TY - JOUR
T1 - Clues from Fe isotope variations on the origin of early Archean BIFs from Greenland
AU - Dauphas, Nicolas
AU - Van Zuilen, Mark
AU - Wadhwa, Meenakshi
AU - Davis, Andrew M.
AU - Marty, Bernard
AU - Janney, Philip E.
PY - 2004/12/17
Y1 - 2004/12/17
N2 - Archean rocks may provide a record of early Earth environments. However, such rocks have often been metamorphosed by high pressure and temperature, which can overprint the signatures of their original formation. Here, we show that the early Archean banded rocks from Isua, Akilia, and Innersuartuut, Greenland, are enriched in heavy iron isotopes by 0.1 to 0.5 per mil per atomic mass unit relative to igneous rocks worldwide. The observed enrichments are compatible with the transport, oxidation, and subsequent precipitation of ferrous iron emanating from hydrothermal vents and thus suggest that the original rocks were banded iron formations (BIFs). These variations therefore support a sedimentary origin for the Akilia banded rocks, which represent one of the oldest known occurrences of water-laid deposits on Earth.
AB - Archean rocks may provide a record of early Earth environments. However, such rocks have often been metamorphosed by high pressure and temperature, which can overprint the signatures of their original formation. Here, we show that the early Archean banded rocks from Isua, Akilia, and Innersuartuut, Greenland, are enriched in heavy iron isotopes by 0.1 to 0.5 per mil per atomic mass unit relative to igneous rocks worldwide. The observed enrichments are compatible with the transport, oxidation, and subsequent precipitation of ferrous iron emanating from hydrothermal vents and thus suggest that the original rocks were banded iron formations (BIFs). These variations therefore support a sedimentary origin for the Akilia banded rocks, which represent one of the oldest known occurrences of water-laid deposits on Earth.
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U2 - 10.1126/science.1104639
DO - 10.1126/science.1104639
M3 - Article
C2 - 15604404
AN - SCOPUS:10844243957
SN - 0036-8075
VL - 306
SP - 2077
EP - 2080
JO - Science
JF - Science
IS - 5704
ER -