Breistroffer Event Explained

The Breistroffer Event (OAE1d) was an oceanic anoxic event (OAE) that occurred during the middle Cretaceous period,[1] specifically in the latest Albian, around 101 million years ago (Ma).[2]

Causes

A rise in carbon dioxide and consequent negative carbon isotope excursion (CIE) ensued at the start of OAE1d, causing global temperatures to rise by 2 °C.[3] During the Breistroffer Thermal Maximum, as this climatic interval has been referred to, Earth's mean surface air temperature was 23.3 °C. Average sea surface temperatures (SSTs) were 3 to 5 °C higher than today. Mercury anomalies from the time of the event implicate large igneous province volcanism from the Kerguelen Plateau as the cause of the rise in global temperatures.[4] [5]

An alternative hypothesis implicating enhanced monsoons forced by Milankovitch cycles rather than volcanism has also been proposed, based on the lack of unradiogenic osmium isotope ratio fluctuations observed during OAE1d.[6] Total organic carbon values and carbon and oxygen isotope records from the La Grita Member of the Capacho Formation of Venezuela show a cyclic variation supporting the enhanced monsoonal hypothesis.[7]

One possible cause of OAE1d relates to a possible 5-6 Myr cycle in the rate of phosphorus weathering throughout the middle of the Cretaceous period, at one of the peaks of which OAE1d ensued. This cycle would have been sustained and enhanced by fast-acting positive feedbacks of increased biological productivity and deoxygenation in response to elevated oceanic phosphate concentrations, but eventually mitigated and reversed by longer term negative feedbacks of increasing atmospheric oxygen content, which would have increased wildfire activity and caused a decline in vegetation, slowing down chemical weathering and returned the phosphorus cycle back to its starting state.[8]

Effects

Anoxia developed because of the reduction of seawater solubility of oxygen caused by global temperature rise. Increased terrigeneous flux of nutrients into the ocean is known to have occurred in Australia and Venezuela during OAE1d and may have been an additional factor helping to deoxygenate seawater.[9] The OAE that occurred resulted in a positive CIE, reflecting an enhancement in burial of organic carbon.[10] The positive CIE's presence in nearshore settings, indicating that deep water anoxia expanded into shallow water.[11]

On land, a brief warm-wet climatic spike and a surge in angiosperm biodiversity occurred coevally with the deposition of black shales during OAE1d. Angiosperm mangal and conifer-dominated swamps thrived during this warm-wet spike in what is now central North America.[12] In Bulgaria, where angiosperms were still a minor component of the flora that was dominated by gymnosperms and pteridophyte spores, plant communities remained stable across OAE1d.[13]

See also

Notes and References

  1. Wilson . Paul A. . Norris . Richard D. . 26 July 2001 . Warm tropical ocean surface and global anoxia during the mid-Cretaceous period . . 412 . 1 . 425–429 . 10.1038/35086553 . 11473314 . 205019330 . 24 May 2023.
  2. Scotese . Christopher Robert . Song . Haijun . Mills . Benjamin J. W. . Van der Meer . Douwe G. . April 2021 . Phanerozoic paleotemperatures: The earth's changing climate during the last 540 million years . . 215 . 103503 . 10.1016/j.earscirev.2021.103503 . 233579194 . 24 May 2023.
  3. Richey . Jon D. . Upchurch . Garland R. . Montañez . Isabel P. . Lomax . Barry H. . Suarez . Marina B. . Crout . Neil M. J. . Joeckel . R. M. . Ludvigson . Greg A. . Smith . Jon J. . 1 June 2018 . Changes in CO2 during Ocean Anoxic Event 1d indicate similarities to other carbon cycle perturbations . . 491 . 172–182 . 10.1016/j.epsl.2018.03.035 . 134252840 . free .
  4. Fan . Qingchao . Xu . Zhaokai . MacLeod . Kenneth G. . Brumsack . Hans-Jürgen . Li . Tiegang . Chang . Fengming . Wang . Shiming . Riquier . Laurent . Fu . Delong . Luan . Zhendong . Duan . Baichuan . Chen . Hongjin . Wang . Wei . Lim . Dhongil . 6 May 2022 . First Record of Oceanic Anoxic Event 1d at Southern High Latitudes: Sedimentary and Geochemical Evidence From International Ocean Discovery Program Expedition 369 . . 49 . 10 . 10.1029/2021GL097641 . 248600904 . free .
  5. Yao . Hanwei . Chen . Xi . Yin . Runsheng . Grasby . Stephen E. . Weissert . Helmut . Gu . Xue . Wang . Chengshan . 19 February 2021 . Mercury Evidence of Intense Volcanism Preceded Oceanic Anoxic Event 1d . . 48 . 5 . 10.1029/2020GL091508 . 233707872 .
  6. Matsumoto . Hironao . Coccioni . Rodolfo . Frontalini . Fabrizio . Shirai . Kotaro . Jovane . Luigi . Trindade . Ricardo . Savian . Jairo F. . 11 January 2022 . Mid-Cretaceous marine Os isotope evidence for heterogeneous cause of oceanic anoxic events . . 13 . 1 . 239 . 10.1038/s41467-021-27817-0 . 35017487 . 8752794 .
  7. Rodríguez-Cuicas . María-Emilia . Montero-Serrano . Jean-Carlos . Garbán . Grony . 1 May 2019 . Paleoenvironmental changes during the late Albian oceanic anoxic event 1d: An example from the Capacho Formation, southwestern Venezuela . . 521 . 10–29 . 10.1016/j.palaeo.2019.02.010 . 133735691 . 14 June 2023.
  8. Handoh . Itsuki C. . Lenton . Timothy M. . 8 October 2003 . Periodic mid-Cretaceous oceanic anoxic events linked by oscillations of the phosphorus and oxygen biogeochemical cycles . Global Biogeochemical Cycles . 17 . 4 . 3-1-3-11 . 10.1029/2003GB002039 . 140194325 . 13 June 2023.
  9. Rodríguez-Cuicas . María-Emilia . Montero-Serrano . Jean-Carlos . Garbán . Grony . January 2020 . Geochemical and mineralogical records of late Albian oceanic anoxic event 1d (OAE-1d) in the La Grita Member (southwestern Venezuela): Implications for weathering and provenance . . 97 . 102408 . 10.1016/j.jsames.2019.102408 . 210247906 . 24 May 2023.
  10. Gambacorta . G. . Bottini . Cinzia . Brumsack . Hans-Jürgen . Schnetger . B. . Erba . Elisabetta . 20 December 2020 . Major and trace element characterization of Oceanic Anoxic Event 1d (OAE 1d): Insight from the Umbria-Marche Basin, central Italy . . 557 . 119834 . 10.1016/j.chemgeo.2020.119834 . 24 May 2023. 2434/775902 . 225148458 . free .
  11. Madhavaraju . Jayagopal . Scott . Robert W. . Sial . Alcides N. . Ramirez-Montoya . Erik . 24 August 2021 . Chemo- and biostratigraphy of the Cretaceous Dalmiapuram Formation, Uttatur Group, Kallakudi II section, Cauvery Basin, South India . Arabian Journal of Geosciences . 14 . 18 . 1–23 . 10.1007/s12517-021-07902-w . 237272278 . 24 May 2023.
  12. Retallack . Gregory J. . Dilcher . David L. . 15 April 2012 . Outcrop versus core and geophysical log interpretation of mid-Cretaceous paleosols from the Dakota Formation of Kansas . . 329-330 . 47–63 . 10.1016/j.palaeo.2012.02.017 . 5 June 2023.
  13. Pavlishina . Polina . 17 November 2016 . Palynostratigraphy and palaeoenvironments around the Albian-Cenomanian boundary interval (OAE1d), North Bulgaria . . 60 . 71–79 . 10.1007/s11430-016-0067-2 . 132079175 . 14 June 2023.

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