Uncovering the neoproterozoic carbon cycle

ABSTRACT Interpretations of major climatic and biological events in Earth history are, in large part, derived from the stable carbon isotope records of carbonate rocks and sedimentary

organic matter1,2. Neoproterozoic carbonate records contain unusual and large negative isotopic anomalies within long periods (10–100 million years) characterized by δ13C in carbonate

(δ13Ccarb) enriched to more than +5 per mil. Classically, δ13Ccarb is interpreted as a metric of the relative fraction of carbon buried as organic matter in marine sediments2,3,4, which can

be linked to oxygen accumulation through the stoichiometry of primary production3,5. If a change in the isotopic composition of marine dissolved inorganic carbon is responsible for these

excursions, it is expected that records of δ13Ccarb and δ13C in organic carbon (δ13Corg) will covary, offset by the fractionation imparted by primary production5. The documentation of

several Neoproterozoic δ13Ccarb excursions that are decoupled from δ13Corg, however, indicates that other mechanisms6,7,8 may account for these excursions. Here we present δ13C data from

Mongolia, northwest Canada and Namibia that capture multiple large-amplitude (over 10 per mil) negative carbon isotope anomalies, and use these data in a new quantitative mixing model to

examine the behaviour of the Neoproterozoic carbon cycle. We find that carbonate and organic carbon isotope data from Mongolia and Canada are tightly coupled through multiple δ13Ccarb

excursions, quantitatively ruling out previously suggested alternative explanations, such as diagenesis7,8 or the presence and terminal oxidation of a large marine dissolved organic carbon

reservoir6. Our data from Namibia, which do not record isotopic covariance, can be explained by simple mixing with a detrital flux of organic matter. We thus interpret δ13Ccarb anomalies as

recording a primary perturbation to the surface carbon cycle. This interpretation requires the revisiting of models linking drastic isotope excursions to deep ocean oxygenation and the

opening of environments capable of supporting animals9,10,11. Access through your institution Buy or subscribe This is a preview of subscription content, access via your institution ACCESS

OPTIONS Access through your institution Subscribe to this journal Receive 51 print issues and online access $199.00 per year only $3.90 per issue Learn more Buy this article * Purchase on

SpringerLink * Instant access to full article PDF Buy now Prices may be subject to local taxes which are calculated during checkout ADDITIONAL ACCESS OPTIONS: * Log in * Learn about

institutional subscriptions * Read our FAQs * Contact customer support SIMILAR CONTENT BEING VIEWED BY OTHERS OCEAN TEMPERATURES THROUGH THE PHANEROZOIC REASSESSED Article Open access 27 May

2022 MULTIPLE CARBON CYCLE MECHANISMS ASSOCIATED WITH THE GLACIATION OF MARINE ISOTOPE STAGE 4 Article Open access 16 September 2022 EOCENE MAAR SEDIMENTS RECORD WARMING OF UP TO 3.5 °C

DURING A HYPERTHERMAL EVENT 47.2 MILLION YEARS AGO Article Open access 29 August 2024 REFERENCES * Halverson, G. P., Wade, B. P., Hurtgen, M. T. & Barovich, K. M. Neoproterozoic

chemostratigraphy. _Precambr. Res._ 182, 337–350 (2010) Article  ADS  CAS  Google Scholar  * Knoll, A. H., Hayes, J. M., Kaufman, A. J., Swett, K. & Lambert, I. B. Secular variation in

carbon isotope ratios from upper Proterozoic successions of Svalbard and east Greenland. _Nature_ 321, 832–838 (1986) Article  ADS  CAS  Google Scholar  * Des Marais, D. J., Strauss, H.,

Summons, R. E. & Hayes, J. M. Carbon isotope evidence for the stepwise oxidation of the Proterozoic environment. _Nature_ 359, 605–609 (1992) Article  ADS  CAS  Google Scholar  *

Kaufman, A. J., Knoll, A. H. & Narbonne, G. M. Isotopes, ice ages, and terminal Proterozoic earth history. _Proc. Natl Acad. Sci. USA_ 94, 6600–6605 (1997) Article  ADS  CAS  Google

Scholar  * Hayes, J. M., Strauss, H. & Kaufman, A. J. The abundance of C-13 in marine organic matter and isotopic fractionation in the global biogeochemical cycle of carbon during the

past 800 Ma. _Chem. Geol._ 161, 103–125 (1999) Article  ADS  CAS  Google Scholar  * Rothman, D. H., Hayes, J. M. & Summons, R. E. Dynamics of the Neoproterozoic carbon cycle. _Proc. Natl

Acad. Sci. USA_ 100, 8124–8129 (2003) Article  ADS  CAS  Google Scholar  * Knauth, L. P. & Kennedy, M. J. The late Precambrian greening of the Earth. _Nature_ 460, 728–732 (2009)

Article  ADS  CAS  Google Scholar  * Derry, L. A. A burial diagenesis origin for the Ediacaran Shuram-Wonoka carbon isotope anomaly. _Earth Planet. Sci. Lett._ 294, 152–162 (2010) Article 

ADS  CAS  Google Scholar  * Canfield, D. E., Poulton, S. W. & Narbonne, G. M. Late-Neoproterozoic deep-ocean oxygenation and the rise of animal life. _Science_ 315, 92–95 (2007) Article

  ADS  CAS  Google Scholar  * Fike, D. A., Grotzinger, J. P., Pratt, L. M. & Summons, R. E. Oxidation of the Ediacaran Ocean. _Nature_ 444, 744–747 (2006) Article  ADS  CAS  Google

Scholar  * McFadden, K. A. et al. Pulsed oxidation and biological evolution in the Ediacaran Doushantuo Formation. _Proc. Natl Acad. Sci. USA_ 105, 3197–3202 (2008) Article  ADS  CAS  Google

Scholar  * Grotzinger, J. P., Fike, D. A. & Fischer, W. W. Enigmatic origin of the largest-known carbon isotope excursion in Earth’s history. _Nature Geosci._ 4, 285–292 (2011) Article

  ADS  CAS  Google Scholar  * Macdonald, F. A., Jones, D. S. & Schrag, D. P. Stratigraphic and tectonic implications of a new glacial diamictite-cap carbonate couplet in southwestern

Mongolia. _Geology_ 37, 123–126 (2009) Article  ADS  CAS  Google Scholar  * Halverson, G. P., Hoffman, P. F., Schrag, D. P., Maloof, A. C. & Rice, A. H. N. Toward a Neoproterozoic

composite carbon-isotope record. _Geol. Soc. Am. Bull._ 117, 1181–1207 (2005) Article  ADS  Google Scholar  * McCay, G. A., Prave, A. R., Alsop, G. I. & Fallick, A. E. Glacial trinity:

Neoproterozoic Earth history within the British-Irish Caledonides. _Geology_ 34, 909–912 (2006) Article  ADS  Google Scholar  * McKirdy, D. M. et al. A chemostratigraphic overview of the

late Cryogenian interglacial sequence in the Adelaide fold-thrust belt, South Australia. _Precambr. Res._ 106, 149–186 (2001) Article  ADS  CAS  Google Scholar  * Halverson, G. P., Hoffman,

P. F., Schrag, D. P. & Kaufman, A. J. A major perturbation of the carbon cycle before the Ghaub glaciation (Neoproterozoic) in Namibia: prelude to snowball Earth? _Geochem. Geophys.

Geosyst_. 3, 1035, http://dx.doi.org/10.1029/2001GC000244 (2002) Article  ADS  Google Scholar  * Hoffman, P. F., Kaufman, A. J., Halverson, G. P. & Schrag, D. P. A Neoproterozoic

snowball earth. _Science_ 281, 1342–1346 (1998) Article  ADS  CAS  Google Scholar  * Hoffmann, K. H., Condon, D. J., Bowring, S. A. & Crowley, J. L. U-Pb zircon date from the

Neoproterozoic Ghaub Formation, Namibia: constraints on Marinoan glaciation. _Geology_ 32, 817–820 (2004) Article  ADS  CAS  Google Scholar  * Macdonald, F. A. et al. Calibrating the

Cryogenian. _Science_ 327, 1241–1243 (2010) Article  ADS  CAS  Google Scholar  * Hoffman, P. F. & Schrag, D. P. The snowball Earth hypothesis: testing the limits of global change. _Terra

Nova_ 14, 129–155 (2002) Article  ADS  CAS  Google Scholar  * Swanson-Hysell, N. L. et al. Cryogenian glaciation and the onset of carbon-isotope decoupling. _Science_ 328, 608–611 (2010)

Article  ADS  CAS  Google Scholar  * Dehler, C. M. et al. High-resolution delta C-13 stratigraphy of the Chuar Group (ca. 770–742 Ma), Grand Canyon: implications for mid-Neoproterozoic

climate change. _Geol. Soc. Am. Bull._ 117, 32–45 (2005) Article  ADS  CAS  Google Scholar  * Tziperman, E., Halevy, I., Johnston, D. T., Knoll, A. H. & Schrag, D. P. Biologically

induced Snowball Earth. _Proc. Natl Acad. Sci._ 108 (37). 15091–15096 (2011) Article  ADS  CAS  Google Scholar  * Hayes, J. M. & Waldbauer, J. R. The carbon cycle and associated redox

processes through time. _Phil. Trans. R. Soc. B_ 361, 931–950 (2006) Article  CAS  Google Scholar  * Schrag, D. P., Berner, R. A., Hoffman, P. F. & Halverson, G. P. On the initiation of

a snowball Earth. _Geochem. Geophys. Geosyst_. 3, 1036, http://dx.doi.org/10.1029/2001gc000219 (2002) Article  Google Scholar  * Halverson, G. P., Hoffman, P. F., Schrag, D. P. &

Kaufman, A. J. A major perturbation of the carbon cycle before the Ghaub glaciation (Neoproterozoic) in Namibia: prelude to snowball Earth? _Geochem. Geophys. Geosyst_. 3, 1035,

http://dx.doi.org/10.1029/2001gc000244 (2002) Article  ADS  Google Scholar  * Bjerrum, C. J. & Canfield, D. E. Towards a quantitative understanding of the late Neoproterozoic carbon

cycle. _Proc. Natl Acad. Sci. USA_ 108, 5542–5547 (2011) Article  ADS  CAS  Google Scholar  * Bristow, T. F. & Kennedy, M. J. Carbon isotope excursions and the oxidant budget of the

Ediacaran atmosphere and ocean. _Geology_ 36, 863–866 (2008) Article  ADS  CAS  Google Scholar  * Johnston, D. T. et al. An emerging picture of Neoproterozoic ocean chemistry: Insights from

the Chuar Group, Grand Canyon, USA. _Earth Planet. Sci. Lett._ 290, 64–73 (2010) Article  ADS  CAS  Google Scholar  * Levashova, N. M. et al. The origin of the Baydaric microcontinent,

Mongolia: constraints from paleomagnetism and geochronology. _Tectonophysics_ 485, 306–320 (2010) Article  ADS  CAS  Google Scholar  Download references ACKNOWLEDGEMENTS Laboratory

assistance was provided by G. Eischeid, E. Northrop, E. Kennedy, T. O’Brien, A. Breus and A. Masterson. We thank G. Halverson, A. Bradley, E. Tziperman and P. Huybers for discussions and

comments. We thank the Yukon Geological Survey, the NSF (grant number EAR-IF 0949227 to D.T.J.), KINSC (Haverford College), Henry and Wendy Breck (to D.P.S.), ESEP (Canadian Institute for

Advanced Research, to P.F.H.), Harvard University and NASA NAI (D.T.J. and F.A.M.) for funding. AUTHOR INFORMATION AUTHORS AND AFFILIATIONS * Department of Earth and Planetary Sciences,

Harvard University, 20 Oxford Street, Cambridge, Massachusetts 02138, USA, D. T. Johnston, F. A. Macdonald, B. C. Gill, P. F. Hoffman & D. P. Schrag * School of Earth and Ocean Sciences,

University of Victoria, Victoria, V8W 2Y2, British Columbia, Canada P. F. Hoffman Authors * D. T. Johnston View author publications You can also search for this author inPubMed Google

Scholar * F. A. Macdonald View author publications You can also search for this author inPubMed Google Scholar * B. C. Gill View author publications You can also search for this author

inPubMed Google Scholar * P. F. Hoffman View author publications You can also search for this author inPubMed Google Scholar * D. P. Schrag View author publications You can also search for

this author inPubMed Google Scholar CONTRIBUTIONS This project was conceived by D.T.J., F.A.M. and D.P.S. Field work was conducted by F.A.M. and P.F.H. Carbonate carbon analyses were

performed by F.A.M. Organic carbon analyses and modelling were carried out by D.T.J. and B.C.G. The paper was written by all authors. CORRESPONDING AUTHOR Correspondence to D. T. Johnston.

ETHICS DECLARATIONS COMPETING INTERESTS The authors declare no competing financial interests. SUPPLEMENTARY INFORMATION SUPPLEMENTARY INFORMATION This file contains Supplementary Text, Data,

Methods and Materials, Supplementary Figures 1-8 with legends, Supplementary Table 1 and Supplementary References. (PDF 1673 kb) POWERPOINT SLIDES POWERPOINT SLIDE FOR FIG. 1 POWERPOINT

SLIDE FOR FIG. 2 POWERPOINT SLIDE FOR FIG. 3 RIGHTS AND PERMISSIONS Reprints and permissions ABOUT THIS ARTICLE CITE THIS ARTICLE Johnston, D., Macdonald, F., Gill, B. _et al._ Uncovering

the Neoproterozoic carbon cycle. _Nature_ 483, 320–323 (2012). https://doi.org/10.1038/nature10854 Download citation * Received: 28 June 2011 * Accepted: 09 January 2012 * Published: 29

February 2012 * Issue Date: 15 March 2012 * DOI: https://doi.org/10.1038/nature10854 SHARE THIS ARTICLE Anyone you share the following link with will be able to read this content: Get

shareable link Sorry, a shareable link is not currently available for this article. Copy to clipboard Provided by the Springer Nature SharedIt content-sharing initiative