Global climate perturbations during the Permo-Triassic mass extinctions recorded by continental tetrapods from South Africa

REY, K; ABDALA, F.; DAY, M

GONDWANA RESEARCH

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2015

1342-937X

Several studies of the marine sedimentary record have documented the evolution of global climate during thePermo-Triassic mass extinction. By contrast, the continental records have been less exploited due to the scarcity of continuous sections from the latest Permian into the Early Triassic. The South African Karoo Basin exposes one of the most continuous geological successions of this time interval, thus offering the possibility to reconstruct cli- mate variations in southern Laurasia from the Middle Permian to Middle Triassic interval. Both air temperature and humidity variations were estimated using stable oxygen (ä18Op) and carbon (ä13Cc) isotope compositions of vertebrate apatite. Significant fluctuations in both ä18Op and ä13Cc values mimic those of marine records and suggest that stable isotope compositions recorded in vertebrate apatite reflect global climate evolution. In terms of air temperature, oxygen isotopes show an abrupt increase of about + 8 °C toward the end of the Wuchiapingian. This occurred during a slight cooling trend from the Capitanian to the Permo-Triassic boundary (PTB). At the end of the Permian, an intense and fast warming of + 16 °C occurred and kept increasing during the Olenekian. These thermal fluctuations may be related to the Emeishan (South China) and Siberian volcanic par- oxysms that took place at the end of the Capitanian and at the end of the Permian, respectively. Vertebrate apatite ä13Cc partly reflects the important fluctuations of the atmospheric ä13C values, the differences with marine curves being likely due to the evolution of local humidity. Both the oxygen and carbon isotope compositions indicate that the PTB was followed by a warm and arid phase that lasted 6 Ma before temperatures decreased, during the Late Anisian, toward that of the end-Permian. Environmental fluctuations occurring around the PTB that af- fected both continental and marine realms with similar magnitude likely originated from volcanism and methane release.