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

16th International Conference on X-ray Absorption Fine Structure

Miyano, Yumiko^1 ; Yoshiasa, Akira^1 ; Tobase, Tsubasa^1 ; Isobe, Hiroshi^1 ; Hongu, Hidetomo^1 ; Okube, Maki^2 ; Nakatsuka, Akihiko^3 ; Sugiyama, Kazumasa^4

Graduated School of Science and Technology, Kumamoto Univ., Kumamoto, Japan^1

IMR, Tokyo Institute of Technology, Yokohama, Japan^2

Graduate School of Science and Engineering, Yamaguchi Univ., Ube, Japan^3

Department of Institute for Material Research, Tohoku Univ., Sendai, Japan^4

关键词: Denmark;    Divalent state;    Exafs analysis;    Local structure;    Meteorite impact;    XANES spectra;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/712/1/012097/pdf
DOI  :  10.1088/1742-6596/712/1/012097

来源: IOP

【 摘 要 】

Ni, Cr, Fe, Ca and Mn K-edge XANES and EXAFS spectra were measured on K-T boundary clays from Stevns Klint in Denmark. According to XANES spectra and EXAFS analyses, the local structures of Ni, Cr and Fe in K-T boundary clays is similar to Ni(OH)2, Cr2O3and FeOOH, respectively. It is assumed that the Ni, Cr and Fe elements in impact related glasses is changing into stable hydrate and oxide by the weathering and diagenesis at the surface of the Earth. Ca in K-T boundary clays maintains the diopside-like structure. Local structure of Ca in K-T clays seems to keep information on the condition at meteorite impact. Mn has a local structure like MnCO3 with divalent state. It is assumed that the origin on low abundant of Mn in the Fe-group element in K-T clays was the consumption by life activity and the diffusion to other parts.