International Geological Journal - Official Journal of the Carpathian-Balkan Geological Association

LOWER CARBONIFEROUS ICHNOFABRICS OF THE CULM FACIES: A CASE STUDY OF THE MORAVICE FORMATION (MORAVIA AND SILESIA, CZECH REPUBLIC)

Pages: 141 - 148

Authors: RADEK MIKULAS, TOMAS LEHOTSKY, ONDREJ BABEK

Abstract: Overall bioturbation of sediments of the Culm facies is much lower compared to the Mesozoic and Cenozoic flysch facies. Totally reworked intervals (up to 1 cm thick) occur locally at the tops of turbiditic beds. Much more frequently, visual equivalents of a „mottled zone“ were observed at the two localities which represent a transitional facies between "laminites" and greywacke bodies. Approximately one-half of the turbidite beds studied show a mottled level. Planolites montanus Ichnofabric and Rhizocorallium Ichnofabric are infrequent. Most of the laminites show no ichnofabric except cross-sections of Dictyodora, which are typically observed on bedding planes only (not in vertical sections). Compared to the Mesozoic and Cenozoic flysch (i.e. Rhenodanubian or Carpathian flysches), the Culm facies appears to have formed in less oxygenated settings possibly with shorter and unequally distributed colonization windows. This explains the prevalence of traces with complex feeding strategies comprising chemosymbiosis and gardening (Chondrites, Dictyodora). Their effect on the integrity of sediment (i.e. the amount of transported material) was weak.

Keywords: Carboniferous, Culm facies, turbidites, ichnofabric, paleoenvironment

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