The Great Oxidation Event preceded a Paleoproterozoic “snowball Earth” Matthew R. Warkea,1, Tommaso Di Roccoa,b, Aubrey L. Zerklea,c, Aivo Leplandd,e, Anthony R. Pravea, Adam P. Martinf,g, Yuichiro Uenoh,i, Daniel J. Condonf, and Mark W. Clairea,c,j aSchool of Earth and Environmental Sciences, University of St Andrews, St Andrews KY16 9AL, Scotland, United Kingdom; bGeowissenschaftliches Zentrum, Universität Göttingen, 37077 Göttingen, Germany; cCentre for Exoplanet Science, University of St Andrews, St Andrews KY16 9AL, Scotland, United Kingdom; dGeological Survey of Norway, 7491 Trondheim, Norway; eDepartment of Geology, University of Tartu, 50441 Tartu, Estonia; fNatural Environment Research Council Isotope Geosciences Laboratory, British Geological Survey, Keyworth NG12 5GG, United Kingdom; gGNS Science, Dunedin, 9054, New Zealand; hDepartment of Earth and Planetary Sciences, Tokyo Institute of Technology, 152-8551 Meguro, Tokyo, Japan; iEarth-Life Science Institute, Tokyo Institute of Technology, Meguro, Tokyo 152-8550, Japan; and jBlue Marble Space Institute of Science, Seattle, WA 98154 Edited by Mark Thiemens, University of California San Diego, La Jolla, CA, and approved April 28, 2020 (received for review February 18, 2020) The inability to resolve the exact temporal relationship between two interpretations of the significance of the S-MIF/S-MDF transition pivotal events in Earth history, the Paleoproterozoic Great Oxidation is the “crustal memory effect” hypothesis (11), namely, the Event (GOE) and the first “snowball Earth” global glaciation, has reduction in Δ33S magnitude and prevalence of positive Δ33S precluded assessing causality between changing atmospheric com- values in the early Paleoproterozoic could reflect oxidative position and ancient climate change. Here we present temporally weathering and erosion with subsequent incorporation of Ar- δ34 Δ33 resolved quadruple sulfur isotope measurements ( S, S, and chean S-MIF signals into younger sediments (11, 12). This has Δ36 S) from the Paleoproterozoic Seidorechka and Polisarka Sedimen- led some workers to suggest that the S-MIF/S-MDF transition in tary Formations on the Fennoscandian Shield, northwest Russia, that the rock record could lag the atmospheric transition by as much address this issue. Sulfides in the former preserve evidence of mass- as 10 to 200 My (11, 13). Such a scenario undermines using the independent fractionation of sulfur isotopes (S-MIF) falling within S-MIF/S-MDF transition as a chemostratigraphic correlation uncertainty of the Archean reference array with a Δ36S/Δ33S slope of −1.8 and have small negative Δ33S values, whereas in the latter surface (14) and a unique time marker of planetary oxygenation mass-dependent fractionation of sulfur isotopes (S-MDF) is evident, (13, 15, 16), as well as obscuring causality between planetary with a Δ36S/Δ33S slope of −8.8. These trends, combined with oxygenation and glaciation (4, 9). Δ33 Δ36 δ34 geochronological constraints, place the S-MIF/S-MDF transition, We present a temporally constrained S, S, and S the key indicator of the GOE, between 2,501.5 ± 1.7Maand dataset from the Seidorechka and Polisarka Sedimentary For- 2,434 ± 6.6 Ma. These are the tightest temporal and stratigraphic mations of the Imandra/Varzuga Greenstone Belt in the north- constraints yet for the S-MIF/S-MDF transition and show that its west Russian portion (Kola Peninsula) of the Fennoscandian timing in Fennoscandia is consistent with the S-MIF/S-MDF tran- Shield (SI Appendix, Fig. S1). Our data enable us to constrain the sition in North America and South Africa. Further, the glacigenic nature of S-MIF recycling within the basin, determine the timing part of the Polisarka Formation occurs 60 m above the sedimentary of the S-MIF/S-MDF transition, and confirm that the GOE pre- succession containing S-MDF signals. Hence, our findings con- ceded the Paleoproterozoic snowball Earth event. firm unambiguously that the S-MIF/S-MDF transition preceded the Paleoproterozoic snowball Earth. Resolution of this tempo- Significance ral relationship constrains cause-and-effect drivers of Earth’s oxygenation, specifically ruling out conceptual models in which The causality between the Paleoproterozic Great Oxidation global glaciation precedes or causes the evolution of oxygenic Event (GOE) and a global “snowball Earth” glaciation has photosynthesis. remained unresolved due to an inability to determine their relative timing. We present quadruple sulfur isotope data from quadruple sulfur isotopes | mass independent fractionation | Great northwest Russia which constrain the GOE between 2,501 and Oxidation Event | snowball Earth 2,434 Ma. These are the tightest temporal and stratigraphic constraints ever presented for the GOE and show that the GOE he early Paleoproterozoic transition from mass-independently predates Paleoproterozic glaciation in Russia and snowball Tfractionated sulfur isotopes (S-MIF) to mass-dependent frac- Earth deposits in South Africa. Our results preclude hypotheses 33 36 tionation (S-MDF; i.e., where Δ SandΔ S ≈ 0) is now recog- of Earth’s oxygenation in which global glaciation precedes or nized as a key proxy identifying a unidirectional and global rise in causes the evolution of oxygenic photosynthesis. atmospheric oxygen (1), the Great Oxidation Event (GOE; ref. 2). In broad temporal proximity with the S-MIF/S-MDF transition Author contributions: M.R.W., T.D.R., A.L.Z., A.L., A.R.P., A.P.M., D.J.C., and M.W.C. de- were periods of severe glaciation, including at least one “snowball signed research; M.R.W., T.D.R., A.L.Z., and M.W.C. performed research; M.R.W., T.D.R., Earth” event (3, 4). However, assessing causality (if any) between, A.L.Z., Y.U., and M.W.C. contributed new reagents/analytic tools; M.R.W., T.D.R., A.L.Z., and M.W.C. analyzed data; M.R.W. wrote the paper; and T.D.R., A.L.Z., A.L., A.R.P., and and enhancing understanding about, changing atmospheric chemistry M.W.C. contributed to writing the paper. and ancient climate change leading to glaciations is hindered by The authors declare no competing interest. the poorly constrained timing of the S-MIF/S-MDF transition with This article is a PNAS Direct Submission. respect to glacial deposits, a problem which is compounded by – This open access article is distributed under Creative Commons Attribution-NonCommercial- spurious intercratonic stratigraphic correlations (4 6). As a conse- NoDerivatives License 4.0 (CC BY-NC-ND). quence, a variety of hypotheses, with disparate ordering of key Earth Data deposition: The data and methods supporting this article can be accessed on the system events, have been advanced including planetary oxygenation University of St Andrews Research Portal (DOI: 10.17630/2faeb51f-7353-4fbc-abdd- being tied to secular changes in planetary degassing following an early cbc7991cf44b). evolution of oxygenic photosynthesis (7, 8), the evolution of oxygenic 1To whom correspondence may be addressed. Email: [email protected]. photosynthesis directly triggering a Paleoproterozoic snowball This article contains supporting information online at https://www.pnas.org/lookup/suppl/ Earth glaciation (4), and/or chemical weathering following de- doi:10.1073/pnas.2003090117/-/DCSupplemental. glaciation leading to the GOE (9, 10). Additionally, complicating First published June 1, 2020. 13314–13320 | PNAS | June 16, 2020 | vol. 117 | no. 24 www.pnas.org/cgi/doi/10.1073/pnas.2003090117 Geological Setting and Chronological Constraints are positive but above ∼140 m they become negative. Δ36Svalues The Imandra–Varzuga Greenstone Belt consists of a suite of are highest in the Quartzite member and portions of the overlying Paleoproterozoic sedimentary and volcanic rocks that rest un- Limestone-Shale member. There is a weak positive correlation 34 33 conformably on a mostly Neoarchean gneissic basement (SI Ap- between δ SandΔ S values in this formation (see Fig. 3). 33 36 pendix,Fig.S1). Key intervals of the succession were targeted for Linear regression of a cross-plot of Δ SandΔ Svaluesfrom − coring as part of the International Continental Scientific Drilling the Seidorechka Sedimentary Formation yields a slope of 1.8 A − Program’s Fennoscandian Arctic Russia - Drilling Early Earth (Fig. 2 ) but shallows to 1.6 if the Quartzite member is excluded. Δ36 Δ33 Project (FAR-DEEP; ref. 17). The calculation of S/ S slopes by linear regression ignores ’ Δ33 FAR-DEEP drillcore 1A recovered the Seidorechka Sedimen- the abscissa s( S) uncertainty and cannot determine an tary Formation, a 120-m-thick succession of shallow-marine shale, uncertainty on the slope value itself; hence, we performed an Δ36 Δ33 siltstone, and minor limestone and sandstone that is divided into orthogonal regression analysis, resulting in a S/ S slope − ± σ five lithostratigraphic members: Sandstone-Siltstone member, of 1.86 0.47 (1 ). Within uncertainty, the data fall along the “ ” B Dolostone member, Quartzite member, Limestone-Shale mem- Archean reference array (ARA; Fig. 2 ). Mass-dependent Δ33 ber, and Shale member (Fig. 1 and ref. 17). The formation overlies fractionation processes can produce small-magnitude S and Δ36 Δ36 Δ33 − − a pervasive zone of calcitization and sericitization developed on S, which yield S/ S slopes ranging from 6 through 12 the underlying Kuksha Volcanic Formation that is interpreted as a (23). Orthogonal regression analysis thus also allows us to state that the sulfur within the Seidorechka Sedimentary Forma- paleoweathering crust (18). The Seidorechka