Environmental changes during the Cretaceous-Paleogene mass extinction and Paleocene-Eocene Thermal Maximum: Implications for the Anthropocene

Keller, Gerta; Mateo, Paula; Punekar, Jahnavi; Khozyem, Hassan; Gertsch, B.; Spangenberg, Jorge E.; Bitchong, André Mbabi; Adatte, Thierry

doi:10.1016/j.gr.2017.12.002

Cited by 97 publications

(67 citation statements)

References 140 publications

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“…TOC contents from the Blake Nose samples are generally too low (<0.2 wt%) to yield reliable Hg/TOC ratios [see Jones et al, 2019]. An elevation in Hg at the base of and within the main body of the PETM CIE is broadly consistent with previous investigations, although individual sedimentary records appear to show different patterns of these enrichments (Jones et al, 2019;Keller et al, 2018). Recent studies indicated that Hg enrichments could also be associated with increased sulfur/pyrite contents in highly reducing conditions (Shen et al, 2019).…”

Section: Resultssupporting

confidence: 72%

“…As such and given the sporadic nature of the Hg peaks at Blake Nose, it cannot be unambiguously stated that the Hg trends reported here reflect increased volcanism during the PETM. However, a trend of Hg enrichments in PETM strata has also been reported from several other locations and largely been interpreted as resulting from processes relating to volcanic/intrusive activity of the NAIP (Jones et al, ; Keller et al, ). Thus, while a sedimentological control on the Hg trends from Millville and Blake Nose cannot not be excluded, a NAIP‐related volcanic/thermogenic source for these Hg enrichments would be consistent with the interpretations of previous PETM Hg studies.…”

Section: Discussionmentioning

confidence: 84%

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Assessing the Contributions of Comet Impact and Volcanism Toward the Climate Perturbations of the Paleocene‐Eocene Thermal Maximum

Zeyang

Horton

Tabor

et al. 2019

Geophysical Research Letters

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The Paleocene-Eocene Thermal Maximum is marked by a prominent negative carbon-isotope excursion, reflecting the injection of thousands of gigatons of isotopically light carbon into the atmosphere. The sources of the isotopically light carbon remain poorly constrained. Utilizing a multiproxy geochemical analysis (osmium isotopes, mercury, sulfur, and platinum group elements) of two Paleocene-Eocene boundary records, we present evidence that a comet impact and major volcanic activity likely contributed to the environmental perturbations during the Paleocene-Eocene interval. Additionally, Earth system model simulations indicate that stratospheric sulfate aerosols, commensurate with the impact magnitude, were likely to have caused transient cooling and reduced precipitation. Plain Language SummaryThe Paleocene-Eocene Thermal Maximum (~55.9 Ma) records a period of climate warming associated with the injection of thousands of gigatons of carbon into the atmosphere. However, the sources of the carbon are still unclear. Our study uses geochemical data (osmium isotopes, mercury, sulfur, and platinum group elements) of two North Atlantic Ocean drill cores across the Paleocene-Eocene interval to suggest that both a comet impact and large-scale volcanism occurred at that time. The comet is estimated to be small (~3.3 km diameter) with~0.4 Gt carbon and thus cannot be responsible for the Paleocene-Eocene Thermal Maximum. However, climate modeling suggests that the comet impact might have caused transient cooling and reduced precipitation.

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Section: Resultssupporting

confidence: 72%

Section: Discussionmentioning

confidence: 84%

Assessing the Contributions of Comet Impact and Volcanism Toward the Climate Perturbations of the Paleocene‐Eocene Thermal Maximum

Zeyang

Horton

Tabor

et al. 2019

Geophysical Research Letters

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“…The reduction of primary productivity of marine carbonates are marked by the inverse gradient of δ 13 C (surface to deep water; negative 2–3‰ δ 13 C) and drop in CaCO 3 (~0.00) levels. The markers of the K–Pg boundary as proposed by Keller et al () are (a) the extinction of planktic foraminifera, (b) smectite‐rich clay layers, (c) evolution of Davian species, (d) Iridium (Ir) anomaly, and (e) δ 13 C negative shift. With the help of these markers, more than 300 K–Pg boundary sequences were identified around the world (Keller et al, ).…”

Section: Discussionmentioning

confidence: 99%

“…The markers of the K–Pg boundary as proposed by Keller et al () are (a) the extinction of planktic foraminifera, (b) smectite‐rich clay layers, (c) evolution of Davian species, (d) Iridium (Ir) anomaly, and (e) δ 13 C negative shift. With the help of these markers, more than 300 K–Pg boundary sequences were identified around the world (Keller et al, ). The Ir anomaly at K–Pg boundary can be related to the Chicxulub impact but other markers of the extinction event cannot be reliably explained with the impact related mass extinction.…”

Section: Discussionmentioning

confidence: 99%

“…The ocean acidification and acid rains resulted in the depletion of carbonate contents and iron oxides which is recorded from detrital magnetite . The reduction of primary productivity of marine carbonates are marked by the inverse gradient of δ 13 C (surface to deep water; negative 2-3‰ With the help of these markers, more than 300 K-Pg boundary sequences were identified around the world (Keller et al, 2018). The Ir anomaly at K-Pg boundary can be related to the Chicxulub impact but other markers of the extinction event cannot be reliably explained with the impact related mass extinction.…”

Section: Deccan Magmatism and K-pg Boundarymentioning

confidence: 99%

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Tholeiitic basalts of Deccan large igneous province, India: An overview

2019

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The Deccan large igneous province (DLIP) of Peninsular India is predominantly composed of tholeiitic basalts with a minor amount of alkaline, carbonatite, and silicic rocks. The tholeiitic basalts of DLIP are enriched in incompatible trace elements and divisible into low‐Ti basalts (TiO2 < 2.5; Ti/Y < 500) and high‐Ti basalts (TiO2 > 2.5; Ti/Y > 500). Despite variable total REE content, both low‐Ti and high‐Ti basalts exhibit almost similar geochemical patterns in the chondrite‐ and primitive‐ mantle‐normalized diagrams. The mantle potential temperature (Tp) of high‐Ti tholeiites estimated at Ca.1368°C, which is consistent with an ambient mantle temperature (1300–1400°C) whereas the Tp of low‐Ti tholeiites is around 1553°C, which indicates its derivation from the mantle plume axis. Extensive assimilation of the crustal components into the ascending plume have masked the nature and compositional characteristics of both high‐ and low‐Ti basalts. The low‐Ti basalts indicate significant contamination with crustal components than the high‐Ti basalts. The geochemical and isotopic compositions indicate the involvement of multiple mantle components. In general, the differentiated tholeiites of DLIP are the products of plume and depleted sections of the mantle with or without contributions from the continental crust. The main phase of Deccan magmatism intensely affected the atmosphere and hydrosphere, which was a possible trigger for the mass extinction event at the K–Pg boundary.

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