DACIAN BASIN - GeoEcoMar

1.3. Outline of the Dacian Basin biostratigraphy
If d) is taken into consideration and all the four models from Fig.1.5 are recalibrated
to the most recent timescale, i.e. ATNTS2004 (Lourens et al., 2004), then the
dating of the chronostratigraphic boundaries of the Upper Miocene-Pliocene stages
in the parallel GTS’s - A, B, C, D is as follows:
■ Pontian/Dacian boundary:
» model A: ~ 5.3 Ma; model B: ~ 4.9 Ma; model C: ~ 5.3 Ma; model D:
~ 5.24 Ma;
■ Dacian/Romanian boundary:
» model A: ~ 4.24 Ma; model B: ~ 4.1 Ma; model C: ~ 4.25 Ma (option
A – according to Rădan & Rădan, 1998 and van Vugt et al., 2001, in Snel
et al., 2006); model D: ~ 3.65 Ma.
If e) is now considered, and an unique nomenclature and subdivisions of the
Pliocene chronostratigraphic units within all the four models is adopted, i.e. the
Siensian is the lower substage of the Romanian, in keeping with the Neogene
chronostratigraphic nomenclature in Romania (Papaianopol et al., 1995; Rădulescu
et al., 1995), then the age of the Dacian/Romanian boundary (according to the
magnetobiostratigraphic data published by Andreescu, 2008) becomes ~ 4.1 Ma
(by calibrating to the ATNTS2004), i.e. identical or close to the ages that are assigned
to this boundary in the models A, B and C – option A .
For the above-mentioned and other specific details related to each of the four
geological time scales illustrated in Fig.1.5 (A, B, C, D), the reader is referred to
Rădan (1998, 2000, 2002), Rădan & Rădan (1996, 1998, 2001), Rădan et al. (1996),
van Vugt et al. (2001), Vasiliev et al. (2004, 2005), Stoica et al. (2007), Snel et al. (2006),
Andreescu (2008).
To conclude, there is not yet an acceptable – unique – Geological Time Scale
assignable to the Dacian Basin, but the models A, B, C, D from Fig.1.5, as inferred
from papers published throughout the last decade, could represent contributions
toward a future reliable chronostratigraphic and geochronologic framework of this
important part of the Parathetys.
1.3. OUTLINE OF THE DACIAN BASIN BIOSTRATIgRAPHY 1
Like the other Paratethian basins, the evolution of the Dacian Basin during Late
Neogene produced specific geological and ecological marker events. That is the
reason why the Dacian Basin corresponds partially to the Paratethys Mio-Pliocene
biostratigraphy, but on the other hand it shows specific fauna (Fig. 1.6). Although
some stratigraphic stages, like Sarmatian, Maeotian or Pontian, have the same
name in more than one Paratethys basins (including the Dacian Basin), they do not
show the same, synchronous biostratigraphic assemblages.
1 Author: Radu Olteanu
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