North-central Nepal Research Articles

Katian (Late Ordovician) sphinctozoan-bearing reefs: Hybrid carbonates before the glacial maximum

With a significant rise of metazoan reef-builders in shallow marine environments, the Late Ordovician saw a substantial increase in precipitation of crystalline crusts in reef systems, which may reflect a dramatic environmental change in the ocean. Isopachous crystalline crusts occur abundantly in boundstone of Katian sphinctozoan-bearing microbial reefs on the Zhe-Gan Platform, South China. These deposits are characterized by in-place carbonate textures that are interpreted as associations of abiotic, bioinduced and biocontrolled fabrics, considered here to be hybrid carbonates. Little previous work has been done to investigate how these hybrid carbonates are related to the transition in biotic composition during the Ordovician. These fabrics occur in well-preserved sphinctozoan-bearing reefs in the lower member of the Sanqushan Formation at the Jitoushan Section in Yushan County, Jiangxi Province. The meter-scale reefs are dominated by Corymbospongia, Amsassia and microbial components, and are cemented by fibrous sparry crusts. The intertwined Corymbospongia and Amsassia build the primary skeletal framework. Microbes and subsequent cementation enhance the stability of the framework by covering most of the macrofossil skeletons. The studied skeletal-microbial-cement reefs share a lot of similarities with contemporaneous reefs of North China and Central Nepal, but differ from Early Ordovician reefs, which lack sparry crusts. Our results provide evidence for extensive synsedimentary cementation on the seafloor, which could have played a crucial role in the consolidation of Late Ordovician reefs during the icehouse conditions before the Hirnantian glacial maximum.

New record on Asiatic Golden Cat Catopuma temminckii Vigors & Horsfield, 1827 (Mammalia: Carnivora: Felidae): photographic evidence of its westernmost distribution in Gaurishankar Conservation Area, Nepal

The Asiatic Golden Cat Catopuma temminckii is poorly known in Nepal and was previously recorded only twice in the eastern part of the country. We conducted a camera trap survey in the Lapchi Valley (32km2) of Gaurishankar Conservation Area (GCA), a protected area in north-central Nepal, from October 2018 to April 2019. Eleven cameras were deployed to record mammalian diversity in a 2×2 km2 grid across Lapchi block of GCA. During the study period, four photos and three videos (each of 10 seconds length) of Asiatic Golden Cats were recorded at an elevation of 2,540m at a single camera trap station. This is the first photographic record of Asiatic Golden Cat in this region of Nepal extending the distribution of the species further west in the Himalaya. A more detailed study on its distribution, population size and behaviour is warranted in the near future to implement appropriate conservation measures.

Plant density and life history traits of Aconitum spicatum in North-central Nepal: effects of elevation and anthropogenic disturbances.

Increasing cross-border trade of medicinal and aromatic plants (MAPs) has put heavy pressure on a considerable number of species in the Himalayas. One of the threatened species in Nepal is Aconitum spicatum. Unfortunately for this species and for many others, our knowledge on population ecology and performance across the distribution range is insufficient, hindering the formulation of species-specific management plans. We therefore studied density and population structure of A. spicatum and assessed variation in its life history traits among three populations (subalpine, lower alpine and alpine) along an elevation gradient (3,000–4,200 m a.s.l.) in Annapurna Conservation Area, north-central Nepal. The results show that human disturbances and topographic factors contributed to the variation in density and life history traits. The overall density ranged between 0.56 ± 0.09 (Mean ± SE) and 2.48 ± 0.24 plants/m2 with highest mean density in the lower alpine and lowest in the subalpine population. The subalpine population was also characterized by lower investment in reproductive structures with lowest seed mass and low seed viability and fecundity. Among the environmental variables tested, harvesting, animal droppings and fire appeared to be the most important factors affecting density of different life stages of A. spicatum. The prevailing harvesting pattern is destructive as it involves uprooting of the whole plant and this appears to be a main reason for low recruitment and reduced density of the subalpine population. The level of disturbance decreased with increasing elevation. In terms of reproductive effort, the alpine population performed best. Our results indicate that the viability of A. spicatum populations depends on controlling over-harvesting and pre-mature harvesting of tubers and protecting younger life stages from grazing, trampling and fire. We therefore recommend that when formulating management guidelines, measures aiming to mitigate such anthropogenic disturbances should be considered.

Estimating snow leopard density using fecal DNA in a large landscape in north-central Nepal

Although abundance estimates have a strong bearing on the conservation status of a species, less than 2% of the global snow leopard distribution range has been sampled systematically, mostly in small survey areas. In order to estimate snow leopard density across a large landscape, we collected 347 putative snow leopard scats from 246 transects (490 km) in twenty-six 5 × 5km sized sampling grid cells within 4393 km2 in Annapurna-Manaslu, Nepal. From 182 confirmed snow leopard scats, 81 were identified as belonging to 34 individuals; the remaining were discarded for their low (<0.625) quality index. Using maximum likelihood based spatial capture recapture analysis, we developed candidate model sets to test effects of various covariates on density and detection of scats on transects. The best models described the variation in density as a quadratic function of elevation and detection as a linear function of topography. The average density estimate of snow leopards for the area of interest within Nepal was 0.95 (SE 0.19) animals per 100 km2 (0.66–1.41 95% CL) with predicted densities varying between 0.1 and 1.9 in different parts, thus highlighting the heterogeneity in densities as a function of habitat types. Our density estimate was low compared to previous estimates from smaller study areas. Probably, estimates from some of these areas were inflated due to locally high abundances in overlap zones (hotspots) of neighboring individuals, whose territories probably range far beyond study area borders. Our results highlight the need for a large-scale approach in snow leopard monitoring, and we recommend that methodological problems related to spatial scale are taken into account in future snow leopard research.

Variation in leaf biomass and fruit output of Juniperus indica along an elevation gradient in north-central Nepal

Biomass and reproductive output are important functional traits that influence aspects of plant performance. Measurements of these attributes by harvesting plant parts are often destructive and impractical. Therefore, non-destructive methods, based on allometric relationships, have been recommended for measuring plant biomass and reproductive output, particularly in the ecosystems where plant harvesting is not very practical or feasible. Here, we assessed the variation in the traits related to vegetative and reproductive performance (including plant height, trunk diameter, canopy area, leaf biomass and number of fruits set) among populations of Juniperus indica distributed along an elevation gradient in Manang district of the north-central Nepal, and finally determined the allometric relationships addressing the leaf biomass and the fruit output. The distribution range of J. indica was divided into lower- (3,350–3,580 m), mid- (3,650–3,880 m) and higher- (3,950–4,250 m) elevation classes where we made 54 sample plots of 10 m × 10 m size. In each plot, we recorded the number of individuals of J. indica classifying into seedling, juvenile and mature classes, and measured their vegetative traits and fruit output. Trunk diameter, leaf dry-weight and fruits set parameters spatially varied within the same elevation class. The individuals at the lower-elevation were larger in vegetative size with larger- trunk, height and canopy area, and produced higher leaf biomass and greater number of fruits as compared to those produced by the individuals situated at the mid- and higher-elevations. The regression analysis showed the strongest relationship between the canopy area and the leaf biomass. Thus, the use of outer canopy dimension is found to be the best option for estimation of leaf biomass of J. indica using non-destructive method.Banko Janakari, Vol. 27, No. 1, 2017, page: 3-10

Integrating Ecological and Ethnobotanical Knowledge to Promote Collaborative Conservation Planning in the Nepal Himalaya

The Manaslu Conservation Area in north-central Nepal is considered a biodiversity hotspot, but very little is known about the ecology of its forests and its residents' ethnobotanical practices. This study integrated data from ecological sample plots in 19 forest patches and an ethnobotanical inventory conducted with village residents to explore spatial patterns of diversity in woody plant species and their local uses. The study identified a total of 155 woody plant species in 103 genera and 54 plant families. Local residents named 96% (149) of these species and cited 404 uses for them. The uses involving the greatest number of species were fuel (104) and fodder (54). Seven forest community types were identified: 2, blue pine and rhododendron, primarily below 2200 m, and 5 communities (mixed laurel, oak–laurel, mixed maple, oak–ash and kharsu oak) mostly above 2200 m. Among the forest community types, the oak–laurel forest, at 1–3 km from the study villages, had the highest number of species, species used ...

A new occurrence of silicified wood from the Early Cretaceous (Berriasian) Kagbeni Formation of north central Nepal

During recent fieldwork a second occurrence of silicified wood has been discovered from the Early Cretaceous Kagbeni Formation of north central Nepal. The wood exhibits anatomical features which are well in accordance with Araucarioxylon nepalense described from another locality in the Kagbeni Formation near Kagbeni in the Thakkhola Valley in central Nepal. It is a pycnoxylic wood with mostly uniseriate and rarely biseriate bordered pits on radial tracheid walls. According to recent taxonomic opinions this type of wood should not be treated as Araucarioxylon, but as Agathoxylon Hartig. Thus, we propose the name Agathoxylon nepalense comb. nov. for this type of wood. The sandstones of the Kagbeni Formation have been interpreted as delta–deposits, with a major flow direction from the south. This suggests that the wood originated from the northern margin of Gondwana (i.e. the Indian Plate).

English

The Tamang community is one of the poor groups living in Middle Mountain of Nepal. It pre-dominantly resides in Buffer Zone of Langtang National Park, located in north-central Nepal. The Buffer zones is areas of settlements and agriculture surrounding the core area set aside for wildlife habitats and rare flora. Access on buffer zone programs depends greatly on their representation on local institutions. There are three tiers of local institutions viz. Syaubari Buffer Zone Community Forest User&rsquo;s Group (SBZCFUG), Laharepauwa Buffer Zone User&rsquo;s Committee (LBZUC) and Buffer Zone Cooperative (BZC). 13.8% households represented in SBZCFUG. Likewise, 5.2 and 2.1% households represented in LBZUC and BZC, respectively. As per Buffer Zone Management Directives (1999), LBZUC is the most important institution among all as it distributes the revenues to buffer zone communities. The Park office prepares a Forest Operational Plan (FOP) and hands over a patch of community forest to a buffer zone community. The FOP outlines harvestable quantity of forest resources, harvesting blocks, price and prescribed forestry works. 84% households were involved in FOP preparation. In return for revenue sharing, the park office expects in-kind (labour) contribution from community in biodiversity conservation. 17% respondents said that the park office highly emphasized local consultation for fixing price of forest resources. 32% said that park&rsquo;s emphasis was fine while 50% were not aware. The half of respondents having no idea of consultation was a big gap. Yearly in-kind contribution of a household for biodiversity conservation was nearly 2 days. The share of forest committee meeting was the highest (58%). Despite park&rsquo;s much talked focus on people&rsquo;s participation, reality is bleak. The study recommends that that contribution should be increased and be more focused on fighting forest fire, plantation, creating water holes for wild animals, non timber forest products (NTFPs) utilization, fire line construction etc. No significant relation was found between in-kind contribution with income level, education and landholding. The study adopted both quantitative and qualitative survey methods. Two stages sampling techniques were applied. Sample households were randomly selected and every third household was approached for survey. Key words: Buffer zone, biodiversity conservation, in-kind contribution, household income, community forest.

The complete mitochondrial genome sequence of the Xizang Plateau frog, Nanorana parkeri (Anura: Dicroglossidae)

The Xizang Plateau frog (Nanorana parkeri) belongs to the family Dicroglossidae, which distributes in southern and eastern Xizang, southern-most Qinghai in China, high elevations of north-central Nepal, Himalayan Bhutan, northeastern Kashmir and India. In this study, the complete mitochondrial genome of N. parkeri was sequenced. The mitogenome was 17,837 bp in length, consisting of 13 protein-coding genes, 22 transfer RNA (tRNA) genes, two ribosomal RNA genes, and a non-coding control region (CR). As in other vertebrates, most mitochondrial genes are encoded on the heavy strand, except for ND6 and eight tRNA genes, which are encoded on the light strand. The overall base composition of the N. parkeri is A: 27.7 % A, T: 30.1 % T, C: 26.6% and G: 15.6%. The alignment of the Nanorana species CRs exhibited high genetic variability and rich A + T content. In comparison with the mtDNA sequences typical of vertebrates, a tandem duplication of the tRNAMet gene and a rearrangement of the tRNAThr, tRNAPro and tRNALeu (CUN) genes were found. The complete mitogenome of N. parkeri can provided an important data for the studies on phylogenetic relationship and population genetics to further explore the taxonomic status of this species.

Regeneration of &lt;i&gt;Pinus wallichiana&lt;/i&gt; AB Jackson in a trans-Himalayan dry valley of north-central Nepal

We studied the elevational pattern of forest composition and regeneration of the subalpine conifer tree species Pinus wallichiana in Manang, a trans-Himalayan dry valley in north-central Nepal. Thirty-five quadrats (10 m × 10 m) were laid between 3300 and 4000 masl on both north- and south-facing slopes. We measured diameter at breast height (DBH) of each mature individual of all tree species (DBH ≥10 cm), and recorded the number of seedlings (DBH &lt;10 cm, height &lt;30 cm) and saplings (DBH &lt;10 cm, height &gt;30 cm). We also measured soil moisture and soil pH, estimated canopy cover, and recorded slope and altitude in each quadrat. For all species together and for several species individually, tree density, seedling density, sapling density and tree basal area were found to decrease with elevation on both north and south aspects. This trend is largely explained by the progressively harsher environment at higher elevations. The north-facing slopes in our study area have denser forests than the south-facing slopes, the density of all size classes (seedling, sapling and mature plants) and basal area being greater on the northern aspects. These aspect-wide differences are attributable to the stark difference in soil moisture between northern and southern aspects, which is in turn due to the difference in insolation. Irrespective of elevation and aspect, all the forests studied are regenerating, as indicated by inverse J-shaped density-diameter curves. The elevational pattern of seedling and sapling abundance is explained only by elevation. Whereas other variables (e.g., canopy) are considered to have an important influence on seed germination and seedling establishment, they turn out not to be significant predictors of density of seedlings and saplings. This failure to identify a relationship is probably due to our use of non-parametric test (tree regression analysis) that we used to establish the relationship between density and its potential explanatory variables or due to our selection of 1 standard error rule yielding sub-optimal models for regression trees. Key words: density-diameter curve; regeneration; seedling; sapling; altitude; canopy; Manang Valley DOI: http://dx.doi.org/10.3126/hjs.v6i8.1798 Himalayan Journal of Sciences Vol.6 Issue 8 2010 pp.19-26

Thermo-tectonic history of the Tethyan Himalayas deduced from the palaeomagnetic record of metacarbonates from Shiar Khola (Central Nepal)

Palaeomagnetic measurements were carried out on low-grade metamorphic carbonates, of Mesozoic age from the Shiar area (85.1°E, 28.6°N) of the Tethyan Himalaya (TH) in north central Nepal. Two characteristic remanence components carried by pyrrhotite (ChRM1) and magnetite (ChRM2) could be identified by their unblocking temperature spectra of 270–340 and 430–580°C, respectively. Fold tests are not significant, due to the uniform bedding of all sites. However, according to results from other areas of the TH, the pyrrhotite component has been probably acquired as a secondary (p)TRM during exhumation and cooling; thus the age of remanence acquisition can be related to the last cooling event (25–17Ma in the surrounding areas). The inclination of the magnetite component matches the value expected from the Indian APWP. This may the primary origin of the ChRM2.Pyrrhotite site-mean directions show a small-circle distribution, with a best fit parallel to the N–S direction. Backtilting to the expected inclination (Iexp) by intersection of the remanence small-circle with the small-circle of constant Iexp yields a clockwise block rotation of 30–35° with respect to the Indian Plate. Characteristics of the pyrrhotite component (small-circle distribution of site-means, secondary origin, (p)TRM with unblocking temperatures below about 300°C), allow the interpretation of the chronologic order of the thermo-tectonic history: (i) an earlier main folding phase at elevated temperatures; (ii) a later event of cooling through about 300°C coinciding with the acquisition of ChRM1; (iii) clockwise block rotations with respect to the Indian Plate and (iv) long-wave folding as the youngest tectonic event.

Echoes of a Yolmo Buddhist's Life, in Death

Shi mandi mareko hoina. Sareko ho. I hear these words as I drive south along Interstate 84, gliding past Worcester and Hartford and a world of unknown places as magnetic trace of a voice recorded months before sounds through an unreliable tape deck set on seat beside me. Time and again during these weekly commutes from Boston to New York and back again, I listen to voice and try to soak up sounds and grammars of sentences heard. I wonder about welfare of speaker, hoping that old man is alive and well and talking still while asking myself why there isn't more of an anthropology of voice, of histories of voicings in their many particulars as they are heard and echoed by others who speak or write in turn. Shi mandi mareko hoina .... Dying does not mean dying.' The voice belongs, if a voice can ever belong to its speaker, especially once it is recorded and resounded electronically, to an elderly man often called Lama or Grandfather Priest by other members of his community, many of whom identify themselves as wa or people, an ethnically Tibetan Buddhist people who for two centuries or so have lived in hamlets and villages along upper ridges of Yolmo or Helambu Valley of north-central Nepal. Meme (pronounced mhem-e) lived in a village on southwestern ridge of this valley until some twenty years ago, when, in seeking a more comfortable life in city, he moved with his second wife and daughter to Chabahil, an ethnically mixed neighborhood on eastern outskirts of Kathmandu, about one mile west of Tibetanesque neighborhood of Boudhanath. Born in 1916, second son of a respected priest from a prestigious Nyingma lama lineage, Meme raised a daughter and three sons with his first wife, who died in 1964. He remarried two years later, and his second wife soon gave birth to a daughter, as yet unmarried and living still with her parents. Much of his life had been spent either farming or practicing the lama work, with former taking priority in his youth and latter gaining importance as he grew older, in part because his weakening body prevented him from working as he once did and in part because

Emplacement of Himalayan leucogranites by magma injection along giant sill complexes: examples from the Cho Oyu, Gyachung Kang and Everest leucogranites (Nepal Himalaya)

The upper part of the High Himalayan slab in north central Nepal is comprised of a thick layer-parallel sheet of biotite + muscovite + tourmaline ± garnet ± sillimanite ± cordierite leucogranite up to 3–4 km thick and dipping north at 5–20°. These strongly peraluminous magmas were emplaced into high temperature–low-pressure sillimanite and cordierite bearing gneisses, calc-silicates and rare amphibolites which were metamorphosed at temperatures of 600–650°C some time during the Oligocene–early Miocene. Parallel stringers of black xenolithic gneisses within the leucogranites suggest passive magmatic intrusion along fractures parallel to the schistosity in the country rocks. In the mountains of Cho Oyu, Gyachung Kang, Pumori, Lingtren and the base of the Everest massif, these leucogranites form part of a single structural horizon bounded at the top by the Lhotse Detachment, the lower of two N-dipping normal faults of the South Tibetan Detachment (STD) system, and below by the Khumbu Thrust (KT), an out-of-sequence fault which was partly responsible for the uplift, erosion and exhumation of the leucogranites. A model for the emplacement of these leucogranites is proposed, where they represent viscous minimum melts, produced by melting of a pelitic protolith, similar to the underlying sillimanite grade gneisses, through muscovite breakdown, either during fluid-absent melting at <750°C, or fluid-saturated melting at <650°C. These leucogranites may have intruded up to ∼40 km horizontally from their source, but were emplaced by hydraulic fracturing along multiple sills into recently metamorphosed high temperature–low pressure rocks of the middle crust. The entire mid-crustal region where the granites were formed and emplaced was later uplifted along the hangingwall of the Khumbu Thrust, and by the structurally lower Main Central Thrust (MCT) to their present position. The location of the leucogranites at the top of the slab, but never intruding across the STD normal faults and the complete lack of leucogranites further down the slab rule out frictional heating along the MCT as a viable heat source and also rule out diapirism as a viable emplacement mechanism. High radioactivity of the crustal source, percolation of fluid from the migmatitic source into sills and dykes during simple shear, heat focussing due to a large thermal conductivity contrast across the STD, and decompression during active low-angle normal faulting above, are all viable processes to explain leucogranite melting and emplacement.

The Thakkhola–Mustang graben in Nepal and the late Cenozoic extension in the Higher Himalayas

The Thakkhola–Mustang graben is located at the northern side of the Dhaulagiri and Annapurna ranges in North Central Nepal. The structural pattern is mainly characterised by the N020–040° Thakkhola Fault system responsible for the development of the half-graben. A detailed study of the substrate and the sedimentary fill in several outcrops indicates polyphased faulting: -pre-sedimentation faulting (Miocene), with a mainly NNW–SSE to N–S compressional stress expressed in the substratum by N020–040° and N180–N010° sinistral and N130–140° dextral conjugate strike-slip faults; -syn-sedimentation faulting (Pliocene–Pleistocene), characterised by a W–E to WNW–ESE extensional stress and tectonic subsidence of the half-graben during the Tetang period (Pliocene probably), followed by a doming of the Tetang deposits and a short period of erosion (cf. Pliocene planation surface and unconformity between the Tetang and Thakkhola Formations); the Thakkhola period (Pleistocene) is characterized by a W–E to WNW–ESE extensional stress and a major subsidence of the half graben; -post-sedimentation recurrent extensional faulting and N–S and NE–SW normal faults in the late Quaternary terrace formations. Geodynamic interpretation of the faulting is discussed in relation to the following: 1. the geographic situation of the Thakkhola–Mustang half-graben in the southern part of Tibet and its setting in the Tethyan series above the South Tibetan Detachment System (STDS); 2. the geodynamic conditions of the convergence between India and Eurasia and the dextral east–west shearing between the High Himalayas and south Tibet; 3. the possible relations between the sinistral Thakkhola and the dextral Karakorum strike-slip faults in a N–S compressional stress regime during the Miocene.

Transforming Herds and Herders: Modeling the Evolution of Himalayan Pastoralism

Introduction: Subsistence Types Adaptation to the (and potentialities) of high-elevation, mountainous environments has been a popular theme of anthropologists, as well as geographers and other writers. Orlove and Guillet (1985) discuss three generalized 'mountain subsistence types: ''alpwirtschaft'; Verticality;' and the 'montane production strategy.' All three fit loosely into an adaptationist perspective'; is, each claims that patterns of economic activity and social organization can be understood as responses to environmental constraints (Orlove and Guillet 1985: 7). They reveal, however, like other such adaptationist arguments, and despite their immediate intuitive appeal, they fail in adequately explaining the precise nature of the goals of adaptation, the specific mechanisms of the process of adaptation, and the selection among alternative means to the goals of adaptation (1985:7). researchers, in particular, have struggled in their attempts to examine subsistence systems in ecological terms, in part because of a heavy and uncritical reliance on the notion of 'adaptation.' Despite the drawbacks listed above, many Himalayanists continue to adhere to the rigid environmental determinism inherent in these 'subsistence types' in their piecemeal attempts to describe such subsistence systems as transhumant pastoralism. For instance, it is often said the transhumant pastoral system is adapted to the lack of resources found at high elevations'. Other researchers have suffered from their tendency to focus almost exclusively on the supposed problems of deforestation, soil erosion, and the general deterioration of the mountain environment as described by Eckholm (1976) and Sterling (1976). Many envision change in the region as inevitably following a rapid, irreversible, and destructive trend (Orlove 1987: 98), labelled the Himalayan crisis (Ives and Messerli 1989), following (or even resulting from) the (uncritically assumed) universal progression towards permanent agriculture, increasing sedentarism, and the intensification of subsistence production. Similarly, this pattern is believed to result in attitudes about ecological change leading to cultural loss and (social, political, and non-human) environmental degradation. This paper will address two major shortcomings of much of the research conducted on transhumant pastoralism and ecological change in the Himalayas. First, there has been no attempt to construct an ecosystem model depicting a transhumant pastoral subsistence system, and second, despite substantial attention devoted to examining change (in the social, cultural, political, and/or physical environments), there has been a conspicuous lack of synthesis and holistic analysis. The aim of this paper is to present a holistic model of a transhumant pastoral subsistence system as it has changed during the present century. The following discussion and models are based primarily, though not exclusively, on the Thakali, a transhumant pastoral people inhabiting northcentral Nepal and one of the few ethnic groups in the Himalayas whose changing circumstances have been given much analytical attention.1 The Thakali2 in the Early 20th Century: Tians-Himalayan Pastoral-Traders The Thakali are an agro-pastoral and trading people who reside in the upper Kali Gandaki River valley of northcentral Nepal, and have long been renowned as traders and merchants of great economic and political acumen (Messerschmidt 1982: 266). Thak Khola, the region of the Kali Gandaki in which the Thakali live, is a relatively isolated mountainous river valley wedged between the towering peaks of the Dhaulagiri and Annapurna massif which rise to over 8,000 meters. It falls within the Nepalese administrative district of Mustang in Daulagiri Zone, and stretches approximately 55 kilometers (c. 35 miles) in length while the inhabited areas range in elevation from 2,500 meters to 4,000 meters (Messerschmidt 1982: 268). …

A Short Note on the Tsergo Ri Landslide, Langtang Himal, Nepal

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.

Evidence for Tibetan plateau uplift before 14 Myr ago from a new minimum age for east–west extension

IMPORTANT changes in South Asian climate occurred in the Late Miocene epoch (~8 Myr ago)1,2, and these have been attributed by some researchers to uplift of the Tibetan plateau at about the same time3–5. Unfortunately, this link has been difficult to test because the timing of plateau uplift remains poorly constrained by independent evidence. One way to determine the minimum age of uplift is to establish the initiation age of the north-striking normal fault systems in southern Tibet that are widely regarded6–10 as being related to gravitational collapse of the Tibetan plateau. Here we report an40Ar/39Ar age of ~14 Myr for hydrothermal mica from an extensional fracture belonging to such a fault system in north-central Nepal. This age implies that east–west extension began before ~ 14 Myr ago in at least some parts of the Tibetan plateau, suggesting that the plateau attained its high mean elevation well before Late Miocene time.

Body and Emotion: The Aesthetics of Illness and Healing in the Nepal Himalayas

Body and Emotion is a study of the relationship between culture and emotional distress, an examination of the cultural forces that influence, make sense of, and heal severe pain and malaise. In order to investigate this relationship, Robert R. Desjarlais served as an apprentice healer among the Yolmo Sherpa, a Tibetan Buddhist people who reside in the Helambu region of north-central Nepal.

Stratigraphic evolution of Mesozoic continental margin and oceanic sequences: Northwest Australia and northern Himalayas

During Mesozoic time the Northwest Australian continental margin and the Thakkhola region of North Central Nepal were “adjacent” passive margins, off Northeast Gondwana. The relatively sediment-starved basins provide excellent opportunities for studying the early structural and depositional evolution of the Indian Ocean, during the Triassic/Jurassic rifting stages (Neo-Tethys), and the Jurassic/Cretaceous transition from rifting to drifting. Nepalese and Australian paleomagnetic studies indicate subtropical paleolatitudes during the Late Triassic to Early Jurassic, but higher latitudes of 35–40°S during the Late Jurassic to Early cretaceous, prior to the sustained northward flight of Australia and Greater India in the Late Cretaceous to Cenozoic. The latitudinal position of the basins and type of sediment are related. Principal continental margin formation along the northern edge of eastern Gondwana started in late Permian to Triassic time. By late Triassic-early Jurassic time platform carbonates with thin, lagoonal shales were laid down in a subtropical climate. The Carnian to “Rhaetian” siliciclastics and carbonates show repeated shallowing-upward sequences. Subsequent southward drift of “Greater India” and Australia during mid-Jurassic time replaced carbonates with more siliciclastic sediment input. Widespread erosion was caused during local uplift of parts of the Northwest Australian continental margin as a result of Jurassic late-rift block faulting. A mid-Callovian-early Oxfordian hiatus in Nepal is a submarine condensed sequence and non-tectonic in origin. In Nepal, the overlying 250 m thick organic-rich dark shales, which are correlated to the Oxfordian/Kimmeridgian clays of circum-Atlantic hydrocarbon bearing basins, can be traced along the northern Himalayan range. These shales probably represent an extensive continental slope deposit formed in a “high-productivity of organics” belt. The diverse foraminiferal microfauna of the belt was previously only known from boreal Laurasia. The Callovian “break up” uncorformity off Northwest Australia is actually a post-rift unconformity and precedes the onset of seafloor spreading by about 5–10 m.y. Seafloor spreading, leading to formation of the present Indian Ocean, started in the Argo Abyssal Plain around 155 Ma ago, in late Jurassic time. Australia and Greater India, including Northern Nepal, separated as early as in the late Valanginian, about 130 Ma ago. Altered ash layers off Northwest Australia record an important volcanic phase in Berriasian-Valanginian time. Mafic volcaniclastics in Nepalese deltaic sediments also testify to continental margin volcanic activity, which may be a precursor to the slightly younger Rajmahal traps in eastern India. An important tectonic event off Northwest Australia took place in Aptian time, 120-115 Ma ago, when hemipelagic sedimentation changed gradually into more pelagic sedimentation, with sharply decreasing rates of deposition. In Nepal, this marks the transition from coarse to fine-grained, organic-rich terrigenous clastics, leading eventually to more carbonate-bearing strata during the mid-Cretaceous global sealevel highstand.

Hydrocarbon Potential, Organic Matter Diagenesis, Sedimentology, and Paleoenvironment of Upper Mesozoic Dark Shales, Northern Himalayas and Argo Abyssal Plain: ABSTRACT

The Late Jurassic was a time favorable for the deposition of black shale-type sediments in shallow environments as known from circum-North Atlantic basins, North Sea, and Himalayan Tethys regions. Locally these shales have excellent hydrocarbon source potential. The site of the Spiti shales in the Thakkola region of north-central Nepal provides the opportunity to study a long-term (Oxfordian-Tithonian) stable, shallow, and oxygen-depleted environment. Strata with calcareous benthic communities show that the environment was not anoxic. Organic geochemical and sedimentological analyses on the Spiti shales (Oxfordian-Valanginian) were done to understand the hydrocarbon potential, organic matter diagenesis, sedimentology, and paleoenvironment of this sequence. The depositional environment changed, driven by tectono-eustatic and climatic events, from an open shelf (approximately 250 m) with low amounts of detrital input and rich macrofossil communities to an extremely shallow, partly continental environment with intercalations of quartzose channel fill, silty shales, rare lumachelle layers, and coal seams. Paleocurrents suggest a north-facing continental margin bordering the Tethys Sea. The organic matter changed from marine (Jurassic) to terrestrial in the Cretaceous. Analysis of coeval strata, deposited in the deep-marine environment off the northern Indian shelf (contiguous with the present-day Argo abyssal plain), demonstrates the changing shallow to deep-water hydrocarbon potential.more » It reflects the more advanced organic matter maturation of the onshore material due to Himalayan tectonics and allows tracing the transport of the organic matter.« less