Fe-oxide concretions formed by interacting carbonate and acidic waters on Earth and Mars.

ABSTRACT: Spherical Fe-oxide concretions on Earth, especially in Utah, USA, have been investigated as an analog of hematite spherules found in Meridiani Planum on Mars to support interpretations of water-rock interactions in early Mars. Although several formation mechanisms have been proposed for the Fe-oxide concretions on Earth, it is still unclear whether these mechanisms are viable because a precise formation process and precursor of the concretions are missing. This paper presents evidence that Fe-oxide concretions in Utah and newly found Fe-oxide concretions in Mongolia had spherical calcite concretions as precursors. Different formation stages of calcite and Fe-oxide concretions observed, both in Utah and Mongolia, indicate that calcite concretions initially formed within eolian sandstone str

SUBMITTER: Yoshida H 

PROVIDER: S-EPMC6281427 | biostudies-literature | 2018 Dec

REPOSITORIES: biostudies-literature