DACIAN BASIN - GeoEcoMar

10.4. Control factors of the sediment filling process
Stage 1. Brackish sediment accumulation restricted to two separated depocenters. This
stage extends through the Middle-Late Sarmatian (s. l.) – Maeotian time interval.
The main distinctive character of the stage 1 is the sediment accumulation
within two distinct Dacian Basin depocenters (Fig. 10.10 A and B). The areas of the
individual depocenters enlarged considerably during the Maeotian, as compared
to the Middle-Late Sarmatian (s. l.) extent.
During the Maeotian time interval the eastern depocenter extended mostly
toward the south-west with a fan-like geometry (Fig. 10.10 B).
The western depocenter enlarged eastward and southward, and the maximal
sediment thickness increased from 200 m during Middle-Late Sarmatian (s. l.) to
600 m in the Maeotian time (Fig. 10.10 B).
In the space between the two depocenters a reduced amount of sediments
accumulated, with around 100 m thickness.
Stage 2. Brackish sediment filling, mainly through the extension of the eastern depocenter.
This stage covers the time span from the Early Pontian to the Early Dacian.
The characteristic of the sediment filling process during the stage 2 is the westward
advance of the sediment accumulation along the sedimentary trench (Fig.
10.10 C and D). The main effect of this process was the filling of the accommodation
space of the former sediment deficient area between the two depocenters.
In the western depocenter, the southward extension of the sediment accumulation
area continued, reaching its maximum during the Early Pontian (Fig. 10.10
C). The Late Pontian-Dacian isopach map (Saulea et al., 1969) shows the end of
this process and the decrease of the sediment accumulation in the western depocenter
of the Dacian Basin (Fig. 10.10 D).
The two depocenters coalesced into a single depocenter sometimes between
Late Pontian and Early Dacian. The stage 2 ends with the filling out and closure of
the brackish-marine Dacian Basin.
Stage 3. Fluvial sediment accumulation subsequent to the filling out of the Dacian
Basin. Starting from the Middle Dacian time, the sedimentation in the area of the
Dacian Basin is fluvial. The isopach map indicates a single area, with an east–west
elongated sediment accumulation front (Fig. 10.10 E). The large scale geometry of
the sediment accumulation, belonging to the piedmont type, indicates an exclusively
Carpathian sediment supply. In contrast with the preceding sediment filling
stage, the sediment accumulation tends to extend southward.
10.4. CONTROL FACTORS OF THE SEDIMENT FILLINg PROCESS
The history of the sediment filling in the Dacian Basin was strongly influenced by
the tectonic factor. Being a foreland unit, the Dacian Basin physiography have been
shaped mainly by the tectonic forces. The Dacian Basin elongation (a typical fore-
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