@article{fdi:010064933,
  title = {{U}biquitous occurrence of basaltic-derived paleosols in the {L}ate {A}rchean {F}ortescue {G}roup, {W}estern {A}ustralia},
  author = {{T}eitler, {Y}. and {P}hilippot, {P}. and {G}{\'e}rard, {M}artine and {L}e {H}ir, {G}. and {F}luteau, {F}. and {A}der, {M}.},
  editor = {},
  language = {{ENG}},
  abstract = {{T}he 2.76 {G}a old {M}ount {R}oe {B}asalt paleosols ({MR}#1 and {MR}$2), recognized near the base of the 2.76-2.69 {G}a {F}ortescue {G}roup in {W}estern {A}ustralia, represent some of the oldest definite examples of {A}rchean paleoweathering profiles. {T}he loss of {F}e and the absence of pedogenic carbonates in these reference paleosols have been considered as strong evidence for low oxygen and moderate carbon dioxide in the {L}ate {A}rchean atmosphere, respectively. {H}owever, the robustness of such interpretations suffers both from the scarcity of paleosol exposures and the superposition of post-weathering alteration over primary soil profiles. {H}ere we report new exposures of the {MR}#1 paleosol as well as a number of new basalt-derived paleosol occurrences distributed in the {M}ount {R}oe {B}asalt and the 2.73 {G}a old {K}ylena {F}ormations of the {F}ortescue {G}roup. {W}e show that all these paleosols, including {MR}$1 and {MR}#2, were strongly affected by post-weathering reductive alteration. {N}evertheless, we discovered early lithologic units, locally preserved within the hydrothermally altered paleosols, which feature distinct chemical and mineralogic compositions. {T}hese include: (i) {C}-13-depleted carbonaceous-rich, diaspore-pyrophyllite boudins likely inherited from the hydrolysis and bauxitization of the parent basalt and (ii) green hard core material, mostly composed of {F}e-sericite associated with authigenic sphene and containing early relics of sulfate-bearing iron-rich smectite or berthierine. {W}e argue that smectite relics may constitute a part of the primary pedogenic mineral assemblage, while berthierine and sphene formed during diagenesis through the circulation of reductive fluids. {B}ecause the depletion of iron observed in the {F}ortescue paleosols is not solely due to pedogenesis, but also to post-weathering alteration, particular care has to be taken when bulk chemical profiles of iron in such paleosols are used as atmospheric paleobarometer. {R}ecognition of the regional-scale, syn-depositional alteration of the {F}ortescue subaerial basalts over the north {P}ilbara suggests the onset of intense continental weathering associated with the uplift and emergence of the {P}ilbara craton during continental break-up and rifting. {S}uch a regional onset of continental weathering may have provided large amounts of nutrients to nearby marine and/or lacustrine systems, favoring the development of microbial life in shallow waters.},
  keywords = {{P}aleosols ; {A}rchean ; {F}ortescue ; {P}ilbara ; {M}ethanotrophy ; {AUSTRALIE}},
  booktitle = {},
  journal = {{P}recambrian {R}esearch},
  volume = {267},
  numero = {},
  pages = {1--27},
  ISSN = {0301-9268},
  year = {2015},
  DOI = {10.1016/j.precamres.2015.05.014},
  URL = {https://www.documentation.ird.fr/hor/fdi:010064933},
}