Depth-dependent δ13C trends in platform and slope settings of the Campbellrand-Malmani carbonate platform and possible implications for Early Earth oxygenation

Eroglu, Suemeyya; Zuilen, Mark A. van; Taubald, Heinrich; Drost, Kerstin; Wille, Martin; Swanner, Elizabeth D.; Beukes, Nicolas J.; Schoenberg, Ronny

doi:10.1016/j.precamres.2017.09.018

Cited by 24 publications

(16 citation statements)

References 132 publications

(219 reference statements)

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“…Because of its redox sensitivity and its ability to form minerals, the estimates for Fe concentrations in ferruginous oceans vary widely in space and time, and depending on the local geochemical conditions, from tens to hundreds of millimolars at the highest (Mel'nik, ; Morris & Horwitz, ) down to a few to hundreds of micromolars (Eroglu et al, ; Holland, ; Sumner, ; Tosca et al, ). Most of this range is encompassed by Brownie Lake and Canyon Lake.…”

Section: Discussionmentioning

confidence: 99%

Geochemical Characterization of Two Ferruginous Meromictic Lakes in the Upper Midwest, USA

et al. 2018

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To elucidate the role of (bio)geochemical processes that fueled iron and carbon cycling in early Earth oceans, modern environments with similar geochemical conditions are needed. As the range of chemical, physical, and biological attributes of the Precambrian oceans must have varied in time and space, lakes of different compositions are useful to ask and answer different questions. Tropical Lake Matano (Indonesia), the largest known ferruginous lake, and Lake Pavin (France), a meromictic crater lake, are the two best studied Precambrian ocean analogs. Here we present seasonal geochemical data from two glacially formed temperate ferruginous lakes: Brownie Lake (MN) and Canyon Lake (MI) in the Upper Midwest, USA. The results of seasonal monitoring over multiple years indicate that (1) each lake is meromictic with a dense, anoxic monimolimnion, which is separated from the less dense, oxic mixolimnion by a sharp chemocline; (2) below this chemocline are ferruginous waters, with maximum dissolved iron concentrations >1 mM; (3) meromixis in Brownie Lake is largely anthropogenic, whereas in Canyon Lake it is natural; (4) the shallow chemocline of Brownie Lake and high phosphorus reservoir make it an ideal analog to study anoxygenic photosynthesis, elemental ratios, and mineralogy; and (5) a deep penetrating suboxic zone in Canyon Lake may support future studies of suboxic microbial activity or mineral transformation.Plain Language Summary Earth's atmosphere acquired oxygen around 2.46-2.33 billion years ago from oxygen-producing bacteria. Researchers are interested in how elements, for instance, iron and carbon, cycled between dissolved and solid phases in the ocean before oxygen was produced. In past oceans with little oxygen, all life would have been microbial. In order to study elemental cycling on early Earth, modern water bodies where oxygen is absent in deep water are needed. Water samples were analyzed from different depths within Brownie Lake in Minneapolis, MN, and Canyon Lake in the Upper Peninsula of MI. We found that these lakes have two distinct chemical layers like past oceans: a top section that has oxygen and a bottom section that has no oxygen. The bottom sections never mix with the water on top and so remain without oxygen year-round. Brownie and Canyon Lakes have different, but applicable water chemistries as compared to well-studied field sites in Europe, Africa, and Asia. With the addition of Brownie Lake and Canyon Lake as early Earth analogs, researchers will have the potential to answer many questions about early Earth's oceans.

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Section: Discussionmentioning

confidence: 99%

Geochemical Characterization of Two Ferruginous Meromictic Lakes in the Upper Midwest, USA

et al. 2018

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“…The anoxic leaching and riverine export of isotopically light Fe(II) from subaerially exposed ferromagnesian minerals and variable mixing with aqueous REE sourced from more isotopically evolved sources prior to reaching the oceans could also account for the continental end-member signatures. Thus, subaerial weathering may be an overlooked source of continental Fe(II) contributing to the Fe budget (along with other elements) of continental margin iron formations and other shallow marine chemical sedimentary reservoirs (Eroglu et al, 2018;Eroglu et al, 2017). Free aqueous Fe(II) reaching open marine environments requires that Fe availability exceeded sulphide precipitation in continental environments, which is reasonable assuming that atmospheric S deposition and bacterial sulphate reduction in soils (Maynard et al, 2013) were outpaced by the Fe(II) released from ferromagnesian silicates.…”

Section: Evidence For Open System Fe Mobility and A Continental Flux mentioning

confidence: 99%

Pervasively anoxic surface conditions at the onset of the Great Oxidation Event: New multi-proxy constraints from the Cooper Lake paleosol

Babechuk

Weimar

Kleinhanns

et al. 2019

Precambrian Research

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Oceanic element inventories derived from marine sedimentary rocks place important constraints on oxidative continental weathering in deep time, but there remains a scarcity in complementary observations directly from continental sedimentary reservoirs. This study focuses on better defining continental weathering conditions near the Archean-Proterozoic boundary through the multi-proxy (major and ultra-trace element, Fe and Cr stable isotopes, μ-XRF elemental mapping, and detrital zircon U-Pb geochronology) investigation of the ca. 2.45 billion year old (giga annum, Ga) Cooper Lake paleosol (saprolith), developed on a sedimenthosted mafic dike within the Huronian Supergroup (Ontario, Canada). Throughout the variably altered Cooper Lake saprolith, ratios of immobile elements (Nb, Ta, Zr, Hf, Th, Al, Ti) are constant, indicating a uniform pre-alteration dike composition, lack of extreme pH weathering conditions, and no major influence from ligand-rich fluids during weathering or burial metasomatism/ metamorphism. The loss of Mg, Fe, Na, Sr, and Li, a signature of albite and ferromagnesian silicate weathering, increases towards the top of the preserved profile (unconformity) and dike margins. Coupled bulk rock behaviour of Fe-Mg-Mn and co-localization of Fe-Mn in clay minerals (predominantly chlorite) indicates these elements were solubilized primarily in their divalent state without Fe/Mn-oxide formation. A lack of a Ce anomaly and immobility of Mo, V, and Cr further support pervasively anoxic weathering conditions. Subtle U enrichment is the only geochemical evidence, if primary, that could be consistent with oxidative element mobilization. The leaching of ferromagnesian silicates was accompanied by variable mobility and depletion of transition metals with a relative depletion order of Fe≈Mg≈Zn>Ni>Co>Cu (Cu being significantly influenced by secondary sulfide formation). Mild enrichment of heavy Fe isotopes (δ56/54Fe from 0.169 to 0.492 ‰) correlating with Fe depletion in the saprolith indicates loss of isotopically light aqueous Fe(II). Minor REE+Y fractionation with increasing alteration intensity, including a decreasing Eu anomaly and Y/Ho ratio, is attributed to albite breakdown and preferential scavenging of HREE>Y by clay minerals, respectively. Younger metasomatism resulted in the addition of several elements (K, Rb, Cs, Be, Tl, Ba, Sn, In, W), partly or wholly obscuring their earlier paleo-weathering trends. The behavior of Cr at Cooper Lake can help test previous hypotheses of an enhanced, low pH-driven continental weathering flux of Cr(III) to marine reservoirs between ca. 2.48-2.32 Ga and the utility of the stable Cr isotope proxy of Mn-oxide induced Cr(III) oxidation. Synchrotron μ-XRF maps and invariant Cr/ Nb ratios reveal complete immobility of Cr despite its distribution amongst both clay-rich groundmass and Fe-Ti oxides. Assuming a pH-dependent, continental source of Cr(III) to marine basins, the Cr immobility at Cooper Lake indicates either that signatures of acidic surface waters were localized to ...

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“…The weakly positive Gd anomaly present in VF dolomite may reflect seawater precipitation (Bau, 1999). Eu is also normally enriched in Archean seawater-precipitated carbonate too (Bolhar and Karnendonk, 2007), the source of which can be either hydrothermal solutions derived from mid-ocean ridges and/or back-arc spreading centres, or burial diagenetic fluids Derry and Jacobsen, 1990;German et al, 1990;Danielson et al, 1992;German et al, 1993;German et al, 1999;Douville et al, 1999;Eroglu et al, 2017;. In VF dolomite significant positive correlation is observed between Eu/Eu* and Ba content ( Fig.…”

Section: Fluid Sourcementioning

confidence: 93%

A Palaeoproterozoic dolomite (Vempalle Formation, Cuddapah Basin, India) showing Phanerozoic-type dolomitisation

Banerjee

Słowakiewicz

Majumder

et al. 2019

Precambrian Research

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The Palaeoproterozoic Vempalle Formation of the Cuddapah Basin, India, significantly adds to our understanding of the evolution of Precambrian marine carbonate systems and the redox state of the Earth's early oceans. A faciesmicrofacies-diagenetic-geochemical examination of samples from a 900-m long exposure in a freshly-cut canal section shows that 10 to 15 % of precursor limestone is still preserved in the Vempalle Formation in the form of remnant patches of calcimicrite and ooids with calcite spar cement. The ooids, preserving primary radial and concentric fabrics and radial fractures, are considered to have been originally precipitated as calcite, which may have been low-Mg. In places the preserved calcite spar, that is partially replaced by fabric-destructive dolomite, shows Type I calcite twin lamellae. Petrographic observations demonstrate that Vempalle Formation dolomite formed through very early precipitation, which in stromatolites preserved microbial filaments, as well as through fabric-destructive dolomitization during shallow to moderate burial. Vempalle Formation dolomite is characterized by micritic dolomite crystals which suggest rapid early dolomitization of lime mud and micritic calcite from a supersaturated Mg-Ca-rich solution, probably near-surface or during shallow burial. Depletion of Na and Sr contents of Vempalle Formation dolomite along with negative 18O values indicate dolomite recrystallisation during burial and further replacement. Dolomite 13C values of-0.5 to 2 ‰ are likely inherited original marine values. Geochemical proxies (trace elements and rare earths) imply that Cuddapah Basin seawater and dolomitizing fluids were anoxic and ferruginous but not euxinic. Geochemical analyses also indicate that the burial diagenetic fluids evolved from Eu-enriched seawater that probably resulted from continental rifting around 1.9-2.0 Ga. This probable ocean chemistry is in contrast with the anoxic, ferruginous and extremely high Mg/Ca "dolomite oceans" that prevailed during Proterozoic time. The Vempalle dolomite shows more similarities with dolomitised Phanerozoic platform carbonates than typical Precambrian dolomite with its well-preserved textures and burial dolospar cements.

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Depth-dependent δ13C trends in platform and slope settings of the Campbellrand-Malmani carbonate platform and possible implications for Early Earth oxygenation

Cited by 24 publications

References 132 publications

Geochemical Characterization of Two Ferruginous Meromictic Lakes in the Upper Midwest, USA

Geochemical Characterization of Two Ferruginous Meromictic Lakes in the Upper Midwest, USA

Pervasively anoxic surface conditions at the onset of the Great Oxidation Event: New multi-proxy constraints from the Cooper Lake paleosol

A Palaeoproterozoic dolomite (Vempalle Formation, Cuddapah Basin, India) showing Phanerozoic-type dolomitisation

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