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| Titel |
Faulted and eroded gravel deposit in western Hungary |
| VerfasserIn |
Gábor Kovács, Tamás Telbisz, Balázs Székely |
| Konferenz |
EGU General Assembly 2010
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 12 (2010) |
| Datensatznummer |
250031904
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| Zusammenfassung |
| During the Pleistocene, rivers of the Eastern Alps drained more water into the Pannonian
Basin as in recent times. The excess discharge, due to the meltwater of glaciers, transported
detrital material from the periglacial areas that built low-relief gravel deposits up in the
transitional regions. Today most of these separated gravel plains highly dissected by the
frequent, N–S stream network developed in the post-Pleistocene times. Exceptions can also
be found, where flat plains form slightly tilted blocks, bordered by W–E steep scarps. Owing
to these scarps, streams are unable to incise as deep as in other aforementioned
areas, thus these flat plains are expected to represent the nearly intact, Pleistocene
paleosurface.
The study area in Western Hungary is bordered by Raba (Raab), Lapincs (Lafnitz)
and Repce (Rabnitz) rivers, and include two parts of the uplifting outcrops of the
Penninic nappe: Koszeg and Vas mountains. The area can be divided to 3 different
sections:
West from the Gyongyos stream almost totally flat area can be found, bordered
by steep scarps followed by Repce river on North
the area between Pinka and Gyongyos streams seems to be tilted blocks, divided
by the W–E steep scarps
the westernmost domain of the study area (in Austria) is characterized by a
highly incised valley network.
Concerning the first mentioned section, suddenly left-turning streams imply neotectonic
movements. The changes of sinuosity of those streams on this area also suggest differential
uplift or subsidence.
Previous studies, using borehole data, proved the neotectonic origin of the most
significant scarp on the second section. W–E lineaments shown by streams frequently turn
into that almost perpendicular secondary main direction, what is often controlled
by steep scarps. Unfortunately this assumption can be verified only a partly by
borehole data in the area of the lignite occurrence where a dense borehole network
exists.
In this paper we assume that previously described neotectonic influences also occur on
the third section. To verify this, a DTM-based study was performed. Since the dissected area
can be divided into almost homogeneous swaths parallel to the general slope, the statistical
analysis of these swaths may reveal internal dependencies. Therefore swath-analyses were
carried out in order to collect elevation data from a previously defined rectangular swaths.
The three dimensional data set was processed to get maximum, minimum, mean and median
of the data. These values were resampled in a previously defined resolution and represented
by the distance from the beginning line of the swath. Thus, if the highly eroded original
paleosurface is still present on the ridges, the large-scale changes of the general slope can be
seen.
Finally the investigation resulted in unexpectedly revealed changes of the general
morphology that correspond to the geological structure and the results of the investigations
about neighboring sections. This observation makes it very likely that the aforementioned
geomorphic features are related to neotectonic features or they are even currently by recent
tectonic activity. |
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