New constraints on global geochemical cycling during Oceanic Anoxic Event 2 (Late Cretaceous) from a 6-million-year long molybdenum-isotope record. / Dickson, Alexander; Jenkyns, Hugh C.; Idiz, Erdem; Sweere, Tim; Murphy, Melissa; van den Boorn, Sander H.J.M.; Ruhl, Micha; Eldrett, J S ; Porcelli, Donald.

In: Geochemistry, Geophysics, Geosystems, Vol. 22, No. 3, 03.2021.

Research output: Contribution to journalArticlepeer-review

Published

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New constraints on global geochemical cycling during Oceanic Anoxic Event 2 (Late Cretaceous) from a 6-million-year long molybdenum-isotope record. / Dickson, Alexander; Jenkyns, Hugh C.; Idiz, Erdem; Sweere, Tim; Murphy, Melissa; van den Boorn, Sander H.J.M.; Ruhl, Micha; Eldrett, J S ; Porcelli, Donald.

In: Geochemistry, Geophysics, Geosystems, Vol. 22, No. 3, 03.2021.

Research output: Contribution to journalArticlepeer-review

Harvard

Dickson, A, Jenkyns, HC, Idiz, E, Sweere, T, Murphy, M, van den Boorn, SHJM, Ruhl, M, Eldrett, JS & Porcelli, D 2021, 'New constraints on global geochemical cycling during Oceanic Anoxic Event 2 (Late Cretaceous) from a 6-million-year long molybdenum-isotope record', Geochemistry, Geophysics, Geosystems, vol. 22, no. 3. https://doi.org/10.1029/2020GC009246

APA

Dickson, A., Jenkyns, H. C., Idiz, E., Sweere, T., Murphy, M., van den Boorn, S. H. J. M., Ruhl, M., Eldrett, J. S., & Porcelli, D. (2021). New constraints on global geochemical cycling during Oceanic Anoxic Event 2 (Late Cretaceous) from a 6-million-year long molybdenum-isotope record. Geochemistry, Geophysics, Geosystems, 22(3). https://doi.org/10.1029/2020GC009246

Vancouver

Author

Dickson, Alexander ; Jenkyns, Hugh C. ; Idiz, Erdem ; Sweere, Tim ; Murphy, Melissa ; van den Boorn, Sander H.J.M. ; Ruhl, Micha ; Eldrett, J S ; Porcelli, Donald. / New constraints on global geochemical cycling during Oceanic Anoxic Event 2 (Late Cretaceous) from a 6-million-year long molybdenum-isotope record. In: Geochemistry, Geophysics, Geosystems. 2021 ; Vol. 22, No. 3.

BibTeX

@article{15b8618d678b4bf5a827dd9a40c05267,
title = "New constraints on global geochemical cycling during Oceanic Anoxic Event 2 (Late Cretaceous) from a 6-million-year long molybdenum-isotope record",
abstract = "Intervals of extreme warmth are predicted to drive a decrease in the oxygen content of the oceans. This prediction has been tested for the acme of short (<1 million years) episodes of significant marine anoxia in the Phanerozoic geological record known as Oceanic Anoxic Events (OAEs). However, there is a paucity of data spanning prolonged multi-million-year intervals of geological time before and after OAEs. We present a Mo-isotope record from limestones and marlstones of the Eagle Ford Group, South Texas, which was deposited in the southern Cretaceous Western Interior Seaway of North America during a 6-million-year period encompassing Oceanic Anoxic Event 2 (Late Cenomanian–early Turonian: ~94 Ma). Mo-isotope compositions from deposits that formed in euxinic (sulfidic) conditions before OAE 2 allow the paleo-seawater composition to be constrained to 1.1–1.9 ‰. This range of values overlaps previous estimates of up to ~1.5 ‰ for the peak of OAE 2 determined from similarly sulfidic sediments deposited in the restricted proto-North Atlantic Ocean. Mo-isotopes thus varied by less than a few tenths of per mil across one of the most extreme intervals of global deoxygenation in the Late Phanerozoic. Rather than a limited change in oceanic deoxygenation, we suggest that the new data reflect changes to global iron cycling linked to basalt-seawater interaction, terrestrial weathering and expanded partially oxygenated shallow shelf-seas that played a key role in the burial of isotopically light molybdenum, thus acting as a counterbalance to its removal into sulfidic sediments. ",
author = "Alexander Dickson and Jenkyns, {Hugh C.} and Erdem Idiz and Tim Sweere and Melissa Murphy and {van den Boorn}, {Sander H.J.M.} and Micha Ruhl and Eldrett, {J S} and Donald Porcelli",
year = "2021",
month = mar,
doi = "10.1029/2020GC009246",
language = "English",
volume = "22",
journal = "Geochemistry, Geophysics, Geosystems",
issn = "1525-2027",
publisher = "American Geophysical Union",
number = "3",

}

RIS

TY - JOUR

T1 - New constraints on global geochemical cycling during Oceanic Anoxic Event 2 (Late Cretaceous) from a 6-million-year long molybdenum-isotope record

AU - Dickson, Alexander

AU - Jenkyns, Hugh C.

AU - Idiz, Erdem

AU - Sweere, Tim

AU - Murphy, Melissa

AU - van den Boorn, Sander H.J.M.

AU - Ruhl, Micha

AU - Eldrett, J S

AU - Porcelli, Donald

PY - 2021/3

Y1 - 2021/3

N2 - Intervals of extreme warmth are predicted to drive a decrease in the oxygen content of the oceans. This prediction has been tested for the acme of short (<1 million years) episodes of significant marine anoxia in the Phanerozoic geological record known as Oceanic Anoxic Events (OAEs). However, there is a paucity of data spanning prolonged multi-million-year intervals of geological time before and after OAEs. We present a Mo-isotope record from limestones and marlstones of the Eagle Ford Group, South Texas, which was deposited in the southern Cretaceous Western Interior Seaway of North America during a 6-million-year period encompassing Oceanic Anoxic Event 2 (Late Cenomanian–early Turonian: ~94 Ma). Mo-isotope compositions from deposits that formed in euxinic (sulfidic) conditions before OAE 2 allow the paleo-seawater composition to be constrained to 1.1–1.9 ‰. This range of values overlaps previous estimates of up to ~1.5 ‰ for the peak of OAE 2 determined from similarly sulfidic sediments deposited in the restricted proto-North Atlantic Ocean. Mo-isotopes thus varied by less than a few tenths of per mil across one of the most extreme intervals of global deoxygenation in the Late Phanerozoic. Rather than a limited change in oceanic deoxygenation, we suggest that the new data reflect changes to global iron cycling linked to basalt-seawater interaction, terrestrial weathering and expanded partially oxygenated shallow shelf-seas that played a key role in the burial of isotopically light molybdenum, thus acting as a counterbalance to its removal into sulfidic sediments.

AB - Intervals of extreme warmth are predicted to drive a decrease in the oxygen content of the oceans. This prediction has been tested for the acme of short (<1 million years) episodes of significant marine anoxia in the Phanerozoic geological record known as Oceanic Anoxic Events (OAEs). However, there is a paucity of data spanning prolonged multi-million-year intervals of geological time before and after OAEs. We present a Mo-isotope record from limestones and marlstones of the Eagle Ford Group, South Texas, which was deposited in the southern Cretaceous Western Interior Seaway of North America during a 6-million-year period encompassing Oceanic Anoxic Event 2 (Late Cenomanian–early Turonian: ~94 Ma). Mo-isotope compositions from deposits that formed in euxinic (sulfidic) conditions before OAE 2 allow the paleo-seawater composition to be constrained to 1.1–1.9 ‰. This range of values overlaps previous estimates of up to ~1.5 ‰ for the peak of OAE 2 determined from similarly sulfidic sediments deposited in the restricted proto-North Atlantic Ocean. Mo-isotopes thus varied by less than a few tenths of per mil across one of the most extreme intervals of global deoxygenation in the Late Phanerozoic. Rather than a limited change in oceanic deoxygenation, we suggest that the new data reflect changes to global iron cycling linked to basalt-seawater interaction, terrestrial weathering and expanded partially oxygenated shallow shelf-seas that played a key role in the burial of isotopically light molybdenum, thus acting as a counterbalance to its removal into sulfidic sediments.

U2 - 10.1029/2020GC009246

DO - 10.1029/2020GC009246

M3 - Article

VL - 22

JO - Geochemistry, Geophysics, Geosystems

JF - Geochemistry, Geophysics, Geosystems

SN - 1525-2027

IS - 3

ER -