Early Paleocene Paleoceanography and Export Productivity in the Chicxulub Crater

Abstract. It is by now unequivocally shown that the mass extinction associated with the Cretaceous-Paleogene (K-Pg) boundary (~ 66 Ma) is related to the environmental effects of a large extraterrestrial impact. The biological and oceanographic consequences of the mass extinction are, however, still poorly understood. According to the Living Ocean model of D’Hondt et al. (1998), the biological crisis at the K-Pg boundary resulted in a reduction of export productivity in the earliest Paleocene. Here, we combine organic-walled dinoflagellate cyst (dinocyst) and benthic foraminiferal analyses to provide crucial new insight into changes in the coupling of pelagic and benthic ecosystems. To this end, we perform dinocyst and benthic foraminiferal analyses on the recently discovered Tethyan K-Pg boundary section at Okçular, Northwestern Turkey, and compare the results with other K-Pg boundary sites in the Tethys. The post-impact dominance of epibenthic taxa and an increase of inferred heterotrophic dinocysts in the earliest Paleocene at Okçular are consistent with published records from other Tethyan sites. Together, these Tethyan records indicate that during the early Paleocene more nutrients were available for the Tethyan planktonic community, whereas benthic communities were deprived of food. Hence, the post-impact phase the reduction of export productivity likely resulted in enhanced recycling of nutrients in the upper part of the water column, all along the Tethyan shelves.

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Ecological response to collapse of the biological pump following the mass extinction at the Cretaceous–Paleogene boundary

Biogeosciences ◽

10.5194/bg-14-885-2017 ◽

2017 ◽

Vol 14 (4) ◽

pp. 885-900 ◽

Cited By ~ 15

Author(s):

Johan Vellekoop ◽

Lineke Woelders ◽

Sanem Açikalin ◽

Jan Smit ◽

Bas van de Schootbrugge ◽

...

Keyword(s):

Mass Extinction ◽

Benthic Communities ◽

Ocean Model ◽

Early Paleocene ◽

Post Impact ◽

Impact Phase ◽

Benthic Ecosystems ◽

Planktonic Community ◽

Export Productivity

Abstract. It is commonly accepted that the mass extinction associated with the Cretaceous–Paleogene (K–Pg) boundary (∼ 66 Ma) is related to the environmental effects of a large extraterrestrial impact. The biological and oceanographic consequences of the mass extinction are, however, still poorly understood. According to the Living Ocean model, the biological crisis at the K–Pg boundary resulted in a long-term reduction of export productivity in the early Paleocene. Here, we combine organic-walled dinoflagellate cyst (dinocyst) and benthic foraminiferal analyses to provide new insights into changes in the coupling of pelagic and benthic ecosystems. To this end, we perform dinocyst and benthic foraminiferal analyses on the recently discovered Tethyan K–Pg boundary section at Okçular, Turkey, and compare the results with other K–Pg boundary sites in the Tethys. The post-impact dominance of epibenthic morphotypes and an increase of inferred heterotrophic dinocysts in the early Paleocene at Okçular are consistent with published records from other western Tethyan sites. Together, these records indicate that during the early Paleocene more nutrients remained available for the Tethyan planktonic community, whereas benthic communities were deprived of food. Hence, in the post-impact phase the reduction of export productivity likely resulted in enhanced recycling of nutrients in the upper part of the water column, all along the western Tethyan margins.

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Stratigraphic position and localities of the Temlyan flora from the Anadyr river lower course basin

Palaeobotany ◽

10.31111/palaeobotany/2015.6.48 ◽

2015 ◽

Vol 6 ◽

pp. 48-67 ◽

Cited By ~ 5

Author(s):

L. B. Golovneva ◽

A. A. Grabovskiy

Keyword(s):

Volcanic Activity ◽

City Area ◽

Plant Fossils ◽

Stratigraphic Position ◽

Early Paleocene ◽

First Time ◽

Systematic Composition ◽

Stratigraphic Range

Plant fossils from the volcano-clastic deposits of the lower part of the Tanyurer Formation and lower part of the Tavaivaam Unit in the Anadyr city area (Northeastrn Russia) are described for the first time. This assemblage was named as the Temlyan flora. It consists of 25 taxa and includes ferns, horsetails, lycophytes, ginkgoaleans, czekanowskialeans, cycadophytes, conifers and angiosperms. The Temlyan flora is similar in systematic composition to the Rarytkin flora from the upper part of the Rarytkin Formation which was dated as the late Maastrichtian-Danian. But it is distinguished from the latter by presence of the numerous relicts (Lokyma, Nilssonia, Encephalartopsis, Phoenicopsis and Ginkgo ex gr. sibirica). Probably the presence of relicts in the Temlyan flora is connected with influence of volcanic activity. Age of the Temlyan flora is determined as the late Maastrichtian-Danian on the basis of systematic similarity with the Rarytkin Flora. However this age may be slightly younger, possibly only early Paleocene, because the Tanyurer Formation superposes the Rarytkin Formation. Stratigraphic range of Lokyma, Nilssonia, Encephalartopsis, Phoenicopsis and Ginkgo ex gr. sibirica is extended from its previously known latest records in the early Campanian or middle Maastrichtian up to as late as the latest Maastrichtian or early Paleocene. It is very possible, that these typical Mesozoic taxa may have persisted into the Paleogene.

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