Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
5787965 | Cretaceous Research | 2017 | 13 Pages |
Abstract
Two distal Cretaceous-Paleogene (K/Pg) boundary sections in the Central Apennine region (Italy) have been studied: Bottaccione Gorge and Contessa Highway. Geochemical and carbon isotope analyses on the infilling of trace fossils and on the host sedimentary rocks were performed to determine paleoenvironmental conditions during the Cretaceous-Paleogene transition. Major and trace element contents were measured in a 63Â cm-thick interval at Bottaccione Gorge (from 22Â cm below to 41Â cm above the K/Pg boundary) and in a 72Â cm-thick interval at Contessa Highway (from 43Â cm below to 29Â cm above the K/Pg boundary). Even though the K/Pg ejecta layer is now depleted at these sections due to continuous oversampling, the uppermost Maastrichtian and lowermost Danian deposits record the paleoenvironmental conditions prior to and after the K/Pg event. We used redox-sensitive element ratios (V/Al, Cr/Al, Co/Al, Ni/Al Cu/Al, Zn/Al, Mo/Al Pb/Al and U/Mo) and detrital element ratios (K/Al, Rb/Al, Zr/Al and Æ©REE/Al) as proxies of certain environmental parameters, used for paleoenvironmental reconstruction. In general, similar values for elemental ratios are registered within Maastrichtian and Danian deposits, which supports similar paleoenvironmental conditions prior to and after the K/Pg event as well as the rapid reestablishment of the pre-impact conditions (i.e., oxygenation, nutrient availability, and/or sedimentary input). An enrichment in certain redox-sensitive elements above the K/Pg at the Bottaccione Gorge section suggests lower oxygenation, as also evidenced by the tracemaker community. Carbon isotope composition data from the infilling material of trace fossils furthermore reveals values similar to those of the host rocks at the corresponding depth, which supports an active infilling by nearly contemporaneous bioturbation during sediment deposition.
Related Topics
Physical Sciences and Engineering
Earth and Planetary Sciences
Palaeontology
Authors
Claudia Sosa-Montes de Oca, Francisco J. RodrÃguez-Tovar, Francisca MartÃnez-Ruiz, Paolo Monaco,