Morphotype variation of orthophragminids as a palaeoecological indicator: A case study of Bartonian limestones, Pod Capkami Quarry, Tatra Mts, Poland

Abstract

Nummulites-Discocyclina bioclastic packstone and Discocyclina rudstone occur in the transgressive sequence of the Middle–Upper Eocene deposits in the Tatra Mts. The succession of the studied facies is a direct response to a rapid environmental change, related to progressive deepening. Facies transition from Nummulites- Discocyclina bioclastic packstone of proximal mid-ramp to Discocylina rudstone of distal mid- and outer-ramp is an exemplary record of a deposition during deepening conditions. Increasing of diversity of the genus Discocyclina, decreasing of diversity of other foraminifera up the section and vertical variation of orthophragminid mor- photypes from the ovate- through saddle- to the disc-shaped tests are related to deepening and shadowing of the depositional environment.