QUATERNARY DEPOSITS, CYCLIC SEDIMENTATION AND ASSOCIATED SEDIMENTRY SRUCTURES OF HOMONID LOCALITY HATHNORA DISTRICT SEHORE M.P.INDIA.

The Narmada river orginated at Amarkantak plateau of Satpura Ranges in Rewa at an elevation of about 1057 m (220 40’ -810 45’), it flows westerly course across the middle of Indian subcontinent before entering Gulf of Cambay in the Arabian sea in Gujarat state. The Quaternary landscape of Narmada basin covers an area of about 17950 sq. km starting from west of Jabalpur (23007079 05 30) to east of Harda (220 29’; 760 58’) , and Gurdeshwar and Bharouche section in Gujarat state for a distance of about 1320 km. It is found to be ideal locus of Quaternary sedimentation in Central India as witness by multi-cyclic sequence of Quaternary terraces in the valley The Narmada River course is conspicuously straight and is controlled by ENE_WSW to E_W lineament is bounded by Vindhyan in the north and Satpura in the south. The Narmada valley has maximum length of about 1300 kms and has maximum width of about 32 kms. The Narmada Rift valley formed a linear trench in the middle of Indian subcontinent was an ideal loci for accumulation of sediments The rift trench is intruded by the dolerite and other mafic and siliceous dykes and sills along lineaments in different phases of tectonic deformation. The Quaternary sedimentation incepting from glacial activity, followed by fluvio-glacial, lacustrine and fluvial phase on unstable platform, where the, block faulting and linear displacement and dislocation, uplifting and isolated domal up- lift, Neogene rifting and is conspicuos feature of Quaternary sedimentation. The rift-bound Pliocene–Pleistocene rifting specifically during glacial and fluvio-glacial phase are major component of the Quaternary period and tectonic processes of the Narmada Rift System which form the base of quaternary deposits. A lot of data has been generated on Narmada Valley Quaternary deposits during last 150 years; the different workers have studied the subject separately in the line of their specializations Roy, A.K. (1971), It is seen that there has been very little coordinated approach towards understanding and building up the complet Quaternary Geology sequence of sedimentlogical history of the valley. In the present work an attempt has been made for the first time to study sedimentary structures of quaternary deposits, cyclic sedimentationand environment of deposition of Narmada valley with a objective to build- up and conceive the model of Quaternary sedimentation & tectonics of the Hominid locality Hathnora in Narmada valley. About 32 sections and 9 bore hole logs were studied round Hathnora to study the different sedimentary features to understand the dynamics of sedimentation. The Narmada Valley in the Hathnora area is occupied by thick Quaternary sediments. These sediments are classified based on sedimentary depositional environments, sedimentological characters and correlation with depositional / erosional terraces. The lowermost units (Boulder bed) is or glacio-fluvial origin (Khan el al 1991), whereas the rest of fluvial origin. The top four formations Sohagpur, Shahganj, Hoshangabad and Janwasa are classified based on morphostratigraphic state (NTo-NT3), degree of oxidation, calcification and compaction. Janwasa formation comprises of sediments of active channel deposition and is the older Sohagpur, Shahganj, Hoshangabad formation are related to older flood plains deposits of paleo-do-main of Narmada and are grouped under older alluvium. Boulder conglomerate of fluvio-glacial origin is assigned an independent formational status based on distinct lithology and fossil assemblage. The sequence of Quaternary events and the history of sedimentation of Narmada indicate that the upper top 90 m of the Narmada alluvium was deposited in a single aggradations episode with minor pauses when dissection of the alluvium formed two terraces (NT3-NT2). The sediments of this aggradations episode constitute three lithostratigraphy units viz. Boulder conglomerate, Sohagpur and Shahganj formation. The sediments of the alluvial phase are underlain by a boulder bed of glacio-fluvial origin. Thus, the fossiliferous boulder conglomerate, the basal unit of alluvium marks a disconformity between the lower glacial-boulder layer and upper fluvial sediments. The fossiliferous basal boulder conglomerate is being of middle Pleistocene age (Khan 1992). These deposits display various sedimentry structuresin these deposits with different intensity and frequency in vertial quaternary coloumn gradded bedding,cross bedding, cut &fill features, ripple marks and cross bedding scour features, climbing ripple , cross lamination. The fossiliferous basal boulder conglomerate is being of middle Pleistocene age (Khan 1992) in the Hathnora section it displays cross bedding, cross lamination, gradded lamination scour features and cut and fill features. The statistical parameters,heavy mineral study,paleosole, quartz grrain analysis indicate three mejor breaks in vertical stratigrphic column between 00.00 to 260 m below the ground level indicate that the sediments consist of three domains viz. glacial, fluvio-glacial and fluvial. Khan( 2015) Khan (2014-15).The study of these concealed sediments, their sedimentary environments and sedimentation and correlation both in vertical and horizontal columns indicates that the lower most units, Boulder bed (20 to 260 m. below ground level ) is of glacial origin, where as the fossiliferous bed Boulder conglomerate (260 to 278m. above m.s.l.) is of fluvio-glacial and top four formations in increasing antiquity Sohagpur, Shahganj, Hoshangabad and Janwasa ( 278 to 350m. above m.s.l.) are of fluvial origin and represent the complete sequence of Quaternary sedimentation which comprise of three distinct groups of deposits viz. glacial, fluvio- glacial and fluvial in Central India.Khan (1984) In Sardrpur –Hathnora—Shahganj -Hoshangabad section critical and crucial study of exposed terrace sections of fluvial domain of Narmada revealed that sediments which constitute various lithouints are characterized by association of distinct and diagnostic rock fabrics clay and silt matrix. The units further constitutes a thick sequence of quaternary strata comprises of thick of boulder, cobble, pebbles of quartzite, gneiss, granite, schist, phyllite, slate, basalt limestone sandstone augate chert and chalcedony in different proportion assemblage. These rock clastics range in size from >64 and < 256 mm and constitute horizontally bedded disposed units of variable thickness depicting various sedimentary structures. Each unit is characterized by specific size association of rock fabric/sediments, and rock composition sedimentary structures and other diagnostic sediment characters, categorizing distinct regime of deposition of that specific unit of specific energy level. The successive repetition of units of allied characters is quite frequent in terrace sections. The repetition of each unit marks the completion of single cycle and represents particular phase of energy condition of the channel under which the sediments were deposited. On the basis of study of about 27 scarp sections around Hathnora Sardarpur, Nathanhkeri, Shahgunj, Hoshangabad in the different fluvial terraces (NT1 to NT3) of Narmada nine types of cycles are identified (Khan (1984), Khan et.al (1985) and Khan et al 1981). These cycles have been classified as main cycles and sub-cycles which suggest cyclic sedimentation in Narmada valley.