Carbon Isotope Record of Trace n-alkanes in a Continental PETM Section Recovered by the Bighorn Basin Coring Project (BBCP)

the Bighorn Basin Coring Project (BBCP) Science Team

Research output: Contribution to journalArticle

1 Citation (Scopus)

Abstract

Continental sedimentary records of early Paleogene hyperthermals are typically limited to weathered, often discontinuous, outcrop exposures. In 2011, the Bighorn Basin Coring Project (BBCP) collected the first continuous terrestrial records of the Paleocene-Eocene Thermal Maximum (PETM) in the Bighorn Basin, Wyoming. Organic matter preservation was poor during the PETM, even in core material. Concentrations of leaf waxes during the PETM are too low for compound-specific carbon isotope analysis by conventional means. However, the recent development of picomolar-scale compound-specific isotope analyses (pico-CSIA) has reduced sample requirements and enabled measurements of carbon isotope ratios of n-alkanes across the PETM in the Basin Substation core. While the prominent, negative carbon isotope excursion in total organic carbon that typically identifies the PETM in the sedimentary record is absent from the core, lithostratigraphic, biostratigraphic, and chemostratigraphic data suggest that the most likely position of the PETM is from ~87.82- to ~50-m composite depth. This ~40-m interval coincides with the lowest weight percent organic carbon, n-alkane abundances, and n-alkane δ13C values and the highest n-alkane average chain lengths. Comparison of the n-alkane isotope record from the core with that from organic-rich rocks exposed in the SE Bighorn Basin suggests that n-alkanes in the core fail to express the full magnitude of the carbon isotope excursion. We hypothesize that floodplain sediments at Basin Substation contain a mixture of PETM and reworked fossil n-alkanes. Low total organic carbon suggests that PETM climate accelerated organic matter decay rates and floodplains may have acted as a carbon source during the PETM.

Original languageEnglish (US)
Pages (from-to)853-865
Number of pages13
JournalPaleoceanography and Paleoclimatology
Volume34
Issue number5
DOIs
StatePublished - May 1 2019

Fingerprint

Hypsithermal
alkane
Paleocene
carbon isotope
Eocene
basin
total organic carbon
floodplain
isotope
project
organic matter
carbon isotope ratio
wax
Paleogene
outcrop
organic carbon
fossil
carbon
climate

All Science Journal Classification (ASJC) codes

  • Oceanography
  • Atmospheric Science
  • Palaeontology

Cite this

@article{9d1cc3047d694177bc7eedab2676aa81,
title = "Carbon Isotope Record of Trace n-alkanes in a Continental PETM Section Recovered by the Bighorn Basin Coring Project (BBCP)",
abstract = "Continental sedimentary records of early Paleogene hyperthermals are typically limited to weathered, often discontinuous, outcrop exposures. In 2011, the Bighorn Basin Coring Project (BBCP) collected the first continuous terrestrial records of the Paleocene-Eocene Thermal Maximum (PETM) in the Bighorn Basin, Wyoming. Organic matter preservation was poor during the PETM, even in core material. Concentrations of leaf waxes during the PETM are too low for compound-specific carbon isotope analysis by conventional means. However, the recent development of picomolar-scale compound-specific isotope analyses (pico-CSIA) has reduced sample requirements and enabled measurements of carbon isotope ratios of n-alkanes across the PETM in the Basin Substation core. While the prominent, negative carbon isotope excursion in total organic carbon that typically identifies the PETM in the sedimentary record is absent from the core, lithostratigraphic, biostratigraphic, and chemostratigraphic data suggest that the most likely position of the PETM is from ~87.82- to ~50-m composite depth. This ~40-m interval coincides with the lowest weight percent organic carbon, n-alkane abundances, and n-alkane δ13C values and the highest n-alkane average chain lengths. Comparison of the n-alkane isotope record from the core with that from organic-rich rocks exposed in the SE Bighorn Basin suggests that n-alkanes in the core fail to express the full magnitude of the carbon isotope excursion. We hypothesize that floodplain sediments at Basin Substation contain a mixture of PETM and reworked fossil n-alkanes. Low total organic carbon suggests that PETM climate accelerated organic matter decay rates and floodplains may have acted as a carbon source during the PETM.",
author = "{the Bighorn Basin Coring Project (BBCP) Science Team} and Baczynski, {Allison A.} and McInerney, {Francesca A.} and Freeman, {Katherine Haines} and Wing, {Scott L.}",
year = "2019",
month = "5",
day = "1",
doi = "10.1029/2019PA003579",
language = "English (US)",
volume = "34",
pages = "853--865",
journal = "Paleoceanography and Paleoclimatology",
issn = "0883-8305",
publisher = "American Geophysical Union",
number = "5",

}

Carbon Isotope Record of Trace n-alkanes in a Continental PETM Section Recovered by the Bighorn Basin Coring Project (BBCP). / the Bighorn Basin Coring Project (BBCP) Science Team.

In: Paleoceanography and Paleoclimatology, Vol. 34, No. 5, 01.05.2019, p. 853-865.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Carbon Isotope Record of Trace n-alkanes in a Continental PETM Section Recovered by the Bighorn Basin Coring Project (BBCP)

AU - the Bighorn Basin Coring Project (BBCP) Science Team

AU - Baczynski, Allison A.

AU - McInerney, Francesca A.

AU - Freeman, Katherine Haines

AU - Wing, Scott L.

PY - 2019/5/1

Y1 - 2019/5/1

N2 - Continental sedimentary records of early Paleogene hyperthermals are typically limited to weathered, often discontinuous, outcrop exposures. In 2011, the Bighorn Basin Coring Project (BBCP) collected the first continuous terrestrial records of the Paleocene-Eocene Thermal Maximum (PETM) in the Bighorn Basin, Wyoming. Organic matter preservation was poor during the PETM, even in core material. Concentrations of leaf waxes during the PETM are too low for compound-specific carbon isotope analysis by conventional means. However, the recent development of picomolar-scale compound-specific isotope analyses (pico-CSIA) has reduced sample requirements and enabled measurements of carbon isotope ratios of n-alkanes across the PETM in the Basin Substation core. While the prominent, negative carbon isotope excursion in total organic carbon that typically identifies the PETM in the sedimentary record is absent from the core, lithostratigraphic, biostratigraphic, and chemostratigraphic data suggest that the most likely position of the PETM is from ~87.82- to ~50-m composite depth. This ~40-m interval coincides with the lowest weight percent organic carbon, n-alkane abundances, and n-alkane δ13C values and the highest n-alkane average chain lengths. Comparison of the n-alkane isotope record from the core with that from organic-rich rocks exposed in the SE Bighorn Basin suggests that n-alkanes in the core fail to express the full magnitude of the carbon isotope excursion. We hypothesize that floodplain sediments at Basin Substation contain a mixture of PETM and reworked fossil n-alkanes. Low total organic carbon suggests that PETM climate accelerated organic matter decay rates and floodplains may have acted as a carbon source during the PETM.

AB - Continental sedimentary records of early Paleogene hyperthermals are typically limited to weathered, often discontinuous, outcrop exposures. In 2011, the Bighorn Basin Coring Project (BBCP) collected the first continuous terrestrial records of the Paleocene-Eocene Thermal Maximum (PETM) in the Bighorn Basin, Wyoming. Organic matter preservation was poor during the PETM, even in core material. Concentrations of leaf waxes during the PETM are too low for compound-specific carbon isotope analysis by conventional means. However, the recent development of picomolar-scale compound-specific isotope analyses (pico-CSIA) has reduced sample requirements and enabled measurements of carbon isotope ratios of n-alkanes across the PETM in the Basin Substation core. While the prominent, negative carbon isotope excursion in total organic carbon that typically identifies the PETM in the sedimentary record is absent from the core, lithostratigraphic, biostratigraphic, and chemostratigraphic data suggest that the most likely position of the PETM is from ~87.82- to ~50-m composite depth. This ~40-m interval coincides with the lowest weight percent organic carbon, n-alkane abundances, and n-alkane δ13C values and the highest n-alkane average chain lengths. Comparison of the n-alkane isotope record from the core with that from organic-rich rocks exposed in the SE Bighorn Basin suggests that n-alkanes in the core fail to express the full magnitude of the carbon isotope excursion. We hypothesize that floodplain sediments at Basin Substation contain a mixture of PETM and reworked fossil n-alkanes. Low total organic carbon suggests that PETM climate accelerated organic matter decay rates and floodplains may have acted as a carbon source during the PETM.

UR - http://www.scopus.com/inward/record.url?scp=85066876013&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85066876013&partnerID=8YFLogxK

U2 - 10.1029/2019PA003579

DO - 10.1029/2019PA003579

M3 - Article

AN - SCOPUS:85066876013

VL - 34

SP - 853

EP - 865

JO - Paleoceanography and Paleoclimatology

JF - Paleoceanography and Paleoclimatology

SN - 0883-8305

IS - 5

ER -