『Abstract
Comparing the timing of mass extinctions with he formation age
of large igneous provinces reveals a close correspondence in five
cases, but previous claims that all such provinces coincide with
extinction events are unduly optimistic. The best correlation
occurs for four consecutive mid-Phanerozoic examples, namely the
end-Guadalupian extinction/Emeishan flood basalts, the end-Permian
extinction/Siberian Traps, the end-Triassic extinction/central
Atlantic volcanism and the early Toarcian extinction/Karoo Traps.
Curiously, the onset of eruption slightly post-dates the main
phase of extinctions in these examples. Of the seven post-Karoo
provinces, only the Deccan Traps coincide with a mass extinction,
but in this case, the nature of the biotic crisis is best reconciled
with the effects of a major bolide impact. Intraoceanic volcanism
may also be implicated in a relatively minor end-Cenomanian extinction
crisis, although once again the main phase of volcanism occurs
after the crisis. The link between large igneous province formation
and extinctions remains enigmatic; volume of extrusives and extinction
intensity are unrelated and neither is there any apparent relationship
with the rapidity of province formation. Violence of eruptions
(proportions of pyroclastics) also appears unimportant. Six out
of 11 provinces coincide with episodes of global warming and marine
anoxia/dysoxia, a relationship that suggests that volcanic CO2 emissions may have an important effect on global
climate. Conversely, there is little, if any, geological evidence
for cooling associated with continental flood basalt eruptions
suggesting little long-term impact of SO2
emissions. Large carbon isotope excursions are associated with
some extinction events and intervals of flood basalt eruption
but these are too great to be accounted for by the release of
volcanic CO2 alone. Thus, voluminous volcanism
may in some circumstances trigger calamitous global environmental
changes (runaway greenhouses), perhaps by causing the dissociation
of gas hydrates. The variable efficiency of global carbon sinks
during volcanic episodes may be an important control on environmental
effects and may explain why the eruption of some vast igneous
provinces, such as the Parana（最後のaの頭に´）-Etendeka
Traps, have little perceptible climatic impact.
Keywords: mass extinctions; flood basalts; marine anoxia; global
warming; runaway greenhouse』
1. Introduction
2. Climatic effects of volcanicity
2.1. Short-term effects
2.2. Long-term climatic effects
2.3. Effects of flood basalt fissure eruptions
3. The genesis of large igneous provinces
4. The Panjal Volcanics and Emeishan flood basalts
5. Siberian Traps
5.1. The volcanics
5.2. Extinction mechanisms
5.3. Carbon isotopic trends
6. Central Atlantic Magmatic Province
7. Karoo and Ferrar Traps
8. Parana（最後のaの頭に´） and Etendeka flood basalts
9. The Ontong Java Plateau
10. The Caribbean-Colombian Plateau and Madagascar flood basalts
11. Deccan Traps
11.1. The volcanics
11.2. Effects of volcanic gas emissions
11.3. The fossil evidence
12. Brito-Arctic flood basalts/North Atlantic Igneous Province
13. Ethiopian and Columbia River flood basalts
14. Discussion
14.1. A partial correlation?
14.2. Volume and violence of eruptions
14.3. Volcanic CO2 emissions
14.4. A lack of pre-Permian LIPs?
15. Conclusion
Acknowledgements