HOTSPOT

• HOTSPOT : active surface expression of mantle plumes on the earth’s surface

• MANTLE PLUME :

  • Nearly vertical columns of hot, upwelling solids ascends from deep within the mantle (D’’ layer)

  • Large head followed by narrower tail

  • shaped like a mushroom with a long conduit (tail)

  • Originated from core-mantle boundary

CONTINENTAL HOTSPOT

• Afar / Ethiopia

• Iceland

• Yellowstone

• The Iceland Hotspot and Afar Hotspot which are situated at the divergent boundary are exceptions.

OCEANIC HOTSPOT

• Hawaii : Mouna loa, Mouna kea, Killuae (Shield volcano)-gentle less viscous

• Reunion : Deccan trap (66 ma)

• Kerguelen : Rajmahal trap

• Galapagus

• Bermuda

• Martin-vas

• Discovery

FACTS

• The Réunion hotspot (produced the Deccan Traps about 66 million years ago) coincides with the Cretaceous–Paleogene extinction event

• The Kerguelen hotspot produced the Rajmahal trap in upper creataceous and it is older than Deccan trap.

• Carlsberg ridge : Spreading

• Ninetyeast ridge : Aseismic

• Pranhita-Godaveri basin : Rifting

• Makran coast : Subduction