Detailed clay mineralogy of the Triassic-Jurassic boundary section at Kendlbachgraben (Northern Calcareous Alps, Austria)

N. Zajzon, F. Kristály, J. Pálfy, T. Németh

Research output: Contribution to journalArticle

16 Citations (Scopus)

Abstract

The Triassic-Jurassic boundary (TJB) is marked by one of the five largest Phanerozoic mass extinctions. To constrain existing models for TJB events, we obtained a stratigraphically highly resolved dataset from a marine section at Kendlbachgraben, Austria. The topmost Triassic Kössen Formation contains low to medium-charged smectite and vermiculite as alteration products of mafic-ultramafic minerals. The clay minerals in the boundary mudstone are kaolinite ≥ illite + muscovite ≫ smectite > chlorite. Predominant kaolinite suggests humid climate and abundant terrigenous input. In the lowermost Jurassic, the clay mineral pattern changes to illite + muscovite ≫ kaolinite ≫ smectite, which reflects change to less humid and more moderate climate. The topmost Kössen Formation also contains clay spherules. Their composition, shape and size indicate that they are alteration products of airborne volcanic glass droplets solidified in the air, settled in the sea and altered rapidly with negligible transport in terrestrial or marine environments. Our data are consistent with sudden climatic change at the TJB, as a result of large-scale volcanic activity of the Central Atlantic Magmatic Province which produced distal airfall volcanic ash.

Original languageEnglish
Pages (from-to)177-189
Number of pages13
JournalClay Minerals
Volume47
Issue number2
DOIs
Publication statusPublished - Jun 1 2012

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Keywords

  • Austria
  • Clay mineralogy
  • Climate change
  • Kendlbachgraben
  • Triassic-Jurassic boundary
  • Volcanic spherules

ASJC Scopus subject areas

  • Geochemistry and Petrology

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