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Palynostratigraphy of John's Nose, a new Cretaceous-Paleogene boundary section in southwestern North Dakota, USA

Bercovici, Antoine LU ; Vajda, Vivi LU ; Pearson, Dean; Villanueva-Amadoz, Uxue and Kline, Doug (2012) In Palynology 36. p.36-47
Abstract
This study documents the terrestrial palynological record at the John's Nose section, a new Cretaceous-Paleogene (K-Pg) boundary site in North Dakota, USA. In addition to Mud Buttes and Pyramid Butte, John's Nose represents the third K-Pg section in southwestern North Dakota that preserves direct evidence of the Chicxulub asteroid impact, allowing for direct comparison over the timing and trends of the palynological record in respect to this event. The palynological analysis of John's Nose section reveals the presence of 68 pollen and spore taxa. Immediately above the boundary clay, a high abundance of fern spores of the genera Cyathidites and Laevigatosporites is recorded (with 59% of the assemblage being represented by Cyathidites). This... (More)
This study documents the terrestrial palynological record at the John's Nose section, a new Cretaceous-Paleogene (K-Pg) boundary site in North Dakota, USA. In addition to Mud Buttes and Pyramid Butte, John's Nose represents the third K-Pg section in southwestern North Dakota that preserves direct evidence of the Chicxulub asteroid impact, allowing for direct comparison over the timing and trends of the palynological record in respect to this event. The palynological analysis of John's Nose section reveals the presence of 68 pollen and spore taxa. Immediately above the boundary clay, a high abundance of fern spores of the genera Cyathidites and Laevigatosporites is recorded (with 59% of the assemblage being represented by Cyathidites). This very distinctive K-Pg 'fern spike' event is correlated with the devastation of land plants immediately following the asteroid impact and matches the composition generally reported from other sites in southwestern North Dakota. Palynostratigraphy demonstrates that the placement of the K-Pg boundary based upon the identification of the Last Appearance Datum (LAD) of typical Maastrichtian taxa (K-taxa) may be misleading. The presence of occasional K-taxa up to a few meters above the boundary clay at John's Nose represents an important difference when compared to previous reports. In light of this observation, LADs should be used cautiously as the primary criteria to identify the boundary; some K-taxa may have a short-term presence in the earliest Paleogene, or be reworked. In the John's Nose section, major changes and extinction in the palynological record occur at the geochemical K-Pg boundary, indicating that a catastrophic turnover took place over a short time. (Less)
Please use this url to cite or link to this publication:
author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Cretaceous-Paleogene boundary, extinction, fern-spore spike, floral, turnover, Last Appearance Datum, palynology
in
Palynology
volume
36
pages
36 - 47
publisher
American Association of Stratigraphical Palynologists
external identifiers
  • wos:000304460700003
  • scopus:84861803240
ISSN
1558-9188
DOI
10.1080/01916122.2012.678695
language
English
LU publication?
yes
id
3ceddcd4-6043-4b62-a95c-6cc1ba32387c (old id 2812814)
date added to LUP
2012-06-25 10:00:55
date last changed
2017-01-01 03:53:23
@article{3ceddcd4-6043-4b62-a95c-6cc1ba32387c,
  abstract     = {This study documents the terrestrial palynological record at the John's Nose section, a new Cretaceous-Paleogene (K-Pg) boundary site in North Dakota, USA. In addition to Mud Buttes and Pyramid Butte, John's Nose represents the third K-Pg section in southwestern North Dakota that preserves direct evidence of the Chicxulub asteroid impact, allowing for direct comparison over the timing and trends of the palynological record in respect to this event. The palynological analysis of John's Nose section reveals the presence of 68 pollen and spore taxa. Immediately above the boundary clay, a high abundance of fern spores of the genera Cyathidites and Laevigatosporites is recorded (with 59% of the assemblage being represented by Cyathidites). This very distinctive K-Pg 'fern spike' event is correlated with the devastation of land plants immediately following the asteroid impact and matches the composition generally reported from other sites in southwestern North Dakota. Palynostratigraphy demonstrates that the placement of the K-Pg boundary based upon the identification of the Last Appearance Datum (LAD) of typical Maastrichtian taxa (K-taxa) may be misleading. The presence of occasional K-taxa up to a few meters above the boundary clay at John's Nose represents an important difference when compared to previous reports. In light of this observation, LADs should be used cautiously as the primary criteria to identify the boundary; some K-taxa may have a short-term presence in the earliest Paleogene, or be reworked. In the John's Nose section, major changes and extinction in the palynological record occur at the geochemical K-Pg boundary, indicating that a catastrophic turnover took place over a short time.},
  author       = {Bercovici, Antoine and Vajda, Vivi and Pearson, Dean and Villanueva-Amadoz, Uxue and Kline, Doug},
  issn         = {1558-9188},
  keyword      = {Cretaceous-Paleogene boundary,extinction,fern-spore spike,floral,turnover,Last Appearance Datum,palynology},
  language     = {eng},
  pages        = {36--47},
  publisher    = {American Association of Stratigraphical Palynologists},
  series       = {Palynology},
  title        = {Palynostratigraphy of John's Nose, a new Cretaceous-Paleogene boundary section in southwestern North Dakota, USA},
  url          = {http://dx.doi.org/10.1080/01916122.2012.678695},
  volume       = {36},
  year         = {2012},
}