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Himalayan Geology, Vol. 31
(2), 2010, pp. 83-95, Printed in India
DAVOD POREH
Tu Freiberg; Freiberg (09599); Germany; Agricolla Str.14-No1702A;
Email:
d.poreh@gmail.com
Abstract: Because drainage networks respond rapidly to tectonic
changes, fluvial geomorphological patterns have the potential to elucidate
the effects of active faulting and folding in the Zagros tectonic belt of
western and southwestern Iran. This paper focuses on utilizing drainage
patterns extracted from SRTM (Shuttle Radar Topography Mission) and SPOT 4
(Satellite Pour l’Observation de la Terre) data along with fractal and river
profile analysis to constrain the tectonic behavior of the Zagros region. We
digitized the drainage networks of entire Zagros Mountains in 1:250,000
scale in the GIS environment and also extracted the drainage network from
DEMs (based on D8 and MFD methods) and analyzed rivers using the stream
power-law scaling.
Lithologic control on river-profile forms is reflected by steepness,
concavity, and knickpoints in a number of longitudinal profiles. Knickpoints
are identified using elevation distance plots. Steepness and concavity are
identified using slope-area log-log plots. Sedimentary rocks are the
principal rocks types underlying the Zagros area (between 26° and 35°N)
where bedrock and mixed bedrock–alluvial channels occur. The highest
concavity measured is (q=
2.90); it is commonly at
q=
0.30-0.50. We observe no systematic relationship between steepness indices
and concavity in the study area.
Fractal analysis (box counting method) executed in the Zagros area to
measure the fractal dimension of streams. The highest calculated fractal
dimension (D) is 1.18 and the lowest fractal dimension is 1.02. We are led
to conclude that channel profiles along the study area reflect a lot of
information about the uplifting, fault activities, and folds evolutions.
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