GEOLOGY OF THE AREA OF A PART OF THE GARHWAL SYNCLINE AROUND NATHUKHAL VILLAGE, DISTRICT PAURI GARHWAL, U. P.

Abstract

LOCATION : The area investigated lies between latitudes 30450' and 30055' and longitude 78°25' and 78°30'. This area 1s around village Nathukhal (Lat.3053'I?, Long2 26'sk) in Lensdowne subdivision of Pauri district, Uttar Pradesh and forms a part of Survey of India toposheet No. 53 K/5• The village Nathukhal is about 50 km northwest of Kotdwara, the railway terminus at the foothill. 1.2 ACCESSIBILITY : The nearest rail terminus is Kotdwara on the Northern Railway Branch line from Najibabad. An all weather road connects Kotdwara to Dugadda. Dugadda is a small town situated near the bifercation of Kotdwara - Lansdowne and Kotdwara-Pauri routes, and at the confluence of two rivers namely Khoh and Bhairaun. A partly metalled road (first 6 kms only) connects Dugadda to Paukhal in a general northwesterly direction and thence to Kandi through Nali Badoli. This road is a fair weathered. The village Paukhal is the nearest place for the access to the area investigated. Nathukhal village is connec-ted to Nali Badoli by a mule road. I 1.3 CLIMATE : Like other areas of Garhwal Himalaya, extreme climate prevails in the area. The winter is very cold with the minimum temperature reaching subzdro, during the month of December and January. The maximum temperature rises in the range of 250_350 C during the summer months of May and June. The rainy season starts by the end of June but becomes severe only in the months of September and October. The average rainfall ranges between 150 ems and 200 ems per year. 1.4 TOPOGRAPHY : The area is marked by rugged to-Pography, characterised by deep valleys and high hills dissected by streams. The highest point in the area is 1723 metres near the village Chuna Maheda. The second highest point is 1550 metres near the village Simla with a number of other smaller peaki.~in the region. The whole area is dissected by a network of streams. The Siwalik hills in the southern part of the area are parti-cularly rugged with shape peaks. 1.5 DRAINAGE : The major valleys are those of the perennial rivers. There are two main rivers flowing through the area, Malin river and Rawasan river. The Rawesan River flows roughly from northwest to southwest and the Malin River flows from east to west then changes its direction to south east for I'5 kms and thence flows in a general southerly direction. Other small streams both perennial and ephemeral form the other component of the drainage features. These streams give rise- to partly Pinnate and partly rectangular drainage pattern. 1.6 GEOMORPHOLOGY : Erosion by the streams has resulted in a rugged network of V-shape valleys. Besides, the prominent erosive agent, the running water, the lithology, climate, vegetation etc. also control the geomorphology of the area. The softer sandstone and mudstone give rise to an intricate network of smaller stream of varying dimension. The geological structure of the area too, has contri-buted to the way the morphology has been carved out. The exi-stance of some of the nallahs is owing to the occurrence of faults and thrust in the area under investigation. 1.7 VEGETATION A major part of they area is covered by dense vegetation which forms a part of the Mungaon reserve forest. A number of species of trees are found in the investigated area. Some of the most common are listed below : 11 v Common Name Mango Ber Amla Semal Bahera Gular Mahua Saihnuna Tun Pipel Bargad Banj Bans Sal Specific names Magnif era indica Zizyphus fur i uba Phyllan thusemlica Bombex melabericum Thrminalia balarica Eicus glomerate Bassialat folia Morin petr_ygosperma Calrela toona Bicus religiosa Ficus bengaensis Ohrcus incana Bendro calamus gj anteus Shorea robersta The vegetation type varies with the nature of soil which again depends upon the underlying lithology. The sand-stones and quartzites give rise to somewhat coarse grained soil, over which Banj and Sal trees are typically seen to grow. Such coarse soils are also usually covered by dense scrub. The higher reaches of the environs of Malin river are generally covered by thick forest of sal trees. In a transverse along the mule track between Kimsera and the Chaundli Sot - v Malin river confluence, it was noted that dense forests were confined to the mudstone member, while quartzites had very sparse distribution of trees. 1 . WILD LIFE : The thick jungle provides an ideal thriving ground for a great number of animals and birds. The area is dangerous because of the presence of ferocious animals like bear, leopard, and jungle cats (locally known as 'Kukribagh) etc. 1 .9 SCOPE OF THE PRESENT 's1ORK AND METHOD OF TREATMEIU : The Department of Geology and Geophysics, Universtiy of Roorkee, has undertaken the work of detailed geological mapping in part of Garhwal Himalaya.' A number of M.Tech. dissertations have already been submitted during the past thirteen years or so. This work forms a part of the over-all approach of the Department to continue detailed investiga-tions of the Garhwal Himalaya. The Lansedowne syncline has attracted grdater attention of this department particularly since 1970-71 when R. C. Arora, M. Tech. student, discovered the first marine fossils from a mudstone unit southeast of Duggada. The specimen was an Aviculopecten and some fenestellids. Systematic mapping has since been undertaken by a number of students, both in the northern and southern limb of the 5d syncline. Some parts of the syncline have also been mapped by the teachers of the department and by Prof. J. A. Talent during his earlier visits to the area. The present work is an attempt to complete part of southern limb. METHODS OP TREATMENT : The field work was carried out in two short field trips during the month of October. 1977, and June 1977. The mapping has been done on enlargements of a part of Survey of India toposhecat No. 53 K/5. The scale of mapping was approxi-mately 4 ems to 1 km. It was endeavoured to map the various formations accurately within the limited time, but due to extensive forests, cultivated fields, dense vegetation, inaccessibility of certain parts and inhospitability of the terrain, the area could not be mapped very satisfactorily. Mostly the river valleys, stream cuttings, bridle paths were followed. The work was further hampdred in view of the prolonged periods of illness of the investigator. The following traverses were selected so as to give a representative section, both along and across the strike. 1. Along Malin river from Mimsera to Kyark 2. Along the mule track from Kimsera to confluence 4W Chaundli Sot with Malin river. 3. A3 ong the fair weather road from Nali to Nathukhal and further. 4. Along Rawasan river from Haldun to Pudiyana 5. Along Thal nadi About 180 rock samples were systematically collected from various lithological units. The laboratory study includes the petrographic study of 35 thin sections. The poles of the bedding planes and joints were plotted on the schmidt's equal area net for a proper understanding of the area. 1.10 PREVIOUS W4RIB : The area under investigation forms a part of the Garhwal Himalaya which in turn forms a part of lesser Himalaya. A number of Geologists have been investigating the lesser Himalaya through ages but published account is as yet very limited and some of the areas have yet remained unexplored. Medlicott (1864) was the first to give the geological account of the area east of Ganga river. He recognised a series of sedimentary formations in the `.Pal valley which he named as Tal series. He also had reported Pre-Tertiary organic remains in the Tal beds near their contact with Nummulitie. Oldham (1884) carried out geological mapping on 1" = 4 miles scale and published a note on the "Geology of the Ganga Sulan Parogona of British Garhwal ".