DACIAN BASIN - GeoEcoMar

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Chapter 11. From Brackish-Marine to Continental-Fluvial Depositional Environment
FIGURE 11.9. The distribution of the coarsening upward unit on the Dacian-age paleogeographic
map (Marinescu, Papaianopol, 1995). The unit has a diachronous character, as the coarsening upward
interval occurs in both the Early Dacian (northern part of the basin) and in Late Dacian deposits
(southern part of the basin, in the present-day Danube River area). Legend: 1. Early Dacian (Getian).
2. Late Dacian (Parscovian). 3. Well locations where the coarsening upward unit was identified
11.1.7. The coarsening upward sequence – a marker unit in the Dacian Basin
The existent data emphasize the presence of the Dacian coarsening upward unit
in outcrops and in well logs on most parts of the Dacian Basin extent. This unit has
not been identified in the northern part of the basin which corresponds to the
Focşani depression. Consequently, the Dacian coarsening upward unit is a marker
level with basinal extent.
The coarsening upward unit was informally used as a stratigraphic marker of
the Dacian/Pontian limit. The existing data indicate that although the coarsening
upward unit may be continuous over a wide area of the Dacian Basin, its geological
age varies from the Early Dacian to the Late Dacian.
The Dacian coarsening upward marker unit is part of the Pontian-Romanian
transgressive-regressive cycle. The marker unit represents the last event with brackish-marine
characteristics. After the deposition of this unit, the brackish-marine Dacian
Basin filled and the sedimentation became fluvial.