Great Volcano Eruptions in Earth History

Plumes are thought to originate very deep in the Earth - perhaps at the core-mantle boundary for the larger ones and at a depth of about 600 km deep for the smaller ones - but they seem to be related to the breakup of continents (rifting), so there is some influence from global plate tectonic processes.

The estimated dates of the younger continental flood basalts compiled from recent sources along with other lines of evidence suggest that in most instances the greatest number of individual eruptions and the largest volumes of lava probably occurred within a million years or less.

Flood Basalts & Mass Extinctions

Every now and again in geology, as in any other science, evidence is obtained and presented that cannot easily be explained in terms of familiar processes or accepted ideas. Such a case was continental drift, proposed by Wegener in 1912, which languished as a theory for about 45 years because there was no logical explanation of HOW continents could move. The mechanism of seafloor spreading proposed in the late 1950's led to the development of the modern theory of plate tectonics, which provides an explanation for continental drift.

USGS/Hawaiian Volcano Observatory Could the catastrophe that killed the dinosaurs have been volcanic?

The time relationship between flood basalt province formation and mass extinctions of organisms is another example of a scientific "hard nut to crack."

Extinction events are increasingly seen as important factors in the history of life on Earth, and recent studies suggest catastrophic causes for at least some mass extinctions. Two catastrophic processes that have been invoked are (1) impacts of asteroids or comets and (2) large volcanic eruptions. The end-Cretaceous (Cretaceous/Tertiary or K/T boundary) mass extinction has been convincingly correlated with the impact of a 10-km diameter asteroid with the Earth about 65 million years ago. Evidence of similar impacts has been found at the times of several other extinction events.