Crystallization Pathways of Iron Formations: Insights From Magnetic Properties and High-Resolution Imaging of the 2.7 Ga Carajas Formation, Brazil.

ABSTRACT: Banded iron formations (BIFs) are chemical sedimentary rocks commonly utilized for exploring the chemistry and redox state of the Precambrian ocean. Despite their significance, many aspects regarding the crystallization pathways of iron oxides in BIFs remain loosely constrained. In this study, we combine magnetic properties characterization with high-resolution optical and electron imaging of finely laminated BIFs from the 2.7 Ga Carajás Formation, Brazil, to investigate their nature and potential for preserving ancient environmental conditions. Our findings reveal that magnetite, in the form of large 0.1-0.5 mm crystals, is the main iron oxide, with an overall averaged saturation magnetization (M_s) of 25 Am²/kg (corresponding to ~27 wt% of magnetite) over the studied

SUBMITTER: Teixeira L 

PROVIDER: S-EPMC11638513 | biostudies-literature | 2024 Nov-Dec

REPOSITORIES: biostudies-literature