LARGE IGNEOUS PROVINCES

Large igneous provinces (LIPs) are the products of planetary volcanism found on Earth, the Moon, Venus, and Mars. On Earth, LIPs occur in many geologic settings, including every ocean basin. LIPs are associated with major transfers of heat and material to Earth's surface, possibly associated with decompression melting of an ascending hot mantle plume. They provide information about mantle composition and dynamics that is not reflected by volcanism at spreading ridges. The episodic nature of LIP production found in the geologic record, especially between 150 and 50 million years ago, is evidence that a more dynamic, unpredictable mode of mantle circulation existed during Earth's past.

• Kerguelen Plateau/Broken Ridge (ODP Leg 183)

• Supercontinent Assembly, Umkondo LIP (S. Africa)

• Ontong Java Plateau (ODP Leg 192)

The two largest LIPs are enormous: the Ontong Java Plateau in the Pacific Ocean, with an area of 1.86 million square kilometers, is nearly three times the size of Texas; the Kerguelen Plateau in the Indian ocean is almost as large at 1.78 million square kilometers. Both lie mostly below sea level.