Permian‐triassic carbon‐isotope anomaly in Greenland and in the southern Alps

Abstract

A carbon isotopic study of selected samples of apparently continuous Permian‐Triassic boundary sections from Jameson Land (Greenland) and from the Southern Alps (Italy) revealed a negative δ^{1 3}C shift by 2–3‰. In the Greenland record the geochemical event is possibly isochronous with the δ^{l 3}C shift reported from other localities, where it occurs in the latest Permian. In the section studied from Northern Italy, the event is slightly younger and straddles the Permian‐Triassic boundary. The δ^{1 3}C change occurred within a few hundred thousand years, but within less than a million years. The worldwide recorded carbon isotopic event documents a change in the global carbon cycle. We suggest that the δ^{1 3} C decrease reflects a reduction in the transfer of organic matter from the production sites (oceans and continents) to the sedimentary reservoir.

Key words:

• Permian‐Triassic boundary
• carbon‐isotope shift
• carbon‐isotope spike(s)
• diagenesis
• global carbon cycle