Scientific Quarterly Journal of Geosciences

Scientific Quarterly Journal of Geosciences

Active tectonic in west of the Shotori mountain range

Document Type : Original Research Paper

Authors
Peyman Navabpour
Abdollah Saeedi
Mohammad Reza Ghassemi
Tectonic Group of Geological Survey of Iran, Tehran, Iran
Abstract
The Shotori mountain range at northern end of the Nayband active fault is one of the east central Iranian ranges in east of Tabas city and playa. Old alluvial cyclic stream terraces and buried Quaternary fault scarps in western mountain front area, and three kinds of old, braided, and active alluvial fans in Tabas plain are witnesses to mountain neotectonic uplift, westward migration of Quaternary sedimentation, and eastward movement of retrograde erosion along seasonal rivers. Ancient perched caves and qanats in alluvial valley slopes present the speed of deep erosion. Outcropped Neogene anticlines, old erosional terraces, meandring antecedent river gorges, and warping of the old fans in Tabas plain all point to periodic active uplift of the plain with respect to the playa. Geomorphic indices, such as knickpoints in longitudinal river profile, valley width/height ratio, and mountain front sinuosity show that the active tectonic movements are due to the Quaternary faults in the Tabas plain and along northern and southern parts of the mountain front, but the middle front seems to be inactive in the present time. Meanwhile, the 1978 earthquake of Tabas (Ms=7.3) after an ll-century seismic gap is a proof to the active westward migration of the deformational front. In this way, the close relationships between the tectonic geomorphology of the area and the seismotectonics of the recent earthquake led us to introducing relic, inactive, active, and new-born mountain fronts in the area; and the role of such studies in better understanding of activity and seismicity history of regions is emphasized.
Keywords
Active tectonics
Quaternary Geology
Geomorphic Indices
Tabas
Shotori Mountain Range
Iran

Subjects

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Scientific Quarterly Journal of Geosciences
Volume 13, 49-50
Autumn & Winter 2004, Vol. 13, No. 49-50
Winter 2004
Pages 2-13