Abstract
Eleven boreholes and one outcrop of the Lower Cretaceous in South Dobrogea (south-eastern Romania) were sampled for charophytes. Twenty species are described and illustrated in two non-marine rock units, the Zăvoaia Member and the Gherghina Formation. The Zăvoaia Member contains a charophyte assemblage dominated by Feistiella bijuescensis, aff. Mesochara harrisii, Nodosoclavator bradleyi, Clavator bilateralis, and Clavator grovesii var. grovesii, indicating a Berriasian age. Other less abundant species include Feistiella sp., Latochara sp., Mesochara dobrogeica sp. nov., Globator maillardii var. nurrensis, Atopochara trivolvis var. micrandra, Clavator grovesii var. discordis, Hemiclavator adnatus, and Hemiclavator neimongolensis var. posticecaptus. The occurrence of G. maillardii var. nurrensis in this assemblage suggests late Berriasian age. The Gherghina Formation is dominated by the species Atopochara trivolvis var. triquetra and Clavator grovesii var. jiuquanensis. Other less abundant species include Sphaerochara andersonii, aff. Mesochara harrisii, Globator maillardii var. trochiliscoides, Globator maillardii var. biutricularis, Clavator harrisii var. reyi, and Clavator ampullaceus var. latibracteatus var. nov. This assemblage indicates a late Barremian–early Aptian age. This study sheds new light on the palaeobiogeographical distribution of Lower Cretaceous charophytes in the Tethyan realm. Well-known western European charophyte species such as F. bijuescensis, S. andersonii, G. maillardii var. trochiliscoides, H. adnatus, and H. neimongolensis var. posticecaptus are herein described for the first time in eastern Europe. Very significantly, this is the first report in Europe of the hitherto North American taxon C. bilateralis, while the species C. ampullaceus has previously been reported only from the Middle East and eastern Africa.
Highlights
Charophyte fructifications have been extensively reported worldwide in non-marine sedimentary rocks as old as Silurian in age (Feist et al, 2005)
Previous studies based on Cretaceous charophytes from South Dobrogea have been performed by Neagu and Georgescu-Donos (1973), who recovered an assemblage of five species including Atopochara trivolvis var. trivolvis, Clavator grovesii var. jiuquanensis, Hemiclavator neimongolensis, and Clavator sp. from marly limestone located in a cliff near the village of Pestera (Medgidia, South Dobrogea)
Ostracod biostratigraphic data and the occurrence of H. adnatus and H. neimongolensis var. posticecaptus associated with G. maillardii var. nurrensis in one of the samples from Cernavoda suggest that the three species may be older in Romania than in western Europe
Summary
Charophyte fructifications (gyrogonites and utricles) have been extensively reported worldwide in non-marine sedimentary rocks as old as Silurian in age (Feist et al, 2005). Previous studies based on Cretaceous charophytes from South Dobrogea have been performed by Neagu and Georgescu-Donos (1973), who recovered an assemblage of five species including Atopochara trivolvis var. From marly limestone located in a cliff near the village of Pestera (Medgidia, South Dobrogea) These authors provided a relative age of uppermost Barremianelower Aptian for the studied deposits. Avram et al (1993) developed a comprehensive biostratigraphic analysis of 20 drilling boreholes in South Dobrogea These authors provided the relative age of several marine and
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