BIOSTRATIGRAPHY OF THE BARTONIAN DEPOSITS FROM GILĂU AREA (NW TRANSYLVANIA, ROMANIA)

Abstract. The present paper focussed on the biostratigraphy of the mollusks, larger foraminifers, benthonic and planktonic foraminifers as well as on calcareous nannofossils, identified in the Bartonian (Middle Eocene) deposits (Căpuşu Formation, Inucu Formation, Văleni Limestone and Ciuleni Formati...

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Bibliographic Details
Main Authors: Anatol Rusu, Despina Brotea, Mihaela Carmen Melinte
Other Authors: The Pennsylvania State University CiteSeerX Archives
Format: Text
Language:English
Subjects:
biostratigraphy
Mollusca
Foraminifera
Calcareous Nannofossils
Bartonian
NW Transylvania
Planktonic foraminifera
Online Access:http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.525.4463
http://www.geo-paleontologica.org/Acta.vol.IV/40Rusu.pdf
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Summary:Abstract. The present paper focussed on the biostratigraphy of the mollusks, larger foraminifers, benthonic and planktonic foraminifers as well as on calcareous nannofossils, identified in the Bartonian (Middle Eocene) deposits (Căpuşu Formation, Inucu Formation, Văleni Limestone and Ciuleni Formation) of the NW Transylvania region. The mollusks could be grouped in three assemblages, with the following ostrein horizons: Pycnodonte brongniarti, Sokolowia eszterhazyi, Ostrea bersonensis and Cubitostrea orientalis. The larger foraminifers are characteristic for SBZ 17 (Lower Bartonian) and SBZ 19 (Lower Priabonian) Standard Zones. The Nummulites perforatus Level is present in the Lower Bartonian. The benthonic foraminifers were assigned to the local biozones Pararotalia calveze, Pararotalia subinermis and Pararotalia lithothamnica. The planktonic foraminifera, identified from the upper part of the Căpuşu Formation belongs to the Morozovella lehneri Zone (P12). The calcareous nannofossil assemblages were assigned to the Discoaster tani nodifer (NP16), Discoaster saipanensis (NP17) and Chiasmolithus oamaruensis (NP18) Zones. The Lutetian/Bartonian boundary is placed just above the Pycnodonte brongniarti Level corresponding with the bloom of the nannofossil Reticulofenestra tokodensis (within the NP16 Zone). The Bartonian/Priabonian boundary could be approximated by the first occurrence of the Priabonian nummulites (bioevent placed within the NP18 Nannofossil Zone) toward the terminal part of the Ciuleni Formation.

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