Trace element geochemistry of the Early to Late Cretaceous deposits of the Grajcarek thrust-sheets – a palaeoenvironmental approach (Małe Pieniny Mts., Pieniny Klippen Belt, Poland)

Abstract

The chemical composition of the Cretaceous deposits of the Grajcarek thrust-sheets (Pieniny Klippen Belt, Poland) has been investigated to provide information on palaeoenvironment and provenance of pelagic and turbiditic particles. The material studied shows large variations in terrigenous and biogenic content. Phyllosilicates (mirrored in amounts of Al2O3, average 15 wt.%) and carbonates (6 wt.% of CaO) are common mineral components of the deposits excluding the Cenomanian radiolarian shales (CRS) that are enriched in silica (mean content of SiO2 is 64 wt.%). “Immobile” elements may be accommodated by phyllosilicates and accessory minerals (i.e. zircon, xenotime, apatite and Ti-oxides). Heavy minerals are significant within the Szlachtowa Fm.  High field strength elements (HFSE) in the Malinowa Fm. are housed in secondary apatite and Fe-oxides. Lithophile trace elements (LILE) concentrations in the material studied are lower/comparable to Post-Archean Australian Shale (PAAS). Ba concentration in the CRS probably reflects enhanced bioproductivity. Interaction between major oxides, distributions of “immobile” and lithophile elements suggest that variation in trace elements through the succession was mainly controlled by the terrigenous input. The material studied was sourced from intermediate to felsic rocks of the Czorsztyn (Oravic) Ridge. The Szlachtowa Fm. and CRS are more mature than others due to low contents of clay minerals. The Szlachtowa Fm. also contains recycled material. The CRS correspond to the oceanic anoxic event 2 (OAE 2) whereas the “Black Flysch” of the Szlachtowa and Opaleniec formations may be related to the Early Cretaceous OAE 1