1. Mineralogical study on a landslide in the area of Kulcs, Hungary
Meetings of Young Scientists
Békéscsaba
2013
Mineralogical study on a landslide in the area of Kulcs, Hungary
Beatrix Udvardi1, 2, István Kovács1, Judit Füri1, Péter Kónya1
1 Lithosphere Fluid Research Lab, Department of Petrology and Geochemistry, Eötvös University
2 Geological and Geophysical Institute of Hungary

2. Landslides occurring more often due to the changing pattern of precipitation!

3. Motivation and rationale
What is new and complementary in our approach with respect to previous studies?
-sampling the vicinity of the supposed sliding zone of a major known landslide
-complex analytical investigation (XRD, DTA and FTIR-ATR) of minerals in the vicinity of the sliding zone (previously due to mainly financial reasons and limited time allocation only grain size distribution was determined).
-Is there a mineralogical, geochemical precursor behind the occurrence of landslides or it is only due to the preexisting sedimentary features or both?

4. Study area 50-70 m above the average water level of Danube
Resort area from 1920, densely built since 1960 on the debris
No appropriate drainage and sewage system
After Újvári et al, 2009
Continuously moving area: first notable sliding event in 1977, last one in 2013
Partial rebuilding in 2010

5. Field observations
28/02/2013
04/10/2012
06/05/2012

6. Sampling
Northing
Easting
Boreholes in the upper part of the sliding mass: C9, C10, C11, C11-1 (Farkas, 2011)- sliding zone was found at -8,30 (C mBf) and -3,3 (C9-93 mBf) in the high bluff

7. Results - SedimentologyK4 K3
Rapid changes in the sediment structure, sand bands

8. Results - Mineralogy Minerals (XRD) % montmorillonite 0-32 illite 0-25
muscovite
0-20
kaolinite
0-3
chlorite
5-16
quartz
17-62
K-feldspar
1-3
plagioclase
0-8
calcite
0-43
dolomite
0-30
goethite
0-4
gypsum
0-1
amorphous
0-5
sheet silicates
17-68

9. Results – Mineral distribution vs. depth
Corrected depth according to the theodolite measurements

10. Results - Clay mineral composition (settled samples)
Minerals (XRD) %
montmorillonite
3-65
illite
0-69
Illit/chlorite
0-18
muscovite
0-52
kaolinite
0-15
chlorite
0-40

11. Results - Clay mineral composition in settled samples

12. Results - IR depth profileK3

13. Results - IR depth profileK4

14. Results- Calcite dissociation
ΔT=0; characteristic thermal dissociation peak of well crystallized calcite (at 895°C)
The temperature of calcite with lower crystallinity is lower about °C that of the well crystallized variation (Földvári, 2011 )

15. Summary
Following field observations phase analysis (XRD, DTA and FTIR-ATR) were carried out on samples coming from 6 boreholes (n=46), that was drilled at the toe of a partially cultivated landslide body in Kulcs to reach and samples the sliding zone.
A distinct zone in mineral composition was clearly identified in the following depth range 1,4-2,4 m and 1,2-2,1 m in two boreholes. This zone is under a grey silt horizon, where elevated clay mineral content and low carbonate content was revealed
The preliminary results indicate that underground water flow and its interaction with sediments may play an important role in the formation of clays and dissolution of carbonates which can contribute to the weakening
It seems that mineralogical study of landslides could contribute to the identification of sliding zone
FTIR-ATR may be a useful complementary tool to identify zone in sedimentary succession which may act as weakness zones

16. Thank you for your attention!
Acknowledgement
Tamás Fancsik, József Vatai, Villő Deák, Balázs Füsi, László Koloszár, Viktor Hermann, András Németh, Géza Kutasi, Péter Nagy, Csaba Jerabek, Éva Pálfi, Ferenc Budai (Geological and Geophysical Institute of Hungary)
Csaba Szabó (Eötvös University)
Judith Mihály, Csaba Németh (Hungarian Academy of Sciences)
Lithosphere Fluid Research Lab (LRG)
This study was supported by a Marie Curie International Reintegration Grant (NAMS ) (IK)
Thank you for your attention!

17. Field observation
09/10/2012
28/02/2013

18. Landslides along Danube loess bluff
Mass movements has appeared on the high bank of Danube since the Roman times
Objective: observe slip zone in the river bank through sediment structure and mineral composition to distinguish discontinuities in the area of Kulcs
water level of the Danube
20-80 m thick loess underlaid by Pliocene-Pannonian clay, silt and sand
previous mass movements
slope gradient
High precipitation events
groundwater level
Slip surface/zone formation induced by:
After Újvári et al, 2009
Causes
+steeping the slope (due to construction, addition of high mass material on a slope (buildings), no drainage, broken pipes
After Karácsonyi & Scheuer, 1972

19. Stabilization of landslide areas
Create a free outflow to collect groundwater behind the soil volume fallen down – well system
Deep long drainage system into the permeable soil layer
Reconstruction of the original soil surface
Remove the slipped soil volume
Soil anchor system
Vegetation
Szemesy, I. 2011