Trilobite and acritarch assemblages from the Lower– Middle Cambrian boundary interval in the Holy Cross Mountains (Poland)
Authors
Anna Zylinska
Faculty of Geology, University of Warsaw, ul. Żwirki i Wigury 93, PL-02-089 Warsaw
Zbigniew Szczepanik
Holy Cross Branch of the Polish Geological Institute, ul. Zgoda 21, PL-25-953 Kielce
Keywords:
Lower Cambrian, Middle Cambrian, Cambrian Series 2 and 3, Stratigraphy, Holy Cross Mountains, Trilobita, Acritarcha, Poland
Abstract
Integrated analysis of trilobite and acritarch assemblages across the traditional Lower–Middle Cambrian boundary in the Holy Cross Mountains (Poland) has documented the development of both groups in this interval. Trilobite assemblages, comprising 31 taxa (13 are revised herein) dominated by the Ellipsocephalidae, change from the protolenoid-dominated in the Lower Cambrian to the kingaspidoid–ornamentaspidoid-dominated in the Middle Cambrian, and correlate well with theAgdzian Stage ofWest Gondwana (Geyer and Landing 2004). Correspondence toWest Gondwana and Avalonia is also evident from the presence of the associated trilobite genera, Palaeolenus, Myopsolenites, Latikingaspis, Kingaspis, Latoucheia and Orodes. The acritarch assemblages, comprising 77 taxa, indicate that their main taxonomic turnover was gradual and preceded the earliest occurrence of Paradoxides spp., as in the Spanish sections. The geological succession studied in the HCMrepresents part of the Cambrian strata that are generally missing in Baltica.
