Phytoplankton contributions to the trace-element composition of Precambrian banded iron formations

Type Article
Date 2018-05
Language English
Author(s) Konhauser Kurt O.1, Robbins Leslie J.1, Alessi Daniel S.1, Flynn Shannon L.1, Gingras Murray K1, Martinez Raul E.2, Kappler Andreas3, Swanner Elizabeth D.4, Li Yi-Liang5, Crowe Sean A.6, 7, Planavsky Noah J.8, Reinhard Christopher T.9, Lalonde Stefan10
Affiliation(s) 1 : Univ Alberta, Dept Earth & Atmospher Sci, Edmonton, AB T6G 2E3, Canada.
2 : Albert Ludwigs Univ, Inst Geo & Umweltnat Wissensch, Mineral Geochem, D-79104 Freiburg, Germany.
3 : Univ Tubingen, Dept Geomicrobiol, Ctr Appl Geosci, D-72074 Tubingen, Germany.
4 : Iowa State Univ, Dept Geol & Atmospher Sci, Ames, IA 50011 USA.
5 : Univ Hong Kong, Dept Earth Sci, Pokfulam Rd, Hong Kong, Hong Kong, Peoples R China.
6 : Univ British Columbia, Dept Microbiol & Immunol, Vancouver, BC V6T 1Z4, Canada.
7 : Univ British Columbia, Dept Earth Ocean & Atmospher Sci, Vancouver, BC V6T 1Z4, Canada.
8 : Yale Univ, Dept Geol & Geophys, POB 6666, New Haven, CT 06511 USA.
9 : Georgia Inst Technol, Sch Earth & Atmospher Sci, Atlanta, GA 30332 USA.
10 : European Inst Marine Studies, CNRS UMR6538, Lab Domaines Ocean, Technopole Brest Iroise, F-29280 Plouzane, France.
Source Geological Society Of America Bulletin (0016-7606) (Geological Soc Amer, Inc), 2018-05 , Vol. 130 , N. 5-6 , P. 941-951
DOI 10.1130/B31648.1
WOS© Times Cited 25

Banded iron formations are economically important sedimentary deposits in Earth's Precambrian rock record, consisting of alternating iron-rich (hematite, magnetite, and siderite) and silicate/carbonate (quartz, claylike minerals, dolomite, and ankerite) layers. Based on chemical analyses from banded iron formation units of the 2.48 Ga Dales Gorge Member of the Hamersley Group in Western Australia, it has been previously suggested that most, if not all, of the iron in banded iron formations could have been oxidized by anoxygenic phototrophic bacteria (photoferrotrophs) at cell densities considerably less than those found in modern iron-rich aqueous environments. However, oxygen-producing phytoplankton may have also been capable of supplying the necessary oxidizing power. Here, we revisit the question of the anoxygenic and oxygenic phytoplankton populations necessary to account for banded iron formation deposition and quantify the amount of selected trace elements (P, Mn, Co, Ni, Cu, Zn, Mo, Cd) that could have been associated with their biomass. Using an expanded geochemical data set for the Dales Gorge Member as an example, we find that with turnover times comparable to those seen in modern ecosystems, the same phytoplankton populations required to form banded iron formations could have supplied the entirety of trace elements found in this iron-rich deposit. Further, spurred by the similarities between banded iron formation and anoxygenic phytoplankton trace-element stoichiometries, we suggest that much of the trace-element inventory preserved in the banded iron formation was at some point biologically assimilated in the water column, released from degrading photoferrotrophic biomass at the seafloor and in the sediment pile, and ultimately fixed in the iron-rich sediment in approximately stoichiometric proportions by near-quantitative adsorption to ferrihydrite. Our observations suggest that, as today, phytoplankton and the recycling of their biomass exerted control over the trace-element composition of ancient seawater and sediment.

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Konhauser Kurt O., Robbins Leslie J., Alessi Daniel S., Flynn Shannon L., Gingras Murray K, Martinez Raul E., Kappler Andreas, Swanner Elizabeth D., Li Yi-Liang, Crowe Sean A., Planavsky Noah J., Reinhard Christopher T., Lalonde Stefan (2018). Phytoplankton contributions to the trace-element composition of Precambrian banded iron formations. Geological Society Of America Bulletin, 130(5-6), 941-951. Publisher's official version : , Open Access version :