The Paleocene-Eocene Thermal Maximum record in the organic matter of the Claret and Tendruy continental sections (South-central Pyrenees, Lleida, Spain)

Abstract

The Carbon Isotope Excursion (CIE) associated with the Paleocene-Eocene Thermal Maximum (PETM) has been detected for the first time in the total organic carbon (TOC) contained within the continental sediments of the Tremp Formation (South Central Pyrenees, Lleida, Spain). The δ13CTOC magnitude of the CIE is ~ 4.3‰ in the Claret section and ~ 3.0‰ in the Tendruy section with minimum values of - 27.6‰ and - 26.7‰, respectively. Previous studies have detected the CIE in the South Central Pyrenees in both marine carbonates and within continental soil carbonate nodules. These studies have located the onset of the CIE either above or within the Claret Conglomerate, interpreted as a megafan produced by a profound change in the precipitation regimen at the beginning of the PETM. Our higher resolution δ13CTOC study in the Claret and Tendruy sections places the onset of the CIE below the base of the Claret Conglomerate and therefore suggests a 4 to 9 kyr time lag between the onset of the CIE and an increase in intense seasonal precipitation rates. Furthermore, this study suggests that the CIE took place ~ 30-55 kyr after the deposition of important late Cernaysian Tremp mammalian sites (Claret-4, Tendruy-V, Tendruy and Palau) which contain the youngest known occurrence of endemic Paleocene mammalian taxa in Europe before the Mammalian Dispersal Event (MDE, migration of new mammal groups, such as perissodactyls, artiodactyls, primates, marsupials, carnivores, creodonts and rodents). The first immigrant mammals in Europe are recorded at Dormaal (Belgium) above a hiatus, the base of which has been dated to around the start of the CIE. Our data indicate that the MDE might have in fact occurred in Europe within a time interval of about 67 kyr around the CIE onset.