DACIAN BASIN - GeoEcoMar

8.6. Conclusions
stratification. In this context, we refer to the bedding which appears in the clay
series where there are no silt or sand sediment intercalations or laminae.
The observations made by comparison with the environmental data offered
by the sandy sediments with sedimentary structures lead to the idea that the clay
stratification is due to the accumulation in an environment affected by currents
activity. On the same line, the homogeneous clay indicates the absence of water
currents during the accumulation of clay particles.
The Late Neogene homogeneous clay (lacking internal stratification) is closely
associated with fluvial sequences. These clay deposits appear in the upper part of
the fluvial fining upward sequences. In this case, the clay reveals the fluvial channel
abandonment stage.
The homogeneous clay deposits are often found cropping out under the coal
beds. This clay may indicate a swamp accumulation environment with no significant
water circulation.
Even in the fluvial environment, the clay deposits are stratified when they associate
with some environments where current activity is involved. This is the case
of the sediments accumulated in the crevasse splay environment.
The study of ostracods confirmed most of the clay environment interpretation
based on sedimentologic analysis. However, some of the sedimentological assumptions
have been proven wrong by the results of the paleontologic investigation.
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