Environmental effects of large igneous province magmatism: a Siberian perspective - Volcanism and Global Environmental Change - page 315

(a) (b)

E1: 240 km 3 pyroclastic eruption
1.46 Gt/year SO 2 (for 1 year)

E5: 2,400 km 3 pyroclastic eruption
14.6 Gt/year SO 2 (for 1 year)

5

5

Siberian Traps

Siberian Traps

Siberia

50˚ N 50˚ N

Siberia

4 4

Baltica
Greenland

Baltica
Greenland

China China

Laurentia Laurentia

3

0˚ N

Tethys Panthalassa

3 0˚ N

Tethys Panthalassa

S. America S. America

Africa Africa

2 2

50˚ S 50˚ S

India India

Australia Australia

1

1 Antarctica

An ta r c t i c a

100 ˚ E 200 ˚ E 300 ˚ E 0 ˚ E 100 ˚ E 200 ˚ E 300 ˚ E

0 ˚ E

(c) (d)

0% 0%

E3: pyroclastic eruption
1.46 Gt/year SO 2 (for 2 years)
0.14 Gt/year HCl (for 2 years)
3x background CH 3 Cl emissions

P2: large pipe
1.43 Gt CH 4
4.29 Gt CH 3 Cl

Siberian Traps

Siberian Traps

10% 10%

Siberia

Siberia

50˚ N 20% 50˚ N 20%

Baltica
Greenland

Baltica
Greenland

30%

30%

China

China

Laurentia

Laurentia

40%

40%

Tethys Panthalassa

Tethys Panthalassa

0˚ N

0˚ N

50%

50%

S. America

60%

S. America

60%

A frica

Africa

70%

70%

50˚ S 50˚ S

India

India Australia

Australia

80% 80%

Antarctica

Antarctica

90% 90%

0 ˚ E 100 ˚ E 200 ˚ E 300 ˚ E 0 ˚ E 100 ˚ E 200 ˚ E 300 ˚ E

Figure 20.4 (a) Rainfall pH during a 1-year, 240 km 3 eruption. Simulation E1
from Black et al .( 2014 ). (b) Rainfall pH during a 1-year, 2400 km 3 eruption.
Simulation E5 from Black et al .( 2014 ). (c) Ozone depletion during a 3-year, 720
km 3 eruption, assuming 75% of degassed HCl reaches the stratosphere, and with
10

pre-industrial CH 3 Cl emissions. Simulation E3 from Black et al .( 2014 ).
(d) Ozone depletion after a large pipe eruption that releases accumulated CH 3 Cl
and CH 4 from contact metamorphism (Aarnes et al ., 2011 ). Simulation P2 from
Black et al .( 2014 ). A black and white version of this figure will appear in some

formats. For the colour version, please refer to the plate section .

area would be expected ( Figure 20.4b ). Such drastically acidic rain could produce
highly stressful environmental conditions for northern hemisphere flora and fauna

(Howells, 1990 ). SO 4 has an e-folding time in the stratosphere of around 1 year
(Barnes and Hofmann, 1997 ); therefore, sulfuric acid rain, which is located in the
troposphere, abates quickly after an eruption ceases.
The expected intensity of acid rain during other flood basalt eruptions depends

largely on atmospheric CO 2 levels and the quantity of sulfur released to the
stratosphere. Sulfur emissions from the Deccan Traps and the Columbia
River flood basalts were volumetrically comparable to those during the Siberian

Traps (Blake et al ., 2010 ; Self et al ., 2008 ). During the eruption of the Central
Atlantic Magmatic Province (CAMP) at the Triassic - Jurassic boundary, CO 2 levels
may have been even higher than during the Permian - Triassic (Schaller et al ., 2011 ).