Analysis of Some Morphotectonic Indices of Shirinrud Subcatchment, Central Kopeh Dagh

Document Type : Research Paper

Authors

Abstract

Geomorphic indices are useful for determining level of tectonic activity which is used for planning research to obtain detailed information about active tectonics. In this paper, in order to evaluate rate of tectonic activity, the drainage basin asymmetry index (AF), stream length-gradient index (SL), ratio of valley floor width to valley height (Vf), transverse topographic system (T), and drainage basin shape (Bs) were calculated. Goal of this research is to separate high activity areas to low activity. For calculating morphometric indices we utilize topographic map & satellite images in GIS & Global mapper. AF index of main basin is 17.20 obtain which is indicating high tilting of this sub-catchment. It seems that folds and trusts parallel to the basin caused such tilting. The results show that the value of AF index in the west and east part of the basin is high. The highest value of SL index is related to the intersection of the conjugate faults and fractures which cut the stream. Computing of Vf for study area shows that almost valleys particular at the north of the basin are V shape and suggest a high rate of incision associated with tectonic uplift. Values of Vf index is high at the areas that SL index increased. High rate erosion of rock is, at the result of, different type of rock's erosion and strike slip faulting. Results of this research show that study area is tectonically active.

Keywords


-بلورچی، محمدحسین، مهر پرتو، محمود. (1365). نقشه 1:250000، سازمان زمین­شناسی ایران.
2-رادفر، شهباز، پورکرمانی، محسن. (1384). ریخت زمین­ساخت گسل کوه­بنان، فصل­نامه­ی علوم زمین، شماره 58، صص 183-166.
3-خادمی، محسن. (1389). محاسبه و تفسیر برخی شاخص­های ریخت­زمین­ساختی پیرامون گسل ترود، جنوب دامغان، فصل­نامه­ علوم زمین، شماره 75، صص 56-47.
4-خاوری، رضوان، منوچهر قرشی، مهران آرین و خسرو تهرانی. (1389). نشانه­های زمین­ریختی زمین‌ساخت فعال حوضه­ رودخانه کرج در دامنه­ی جنوبی البرز مرکزی، شمال ایران، فصل­نامه­ی علوم زمین، شماره 75، صص 74-67.
5-گورابی، ابوالقاسم و احمد نوحه­گر. (1384). شواهد ژئومورفولوژیکی تکتونیک فعال حوضه­ آبخیز درکه، پژوهش جغرافیایی- شماره 60، صص 177-196.
6-وحدتی دانشمند، بهارک؛ محمدرضا قاسمی؛ منوچهر قرشی و نگار حقی‌پور. (1385). نو زمین‌ساخت سپیدرود و دشت گیلان، فصل‌نامه‌ علوم زمین، شماره 65، صص 25-12.
 
7.Afshar Harb, A., Bolourch, M., and Mehrparto, M. 1987. Geological quadrangle map of Iran no. J5 (Bojnurd sheet), scale 1:250,000, Geological Survey of Iran.
8.Alavi, M. 1996. Tectono-stratigraphic synthesis and structural style of the Alborz mountain system in northern Iran. J. Geodyn., 21(1), 1-33.
9.Arisco, G., Arnone, G., Favara, R., Nigro, F., Perricone, M., Renda, P. and Mondello, C. 2006. Integrated geotectonic and morphometric analysis of northern Sicily, Boll. Soc. Geol. It, 125, 1-24.
10.Berberian, M. 1976. Contribution to the Seismo-tectonics of Iran (Part II). Vol., 39, Geological Survey of Iran.
11.Bull, W.B., and Mc Fadden, L.D. 1977. Tectonic geomorphology north and south of the Garlock fault. California: In: Doehring, D.O (eds), Geomorphology in Arid Regions Proceedings of the Eighth Annual Geomorphology Symposium. State University of NewYork, Binghamton, 115-138.
12.Dehbozorgi, M., Pourkermani, M., Arian, M., Matkan, A.A., Motamedi, H., Hosseiniasl, A. 2010. Quantitative analysis of relative tectonic activity in the Sarvestan area, central Zagros, Iran. Geomorphology, 121, 329-341.
13.EL Hamdouni, R., Irigaray, C., Fernandez, T., Chacon, J., and Keller and pinter, E.A. 2008. Assessment of relative active tectonics, southwest border of Sierra Nevada (southern Spain). Geomorphology. Article in press.150-173.
14.Hollingsworth, J., Jackson, J., Walker, R., Gheitanchi, M.R., Bolorchi, MJ. 2006. Strike-slip faulting, rotation, and along-strike elongation in the kopeh dagh mountains, NE Iran. Geophysics. J. Int., 166, 1161-1177.
15.Keller and pinter, Edward, A. and Nicholas, P. 1996. Active tectonic, Earthquickes, Uplift and Landscape. Prentice Hall Publisher. New, Jeresy. Pp 121-174.
16.Ramazani Oomali, R., Shahriari, S., Hafezi Moghaddas, N., Omidi, P., Eftekharnejad, J. 2008. A model for active tectonics in Kope dagh (north-east Iran).World applied Sciences Journal, 3(2): 312-316.
17.Ramirwz-Herrera, M.A. 1998. Geomorphic assessment of Active tectonics in the Acambay Garben, Mexican volcanic belt. Earth surface process landforms, 23: 317-332.
18.Stepancikova P., Stemberk J., Vilimek V. and Kostak B. 2008. Neotectonic development of drainage networks in the East Sudeten Mountains and monitoring of recent fault displacements (Czech Republic). Geomorphology 102, 68–80.
19. Stocklin, J. 1974. Possible ancient continental margins in Iran, in Geology of Continental Margins., eds Burke, C. & Drake, C., Springer- Verlag, New York. 873-877.
20.Verrior, S., Zygouri, V., Kokkalas, S. 2004. Morphotectonic analysis in the Eliki fault zone (Gulf of Corinth, Greece). Department of Geology, University of Patras, 1706-1714.