The Paleocene-Eocene thermal maximum (PETM) has been attributed to the rapid release of È2000 109 metric tons of carbon in the form of methane. In theory, oxidation and ocean absorption of this carbon should have lowered deep-sea pH, thereby triggering a rapid (G10,000-year) shoaling of the calcite compensation depth (CCD), followed by gradual recovery. Here we present geochemical data from five new South Atlantic deep-sea sections that constrain the timing and extent of massive sea-floor carbonate dissolution coincident with the PETM. The sections, from between 2.7 and 4.8 kilometers water depth, are marked by a prominent clay layer, the character of which indicates that the CCD shoaled rapidly (G10,000 years) by more than 2 kilometers and recovered gradually (9100,000 years). These findings indicate that a large mass of carbon (d2000 109 metric tons of carbon) dissolved in the ocean at the Paleocene-Eocene boundary and that permanent seques- tration of this carbon occurred through silicate weathering feedback.
Rapid Acidification of the Ocean during the Paleocene/Eocene Thermal Maximum
RAFFI, Isabella;
2005-01-01
Abstract
The Paleocene-Eocene thermal maximum (PETM) has been attributed to the rapid release of È2000 109 metric tons of carbon in the form of methane. In theory, oxidation and ocean absorption of this carbon should have lowered deep-sea pH, thereby triggering a rapid (G10,000-year) shoaling of the calcite compensation depth (CCD), followed by gradual recovery. Here we present geochemical data from five new South Atlantic deep-sea sections that constrain the timing and extent of massive sea-floor carbonate dissolution coincident with the PETM. The sections, from between 2.7 and 4.8 kilometers water depth, are marked by a prominent clay layer, the character of which indicates that the CCD shoaled rapidly (G10,000 years) by more than 2 kilometers and recovered gradually (9100,000 years). These findings indicate that a large mass of carbon (d2000 109 metric tons of carbon) dissolved in the ocean at the Paleocene-Eocene boundary and that permanent seques- tration of this carbon occurred through silicate weathering feedback.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
