Digital, image processing of Landsat MSS data for identified, geomorphic, litho logical and structural, features in P.I.Shiresh Satpuli area of Garhwal Himalaya, India
Sayed Ahmad Ali, Liagat A.K. Rao
Department of Geology, Aligarh Muslim University,
Aligarh 202002
Abstract
Landsat MSS data is digitally enhanced through VAX 11/180 computer system using VIPS-32, software with a view to select appropriate band combination and spatial filtering functions for delineating certain geomorphic, litho logical and structural features. Among the various enhancement technique of digital image processing it has been observed that the band in his 4/5, 5/1 and 4/1 are useful for delineating broad litho logical, structural elements, flood pains, pediment zone with alluvial fans and perennial streams. FCC of brightness index shows that it is good for drainage studies. The principal component analysis, PC
1 and PC
3 are good for interpretation of regional structure whereas PC
2 proved good for geomorphic studies. It has also been observed that the directional filtering using SOBEL operators is good for delineating lineaments and good fractures.
Introduction
The present study area which forms a part of sub-Himalaya and Lesser Himalaya is bounded by latitude 29°50' to 30°15' and longitude 79915' to 78°40' E, covering an are of about 1322 sq. km., was selected as tost site for digital image processing. The analysis of the enhanced images after applying various functions were carried out by visual interpretation method using tonal and textural contrast. An attempt has been made to delineate geomorphologic, litho logical and structural features from digitally enhanced images and correlate them with field data.
Geological set up
Geologically, this study area may be divided into three broad zones each of which is separated by a major thrust. The southern part of the area is occupied by siwalik belt, whose fringing zone is occupied recent alluvium. The central portion of the area is occupied by Karol Belt which is separated from the Siwaliks by the Main Boundary thrust, whereas the chail Group belonging to Kumaun Super group is exposed on the north of the area (Fuche and Sinha 978). The two thrusts that separated the three geological untis are Main Boundary Thrust of the Himalaya on the south name and Garhwal thrust on the north. These thrust zones trend more or less in HW-SE direction almost parallel to that of the Himalaya Trend. The two major rivers of this area, viz. the Ganga and Hayar cut across there thrusts by at some places their sources appear to have been affects by these thrusts. A generalized stratigrapchic sequence of different litho units and their litho-characters encountered in teh area are given (after, Kumar and Dhaundiyal, 1979, Gairola 1980) in Table 1 and shown in Fig. 2.
| Formations |
Age |
Characteristic Litho-types |
| Lower Siwalik |
Mid Niocene to
Lr. Pleistocene |
Sandstone with frequent clay bands. |
| Subathu |
Eocene |
Sandstone sahle and argillaceous |
| Tal |
Hid Triassic
to Upper
Cretaceous |
Sandstone, quartsite, pebbly grits, Shale and limestone. |
| Krol |
Mid Permian
to
Lr. Triassic |
Siliceous/Dolomitic Limestone, shale |
| Blaini |
Carboniferous
to
Lr. Permian |
Boulder beds of shale, slate and limestone. |
| Nagthat |
Devonian |
Quartzite, siltstone, slate |
| Chandpur |
Ordovician
to cilurian |
Slat, phyllite with quartzite and quarts schist. |
| Damta |
Precambrian |
Quartizite, slates, siltstone and greywacke |
| ------------------- |
------------ Garhwal |
Thrust --------------------------------- |
| Low grade |
Metamorphics |
Phyllite. Schist, quartzite and quartzite schist. |
