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Severest crisis overlooked-Worst disruption of terrestrial environments postdates the Permian-Triassic mass extinction.

Hochuli PA, Sanson-Barrera A, Schneebeli-Hermann E, Bucher H - Sci Rep (2016)

Bottom Line: This event is marked by a swap in dominating floral elements, changing from gymnosperm pollen-dominated associations in the Griesbachian to lycopsid spore-dominated assemblages in the Dienerian.Estimates of sedimentation rates suggest that this environmental alteration took place within some 1000 years.Similar, coeval changes documented on the North Indian Margin (Pakistan) and the Bowen Basin (Australia) indicate the global extent of this crisis.

View Article: PubMed Central - PubMed

Affiliation: Institute and Museum of Palaeontology, University of Zurich, Karl Schmid-Str. 4, CH-8006 Zurich, Switzerland.

ABSTRACT
Generally Early Triassic floras are believed to be depauperate, suffering from protracted recovery following the Permian-Triassic extinction event. Here we present palynological data of an expanded East Greenland section documenting recovered floras in the basal Triassic (Griesbachian) and a subsequent fundamental floral turnover, postdating the Permian-Triassic boundary extinction by about 500 kyrs. This event is marked by a swap in dominating floral elements, changing from gymnosperm pollen-dominated associations in the Griesbachian to lycopsid spore-dominated assemblages in the Dienerian. This turnover coincides with an extreme δ(13)Corg negative shift revealing a severe environmental crisis, probably induced by volcanic outbursts of the Siberian Traps, accompanied by a climatic turnover, changing from cool and dry in the Griesbachian to hot and humid in the Dienerian. Estimates of sedimentation rates suggest that this environmental alteration took place within some 1000 years. Similar, coeval changes documented on the North Indian Margin (Pakistan) and the Bowen Basin (Australia) indicate the global extent of this crisis. Our results evidence the first profound disruption of the recovery of terrestrial environments about 500kyrs after the Permian-Triassic extinction event. It was followed by another crisis, about 1myrs later thus, the Early Triassic can be characterised as a time of successive environmental crises.

No MeSH data available.


Related in: MedlinePlus

Overview on Griesbachian–Dienerian floras with generalized C-isotope curve.(a) Age (b) lithology (c) sample levels (d) bulk organic carbon isotopes46 (e) palynological data including relative abundances of groups of spore and pollen grains, spore/pollen ratios as well as spore tetrads, fungal remains and Reduviasporonites spp.
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f1: Overview on Griesbachian–Dienerian floras with generalized C-isotope curve.(a) Age (b) lithology (c) sample levels (d) bulk organic carbon isotopes46 (e) palynological data including relative abundances of groups of spore and pollen grains, spore/pollen ratios as well as spore tetrads, fungal remains and Reduviasporonites spp.

Mentions: Here the general bulk palynological record with over 80 samples covering the upper part of the Griesbachian and the Dienerian from Kap Stosch is presented. The studied section is part of the Late Permian–Early Triassic Greenland-Norway rift basin. Deltaic sediments of the Wordie Creek Formation with changing marine influence were deposited during the latest Permian and the Induan (Griesbachian and Dienerian). The Griesbachian part of the formation comprises about 270m of section of which the upper 110 metres are included in the present study (Fig. 1). Age control is provided by a few horizons with ammonoids and bulk organic carbon isotope chemostratigraphy4748. The Griesbachian–Dienerian boundary (GDB) is placed at the onset of a negative δ13Corg shift with the ammonoid Bukkenites rosenkrantzi occurring just above this level. Diverging from the interpretation of Bjerager et al.45B. rosenkrantzi is considered here to be of Dienerian age because the worldwide oldest occurrences of proptychitids to which this species belongs are of Dienerian age or younger21.


Severest crisis overlooked-Worst disruption of terrestrial environments postdates the Permian-Triassic mass extinction.

Hochuli PA, Sanson-Barrera A, Schneebeli-Hermann E, Bucher H - Sci Rep (2016)

Overview on Griesbachian–Dienerian floras with generalized C-isotope curve.(a) Age (b) lithology (c) sample levels (d) bulk organic carbon isotopes46 (e) palynological data including relative abundances of groups of spore and pollen grains, spore/pollen ratios as well as spore tetrads, fungal remains and Reduviasporonites spp.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4920029&req=5

f1: Overview on Griesbachian–Dienerian floras with generalized C-isotope curve.(a) Age (b) lithology (c) sample levels (d) bulk organic carbon isotopes46 (e) palynological data including relative abundances of groups of spore and pollen grains, spore/pollen ratios as well as spore tetrads, fungal remains and Reduviasporonites spp.
Mentions: Here the general bulk palynological record with over 80 samples covering the upper part of the Griesbachian and the Dienerian from Kap Stosch is presented. The studied section is part of the Late Permian–Early Triassic Greenland-Norway rift basin. Deltaic sediments of the Wordie Creek Formation with changing marine influence were deposited during the latest Permian and the Induan (Griesbachian and Dienerian). The Griesbachian part of the formation comprises about 270m of section of which the upper 110 metres are included in the present study (Fig. 1). Age control is provided by a few horizons with ammonoids and bulk organic carbon isotope chemostratigraphy4748. The Griesbachian–Dienerian boundary (GDB) is placed at the onset of a negative δ13Corg shift with the ammonoid Bukkenites rosenkrantzi occurring just above this level. Diverging from the interpretation of Bjerager et al.45B. rosenkrantzi is considered here to be of Dienerian age because the worldwide oldest occurrences of proptychitids to which this species belongs are of Dienerian age or younger21.

Bottom Line: This event is marked by a swap in dominating floral elements, changing from gymnosperm pollen-dominated associations in the Griesbachian to lycopsid spore-dominated assemblages in the Dienerian.Estimates of sedimentation rates suggest that this environmental alteration took place within some 1000 years.Similar, coeval changes documented on the North Indian Margin (Pakistan) and the Bowen Basin (Australia) indicate the global extent of this crisis.

View Article: PubMed Central - PubMed

Affiliation: Institute and Museum of Palaeontology, University of Zurich, Karl Schmid-Str. 4, CH-8006 Zurich, Switzerland.

ABSTRACT
Generally Early Triassic floras are believed to be depauperate, suffering from protracted recovery following the Permian-Triassic extinction event. Here we present palynological data of an expanded East Greenland section documenting recovered floras in the basal Triassic (Griesbachian) and a subsequent fundamental floral turnover, postdating the Permian-Triassic boundary extinction by about 500 kyrs. This event is marked by a swap in dominating floral elements, changing from gymnosperm pollen-dominated associations in the Griesbachian to lycopsid spore-dominated assemblages in the Dienerian. This turnover coincides with an extreme δ(13)Corg negative shift revealing a severe environmental crisis, probably induced by volcanic outbursts of the Siberian Traps, accompanied by a climatic turnover, changing from cool and dry in the Griesbachian to hot and humid in the Dienerian. Estimates of sedimentation rates suggest that this environmental alteration took place within some 1000 years. Similar, coeval changes documented on the North Indian Margin (Pakistan) and the Bowen Basin (Australia) indicate the global extent of this crisis. Our results evidence the first profound disruption of the recovery of terrestrial environments about 500kyrs after the Permian-Triassic extinction event. It was followed by another crisis, about 1myrs later thus, the Early Triassic can be characterised as a time of successive environmental crises.

No MeSH data available.


Related in: MedlinePlus