath the Mid-Atlantic Ridge; magma supply from the plume interacts with ridge spreading to build an unusually large, volcanically active island.
- Galápagos Islands: Oceanic hotspot that creates islands and seamounts with diverse volcanic and biological environments.
- Réunion / Deccan connection: The Réunion hotspot is associated with the Réunion Island volcanism today and is linked to the Deccan Traps flood basalts in India ~66 Ma.
- Afar/Ethiopian plume: A hotspot underlying the Afar region and East African Rift — linked to huge flood basalts (Ethiopian traps), active rifting, and volcanic features in Ethiopia and Eritrea.
- Canary Islands (and Madeira): Often interpreted as hotspot-related intraplate volcanism (though some details are debated).
- Louisville Seamount Chain, Tristan–Gough, and other oceanic chains: Examples of seamount/island chains attributed to hotspots.

How to recognize a hotspot’s imprint
- A chain of volcanic islands/seamounts with progressively older ages away from an active center.
- Large shield volcanoes or flood-basalt provinces.
- Geochemical signatures in the lavas that differ from typical mid-ocean-ridge basalts.
- Seismic tomography sometimes images plume-like thermal anomalies in the mantle beneath hotspots.

Note: The classical “fixed plume under moving plate” model explains many hotspot features, but some hotspots are more complex and other mechanisms (small-scale mantle convection, lithospheric controls, plume–ridge interactions) also play roles.