Weathering and precipitation after meteorite impact of Ni, Cr, Fe, Ca and Mn in K-T boundary clays from Stevns Klint

A study of K-T boundary clays from Stevns Klint, Denmark, reveals that elements such as Ni, Cr, and Fe in impact-related glasses undergo weathering and diagenesis to form stable hydrates and oxides. XANES and EXAFS analyses indicate that these elements adopt structures similar to Ni(OH)₂, Cr₂O₃, and FeOOH, respectively. Notably, Ca maintains a diopside-like structure, potentially retaining information about the meteorite impact conditions. Mn exhibits a divalent state akin to MnCO₃, with its scarcity in Fe-group elements attributed to consumption by life activity or diffusion. This research provides insights into the post-impact chemical transformations and environmental processes at this UNESCO World Heritage Site.

Miyano, Y., Yoshiasa, A., Tobase, T., Isobe, H., Hongu, H., Okube, M., Nakatsuka, A., & Sugiyama, K. (2016). Weathering and precipitation after meteorite impact of Ni, Cr, Fe, Ca and Mn in K-T boundary clays from Stevns Klint. Journal of Physics: Conference Series, 712, 12097. https://doi.org/10.1088/1742-6596/712/1/012097