Precambrian solution photochemistry, inverse segregation, and banded iron formations

  title={Precambrian solution photochemistry, inverse segregation, and banded iron formations},
  author={A. G. Cairns-smith},
SOLAR radiation on an early Precambrian sea would generate short-lived excited species near the surface of the water. Many of the species would be powerful oxidising or reducing agents. Despite back-reactions, net reducing power would be lost to the atmosphere. This effect would be the opposite of present day photosynthesis and can be termed ‘inverse segregation’. Its possible relevance to banded iron formation is discussed here. 
Photoprecipitation and the banded iron-formations — Some quantitative aspects
The oxidative deposition of iron in the Banded iron-Formations can be quantitatively accounted for by direct abiotic photo-oxidation, by extrapolating from laboratory conditions and making reasonable
Extensive deposition of banded iron formations was possible without photosynthesis
Precambrian banded iron formations (BIFs) consist of alternating layers of silica and iron minerals such as haematite, magnetite and siderite1,2, but there is controversy as to the origin of the
Deposition of banded iron formations by anoxygenic phototrophic Fe(II)-oxidizing bacteria
The mechanism of banded iron formation (BIF) deposition is controversial, but classically has been interpreted to reflect ferrous iron [Fe(II)] oxidation by molecular oxygen after cyanobacteria
Photoprecipitation and the bifs: Some quantitative aspects
The deposition of iron in the BIFs can be quantitatively accounted for by direct abiotic photoprecipitation, making reasonable assumptions about the early Earth and Precambrian ocean waters. The
Abiotic photosynthesis from ferrous carbonate (siderite) and water
Photoemission and solvation of electrons from iron (II) ion in aqueous solution has been shown to lead to reduction of water to hydrogen (Cairns-Smith, 1981; Braterman et al., 1983). In the presence
Role of Microorganisms in Banded Iron Formations
Banded iron formations (BIF) represent the largest source of iron in the world. They formed throughout the Precambrian, and today are globally distributed on the remnants of the ancient cratons. The
Suboxic diagenesis in banded iron formations
The electron acceptor that permits oxidation in the absence of free oxygen is presumed to be iron(III) which may have been significantly more abundant in the initial chemical precipitate than in the post-diagenetic sedimentary rock.
Anoxic photochemical oxidation of siderite generates molecular hydrogen and iron oxides
It is proposed that the photochemistry of Earth-abundant minerals with wide band gaps would have potentially played a critical role in shaping the biogeochemical evolution of early Earth.
Decoupling photochemical Fe(II) oxidation from shallow-water BIF deposition
Abstract Oxidized Fe minerals in Archean–Paleoproterozoic banded iron formations (BIFs) are commonly taken to indicate the presence of biogenic O 2 or photosynthetic Fe(II)-oxidizing bacteria in the
Photo-oxidation of hydrated Fe2+—significance for banded iron formations
The Precambrian banded iron formations (BIFs) are the major iron ore sources on the Earth. They consist of extensive iron-rich and iron-poor layers within siliceous sedimentary rocks1,2. The banding


Early Precambrian oxygen: a case against photosynthesis
Recent biological–biochemical and geological–geochemical data are inconsistent with the currently accepted view that early Precambrian fossil microbiotas are evidence of oxygen-generating
Paleoecological Significance of the Banded Iron-Formation
Banded iron-formation (BIF) is rare in rocks younger than about 2 aeons (years X 10 9 ). It records a major episode of chemical iron sedimentation, however, at about 2 to 2.1 aeons, just before the
Conversion of Solvated Electrons into Hydrogen Atoms in the Photo‐ and Radiation Chemistry of Aqueous Solutions
Radiation chemical and photochemical experiments are reported which show that the conversion of solvated electrons to H atoms is not specific to the H3O+ ion. Proton donors in general may react in
Ages of Precambrian Banded Iron-Formations
Considerable progress has been made in the radiometric dating of Precambrian iron-formations, but the age of relatively few is known precisely. Early Precambrian or Archean deposits, older than 2,600
Photochemical Reactions connected with the Quenching of Fluorescence of Dyestuffs by Ferrous Ions in Solution
IT has been found recently that ferrous ions exert a strong quenching effect on different fluorescent dyestuffs in solution1. According to previous theoretical discussions2, in the elementary process
Chemical events on the primitive Earth.
  • P. Abelson
  • Chemistry, Medicine
    Proceedings of the National Academy of Sciences of the United States of America
  • 1966
The hypothesis of an early methane-ammonia atmosphere is found to be without solid foundation and indeed is contraindicated, and arguments concerning feasible components support the view that amino acids and proteins preceded sugars and nucleic acids.
Atmospheric and hydrospheric evolution on the primitive earth. Both secular accretion and biological and geochemical processes have affected earth's volatile envelope.
Biospheric, hydrospheric, lithospheric and atmospheric evolution on primitive earth, discussing secular accretion and biological and geochemical processes effect on volatile envelope
Early Archaean Age for the Isua Iron Formation, West Greenland
SOME 150 km north-east of Godthaab, on the edge of the inland ice cap, a refolded syncline of mainly basic rocks containing banded ironstones and other rocks of supracrustal origin is enclosed by
Polymeric film precursors in the homogeneous crystallisation of some metal oxides
WE have already reported1,2 the occurrence of two-dimensional polymeric structures prior to precipitation in the system ZrOCl2 (aqueous solution)→ZrO2 (monoclinic). Here we show that similar thin
Varve Cycles in the Weeli Wolli Formation of the Precambrian Hamersley Group, Western Australia
Chert and chert-matrix bands, internal striping, comparison with Dales Gorge Member of Brockman Iron Formation