PEDOGENESIS AND QUATERNARY SEDIMENTOGENESIS IN NORTHERN-DOBRUDGEA (SOUTH-EASTERN PART OF ROMANIA)
Ioan MUNTEANU & Petru IGNAT
National Research & Development Institute for Soil Science, Agrochemistry and Environmental Protection Bucharest, Blvd. Mărăşti, 61, 011464, sector 1, Bucharest, Romania, munteanu_johny@yahoo.com, petruignat.icpa@gmail.com
Abstract
The Northern Dobrudgea consists of Palaeozoic and Triassic formations, geologically being one of the oldest regions of Romania. In this area, in post tertiary times, pedogenesis and sedimentogenesis may be differentiated into two main periods: before and synchronous with quaternary loess deposits and soil development. During the first period, the sedimentogenesis seems to have been weak and pedogenesis strong. The soil cover developed on the account of Paleozoic and Triassic rocks.
The pedogenesis would be of “denudational – compensative” type. The soil cover developed then, have been subsequently destroyed by erosion or buried beneath quaternary sediments (mainly loess deposits)
either. The remnants preserved on some cretaceous surfaces (of residual relief) witness that the soils were deep, clayey and red similar to the present day Haplic Luvisols (Rhodic-Abruptic). They may belong to
the end of Pliocene or to the beginning of Quaternary. The second period is characterized by the interference of pedogenesis and intense sedimentogenesis generated by wind-borne dust fall-out and
formation of sequences consisting of soils, loess and loess-like deposits. The loess layers and associated fossil-soils strips formed during that period may be considered as complex entities and called
“Pedolithological complexes”. The pedogenesis of this period is of “sedialternating” type. This means that the periods with prevailing pedogenesis alternated with those of prevailing sedimentogenesis. The thickness of “pedolithological complexes” varies from 3-5 m on highlands up to 15-25 m in low-lying areas and inner depressions of the region. The upper part of them is of Würmian and Holocene age but some basal layers may be Rissian even Mindelian. For spatial juxtapositions of palaeosols and actual soils the term “chronopedogeographic discontinuity or contrast” has been introduced.
- pedogenesis
- Quaternary
- sedimentogenesis
- loess
- and
- loess-like
- deposits
- fossil
- soils
- Northern
- Dobrudgea