International Journal of Geology, Earth & Environmental Sciences ISSN: 2277-2081 (Online) An Open Access, Online International Journal Available at http://www.cibtech.org/jgee.htm 2016 Vol. 6 (1) January-April, pp. 54-65/Ahmed and Rao. Research Article MORPHOTECTONIC STUDIES OF THE TUIRINI DRAINAGE BASIN: A REMOTE SENSING AND GEOGRAPHIC INFORMATION SYSTEM PERSPECTIVE *Fuzal Ahmed and K. Srinivasa Rao Department of Geology, School of Earth Sciences and Natural Resources Management, Mizoram University, Aizawl – 796004, Mizoram, India *Author for Correspondence ABSTRACT Morphotectonic indices have been proven to be useful tools in evaluating the degree and nature of tectonic activity in a specific area, and are commonly used to identify areas affected by recent tectonic deformation. Remote sensing and GIS techniques are considered to be suitable for identifying and quantifying the effects of neotectonic activity over a large area. The analysis has been carried out by using remote sensing and GIS tools in order to understand the ongoing tectonic changes of the terrain in response to neotectonic activities. The study area exhibits complex topography as a result of folding and faulting of sedimentary sequences, and the drainage system is controlled by underlying lithology and geological structures. The basin is elongated in shape due to the combined effects of thrusting and folding in the area. As a whole the terrain is tilted towards the west with asymmetric nature of the basin. The overall results reflect that the Tuirini drainage area is tectonically active in nature. Keywords: Morphotectonic Indices, Neotectonism, GIS, Tuirini River, Mizoram INTRODUCTION The Himalayan mountain belt was evolved during the late Cenozoic deformation caused by convergence collision between the Indian and the Eurasian plates (Molnar and Tapponnier, 1975), which represents one of the youngest and largest foreland belts in the world. The entire northeastern region of India is a part of the Himalayan mountain belt, which is tectonically active zone due to collision between the two arcs, the Himalayan arc in the north and subduction zone along the Indo-Burma arc in the east (Kayal, 1996 & 1998; Molnar and Tapponnier, 1975; Baruah et al., 1967). The state of Mizoram is one of the seven states in the northeast India. The terrain is tectonically active, geologically unstable and hence comprises of younger sedimentary strata. The Tertiary rock sequences are complexly folded and faulted due to neotectonic activities in this region. Tectonically, Mizoram forms a part of the Patkai-Naga-Lushai-Arakan-Yoma fold belt (Nandi et al., 1983) and is generally referred to as the Indo-Burmese fold-thrust belt. The folded belt of Mizoram comprises a repetitive succession of argillaceous and arenaceous strata, which are thrown into a series of approximately N-S trending, sub-parallel, arcuate elongated, doubly plunging folds arranged en-echelon with asymmetric and tight anticlines and broad synclines with a slight convexity towards the west (Ganju, 1975; Ganguly, 1975 & 1983; Shrivastava et al., 1979). These structures are offset by numerous faults and thrusts and comprise Early Miocene and Late Paleocene clastic sediments of Surma Group (Ram and Venkataraman, 1984). Tectonic activity plays an important role in the development of drainage basin morphology. Analysis of a drainage basin in response to the tectonic processes can provide an insight into the past and recent deformational events of the region. Drainage networks are the most active and sensitive elements which can be used as a powerful tool to understand the neotectonic activities of an area. Morphotectonics deals with the landscape morphology that has evolved as a result of past or recent tectonic activity. An analysis of active structures can be done by using morphotectonic indices, which are sensitive to rock resistance, climatic changes and tectonic processes resulting into landscape evolution. The information about tectonic history of an area can be retrieved through analysis of topographic maps, aerial photographs, satellite data and quantification of different morphotectonic indices (Keller, 1986). Remotely sensed data © Copyright 2014 | Centre for Info Bio Technology (CIBTech) 54 International Journal of Geology, Earth & Environmental Sciences ISSN: 2277-2081 (Online) An Open Access, Online International Journal Available at http://www.cibtech.org/jgee.htm 2016 Vol. 6 (1) January-April, pp. 54-65/Ahmed and Rao. Research Article and geographic information system (GIS) techniques are widely applied for the studies of tectonic geomorphology. Recently, geoinformatics has become one of the most widespread advance technology for the analysis of topography and assessment of crustal deformation or movement. Therefore, an attempt has been made to understand the tectonic status of the Tuirini drainage basin through remote sensing and GIS techniques. 92°52'E 92°56'E N 23°51'N 23°51'N Aizawl 23°42'N I N D I A Serchhip 23°42'N M I Z O R A M M I A Z O R S T U D Y A A R E A S T U Y D 23°33'N 23°33'N 0 3 6 Km 92°52'E 92°56'E Figure 1: Location Map of the Study Area Location and Geotectonic Setting of the Study Area The study area falls in two districts of Mizoram viz. Aizawl and Serchhip at longitudes between 92o49΄34΄΄ and 92o58΄22΄΄ and latitudes between 23o28΄37΄΄ and 23o53΄20΄΄ (Figure 1). The basin covers an area of about 420.07 sq.km occupied by structural hills and elevation of the study area varies from 78 m to 1905 m above mean sea level (Figure 3). The drainage basin is bounded on the east by the river Tuivawl and west by the Tuirial river. The study area is drained by Tuirini river which is initially flows towards the north, then turns westward and finally joins the Tuirial river (Figure 2a). The Tuirini drainage system shows well developed drainage networks ranging from the first to six order streams. The climate of the study area is characterised by humid tropical. The area receives an average annual rainfall of about 2300 mm as it is under the direct influence of south-west monsoon. The average maximum and minimum temperatures of the basin area are about 30°C and 10°C, respectively. (a) (b) Tuirini River Tuirial River Figure 2: Field Photograph Showing (a) Junction of Tuirini and Tuirial Rivers; (b) Deposition of large Amount of Sediments (Gravels and Pebbles) along the Tuirini River near Tuirinikai Village © Copyright 2014 | Centre for Info Bio Technology (CIBTech) 55 International Journal of Geology, Earth & Environmental Sciences ISSN: 2277-2081 (Online) An Open Access, Online International Journal Available at http://www.cibtech.org/jgee.htm 2016 Vol. 6 (1) January-April, pp. 54-65/Ahmed and Rao. Research Article 92°48'E 92°52'E 92°56'E 92°48'E 92°52'E 92°56'E ±N ±N 23°51'N 23°51'N 23°51'N 23°51'N 23°42'N 23°42'N 23°42'N 23°42'N Legend Legend Elevation range Fault (meters) Lineament 78 - 400 Anticline 400 - 700 23°33'N 23°33'N 23°33'N 700 - 1000 23°33'N Syncline 1000 - 1300 Sandstone 1300 - 1600 Shale and 0 2 4 8 0 2 4 8 1600 - 1905 Siltstone km km 92°48'E 92°52'E 92°56'E 92°48'E 92°52'E 92°56'E Figure 3: Elevation Map Figure 4: Geological Map As the study area is the part of the Indo-Burma region, hence, the landforms form the part of the active tectonic belt. The basin is structurally very complex, with a number of faults and lineaments (Figure 4). The rocks have been folded into a series of longitudinal en-echelon anticlines and synclines. The anticlines are very tight, asymmetric while the synclines are narrow valleys. Most of the anticlines and synclines are doubly plunging. The main course of the river and its tributaries are controlled by lineaments. Geologically, the basin area is occupied by the Tertiary succession of Surma Group that ranges from the Lower Miocene to Middle Miocene age. The study area comprises of sandstones, shales, siltstones and their various intermixtures in varying proportions, which were deposited in deltaic to shallow marine environment. These sedimentary rocks are subjected to tectonic activities, resulting in the present configuration of topography that is anticlinal hills and synclinal valleys. ' F (a) (b) Terraces Tuirini River (T2) (T1) Sandstone Beds F F Right Bank Figure 5: Field Photograph Showing (a) The Sandstone Beds and Fault (F-F) Controlled River Course in the Lower Part of the River. At Places Sediment Deposits (Valley Fills) are also Observed on Left Bank; (b) Synclinal Valley with River Terraces in the Middle Reaches of the Tuirini River © Copyright 2014 | Centre for Info Bio Technology (CIBTech) 56 International Journal of Geology, Earth & Environmental Sciences ISSN: 2277-2081 (Online) An Open Access, Online International Journal Available at http://www.cibtech.org/jgee.htm 2016 Vol. 6 (1) January-April, pp. 54-65/Ahmed and Rao. Research Article MATERIALS AND METHODS Geocoded Indian Remote Sensing satellite data (IRS -1D, LISS III) was obtained for 055 row and 113 path of 04th February, 2001 with 23.5 m spatial resolution on 1: 50,000 scale and Survey of India (SoI) toposheets (No. 84/A13, 84/A14 and 84/A15) on 1: 50,000 scale have been used for the present study. ASTER Global Digital Elevation Model with 30 m resolution tile number ASTGTM2_N23E092 was also utilized for this study. All the data set were geo referenced with Zone 46 N and WGS - 84 datum of Universal Transverse Mercator (UTM) projection system so that errors can be minimized in spatial analysis. The morphotectonic indices were estimated based on mathematical formulae proposed by Muller (1968), Pike & Wilson (1971), Hack (1973), Bull & McFadden (1977) and Cox (1994).