carbon isotopic excursions are shown in the same places, making the case for a volcanic cause of a mass extinction. Some scientists initially rejected the volcanic eruption theory, because the Newark Supergroup, a section of rock in eastern North America that records the Triassic–Jurassic boundary, contains no ash-fall horizons and its oldest basalt flows were estimated to lie around 10 m above the transition zone. However, updated dating protocol and wider sampling has confirmed that the CAMP eruptions started in Nova Scotia and Morocco only a few thousand years before the extinction, and continued in several more pulses for the next 600,000 years. References Literature McHone, J.G. (2003), Volatile emissions of Central Atlantic Magmatic Province basalts: Mass assumptions and environmental consequences, in Hames, W.E. et al., eds., The Central Atlantic Magmatic Province: Insights from Fragments of Pangea. American Geophysical Union Monograph 136, p. 241-254. External links Theories on the Triassic–Jurassic Extinction The Triassic–Jurassic Mass Extinction 200 million year old mystery BBC News story, 12-Oct-2011 Extinction events . . Jurassic events Triassic events History of climate variability and change Events that forced the climate Evolutionary biology . .