Environmental Engineering Reference
In-Depth Information
90˚ N
Siberia
60˚ N
Balt
i
ca
Greenland
30˚ N
N
. America
China
Tethys
Panthalassa
0˚ N
S. America
Africa
30˚ S
India
60˚ S
Australia
Antarctica
90˚ S
0˚ E
30˚ E
60˚ E
90˚ E
120˚ E 150˚ E 180˚ E 210˚ E 240˚ E 270˚ E 300˚ E 330˚ E
0˚ E
-4000
-2000
-500
0
400
800
1500
2500
Topography (metres)
Figure 20.1 End-Permian palaeotopographic reconstruction, after Kiehl and
Shields (
2005
), shown here at 0.5
by 0.5
horizontal resolution.
constant at either 355 ppm or 3550 ppm, following Kiehl and Shields (
2005
).
Volcanic emissions of sulfur derive from Black
et al
.(
2012
), and thermogenic
emissions of CH
3
Cl and CH
4
derive from Aarnes
et al
.(
2011
). Complete emis-
sions and boundary conditions are tabulated in Black
et al
.(
2014
).
20.5 Global warming
Studies of oxygen isotopes in conodont microfossils suggest that sea-surface tem-
peratures began to warm rapidly in the latest Permian. Joachimski
et al
.(
2012
)
report a low-latitude temperature increase of
8
C spanning a short interval across
the Permian
-
Triassic boundary. Sun
et al
.(
2012
) consider oxygen isotopic vari-
ations from the middle Permian to the Middle Triassic, and estimate a
þ
15
C
increase in low-latitude sea-surface temperatures during this time. This strong
warming has been attributed to volcanic or thermogenic release of greenhouse gases
associated with Siberian Traps magmatism, though the correspondence of carbon
and oxygen isotopic variations with pulses of magmatism has not been conclusively
demonstrated geochronologically (Joachimski
et al
.,
2012
; Sun
et al
.,
2012
).
Comparing the warming predicted from oxygen isotopic records with results
from global climate models presents an interesting opportunity (
Figure 20.2
).
Global climate model simulations have shown that the palaeotectonic con
þ
gur-
ation in the Permian was conducive to localized warm sea-surface temperatures in
the Tethys Ocean (Kiehl and Shields,
2005
). As shown in
Figure 20.2
, a ten-fold
