bluuebunny/crossref_metadata_2025 huggingface dataset:
Entertaining a Great Earthquake in Western Nepal: Historic Inactivity and Geodetic Test for the Development of Strain
Authors: Bilham Roger , Bodin Paul , Jackson Michael
Published: April 2021

A 500-800 km long segment of the Himalaya bordered by the rupture zones of the great Bihar, 1934, and Kangra, 1905, earthquakes has not experienced a great earthquake for at least 200 years, and perhaps for as long as 750 years. The observed rate of occurrence of earthquakes is evidently too low to accommodate lndo/Tibetanslip which must therefore be accommodated by creep or occasional great earthquakes. Creep processes do not appear to be sufficiently fast, at least in central Nepal, where levelling data in the last two decades, and GPS data in the past 3 years, have been interpreted to account for at most 7 mm/year, or 30% of the inferred ≈20 mm/yr convergence signal. The measurement of 19th century geodetic networks in northern India, which have hitherto been neglected, potentially provides an estimate the rate of accumulation of elastic strain in W. Nepal. In view of the possibly disastrous consequences to the many tens of millions inhabitants of northern India and Nepal who would be affected by a great earthquake, an intense effort to explore further the historic record and the geographic limits of historic and future rupture is desirable.
Volatile Alteration and Metamorphic Facies: Release of H2O and CO2 in the Panjal Volcanics of the NW Himalaya
Authors: Spencer David A.
Published: April 2021

Whilst the bulk rock geochemistry of a basalt, subjected to progressively increasing metamorphic grade, may remain on the whole isochemical, it has been long known that volatiles are likely to be released. Three volatiles which should change through an increase in metamorphic grade are H2O, CO2 and O2. The various metamorphic grades of the Panjal Volcanics in the NW Himalayas (unmetamorphosed, greenschist, amphibolite and eclogite facies) provide an ideal opportunity to test these ideas and possibly act as chemical indicators of the prograde metamorphism. Direct and indirect determination of CO2 and H2O were made on numerous samples. Direct determination of CO2 content in a rock sample has been made by coulometric titration for five main groups: Zanskar Tethyan Shelf - Panjal Volcanic basalts (Ba); Lesser Himalaya- Panjal Volcanic basalts (PJ); Higher Himalaya Second Cover - Panjal Volcanic amphibolites (A); Higher Himalaya Second Cover - Panjal Volcanic dolerites (D) and Higher Himalaya Second Cover - Panjal Volcanic eclogites (E). The main observation on the occurrence of % CO2 in the Panjal Volcanics with increasing metamorphic grade is that there is a decrease in CO2 that appears to be fairly gradual. This therefore suggests that with increasing metamorphism, CO2 is being driven off by decarbonation reactions. Estimation of the volatile content in a sample can be made by the simple2weight loss on ignition, and used as a method of indirect determination of H2O. The loss on ignition (L.O.I.) and the H2O (+ FeO) in the Panjal Volcanics show that with an increase in metamorphic grade there is a decrease in the L.O.I. and H2O (+ FeO) content. This therefore suggests that with increasing metamorphism, volatiles are being removed by dehydration reactions. Comparison of the results of this work with the results of some published theoretical calculations are made for the wt. % H2O of a subducting, and therefore dehydrating, oceanic crust or tholeiitic basalt. Here, predictions were made by combining calculated pressure - temperature paths with a model of metabasalt phase equilibria, where a progression (for the upper parts of the oceanic crust) pass through greenschist to amphibolite to eclogite facies. The agreement between these two independently produced sets of data is clearly apparent.
Quartz C-axis fabric along Main Central Thrust (MCT), Garhwal Himalaya, India
Authors: Singh V. K.
Published: April 2021

The granite-gneisses are thrust over the less metamorphosed quartzites along the Main Central Thrust (MCT) in Garhwal Himalaya. The quartz C-axes fabrics from the plastically deformed quartzites and granite-gneisses were studied with the help of universal stage in XZ sections. The measurements of quartz C-axes in quartzite exhibit single and cross girdles. The C-axes maxima are located at the peripheries and towards the Y-axis. The quartz C-axes maxima in granite-gneisses are characterised by diffuse cross girdles with unequally populated pattern. The concentration of the quartz C-axes maxima is recorded progressively towards Y-axis.

The single inclined girdles are generally exhibited by the quartz grains due to simple shear. The cross girdle patterns are due to conjugate direction of shear acting simultaneously under the influence of non-coaxial flattening (Bouchez and Pecher, 1981). The fabric of C-axes, commonly encountered in the shear zone are characterised by the maxima forming cross girdles which are asymmetric to the MCT transport direction. The quartz C-axes fabrics in quartzite formed by glide on the basal  and rhomb  systems. The deformation movements were of sinistral type during the formation of the MCT.
Structural and Thermal Evolution of the Siwaliks of Western Nepal
Authors: Mugnier J. L. , Chalaron E. , Mascle G. , Pradier B. , Herail G.
Published: April 2021

The piedmont of the Himalayas is formed in Western Nepal by: a) Siwalik sediments affected by folds, thrust and back­ thrust structures and b) intra-belt basins (Duns) that are dis laced piggyback above the thrust sheets. Vitrinite reflectance values (VRo) are found between 0.3% and 0.5% in Middle Siwalik sediments and between 0.6 and 1% in Lower Siwaliks. The thermal maturity of the organic matter agrees with maximum burial depth (3500 m for Middle Siwaliks and 6000 m for Lower Siwaliks) that do not strongly exceed the stratigraphic thickness of the Siwaliks Group. Intense erosion concomitant with deformation balances closely tectonic thickening and prevent burial of the Siwalik sediments at great depth. Nonetheless, Duns developed above the steeper part of the basal decollement and/or ahead of back-thrusts prevent the exhumation of rock and could lead to greater burial depth.
A note on the Occurrence of Fresh Water Ostracods in the Siwalik Group of Surai Khola Section, Western Nepal
Authors: Khosla S. C. , Upreti B. N. , Corvinus G.
Published: April 2021

The occurrence of fresh water ostracodes-Candona lactea Baird, Cypria ophthalmica (Jurine), Cyprinotus sp., Jlyocypris gibba (Ramdohr),  Limnocythere sp., and  Potamocypris sp- is  recorded  from the Siwalik Group of Surai Khola Section, southeast of Dang in West Nepal.
Active Faults in Southwestern Kathmandu Basin, Central Nepal
Authors: Saijo Kiyoshi , Kimura Kazuo , Dongol Gopal , Komatsubara Taku , Yagi Hiroshi
Published: April 2021

Two active faults running in NW-SE direction are discussed in the southwestern margin of the Kathmandu Basin. The fault morphology is expressed by isolated mounds, scarps, and depressions. The faults dislocate the colluvial slopes and terraces of the late Pleistocene. The Quaternary sediments in the vicinity of the fault zone are tilted. The field evidences suggest the downthrow of the foot wall along the southwestward dipping fault plane. The vertical rate of displacement along the fault exceeds 1.0 mm/yr. The right-lateral slip, which is characteristic of the NW-SE trending faults in the Nepal Himalaya (Nakata 1988), is not recognised in this area.
Khewra Trap: An Unusual Ultrapotassic Rock in the Salt Range of Pakistan
Authors: Jan M. Q. , Faruqi S. H.
Published: April 2021

The classical stratigraphic sequence of the Salt Range contains thin flows of an ultrapotassic rock at its base. Commonly known as Khewra trap, it occurs at the top of the very late Proterozoic to Early Cambrian rocks consisting of marly anhydrite/gypsum, and oil shales overlying evaporites. The trap is an unusual rock consisting of euhedral to skeletal, spinifex, stellate phenocrysts in a very fine-grained to cryptocrystalline, locally glassy, matrix. The phenocrysts (up to 3 cm long) are considered to be Mg-rich enstatite now completely pseudomorphed by a mineral aggregate principally made up of talc with subordinate amounts of Mg-rich clays and, locally, quartz. The matrix is unaltered and almost entirely made up of Na-Ca-poor and Mg-Fe-rich K-Feldspar (sanidine-orthoclase), with granules, specks and dendroids of Fe-Oxide. Talc, Mg-rich clays, quartz, dolomite, and Fe-oxide constitute the amygdules.

Chemical analyses of the rock samples from the trap are remarkably similar in composition except for some variation in iron oxide due, probably, to leaching during alteration. The rocks consist approximately of 60 wt% SiO2, 0.7% TiO2,  11% Al2O3,  2-5% Fe2O3, (total), 0.02% MnO, 10% MgO, 0.4% CaO, 0.5% Na2O, 9% K1O, and 0.04% P2O5. Normatively the rocks are essentially made up of orthoclase and orthopyroxene. The volcanism may be related to Late Proterozoic-Early Paleozoic rifting which also resulted in deposition of the evaporites, however, the major element chemistry casts doubts on such an interpretation. Detailed trace- and rare earth element geochemistry is in progress to throw light on the petrogenesis of these highly unusual rocks.
Influence of Reservoir Load on a Neighbouring Reverse Fault: A Simulation
Authors: Chander R. , Sarkar I.
Published: April 2021

The simulation of reservoir induced seismicity indicates that a finite reservoir situated on the footwall of a reverse fault can induce a tendency towards instability.
The Himalayan Glaciation: Myth and Reality
Authors: Fort Monique
Published: April 2021

The frequency, age and type of glaciation in the Himalayas remain a matter of controversy and uncertainty. In this paper, current knowledge of Quaternary glaciation on both the south and north sides of the Central Nepal Himalayan range is reviewed in the light of recent data dealing with the palaeoclimatic evolution of the Himalaya-Tibet ensemble during the Late Cenozoic. Besides the global climatic factor, the Himalayan glaciation was mostly generated and controlled, in its regional extent, by topographical factors.
Glacier Lake Outburst Floods in Nepal
Authors: Mool P. K.
Published: April 2021

The most active glaciers of Nepal, and adjoining Tibet in China, are located in the eastern part of the region. There are numerous occurrences of glacier lakes in this region. There are evidences that Glacier Lake Outburst Floods (GLOFs) have occurred throughout the Himalaya. However there is no detailed catalogue of the number and location of these past events. Most of the known cases occurred on the major rivers in the Kosi basin. The transport of sediment during GLOFs can be exceptionally high, with suspended sediment concentrations as high as 350,000 mg/l. The vertical and lateral erosion of the stream channel has the potential to destabilise talus slopes, former debris flows and landslides and to initiate new ones.

The impacts of GLOFs downstream are extensive loss of human lives and cattle, loss of infrastructures, destruction of land, and interruption of tourism in mountainous areas. The GLOF on 11 July 1981 from Zhangzanbo Lake destroyed the diversion weir at the Sun Kosi Hydro Project in Nepal. The GLOF on 4 August 1985 from Dig Tsho lake along the Bhote­ (Dudh) Kosi destroyed the nearly completed Namche Small Hyde) Project. Even the very small GLOF of Chubung on 12 July 199 1, destroyed six houses and a long stretch of river banks in Beding village, in the Rolwaling Valley.

Compilation of the inventory of glaciers and glacier lakes using remote sensing technology is the first step in identifying the occurrence of GLOF prone areas. Mitigating the impact of a GLOF surge can be done by reducing the volume of water in the glacier lakes in order to reduce the peak surge discharge. This can be achieved by: controlled breaching; construction of an outlet control structure; pumping out of a lake; and construction of a tunnel through the moraine barrier, or under an ice dam. Preventive measures, such as blasting masses of loose rock and ice, can be applied to ensure against avalanches into lakes.
A Short Note on the Tsergo Ri Landslide, Langtang Himal, Nepal
Authors: Weidinger J. T. , Schramm J. M.
Published: April 2021

The large-scale mass movement at Tsergo-Ri (Langtang valley) in north-central Nepal was mapped in detail and an engineering geological map was prepared. Five different phases of displacement, deposition and erosion of the landslide are reconstructed. The present morphology of the area is largely the result of the above movement.
Terrain Attributes and Drainage Texture as Indicators of Landslide Occurrence in a Part of Garhwal Himalaya, India
Authors: Awasthi A. K. , Tabatabaei S. H. , Singh Bhawani , Mehrotra G. S.
Published: April 2021

Slope movement processes along with other terrain attributes influence surface morphology of an area. Correlation analysis of nineteen morphometric parameters and the landslide areal extent in 26 third order basins in a part of Garhwal region of the Lesser Himalaya, U.P. India, indicates that fraction of landslide area (Ls) in a basin has statistically significant correlation coefficient of about 0.86, 0.84, 0.68 and -0.55 (at 99% confidence level) with drainage texture (DT), stream frequency (SF), drainage density (DD) and basin circularity (BC) respectively. Drainage texture which is the product of stream frequency and drainage density, is one single morphometric parameter in a basin that has in it, the influence of many morphometric parameters which in turn, are reflection of the cumulative effect of elevation, slope, lithology, structural features, vegetation and hydrological condition. Higher the drainage texture, higher is the landslide areal extent. Based on regression analysis, a relationship between fraction of landslide area (Ls) and drainage texture (DT) of third order basin has been worked out which suggests that the third order basins always have some unstable slope faces. With a drainage texture of about 185, almost all the slopes are expected to be unstable. Relatively stable areas are associated with lower values of drainage texture. Circular basins with low relief have lower values of DT and therefore, their slopes are relatively more stable. This identified relationship is found to be useful within the error limit of 25 percent and is, therefore, recommended for use as a first step towards the landslide hazard zonation in similar terrains.
Stratigraphy of the western Nepal Lesser Himalaya: A synthesis
Authors: Upreti B. N.
Published: April 2021

The western Nepal Lesser Himalaya, lying between the Marsyangdi and Bheri Rivers, is generally free from crystalline nappes and exposes the sedimentary and metasedimentary rock sequences in a wide zone between the MBT and the MCT. Geologically, the area is complicated by the presence of a number of folds, thrusts and imbricate zones. Despite the complicated geology, excellent studies have been carried out in recent years on the stratigraphy of this region. However, individual work has been confined in areas separated by wide intervening parts that are not as well studied. Many researchers have proposed different stratigraphic nomenclatures in their respective study areas, and their stratigraphic subdivisions do not always correspond well with each other. Therefore, confusion and uncertainties have remained in the stratigraphic interpretation of the western Nepal Lesser Himalaya. An attempt has been made here to appraise and synthesize the work done so far to bring out a clearer picture of the problems and prospects in the stratigraphic investigations in western Nepal.

For convenience, the stratigraphy of the Lesser Himalayan metasediments the younger group of fossiliferous sedimentary rocks and the Jajarkot Nappe are treated separately. An attempt has been made to extend the stratigraphic nomenclature of the Nawakot Complex of central Nepal established by Stocklin and Bhattarai (1977) and Stocklin (1980) to western Nepal. In spite of the type sections of these rocks in central Nepal and the rocks of western Nepal being separated by a large intervening area, there is a fair consistency in the stratigraphic sequence and rock assemblages in the two areas. The uniformity in the use of nomenclature of rock units will greatly help to build up a more systematic and reliable stratigraphy of Nepal Lesser Himalaya in the future.

The low grade metamorphic and the sedimentary rocks of the Lesser Himalaya are divided into the older Nawakot Unit and the younger Tansen Unit. Only the Tansen Unit is fossiliferous. Whereas the Nawakot Unit is largely of Precambrian age, the Tansen Unit ranges in age from Permo-Carboniferous to Lower Tertiary. The Jajarkot Nappe, tectonically overlying the Lesser Himalayan metasediments, consists of medium grade metamorphic rocks such as garnet bearing schists, feldspathic schists and quartzites. These rocks are succeeded conformably by unmetamorphosed carbonate rocks of possibly Cambro­ Ordovician age and stratigraphically and tectonically comparable to the Phulchauki Group of the Kathmandu Nappe of central Nepal.
The Lower Siwalik - Basement unconformity in the Sub-Himalaya of eastern Nepal and its significance
Authors: Shrestha R. B. , Sharma S. R.
Published: April 2021

South of the Main Boundary Thrust (MBT), in the Sub-Himalaya of central and eastern Nepal, pre­ Siwalik rocks in the form of fault bound slices are known to occur. Recently the present authors have mapped these rocks in the Udayapur district of south eastern Nepal. In the area about 1 km wide pre­ Siwalik rocks extend for over 50 km along a NE-SW direction. In the eastern area around Ttntale village (near the Tawa Khola-Baijanatb Khola confluence), the stromatolitic dolomites of Tintale Formation of the pre-Siwalik Group is overlain by the Lower Siwalik with a prominent unconformity marked by a 4.5 m thick basal conglomerate. Likewise, in the western area along the Manba Khola, the Siwalik Group overlies the pink sandstones and shales of the Manba Formation of the pre-Siwalik Group with an unconformity, again with a conglomerate horizon at the base. It is perhaps the only occurrence where the base of the Siwalik Group is recorded in Nepal. In this part of the Himalaya, the Siwalik sediments directly overlie the Precambrian-Lower Paleozoic (?) basement rocks with an unconformity. The basement rocks along with its Siwalik cover was brought to the surface by thrusting within the Sub-Himalaya.
Stratigraphy and structural framework of the Sub-Himalaya, Bagmati River region, Central Nepal
Authors: Adhikary T. P. , Rimal L. N.
Published: April 2021

The Sub-Himalaya in the Bagmati River region of central Nepal consists of two groups of rocks very different in age and characters. The Bagmati Group, an assemblage of pre-Siwalik rocks are found within the Siwalik Group. The Bagmati Group consists of sedimentary rocks, metasediments and basic rocks. The Siwalik Group is divided into the Lower, Middle and Upper Siwaliks. The Upper Siwalik is further subdivided into the Gadhan Khola, Chiruwa Khola and Bhainse Khola Formations. Vertebrate fossils were found in the lower and middle part of the Upper Siwaliks. An index fossil identified as Elephas planifrons was discovered for the first time in this region from a massive sandstone bed belonging to the upper part of the Upper Siwaliks. A conglomerate horizon with predominantly Siwalik sandstone clasts occur at the uppermost level of the Siwalik Group exposed in the southern belt. They in turn are unconformably overlain by flat lying younger Dun gravels.

The Sub-Himalayan rocks are distributed into the northern and the southern belts, separated by the Chaura-Marin Thrust. The northern belt is characterised by a number of thrusts and faults resulting in the cropping out of the Bagmati Group sediments and the repetition of the formations of the Siwalik Group. The southern belt shows largely north dipping sequences from the Lower to the Upper Siwaliks. Both the belts show plunging folds in the vicinity of the thrusts. Several NW-SE, NE-SW and N-S trending faults have cut across the entire Siwalik Range.
The Kohistan between Gilgit and Chilas, northern Pakistan: regional tectonic implications
Authors: Khan T. , Khan M. A. , Jan M. Q. , Latif M.
Published: April 2021

In this paper, we present geological description of an area located between Gilgit and Chilas within the Kohistan terrane. This terrane has been considered an intra-oceanic island arc, formed due to northward subduction of the Neo-tethyan lithospheric plate. At present, it is squeezed between the Karakoram­ Asian and Indian continental plates. Both the contacts are marked by suture zones, that is, Shyok (MKT) in the north and Indus (MMT) sutures in the south, respectively. The investigated area consists of plutonic, metamorphosed volcanic and sedimentary rocks, the Chilas Complex, and the Kamila Amphibolite. The metamorphosed volcanic and sedimentary rocks are packaged into the Jagfot Group. This group comprises basal turbiditic sediments, intercalated with amphibolites and calc-silicates (the Gilgit Formation), followed upward by the Gashu-Confluence Volcanics = Chait Volcanic Group, and finally the Thelichi Formation = Yasin Group of Aptian-Albian age. The Thelichi Formation comprises a volcanic base (Majne volcanics) and overlying turbidites, local intercalation of marbles, volcaniclastics and lava flows. Greenschist and amphibolite facies are common in the Jaglot Group, and particularly the sillimanite in the Gilgit Formation. A pair of anticline (the Gilgit anticline) and syncline (the Jaglot syncline) make up the structural scenario. On the basis of field geology, we conclude that the entire Jaglot Group and its equivalents, the Yasin Group, Chait Volcanic Group in Kohistan, and Burjila Formation, Bauma Harel Formation and Katzarah Formation in Ladakh show intra-oceanic back-arc basin rather than island arc affinities as suggested in the past.
Middle Bathonian Foraminifers from the Patcham Formation, Jumara Dome, Kachchh, western India
Authors: Gupta S. , Singh S. K.
Published: April 2021

The Patcham Shell Limestone and Coral Limestone of Jumara Dome have yielded a rich foraminiferal assemblage including species of Garantella, Epistomina, Reinholdella, Pseudomarssonella, and Reyadhella. On this basis middle Bathonian age is assigned to the fossil yielding basal part (Patcham Shell - Coral Limestone) of the Jumara Dome.
Environment of deposition of the sandstones of Lower Vindhyans of parts of Durg district, Madhya Pradesh, India
Authors: Chandra M. , Singhal B. B. S. , Awasthi A. K.
Published: April 2021

Present paper attempts to establish the environment of deposition of the sandstones belonging to the Chandarpur Group exposed in parts of the Durg district, Madhya Pradesh (India). Grain size and shape analyses of the sandstones are carried out. Vertical variations of the different grain size statistics of the fluvial and beach sediments are also studied. A multivariate linear discriminant technique was adopted for discriminating the sediments of these two environments. The palaeocurrents are towards north, northeast and southeast.

Petrographic studies and provenance analysis of the sandstones show that the beach environment is richer in quartz and poorer in matrix as compared to the fluvial ones. The sandstones have been clearly differentiated with the help of multivariate discriminant analysis using thin section modal constituents like quartz, feldspars, iron oxide, matrix, etc. Results of the lithostratigraphic, grain size and petrographic studies fairly tally with each other suggesting that the sandstones under study were deposited under two very different fluvial and beach environments.
Bimodal felsic plutonism in the North Delhi fold belt, India
Authors: Khatatneh M. K. , Pandit M. K.
Published: April 2021

The late Proterozoic rocks of the Delhi Supergroup in the northern part of the Indian shield have undergone multiphase deformation and subsequent felsic plutonism. The magmatic activity in the Ajitgarh pluton in the North Delhi Fold Belt (NDFB) is characterized by a bimodal trondhjemite-granite association. This is the first report of trondhjemite occurrence in late Proterozoic environs from this region. The bimodal character of the suite as indicated by the field disposition and petrographic characters is also confirmed by statistical and geochemical parameters. The trondhjemite and granite represent two different pulses of felsic magmatism. These two types also demonstrate a time gap of emplacement and the evolution most probably took place through distinct trondhjemitic and calc-alkaline trend.
Petrology of the Doda Granites, Jammu Lesser Himalaya, India
Authors: Dhar B. L. , Raina A. K. , Fotedar B. K. , Singh R.
Published: April 2021

Granitic rocks in the Doda district of Jammu and Kashmir State, NW Himalaya are exposed at eight places. They are named as Dramman, Piparan, Kaplas, Khol Dedni, Chinta, Bhala, Kai Nala, and Nagin Dhar Granites. They occur in the form of irregular bodies of varying dimensions. These granites are mostly leucocratic, two-mica, porphyritic to aplitic, massive and highly jointed with crude foliation in some cases. The contact with the Older Metamorphics is sharp and thermal aureole is absent. These granites are monzo- to syeno-granitic in composition with peraluminous, S-type (equivalent to ilmenite series) and calc-alkaline affinity. These intrusive bodies are emplaced within the Older Metamorphics under tectonic influences at later stages of metamorphism. They have formed from highly evolved anatectic granites derived by partial melting of lower crustal material with diapiric situations. These processes had been operative at a temperature of 600-700°C at a depth of 20-30 km under 5 Kb Pressure. The emplacement of these granites is suggested to be due to transient dilation where the diapir is enhanced by sheeting mechanism.
Hydrogeological conditions in Dun valley of Dang, western Nepal: a case study
Authors: Rao G. K. , Piya B.
Published: April 2021

The Dun Dang Valley constitutes a closed groundwater basin in the midst of Himalaya. It is underlain by fluvio-lacustrine sediments which form unconfined to confined aquifer system. The hydrogeological situation in the valley is inferred from drilling data of the Groundwater Resources Development Board (GWRDB), HMG/N. The study reveals existence of a number of groundwater sub-basins each having its own hydraulic system.
Erosion and sedimentation processes and river training works in Nepal
Authors: Upadhyay S. P.
Published: April 2021

This paper attempts to present an overview of erosion and sedimentation processes in Nepal. The rivers that flow through the Nepalese territory originate not only from different altitudes of the country but also have catchment areas lying in India and Tibetan region of the People's Republic of China, too. All the rivers ultimately join the Ganges. GLOF and erosion of the upper reaches of the catchment area are the major professes of sediment production. Depositional areas are mainly the foot hills and wide river channels. The author also tries to demonstrate the impact of erosion and sedimentation on the geo­ environment in Nepal. Finally, mitigative measures and importance of river training works are highlighted.
Origin of the Phoksundo Tal (lake), Dolpa district, western Nepal
Authors: Yagi H.
Published: April 2021

The typical geomorphic features of a landslide such as horseshoe shaped steep scarp and debris mounds are observed adjacent to the southeastern end of the Phoksundo Lake. The mounds consist of rock detritus ranging from cobble size to boulders of several tens of meters in diameter. The total volume of the debris deposited on the left side of the Bauli Gad is estimated to be about l.5 billion m3. The Phoksundo Lake is originated due to landslide damming resulting from a mountain collapse. The detritus is overlying the glacial drift. It implies that one of the glacial valley walls became unstable after the glacial retreat and collapsed over its own glacial drift, probably triggered by an earthquake. The mountain collapse may have occurred around 30 to 40 ka, just after the early substage of the glacial advance in the Last Glacial age.
Foraminifera from the lower Eocene Sakesar Limestone at Nammal, western Salt Range, northern Pakistan
Authors: Sameeni S. J. , Butt A. A.
Published: April 2021

Study of the Sakesar Limestone of the lower Eocene age in the Nammal Gorge in western Salt Range is carried out. During the field investigation eight samples were collected from an 80 ft. thick limestone horizon, at equal interval. A new Alveolinid, foraminifera assemblage is identified.
Jurassic shelf sedimentation and sequence stratigraphy of the Surghar Range, Pakistan
Authors: Ahmed S. , Mertmann D. , Manutsoglu E.
Published: April 2021

In the Surghar Range, facies and biostratigraphical analysis of Jurassic deposits show that the platform development was affected by both the variations in sea-level and the influences of a nearby hinterland. The well exposed shallow marine to intertidal sediments of the Shinawari Formation and the Samana Suk Formation were deposited from the Toarcian to the middle Callovian.

A rise in sea-level during the lower Toarcian submerged the area which was a delta plain before. Shallowing upward cycles and smaller-scale paracycles are characteristic for the marine sequence. Relative sea-level lowstands occurred during the Bajocian, the Bathonian and the Callovian. The lower two coincide with terrigenous influx from the southeast. A lower Callovian hardground is overlain by transgressive middle Callovian open marine limestones. The Jurassic shallow marine platform development ends with another hardground. Drowning of the platform is indicated by the overlying deeper shelf deposits of the Oxfordian - Neocomian Chichali Formation.
Sediment - ostracode relationship in the gulf of Mannar, off Toticorin, east coast of India
Authors: Hussain S. M. , Manivannan V. , Ragothaman V.
Published: April 2021

An attempt has been made to establish the sediment-ostracode relationship, in the gulf of Mannar, off Tuticorin, south east coast of India. 48 sediment samples were collected from 12 sampling stations. Twelve bottom sediment samples were collected once in three months, for a period of one year, so as to represent the four seasons (winter, summer, southwest Monsoon and northeast Monsoon). Calcium carbonate and organic matter content of each sample were correlated against the ostracode population recovered in the respective sample. An increase in the CaCO3 percentage and a decrease in the organic matter content generally favor a higher population size.
Freshwater molluscs from the Late Neogene Siwalik Group, Surai Khola, western Nepal
Authors: Gurung Damayanti
Published: April 2021

The fossil freshwater molluscs collected from the Siwalik (Churia) Group, along the Surai Khola section, western Nepal, are systematically studied. The molluscan fauna is represented by gastropods belonging to family Viviparidae, Ampullariidae , Bithyniidae, Thiaridae, and bivalves belonging to family Unionidae, Corbiculidae and Pisidiidae. Four new species Angulyagra shiddarthai, Brotia dobataensis, Paludomus suraiensis and Parreysia chureii are described in this paper.
Groundwater recharge to the confined aquifer system in the Terai plain of Nawalparasi district, western Nepal: a hydrochemical approach
Authors: Pathak Dinesh , Rao G. Krishna
Published: April 2021

Groundwater recharge estimate is an essential part of the management of the water resources. The Terai plain of Nepal with multi-aquifer system and a number of river systems need thorough understanding on their interconnection.

Groundwater samples from the dugwells, shallow tube wells, deep tube wells, and river water were analysed for major chemical constituents. The chemistry of confined aquifer system is found to be different from the unconfined aquifers. The groundwater recharge to the confined aquifers is therefore believed to be not by vertical infiltration from the shallow aquifers but directly from the palaeo and present river beds. Estimation of groundwater recharge in parts of the Terai plain by rainfall factor warrants rethinking.
Lithological controls on hydrogeochemical parameters: a case study from parts of Vaigai River basin, Madurai, India
Authors: Sharma K. K. , Jayashree S.
Published: April 2021

Water being a universal solvent carries minerals in solution which though present in small quantities determine its suitability for various purposes. The suitability of a well is determined more by the quality of water and not by the quantity of water which it can yield. Geochemical studies provide complete know ledge of the water resources of a hydrological region.

The influence of mineralogical composition upon the filtering properties and the water quality can be analysed form the point of view of the mineral properties. Quality of ground water varies from place to place and from stratum to stratum, it also varies from season to season. There are various techniques to analyse the groundwater quality. However, not much work has been carried out to study the variations in water quality as a result of 1ithological and structural controls. In the present paper, an attempt has been made in this direction. It is found that the first step for any groundwater quality data analysis should be its correlation with the lithological variations. This paper presents the details of the work carried out in the Vaigai River basin of Tamilnadu.
Geological effects and Intensity distribution of the Udayapur (Nepal) earthquake of August 20, 1988
Authors: Dikshit A. M.
Published: April 2021

N/A
The aftershock sequence of the Udaypur (Nepal) earthquake of August 20, 1988
Authors: Pande M. R. , Nicolas M.
Published: April 2021

N/A
Stratabound Zinc-Lead mineralization in the Phakuwa area Sankhuwasabha district, eastern Nepal
Authors: Tuladhar R. M.
Published: April 2021

A massive to disseminated stratabound zinc-lead mineralized horizon confined within the metamorphosed sequence (Phakuwa Group) of the Kathmandu Complex has been traced for over a strike length of one kilometer in the Phakuwa area of the Sankhuwasabha District in eastern Nepal. Its geotectonic setting, metamorphism and deformation and above all, style of mineralization are comparable with the Ganesh Himal zinc-lead deposit Detailed ore-mineralogical studies from both areas revealed similar mineralogical assemblages and associations. Electron microprobe analyses of common sulphides resulted in analogous mineral chemistry which is strongly indicative of similar depositional environment of these two deposits.
Detached carbonate blocks in the northern Dang area Lesser Himalaya (Nepal)
Authors: Dhital M. R.
Published: April 2021

The process of movement of roof thrust in the northern Dang Lesser Himalaya gave rise to the deformation of various incompetent beds of limestone and dolomite from the underlying Gwar Group. Some of them are also disrupted from the footwall ramp and produced a stacked imbricate antiform of carbonates. In this process the floor thrust of the duplex became more active and later the displacement continued along the same. Afterwards, another larger duplex has formed beneath the stacked antiform. As a result, underneath the roof thrust consisting of the low-grade metamorphic rocks of the Sharda Group are found the detached and haphazardly distributed carbonates from the underlying Gwar Group. Characteristic feature and mode of occurrence of the detached carbonates, their lithology, and possible mechanism of thrusting are discussed here.
Characteristics of Benighat group in the context of geological framework of Gorkha - Mugling area and the southern Chure range
Authors: Adhikary T. P.
Published: April 2021

A separate Benighat group is suggested for the Upper Nawakot Group, occupying the core of the Mahabharat syncline in the Gorkha-Mugling area. Lower Nawakot Group is also divided into two lithologically ahd structurally distinct groups, Dhading& Kunchha.

Benighat Group is an assemblage of alternating calcareous and argillaceous rock units. Six mappable units are distinguished, viz. Hushdi Beds, Dhungre Slates, Jogimara Limestone, Sairling Phyllites, Malekhu Limestone and Robang Phyllites. Basic rocks are found to occur in the upper and middle parts of the Benighat Group.
Drainage pattern and its distribution in the Kathmandu valley
Authors: Bajracharya S. R.
Published: April 2021

Drainages in the Kathmandu Valley traverse the hills made up of metasedimentary rocks and Sheopuri Injection Gneiss, and the plains of fluvio-lacustrine sediments. As the streams cut into the underlying rocks and structures of the region, they give rise to certain drainage arrangement seven types of drainage patterns are identified in the valley. They are Dendritic, Rectangular, Trellis, Sub-parallel, Barbed, Radial and Centripetal. The Kathmandu Valley as a whole is a centripetal drainage pattern and the other drainage patterns are distributed in different tributaries within the valley.
A balanced cross-section through the eastern Nepal Siwalik hills, Bagmati river region, implications for the structure of the southern Himalaya
Authors: Schelling Daniel
Published: April 2021

A balanced cross-section has been constructed across the eastern Nepal Siwalik Hills along the Bagmati River in order to determine the structural geometry of the Himalayan foreland fold- thrust belt and to estimate tectonic shortening. The Siwalik Hills are underlain by a basal detachment, the Main Detachment Fault, at a depth of about 6.9km to 8km. The Main Boundary Thrust, the Chaura- Marin Thrust and the Main Frontal Thrust are splay thrusts off the Main Detachment Fault which ramp directly up-section to the surface through 6.8 to 7.7km of Siwalik Sediments with no major intervening thrust flats; the Sub-Himalayan foreland fold thrust belt displays an emergent imbricate- fan geometry. Shortening across the Bagmati section of the Siwalik Hills has been 20km, or 40%, while thrusting along the Main Boundary Thrust has resulted in a minimum of another 25km of shortening.
Occurrence of volcanites in the Lower Siwalik Formation, an evidence of Late Tertiary igneous activity in the central Siwalik of Nepal
Authors: Kaphle K. P. , Einfalt H. C.
Published: April 2021

Small bodies of volcanite are recorded in the Lower Siwalik Formation in central Nepal. Petrological and geochemical studies of these rocks confined that they are basaltic in composition and possibly formed from the alkaline basaltic magma. Occurrence of these rocks within the Lower Siwalik Formation indicate a late Tertiary volcanic activity in this region.
Stratigraphy of the Lower Tertiary rocks of Nepal Himalaya
Authors: Kayastha N. B.
Published: April 2021

The Lower Tertiary rocks of Nepal Himalaya are classified under the Surkhet Group which comprises Melpani, Swat and Suntar Formations (Paleocene - Lower Miocene). There is perfect stratigraphic harmony between Surkhet Group and underlying Metasediments of Mahabharat Group, Lesser Himalaya (Palaeozoic­ Mesozoic) with an unconformity. Correlation of the Lower Tertiary rocks of Nepal, India, Pakistan, and their European and North American equivalent is tabulated (Table 2).
The Intra-Montane basins of the midland zone, geological hazards with special reference to human activities
Authors: Sharma Toran
Published: April 2021

Intra-montane basins of the Midland zone are made up of Pli- Quaternary deposits and are represented by terrace landform which are still on the formative stages. Their geological environment is very delicate and unmindful land utilization could have an unrepairable consequences.

Over the recent years, unmanaged land utilization practices have initiated a series of land degradational processes which are not conducive to the population thriving on the landform. This paper is an attempt to highlight the geological environment of the basins and also to point out how the socioeconomic activities are accelerating the geological hazards.
Lithostratigraphic comparison of three Diamictite successions of Nepal Lesser Himalaya
Authors: Dhital M. R.
Published: April 2021

ABSTRACT

The Proterozoic Blaini-type of diamictite sequences have been identified from the Lesser Himalaya (Brookfield, 1987). A tillitic sequence called the Sisne Formation of Gondwana age was reported by Sakai (1983) from Tansen, the Western Nepal Lesser Himalaya. The newly reported Kokaha Diamictite and Sallyan Diamictite situated to the east and west of Tansen, respectively, exhibit some lithostratigraphic similarity with the Sisne Formation, though the underlying and overlying rocks are quite different

The Kokaha Diamictite from the Barahakshetra area of Eastern Nepal is underlain by grey quartzite with coal seams and conglomerate lenses. Sometimes tuffs and agglomerates are also found together with the diamictite in some places. It is followed upsection by grey calcareous sandstone, siltstone and shale. The Sisne Formation from the Tansen area of Western Nepal overlies grey dolomite with a disconformity and is followed by the Taltung Formation separated by another disconformity. The Taltung Formation itself is composed of basic volcanics, conglomerate, sandstone and siltstone. A non-Blaini type of diamictite horizon called the Sallyan Diamictite from the Sallyan area of West Nepal occurs in low -grade metamorphic rocks. It disconformably overlies quartzite, meta-conglomerates and phyllites, and is transitionally followed by black carbonaceou s slates. Lack of reliable fossils, metamorphism and strong deformation pose difficulties in correlating it with other diamictites.
Application of Geochemical Technique in Exploration and Evaluation of Copper, Lead and Zinc Resources of Nepal
Authors: Jnawali B. M. , Amatya K. M.
Published: April 2021

Application of Geochemical technique in mineral exploration was used in Nepal during 1975-1985 by the Mineral Exploration Development Board (MEDR). Systematic drainage reconnaissance over 40,000 km2 area resulted in the recognition of a large number of anomalies several of which are related to previously unknown mineralizations. The anomalies were categorized  into  1  to 4   assessed  on  the  basis  of  magnitude,  homogeneity,  area and potential host rock. All anomalies of category 1 and 2 that were investigated by follow-up stream sediment and soil geochemistry of varying stages were finally found to disclose the mineralized sources. In all cases, detailed grid soil sampling results in conjunction with geologic observations enabled to ascertain the location, extent and continuity of sub­ outcropping bedrock source with considerable precision, but it was not possible to make reliable estimate of grade.

It has been attempted to evaluate the base metal resource based on the data available of the MEDR work as well as Department of Mines and Geology (DMG) and others. Although no economic deposits have been discovered except Ganesh Himal Zinc Lead, about 20 base metal prospects have been drilled and tonnage and grade proved and estimated. Of these, Kalitar Copper and Wapsa Copper deposits are considered to be of marginal economic grade, while the rest are inventoried a deposits of subeconomic to non-economic grade.
Hydrogeological Conditions of the "Dhunge Dharas" in the Kathmandu Valley
Authors: Karmacharya R. , Shrestha S. D. , Rao G. Krishna
Published: April 2021

Groundwater has been tapped in the Kathmandu valley since ancient times through the traditional stone-carved water-spouts called Dhunge Dharas and dug wells. Present study deals with hydrogeological situation of dug wells and Dhunge Dharas. Quality of groundwater is evaluated on the basis of pH versus topography. The Dharas are classified into natural types on slopes and artificial ones in the valley poor. Depth of water table is observed to be between nearly at ground surface to 6m below the sloping ground and exceptionally up to 12.25m below ground level (bg l) on the terraces. Chemical quality of groundwater is found to be good except at a few places.
Impact of Climate Change on Plant Diseases
Authors: Karki A. , GC S.
Published: April 2021

Abstract available with the full text.
A Review on Status and Prospects of Legumes Viral Disease in Nepal
Authors: Acharya B. , Regmi H.
Published: April 2021

Abstract available with the full text.
Fall Armyworm (Spodoptera frugiperda) in Maize: Current Status and Collaborative Efforts for its Management in Nepal
Authors: Sah L.P. , Lamichhaney D. , KC H.B. , Acharya M.C. , Humagain S.P. , Bhandari G. , Maniappan R.
Published: April 2021

Abstract available with the full text.
Desert Locust [Schistocerca gregaria (Forskal)] (Orthoptera: Acrididae) Invasion and Strategies for its Management in Nepal
Authors: Sah L.P. , Aryal S. , Lamichhaney D. , KC H.B. , Acharya M.C. , Humagain S.P. , Subedi R.K. , Rajbhandari R.D. , Bhandari G. , Muniappan R.
Published: April 2021

Abstract available with the full text.
Effect of Different Preys on Certain Biological Characteristics of Green Lacewing, Chrysoperia carnea (Stephens) (Neuroptera: Chrysopidae) under Laboratory Conditions
Authors: Rana L.B. , Mainali R.P. , Regmi H. , Rajbhandari B.P.
Published: April 2021

Abstract available with the full text.
Field Efficacy of Selected Insecticides against Fall Armyworm, Spodoptera frugiperda (J.E. Smith) in Maize
Authors: Bajracharya A.S.R. , Bhat B. , Sharma P.
Published: April 2021

Abstract availalble with the full text.
A Case Study of Chinese Citrus Fly (Bactrocera minax Enderlin) (Diptera: Tephritidae) Pupae in Sindhuli District, Nepal
Authors: Thapaliya R. , Adhikari D. , Bhattarai A.M.
Published: April 2021

Abstract available with the full text.
Spatial and Seasonal Distribution of Fall Armyworm, Spodoptera frugiperda (J.E. Smith) in Nepal
Authors: Bajracharya A.S.R. , Bhat B. , Sharma P.
Published: April 2021

Abstract is available with the full text.
Major Insect Pests and Pesticide Use Practices among Tomato Growers in Kathmandu and Bhaktapur Districts
Authors: Gauli K. , Sah L.P. , Shrestha J.B. , Rajbhandari B.P. , Ghimire A.R.
Published: April 2021

Abstract available with the full text.