Journal of Geological Society of India (Online archive from Vol 1 to Vol 78)

K. S. Valdiya ¹, G. Raja Gopalan ², A. C. Nanda ³, G. C. Suresh ¹, T. Upendra ⁴

Affiliations
1 Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore - 560 064, IN
2 Birbal Sahni Institute of Palaeobotany, Lucknow - 226 007, IN
3 Wadia Institute of Himalayan Geology, Dehradun - 248 001, IN
4 Government Science College, Chikamagalur - 577 101, IN

Abstract

Neotectonic reactivation of an ancient shear zone as active faults in the upper catchment of the Hemavati River caused ponding of a petty stream, resulting in the formation of a more than 10 km long take. Carbonaceous clay and mud characterized by abundant calcareous concretions including rhizocretions represent the lake that originated nearly 14 ka ago and dried up about 1300 yr B.P. In the upper 2-m sequence of the lake sediments were found remains of vertebrate animals which lived near the swamp in the terrain experiencing conditions of increasing dryness in the environment. The fragmentary nature of the fossils does not allow generic identification of the animals belonging to the Family Bovidae.

Keywords

Palaeolake, Active Faults, Bovid Fossils, Late Pleistocene to Holocene.

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A. C. Nanda ¹

Affiliations
1 Wadia Institute of Himalayan Geology, 15, Municipal Road, Dehra Dun 248001., IN

Abstract

The paper gives the first detailed morphological description of a partial mandibular ramus of Camelus sivalensis Falconer and Cautley from the Tatrot Formation of the Siwalik Hills of Ambala district and discusses in brief its stratigraphic occurrence.

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A. Ranga Rao ¹, R. P. Agarwal ¹, U. N. Sharma ¹, M. S. Bhalla ², A. C. Nanda ³

Affiliations
1 Oil and Natural Gas Commission, Dehradun, IN
2 National Geophysical Research Institute, Hyderabad, IN
3 Wadia Institute of Himalayan Geology, Dehradun, IN

Abstract

Magnetic polarity stratigraphy of Upper Siwalik Subgroup, Jammu Hills was worked out based on partially demagnetized data from 208 sites in three sections: Parmandal-Utterbeni, Nagrota-Jammu and Balli. One/two bentonitized tuff horizons occur close to the base of a long reversed polarity zone associated with Pinjor age fossils. Fisson track dates of 2.8±0.56 m.y. and 2.31±0.54 m.y. have been obtained on the zircon phenocrysts from these tuffs. These data permit correlation of our magnetic stratigraphy with the standard magnetic polarity time scale. The longest sampled section spans the interval from 4.92 to 0.22 m.y. This dating places the lower part of Upper Siwalik in the early Pliocene.

In the sampled parts of the sections, the magnetic polarity zonation establishes 16 magnetozones in Parmandal-Utterbeni, 13 in Nagrota and one in Balli. Individual magnetic transitions can be correlated over a lateral distance of 62 km and these provide time lines for correlation of lithology from one section to the other.

Estimated rates of sedimentation indicate rates varying from 0-45 m to 0.71 m/l000 years for Gilbert and Gauss epochs, while a decreased rate varying from 0.21 m to 0.37 m/l000 years is indicated during the Matuyama epoch.

The ]ast folding event of Suruin-Mastgarh anticline is not older than 0.22 m.y. However, the decrease in the rate of sedimentation during post Gauss time could possibly be due to an earlier period of deformation.

A significant change in fauna near the Gauss-Matuyama boundary is observed by the appearance of Equus and cervids with antlers and by the absence of Hipparion. We correlate this boundary with the Tatrot-Pinjor faunal boundary, No change either in lithology or in the vertebrate fauna is observed at the Pliocene-Pleistocene boundary if it is to be placed at the top of the Olduvai Normal Subchron.

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Rohtash Kumar ¹, A. C. Nanda ¹

Affiliations
1 Wadia Institute of Himalayan Geology, 33, General Mahadev Singh Road, Dehra Dun-248001, IN

Abstract

The Middle Siwalik Subgroup of Mohand area (1800 m thick) is divided into three units: (1) sandstone-mudstone interval (340 m), (2) thickly bedded multi storied sandstone (1060 m), and (3) conglomerate-sandstone-mudstone interval (400 m). Three major facies are recognised, namely: conglomerate, sandstone, and mudstone facies. Sandstone is the dominant litho-facies and displays frequent erosional surfaces along which mud-clasts are present. The common sedimentary structure is trough and planar cross-stratification. 

Palaeo-flow measurements of trough cross-stratification show prominent modes in SE and NW directions. However, planar cross-stratification shows a high order of deviation in mean vector azimuth from trough cross-stratification. The fining-up in grain-size from erosional surface (Se facies) to mudstone (Fm facies) through trough and planar cross-stratified sandstone (St-Sp facies) and ripple drift laminated sandstone (Sr facies) has been recognised.

The mudstone intervals are almost negligible, while mud-clasts and suspension load in the sandstone (channel facies) are high (to to 25%). The absence of mudstone unit in multi storied sandstone complex may be attributed to the extensive and frequent avulsion on the large braided alluvial fan. This study reveals that sedimentation pattern of multi storied complex is similar to that of modern radial fan of Kosi river.

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D. Sati ¹, A. C. Nanda ¹, G. S. Mehra ¹

Affiliations
1 Wadia Institute of Himalayan Geology, Dehra Dun-248 001, IN

Abstract

Unconformably resting over the Ladakh magmatic arc complex, the molassic sediments (Ladakh molasse) have been thrust over mainly by Dras and Indus formations within the Indus-Suture Zone of Ladakh Himalaya. The convergence between the Indian plate and Tibetan microplate initially produced NW-SE trending cylindrical folds, but the continued NE-SW compression ultimately led to the collision between the two plates and resulted in northeast translated thrusting in molassic sequence. Indentation of Indian plate around the northwest corner during collision led to the accumulation of high compressive strain in the plate boundary i.e. along the Indus Suture Zone. This strain not only caused the intervening material to get escaped laterally eastwards in this zone but also activated the various NW-SE trending thrusts with simultaneous dextral strike slip movement. The latter movement produced many N-S oriented secondary fractures (faults) in the crystalline arc complex and subsequently forced them to undergo strike slip activation. In this manner the blocks formed by these two sets of faults were rotated dextrally together with overlying folded molassic sediments.

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A. C. Nanda ¹, R. K. Sehgal ¹

Affiliations
1 Wadia Institute of Himalayan Geology, Dehra Dun 248001, IN

Abstract

Recent collections of mammalian fossils from the Siwalik sediments of Ramnagar (J.& K.) and Nurpur (Kangra, H. P.) indicate the presence of Chinji Fauna in the red bed sequence exposed in the vicinity of Ramnagar, but in Nurpur despite the dominance of the red clays which are usually considered as characteristic for the Lower Siwalik Subgroup, the fauna indicates an age equivalent to the Middle Siwalik. The mammalian fossils collected by the earlier workers are reinterpreted and the fossils, which include Propotamochoerus hysudricus. Merycopolamus dissimilis and Bramatherium megacephalum minus, are found to be indicative of Middle Siwalik age rather than the Lower Siwalik or the Lower-Middle Siwalik transitional age as was considered earlier. Hipparion (includes Hipparion and Cormohipparion) has been recorded by all the workers in Nurpur and now its arrival in India is considered at about 10m.y. The 12.5 m.y. dispersal event of hipparion in the Old World is found missing in the Siwalik Group. Though hipparion has been recorded from the so-called Lower Siwalik sequence of Kalagarh, U. P. but so far it is not recorded from the type section of Chinji in Potwar and in Dang Valley, Nepal. In the present collection, the presence of hipparion along with Dicoryphochocrus vinayaki, Hydaspifherium megacephalum, etc. from Nurpur is indicative of the Middle Siwalik age for the Nurpur Local Fauna. It is inferred that the red clays considered characterisitic of the Lower Siwalik are time transgressive and even the fauna colIected by earlier workers from Haritalyangar (Himachal) and Kalagarh (U.P.) is (at least a part of it) of Middle Siwalik age.

Ramnagar Fauna, recently collected by the authors, is true Chinji Fauna and is characterised by the presence of Dicoryphochoerus haydeni, Conohyus chinjiensis, Anthracotherium punjabiense, Dorcabune anthracotherioides, Hemimeryx pusillus, Giraffa priscilla etc. In Ramnagar area the Lower Siwalik Subgroup and the underlying Murree Formation have a conformable contact and fauna collected at the base of the Lower Siwalik Subgroup is found to be of Chinji age. So there are all possibilities that upper part of the Murree Formation may be of Kamlial age (i.e., lower part of the Lower Siwalik).

Keywords

Red Beds, Hipparion, Mammalian Fauna, Vertebrate Paleontology, Siwaliks, Jammu & Kashmir, Himachal Pradesh.

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J. S. Guleria ¹, Rashmi Srivastava ¹, A. C. Nanda ², R. K. Sehgal ²

Affiliations
1 Birbal Sahni Institute of Palaeobotany, 53 University Road, Lucknow - 226 007, IN
2 Wadia Institute of Himalayan Geology, 33, General Mahadeo Singh Road, Dehra Dun - 248 001, IN

Abstract

The paper reports the occurrence of a fossil wood of Terminalia for the first time from the Lower Siwalik Subgroup of Panchkula, Haryana along with a fossil Dipterocarpus wood from further east in the Middle Siwalik Subgroup, exposed south of Dehra Dun, Uttaranchal. These woods indicate the prevalence of moist conditions and existence of tropical lowland vegetation in the western part of Himalayan Foot-Hills till the Middle Siwalik.

Keywords

Fossil Woods, Xylotomy, Lower Siwalik (Middl Meiocene), Middle Siwalik, (Upper Miocene), Palaeoclimate, Phytogeography, Haryana, Uttaranchal.

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R. K. Sehgal ¹, A. C. Nanda ¹

Affiliations
1 Wadia Institute of Himalayan Geology, Dehra Dun - 248 001, Uttaranchal, IN

Abstract

The faunal assemblages from the red bed successions exposed at Ramnagar (J.&K.) and Nurpur (H. P.) have been used to reconstruct the palaeoenvironment and palaeoecology of the two areas. The two assemblages are of different ages. The succession at Ramnagar is equivalent to the Chinji Formation (Astarcian) of the Lower Siwalik Subgroup, whereas the Nurpur succession represents the Middle Siwalik Subgroup (Turolian). Red mudstones are dominant in both areas and indicate deposition in a meandering fluvial regime with broad flood plains, but in Nurpur, occasional high energy conditions also existed, as suggested by the presence of multistoried sandstone bodies.

The faunal assemblages of the Ramnagar and Nurpur areas comprise aquatic and semi-aquatic, arboreal and terrestrial communities. The terrestrial community, represented by mammals, is the most dominant in both areas. In the Ramnagar assemblage, suids, tragulids, bovids and giraffids are better represented and point towards a tropical humid environment with prominent swampy conditions. In Nurpur assemblage, besides suids, tragulids and bovids, hipparionines and large giraffids are common. This suggests reduction of tropical rain forests and development of wide and open grasslands separated by tree canopy forests. The habitat characteristics of the various taxa have been discussed to work out the palaeoecology of the two areas.

Keywords

Siwalik Group, Faunal Assemblage, Palaeoenvironment, Palaeoecology, Ramnagar, Nurpur, Himalaya.

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