Regional chemostratigraphic key horizons in the macrofossil-barren siliciclastic lower Miocene lacustrine sediments (Most Basin, Eger Graben, Czech Republic)

• DOI: 10.3140/bull.geosci.1372
• Publication Date: 2013-02-19T00:02:04Z
• Authors: T. Matys Grygar; K. Mach
• Keywords: Macrofossil; Siliciclastic

Six sediment cores from two of four depocentres in the Most Basin, mostly consisting macrofossil barren fluviodeltaic and lacustrine sediments Holešice Libkovice members Formation (lower Miocene, Burdigalian) were subjected to chemostratigraphic correlation, based on CEC EDXRF proxy element analyses.CEC-step, prominent K/Al minima crandallite-bearing horizons monotonous mudstones Member provide several local isochronous or nearly key horizons, which we propose for a basin-scale correlation upper Basin fill.These prove spatially uniform sedimentary environment single lake (original area ~1,000 km2 ) during deposition considerable part siliciclastics overlying main coal seam that tops lower basin fill.We CEC-step horizon as novel boundary between members, i.e. conversion previously formal lithostratigraphic units with an boundary.That together recent sedimentological studies would assign Břešťany clay top Member.The could be coarsening related level decrease before Lom seam.The study will allow progress palaeogeographic palaeoenviromental reconstruction Miocene Basin.The analyses (CEC vs Al/Si ratios) reliable numeric differentiation kaolinite-rich, smectite-poor smectite-rich assemblages members.The plots ratios should applicable fingerprinting any other clastics variable mineralogy assemblage.•