Russian Journal of Earth Sciences Russian Journal of Earth Sciences Russian Journal of Earth Sciences 1681-1208 46999 ОРИГИНАЛЬНЫЕ СТАТЬИ ORIGINAL ARTICLES ОРИГИНАЛЬНЫЕ СТАТЬИ Two spinel populations from the Cretaceous-Paleogene K/T boundary clay layer in the Gams stratigraphic sequence, Eastern Alps Two spinel populations from the Cretaceous-Paleogene K/T boundary clay layer in the Gams stratigraphic sequence, Eastern Alps Grachev A F Grachev A F Tselmovich V A Tselmovich V A Korchagin O A Korchagin O A Kollmann H A Kollmann H A Schmidt Institute of Physics of the Earth, Russian Academy of Sciences, Moscow, Russia ru Schmidt Institute of Physics of the Earth, Russian Academy of Sciences, Moscow, Russia ru Geophysical Observatory, Schmidt Institute of Physics of the Earth, Russian Academy of Sciences, Borok, Yaroslavl oblast, Russia ru Geophysical Observatory, Schmidt Institute of Physics of the Earth, Russian Academy of Sciences, Borok, Yaroslavl oblast, Russia ru Geological Institute, Russian Academy of Sciences, Moscow, Russia ru Geological Institute, Russian Academy of Sciences, Moscow, Russia ru Museum of Natural History, Vienna, Austria ru Museum of Natural History, Vienna, Austria ru 9 2 1 11 10 11 2021 https://rjes.ru/en/nauka/article/46999/view

The K/T boundary layer in the Gams stratigraphic sequence, Eastern Alps, was determined to contain two spinel populations. One of them is dominated by Cr spinel, which originated from eroded high-pressure metamorphic rocks of eclogite composition, which are widespread in the Eastern Alps. This spinel is not only typical of the whole K/T boundary layer but was also found farther upsection in Maestrichtian clay. The other spinel population principally differs from the first one in having high Ni concentrations. Ni spinel from the Gams section differs by the high content of zinc up to 5.6% in a rust crust, that is not characteristic for other known sections at the K/T boundary. Alongside with well expressed crystals octahedral forms, one grain of drop-like mode of Ni spinel has been found. It is considered, that Ni spinel is confined to 1-3nbsp;mm rust colored layer which has deposited in less than 100 years, while in the Gams section it meets in all parts of the transition layer. The question of origin Ni spinel from the transitional layer at the K/T boundary remains opened and demands the further researches.

The K/T boundary layer in the Gams stratigraphic sequence, Eastern Alps, was determined to contain two spinel populations. One of them is dominated by Cr spinel, which originated from eroded high-pressure metamorphic rocks of eclogite composition, which are widespread in the Eastern Alps. This spinel is not only typical of the whole K/T boundary layer but was also found farther upsection in Maestrichtian clay. The other spinel population principally differs from the first one in having high Ni concentrations. Ni spinel from the Gams section differs by the high content of zinc up to 5.6% in a rust crust, that is not characteristic for other known sections at the K/T boundary. Alongside with well expressed crystals octahedral forms, one grain of drop-like mode of Ni spinel has been found. It is considered, that Ni spinel is confined to 1-3nbsp;mm rust colored layer which has deposited in less than 100 years, while in the Gams section it meets in all parts of the transition layer. The question of origin Ni spinel from the transitional layer at the K/T boundary remains opened and demands the further researches.

 K/T boundary spinel impact Eastern Alps. K/T boundary spinel impact Eastern Alps.

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