The mid/late Eocene transition in the Eastern Carpathians (Romania) based on foraminifera and calcareous nannofossil assemblages

Abstract

Foraminiferal and cal car e ous nannofossil as sem blages from the East ern Carpathians (north ern part of the Tarcãu Nappe, Ro ma nia) were doc u mented and cor re lated in or der to re con struct the palaeonvironmental set tings and pro vide a biostratigraphic frame work of the Plopu For ma tion. The ben thic foraminiferal as sem blages are dom i nated by flysch-type agglu ti nated taxa, sug gest ing a bathyal palaeodepth with fre quent os cil la tions of the car bon com pen sa tion depth. The ag glu tinated foraminifera morphogroup anal y ses sug gest dif fer ent lev els of or ganic mat ter in flux and ox y gen a tion. Both the foraminifera and cal car e ous nannofossil as sem blages sug gest a shift be tween the warm Mid dle Eocene to the cooler Late Eocene cli mate. Biostratigraphic data based on cal car e ous nannofossils (NP15-NP19/NNTe8-NNTe12 biozones) helped to es tab lish the age of the for ma tion. Four as sem blages of ben thic ag glu ti nated foraminifera (Psammosiphonella cylindrica-No thia excelsa; Paratrochamminoides spp.-Trochamminoides spp.; Karrerulina spp.-Reticulophragmium amplectens; Spiroplectammina spectabilis) cor re lated with cal car e ous nannofossil bioevents sup ported the place ment of the Middle to Late Eocene tran si tion within the Plopu For ma tion.

Paleocene “flysch-type” agglutinated foraminifera from the northern part of the Eastern Carpathians (Romania)

“…Additional information was provided by planktonic foraminifera (only for sample 1). Ionesi, 1971;Juravle, 2007;Bindiu et al, 2016). Ionesi, 1971).…”

Agglutinated Foraminiferal Acmes and Their Role in the Biostratigraphy of the Campanian–Eocene Outer Carpathians

“…It was observed in the Magura Nappe [16,17,19,21,26,43,53,81], in the Silesian Nappe [12,41,54,[82][83][84], in the Dukla Nappe [32], in the Subsilesian Nappe [18], and in the Skole Nappe [30,76]. The R. amplectens acme is known from the Eastern Carpathians (e.g., [85][86][87][88], and from the deep-water Atlantic and North Sea [89,90]. The R. amplectens assemblages occur in different types of middle Eocene shales, the most numerous occur in red shales.…”

“…It occurs in the Eocene in the Silesian Nappe [28,40,82,89], and in the Skole Nappe [40,76]. A Spiroplectammina spectabilis zone marked by the dominance of S. spectabilis was distinguished in the upper Eocene of the Eastern Carpathians [86,103]. Mass occurrences were reported from the Paleocene in the boreal North Atlantic [89], and Trinidad [36].…”

The Early Miocene residual flysch basin at the front of the Central Western Carpathians and its palaeogeographic implications (Magura Nappe, Poland)

“…In the PSM, there are cal car e ous nannoplankton be long ing to NP15/17 in the Piwniczna area (Oszczypko-Clowes, 2001;Oszczypko and Oszczypko-Clowes, 2010) and NP18-20 in the Muszyna area (Dudziak in Oszczypko et al, 1990). The MSM is rep re sented by var ie gated shales with Reticulophragmium amplectens which was tra di tion ally re garded as a Mid dle Eocene form, while now it in di cates the Late Eocene (Bindiu et al, 2015).…”