TY - JOUR
T1 - Titanium local coordination environments in Cretaceous–Paleogene and Devonian–Carboniferous boundary sediments as a possible marker for large meteorite impact
AU - Tobase, Tsubasa
AU - Yoshiasa, Akira
AU - Komatsu, Toshifumi
AU - Maekawa, Takumi
AU - Hongu, Hidetomo
AU - Okube, Maki
AU - Arima, Hiroshi
AU - Sugiyama, Kazumasa
N1 - Funding Information:
Acknowledgements This study was performed within the Photon Factory Project PAC No. 2012G526, and financially supported by the JSPS-VAST Joint Research Program and a Grant-in-Aid from the Japan Society for Promotion of Science (25400500 and 16K05593 to Komatsu) and JSPS Grant-in-Aid for JSPS Research (JP16J10062 to Tobase).
Publisher Copyright:
© 2019, Springer-Verlag GmbH Germany, part of Springer Nature.
PY - 2019/7/1
Y1 - 2019/7/1
N2 - The local coordination environments of Ti in Cretaceous–Paleogene (K–Pg) from Stevns Klint and Devonian–Carboniferous (D–C) boundary from western part of Cat Co Beach on Cat Ba Island sediments are studied by K-edge X-ray absorption fine structure (XAFS) in order to provide local atomic information by X-ray absorption near edge structure (XANES) and coordination environments by extended X-ray absorption fine structure (EXAFS). Ti K-edge XAFS spectra in bulk part of K–Pg and D–C boundary sediments are compared with those of reference materials such as TiO2 (rutile, anatase and brookite polymorph), CaTiO3, MgTiO3, SrTiO3, PbTiO3, moldavite-brownish, moldavite-green, suevite from Ries crater, impactite, obsidian and Kilauea volcanic glass. The shapes of XANES and EXAFS spectra in K–Pg sediments are similar to those in suevite. Suevite was formed under meteorite impact and its glass component was formed under high temperature and high pressure. Similarities of XANES and EXAFS between K–Pg sediments and suevite indicate that formation process of K–Pg sediments is related to a meteorite impact event. On the other hand, the shape of XANES spectrum in D–C sediments is similar to those in anatase and obsidian. However, the shape of EXAFS spectra in D–C sediments is similar to those in obsidian, rather than anatase. Coordination environments of Ti in D–C sediments suggest that the original glass-like local environments were changed to anatase-like local environments by devitrification. This leads to the conclusion that the analysis of the atomic coordination environments of Ti in boundary sediments can in principle be used as a marker of large meteorite impact, though this Ti local environmental information is actually lost due to the devitrification phenomenon to anatase by quenching process or long-time diagenesis. This may be compensated by the XAFS analysis of Zr because local coordination environments of Zr in same analytical point of K–Pg sediments were not affected by diagenesis (Tobase et al., J Miner Petrol Sci 110:88–91, 2015a).
AB - The local coordination environments of Ti in Cretaceous–Paleogene (K–Pg) from Stevns Klint and Devonian–Carboniferous (D–C) boundary from western part of Cat Co Beach on Cat Ba Island sediments are studied by K-edge X-ray absorption fine structure (XAFS) in order to provide local atomic information by X-ray absorption near edge structure (XANES) and coordination environments by extended X-ray absorption fine structure (EXAFS). Ti K-edge XAFS spectra in bulk part of K–Pg and D–C boundary sediments are compared with those of reference materials such as TiO2 (rutile, anatase and brookite polymorph), CaTiO3, MgTiO3, SrTiO3, PbTiO3, moldavite-brownish, moldavite-green, suevite from Ries crater, impactite, obsidian and Kilauea volcanic glass. The shapes of XANES and EXAFS spectra in K–Pg sediments are similar to those in suevite. Suevite was formed under meteorite impact and its glass component was formed under high temperature and high pressure. Similarities of XANES and EXAFS between K–Pg sediments and suevite indicate that formation process of K–Pg sediments is related to a meteorite impact event. On the other hand, the shape of XANES spectrum in D–C sediments is similar to those in anatase and obsidian. However, the shape of EXAFS spectra in D–C sediments is similar to those in obsidian, rather than anatase. Coordination environments of Ti in D–C sediments suggest that the original glass-like local environments were changed to anatase-like local environments by devitrification. This leads to the conclusion that the analysis of the atomic coordination environments of Ti in boundary sediments can in principle be used as a marker of large meteorite impact, though this Ti local environmental information is actually lost due to the devitrification phenomenon to anatase by quenching process or long-time diagenesis. This may be compensated by the XAFS analysis of Zr because local coordination environments of Zr in same analytical point of K–Pg sediments were not affected by diagenesis (Tobase et al., J Miner Petrol Sci 110:88–91, 2015a).
KW - D–C boundary sediments
KW - EXAFS
KW - K–Pg boundary sediments
KW - Ti coordination environments
KW - XANES
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U2 - 10.1007/s00269-019-01030-4
DO - 10.1007/s00269-019-01030-4
M3 - Article
AN - SCOPUS:85064281537
VL - 46
SP - 675
EP - 685
JO - Physics and Chemistry of Minerals
JF - Physics and Chemistry of Minerals
SN - 0342-1791
IS - 7
ER -