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- Title
A MAGNETIC SUSCEPTIBILITY SCALE FOR LAKE SEDIMENTS; INFERENCES FROM THE DANUBE DELTA AND THE RAZIM - SINOIE LAGOONAL COMPLEX (ROMANIA).
- Authors
Rădan, Sorin - Corneliu; Radan, Silviu
- Abstract
The magnetic susceptibility (MS) research carried out in Romania, since 1977, on thousands of bottom sediment samples collected from various environments of the Danube River - Danube Delta - Black Sea geosystem, have demonstrated that the MS (k) values mainly reflect the lithological variations of the deposits. On the other hand, the results have shown that the k values can reveal the metallic contamination levels in the finer sediments; the most important of these are clearly evidenced by high magnetic susceptibilities. Taking into consideration the noticeable connections between the MS values and the lithological characteristics of the bottom sediment samples, a data sorting based on several susceptibility classes was quite feasible. It must be emphasized that for the Danube Delta and the Razim - Sinoie Lagoonal Complex (RSLC) area, more than 2000 k values have been measured and analysed. Five MS (k) categories related to certain lithological types of bottom sediments have been identified, the last one (Vth class) being subdivided into 4 sub-classes: Va, Vb, Vc and Vd. They subsequently became "magnetic susceptibility classes". The version in use of the scale extends between k values lower than 10x10-6 SI u. (negative values included) and k values higher than 1000x10-6 SI u. The lower classes (i.e. I and II) correspond to the fine sediments, usually rich in organic material and/or carbonates, the intermediate class III is characteristic for the fine clayey up to silty sediments, and the higher classes (i.e. IV and V) are commonly recorded for the coarser silts and sands. A series of examples are given in the paper, where the patterns integrate - through the MS classes - all the k values that have been used for the MS characterisation of the bottom sediments in the Danube Delta, its main branches, as well as in the RSLC. A comparative analysis of the percentage weight distribution of the MS values that characterise the sedimentary deposits from the deltaic, fluvial-deltaic and the lagoonal aquatic environments is done. The presented cases exemplify the way the elaborated and experimented "k scale" works. The correlation to the Environment Quality Scale is pointed out. To conclude, the Danube Delta lake sediments provided a high resolution enviromagnetic instrument, a Magnetic Susceptibility Scale with a genuine lithological support.
- Subjects
DANUBE River Delta (Romania &; Ukraine); ROMANIA; MAGNETIC susceptibility; LAKE sediments; MARINE sediments; PETROLOGY; AQUATIC ecology
- Publication
GeoEcoMarina, 2007, Vol 13, Issue 1, p61
- ISSN
1224-6808
- Publication type
Article