TY - JOUR
T1 - Minor changes in biomarker assemblages in the aftermath of the Cretaceous-Paleogene mass extinction event at the Agost distal section (Spain)
AU - Sosa Montes De Oca, Claudia
AU - Rodrigo Gámiz, Marta
AU - Martínez-Ruiz, Francisca
AU - Rodriguez-Tovar, Francisco Javier
AU - Castro , Jose Manuel
AU - Quijano , Maria Luisa
AU - Pancost, Rich D
PY - 2021
Y1 - 2021
N2 - The Cretaceous/Palaeogene Boundary (KPgB) represents one of the five major mass extinctions in Earth´s history, and determining the nature of associated environmental change and biotic recovery is critical for understanding the history of life on our planet. To explore that, we examined the distributions of selected biomarkers (n-alkanes, acyclic isoprenoids, steranes and hopanes), organic and carbonate 13C values, total organic carbon contents and major and trace elements in a distal section spanning the KPgB (Agost, SE Spain). The studied Agost section is an ~32 cm-thick bathyal sequence of marlstones, clays and marly limestones, and high sedimentation rates allow high (cm) resolution analysis. These analyses exhibit sample-to-sample variability, but there are few significant differences between pre- and post-KPgB biomarker assemblages, suggesting a rapid recovery of the non-fossilizing phytoplankton community after the KPgB. Despite the persistence of life, the organic matter assemblage is rather variable through the first 10 kyr after the impact event. This interval is associated with changing terrigenous and petrogenic inputs as well as varying redox conditions as reflected by the enrichment factor of uranium (UEF) vs that of molybdenum (MoEF) as well as biomarker indices (gammacerane and homohopane indices). Moreover, sterane distributions do differ between pre- and post-KPgB sediments. Thus, the KPgB impact did affect environmental conditions and non-fossilizing algal and bacterial communities even in distal sites, but these organisms appear to have rapidly recovered, within 10 kyr after the KPgB.
AB - The Cretaceous/Palaeogene Boundary (KPgB) represents one of the five major mass extinctions in Earth´s history, and determining the nature of associated environmental change and biotic recovery is critical for understanding the history of life on our planet. To explore that, we examined the distributions of selected biomarkers (n-alkanes, acyclic isoprenoids, steranes and hopanes), organic and carbonate 13C values, total organic carbon contents and major and trace elements in a distal section spanning the KPgB (Agost, SE Spain). The studied Agost section is an ~32 cm-thick bathyal sequence of marlstones, clays and marly limestones, and high sedimentation rates allow high (cm) resolution analysis. These analyses exhibit sample-to-sample variability, but there are few significant differences between pre- and post-KPgB biomarker assemblages, suggesting a rapid recovery of the non-fossilizing phytoplankton community after the KPgB. Despite the persistence of life, the organic matter assemblage is rather variable through the first 10 kyr after the impact event. This interval is associated with changing terrigenous and petrogenic inputs as well as varying redox conditions as reflected by the enrichment factor of uranium (UEF) vs that of molybdenum (MoEF) as well as biomarker indices (gammacerane and homohopane indices). Moreover, sterane distributions do differ between pre- and post-KPgB sediments. Thus, the KPgB impact did affect environmental conditions and non-fossilizing algal and bacterial communities even in distal sites, but these organisms appear to have rapidly recovered, within 10 kyr after the KPgB.
KW - Cretaceous/Paleogene boundary
KW - Organic matter sources
KW - Phytoplankton and bacterial communities
KW - High-resolution paleoenvironmental reconstruction
KW - Thermal maturity
M3 - Article (Academic Journal)
JO - Palaeogeography, Palaeoclimatology, Palaeoecology
JF - Palaeogeography, Palaeoclimatology, Palaeoecology
SN - 0031-0182
ER -