TY - JOUR
T1 - Oceanic primary productivity and dissolved oxygen levels at the Cretaceous/Tertiary boundary
T2 - Their decrease, subsequent warming, and recovery
AU - Kaiho, Kunio
AU - Kajiwara, Yoshimichi
AU - Tazaki, Kazue
AU - Ueshima, Masato
AU - Takeda, Nobuyori
AU - Kawahata, Hodaka
AU - Arinobu, Tetsuya
AU - Ishiwatari, Ryoshi
AU - Hirai, Akio
AU - Lamolda, Marcos A.
N1 - Copyright:
Copyright 2017 Elsevier B.V., All rights reserved.
PY - 1999/8
Y1 - 1999/8
N2 - Thirty-six different geochemical and foraminiferal analyses were conducted on samples collected at closely spaced intervals across the Cretaceous/Tertiary (K/T) boundary exposed at Caravaca, Spain. A rapid reduction in the gradient between δ13C values in fine fraction carbonate and benthic foraminiferal calcite and a decrease in the abundance of phosphorus (a proxy for organic carbon) and calcium were recorded in sediments 0-0.5 cm above the K/T boundary. These trends imply that an abrupt mass mortality occurred among pelagic organisms, leading to a significant reduction in the flux of organic carbon to the seafloor. In addition, variations in sulfur isotope ratios, the hydrocarbon-generating potential of kerogen (measured as the hydrogen index), and foraminiferal indices of dissolved oxygen level all imply that a rapid decrease in dissolved oxygen was coincident with the δ13C event. Evidence of the low oxygen event has also been recognized in Japan and New Zealand, suggesting that intermediate water oxygen minima were widely developed during earliest Danian time. A threefold increase in the kaolinite/illite ratio and a 1.2‰ decrease in δ18O (carbonate fine fraction) were recorded in the basal 0.1-2 cm of Danian age sediments. These trends suggest that atmospheric warming and an increase in surface water temperature occurred 0-3 kyr after the δ13C event. Recovery in the difference between δ13C values in the carbonate fine fraction and in benthic foraminiferal calcite as well as increases in phosphorus and calcium contents occur at the base of planktonic foraminiferal Zone P1a, implying that an increase in primary productivity commenced some 13 kyr after the K/T boundary.
AB - Thirty-six different geochemical and foraminiferal analyses were conducted on samples collected at closely spaced intervals across the Cretaceous/Tertiary (K/T) boundary exposed at Caravaca, Spain. A rapid reduction in the gradient between δ13C values in fine fraction carbonate and benthic foraminiferal calcite and a decrease in the abundance of phosphorus (a proxy for organic carbon) and calcium were recorded in sediments 0-0.5 cm above the K/T boundary. These trends imply that an abrupt mass mortality occurred among pelagic organisms, leading to a significant reduction in the flux of organic carbon to the seafloor. In addition, variations in sulfur isotope ratios, the hydrocarbon-generating potential of kerogen (measured as the hydrogen index), and foraminiferal indices of dissolved oxygen level all imply that a rapid decrease in dissolved oxygen was coincident with the δ13C event. Evidence of the low oxygen event has also been recognized in Japan and New Zealand, suggesting that intermediate water oxygen minima were widely developed during earliest Danian time. A threefold increase in the kaolinite/illite ratio and a 1.2‰ decrease in δ18O (carbonate fine fraction) were recorded in the basal 0.1-2 cm of Danian age sediments. These trends suggest that atmospheric warming and an increase in surface water temperature occurred 0-3 kyr after the δ13C event. Recovery in the difference between δ13C values in the carbonate fine fraction and in benthic foraminiferal calcite as well as increases in phosphorus and calcium contents occur at the base of planktonic foraminiferal Zone P1a, implying that an increase in primary productivity commenced some 13 kyr after the K/T boundary.
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U2 - 10.1029/1999PA900022
DO - 10.1029/1999PA900022
M3 - Article
AN - SCOPUS:0033388455
VL - 14
SP - 511
EP - 524
JO - Paleoceanography and Paleoclimatology
JF - Paleoceanography and Paleoclimatology
SN - 0883-8305
IS - 4
ER -