Document Type : Original Research Paper
Geological Survey of Iran, Tehran, Iran
Folded and faulted Kopeh Dagh-Binalud belt in the northeast of Iran is a part of Eurasia and southern margin of Touran plate. What is now observed is the result of the latest Phase of Alpine folding. The morphology of the area is in early stage and its young folds express direct relevance between topography and geological structures. In order to evaluate uplift and distribution of compressional forces, stream- gradient (SL) and hypsometric (HI) analyses were carried out for 85 subbasins and 98 rivers of the major basins of the area (Atrakrud, Kashafrud, Jajarm, Gorganrud and Tourkamanestan plain rivers). Integration of the morphometric maps of SL and HI illustrates clearly the tectonic anomalies. Five highly uplifted morphotectonic zones were identified based on the morphotectonic indices as follows:
1) The middle part of Ashkabad Fault between geographical coordinates of: 56 47 E, 38 35 N to 57 34 E, 37 56N.
2) Gorganrud's sub-basins particularly located between Shavard fault (in the south) and eastern part of the Khazar fault (in the north).
3) Basins associated with Nokhandan, Qareh –Dagh, Sorkhdeh and Amrudak Faults.
4) Basins associated with Shogan and Gelli Faults are the Jajarm subbasins.
5) The northern foothill basins of BinaludMountain, compared with the southern foothill basins, show remarkable higher uplifting and shortening which seem to be related to the Binaloud and North Neyshabur fault.
In addition to high uplifted zones, some intermediate – low uplifted zones such as west - southwest part of Sarakhs, southern foothill subbasins of Atrakrud (associated with Takalkuh Fault and Ashkhaneh fault zone), Jajarm's subbasin in the eastern part of AladaghMountain were recognized.