Eastern Himalaya Research Articles

Late Neogene monsoonal climate in the southeastern margin of the Tibet Plateau revealed by leaf physiognomy evidence

Four fossil leaf assemblages from the Late Miocene to the early Late Pliocene of the Tengchong-Lianghe region, western Yunnan, China, are subjected to the Climate-Leaf Analysis Multivariate Program (CLAMP) and Leaf Margin Analysis (LMA) analysis and compared with other late Neogene fossil flora from the southeastern margin of the Tibetan Plateau (SEMTP) and the eastern Himalayan foreland basins to reconstruct paleoclimate and capture ancient monsoon signature. The CLAMP-derived mean annual temperature (MAT) for the Late Neogene in Tengchong-Lianghe range from 17.9 ± 2.3 °C to 21.0 ± 2.3 °C, with the Early Pliocene being the warmest period, while the growing season precipitation (GSP) range from 1905 ± 481 mm to 2006 ± 481 mm with minimal change over time. The CLAMP and LMA results indicate a warmer and wetter climate in the late Neogene of the SEMTP and suggest that the paleoclimate in western Yunnan from the Late Miocene to early Late Pliocene was primarily influenced by global climate evolution rather than topographic changes. CLAMP results indicate that the modern pattern of the Asian Monsoon was established at least by the Late Miocene, though precipitation seasonality in the late Neogene of the SEMTP was weaker than today, likely attributed to the intensification of the East Asian Winter Monsoon driven by global cooling.

Total soil carbon modelling along the altitudinal gradients in Eastern Himalaya, Arunachal Pradesh

Total soil carbon modelling along the altitudinal gradients in Eastern Himalaya, Arunachal Pradesh

Vapor Pressure Deficit Controls the Extent of Burned Area Over the Himalayas

AbstractGlobally, increasing occurrences of forest fires are major threats to the ecosystem. The rich forests in the Himalayas also suffer from high incidents of forest fires in the pre‐monsoon summer months, March to June. Research studies are limited in identifying the meteorological factors governing the spatiotemporal distribution of forest fires. Using three satellite‐based data sets of monthly burned area (BA) for March to June, we found higher BA in the Eastern Himalayas (EH) compared to the Central (CH) and Western Himalayas (WH). Using statistical methods, we found Vapor Pressure Deficit (VPD) to be the most dominating variable controlling BA in the Himalayas. Precipitation, soil moisture and temperature, with their relative variability, control VPD that governs the interannual and intraseasonal variations of BA. Our results imply that a good forecast of VPD will facilitate alert generation for the Himalayan forest fires.

New Late Cretaceous Paleomagnetic Results From the Eastern Qiangtang Terrane: Implications for the Postcollisional Extrusion and Convergence of the Southeastern Tibetan Plateau

AbstractTo refine the postcollisional extrusion and convergence history of the southeastern Tibetan Plateau, we report a quality paleomagnetic data set from Upper Cretaceous redbeds of the eastern Qiangtang Terrane (QT), where is situated at the front edge of eastern Himalayan Syntaxis. The 32 site‐mean directions provide a mean pole at 75.4°N, 176.8°E (A95 = 2.4°) and a paleolatitude of 31.8 ± 2.4°N for the Mangkang area. Comparison with reliable Late Cretaceous paleomagnetic data from the eastern QT and East Asia indicates that the eastern QT experienced a southward extrusion of 940 ± 310 km after the Late Cretaceous. Comparing Late Cretaceous paleolatitudes estimated from the eastern QT and Lhasa terrane (LT) reveals a paleolatitude difference of 2,390 ± 620 km. Such a great latitudinal convergence can be attributed to the fact that some continental terranes originally located between the eastern LT and QT were laterally extruded after the Late Cretaceous.

Identifying Alpine Lakes with Shoreline Features

Alpine lakes located in high-altitude mountainous regions act as vital sentinels of environmental change. Remote-sensing-based identification of these lakes is crucial for understanding their response to climate variations and for assessing associated disaster risks. However, the complex terrain and weather conditions in these areas pose significant challenges to accurate detection. This paper proposes a method that leverages the high precision of deep learning for small lake and lake boundary extraction combined with deep learning to eliminate noise and errors in the identification results. Using Sentinel-2 data, we accurately identified and delineated alpine lakes in the eastern Himalayas. A total of 2123 lakes were detected, with an average lake area of 0.035 km². Notably, 76% of these lakes had areas smaller than 0.01 km². The slope data is crucial for the lake classification model in eliminating shadow noise. The accuracy of the proposed lake classification model reached 97.7%. In the identification of small alpine lakes, the recognition rate of this method was 96.4%, significantly surpassing that of traditional deep learning approaches. Additionally, this method effectively eliminated most shadow noise present in water body detection results obtained through machine learning techniques.

Acute poisoning with Jatropha curcas in North Eastern Himalayan region – A case series and review of literature

Plant poisoning is one of the common accidental sources of poisoning amongst the villagers and the troops going on long-range patrolling. Seeds of Jatropha curcas a/k/a biodiesel pant mimicking nuts are an uncommon source of poisoning, manifesting as mainly gastrointestinal symptoms and less frequently the other systemic manifestations. Here, we report a case series of two cases of serving soldiers who presented with gastrointestinal symptoms after consumption of seeds of unknown plants mimicking nuts, which was later identified as J. curcas. Both patients had favorable outcomes with syndromic management of the unknown poisoning.

Discovery of Whittieria hengduanensis sp. nov. (Ophioglossaceae) from Southwest China demonstrates a unique intercontinental disjunct pattern in plants between the Himalaya and the Americas

A new fern species, Whittieria hengduanensis (Ophioglossaceae), from Sichuan, Xizang, and Yunnan, Southwest China (eastern Himalaya), is described and illustrated. This species is similar to W. engelmannii in the Americas in having a cylindrical rhizome and complex-reticulate venation. In addition, both species grow in open habitat on basic soil. However, the two species are distinguishable in root number per rhizome and the number of the larger areolae per trophophore. Our molecular study also supports that they are sister to each other but divergent at the molecular level. The discovery of W. hengduanensis shows that the genus is intercontinentally disjunct between the Himalaya and the Americas, a unique pattern not having been documented in the literature.

Mann-Kendall and Sen's Slope Estimator Test to Analyze Trends for Temperature and Rainfall in Eastern Himalayas of Arunachal Pradesh, India

In the past ten years, climate change has gained significant attention. Global climate change does not always affect various places in the same way. One important weather factor associated with climate change is rainfall. An appropriate first step in assessing how climate change may impact food security and water availability is to examine patterns in temperature and rainfall. The temperature, precipitation, and changes at several Arunachal Pradesh districts from 2001 to 2021 are examined in this study. We examined fourteen districts using the Mann-Kendall (MK) and Sen's Slope estimator test, which may identify long-term monotonic trends as well as variations in temperature and rainfall. The maximum and lowest temperature data revealed notable upward and decrease patterns, indicating that the region had experienced a change in climate. Nonetheless, there was an increase in rainfall patterns.

Genetic Diversity and Evolutionary Biology of Indian Wildlife- A Review

The genetic diversity and evolutionary biology of Indian wildlife, emphasizing the critical role of genetic variability in ensuring species adaptability and long-term survival. India is one of the world’s megadiverse countries, home to a wide range of unique flora and fauna spread across its biodiversity hotspots, including the Western Ghats and the Eastern Himalayas. However, rapid habitat fragmentation, deforestation, and poaching have severely impacted the genetic health of many wildlife species, leading to reduced gene flow, population bottlenecks, and increased inbreeding. This has heightened the risk of extinction for small, isolated populations such as the Asiatic lion and the Great Indian bustard. Genetic studies using advanced genomic tools have provided key insights into the population structure, phylogenetic relationships, and adaptive potential of species like the Bengal tiger, Asian elephant, and snow leopard. Conservation strategies, including genetic rescue, habitat corridors, and the use of captive breeding programs, are recommended to preserve genetic diversity and prevent further genetic erosion. Technological advances, such as non-invasive sampling and bioinformatics, are transforming wildlife research, enabling more precise and less intrusive genetic monitoring. The integration of genetic data into conservation policies and practices is essential for developing targeted management plans that maintain the evolutionary potential of Indian wildlife.

Top-to-south shear at the base of the eastern Tethyan Himalayan Sequence during the Eocene-Oligocene Himalayan orogeny

The early mountain building processes in the Himalayan orogen are still not clear because of extensive deformation and metamorphism since the Miocene. A large gently dipping ductile shear zone, referred as the Tethyan Himalayan Décollement (THD), is defined here as the sole décollement of the south-verging Tethyan fold-and-thrust belt in the Lhozag-Cuona area of the eastern Himalayan orogen. The ~4 km-thick THD is characterized by a top-to-south shear sense, moderate T/P Barrovian to high T/P Buchan type metamorphism and Eocene-Miocene partial melting. Zircon UPb dating of metasedimentary rocks and granitic gneisses from the THD yields protolith ages of the Late Cambrian to Early Ordovician. Based on structural analysis, zircon UPb ages, monazite UPb ages and mica 40Ar/39Ar thermochronology, the THD was the boundary shear zone at the top of the Greater Himalayan Crystalline Complex (GHC) and accommodated the persistent north-south shortening in the Tethyan Himalayan Sequence (THS) from ~50 Ma to 20–17 Ma. From ~20–17 Ma, the top-to-north South Tibetan Detachment System (STDS) was predominantly activated to juxtapose the unmetamorphosed or low-grade THS over the GHC. This tectonic transition can be attributed to the roof collapse in the eastern Himalaya (younger than that of the central-western Himalaya), which triggered rapid exhumation of the GHC and the northern Tethyan Himalayan gneiss domes. Hence, the THD was the predecessor of the STDS and a prolonged pathway for leucogranitic melts from the Eocene to early Miocene. The transition from the THD-controlled crustal thickening in the Eocene and Oligocene to the STDS-controlled extrusion in the Miocene shed insights on a new synthesis of the tectonic wedging model for the Himalayan evolution.

Landslide susceptibility assessment in Eastern Himalayas, India: a comprehensive exploration of four novel hybrid ensemble data driven techniques integrating explainable artificial intelligence approach

Landslide susceptibility assessment in Eastern Himalayas, India: a comprehensive exploration of four novel hybrid ensemble data driven techniques integrating explainable artificial intelligence approach

TEMPORARY REMOVAL: Bioprospecting amylase from Samiti Lake, situated in the eastern Himalayas

Enzymes, especially amylases, have been an economic boon to the industrial sector, their bioprospective and biotechnological use is an added advantage. Our primary focus of the study was to isolate the most potent amylase producer and to optimize its production parameters through One Factor At A Time (OFAT), Central Composite Rotatable Design Response Surface Methodology (CCRD RSM) and Artificial Neural Network (ANN). Based on the qualitative and quantitative analysis, SLAB1 was selected as the most potent amylase producer out of the potential isolates. Further SLAB1 was identified as Priestia flexa via 16SrRNA identification protocol. Optimization of the production parameters showed the best carbon, nitrogen sources, temperature and pH to be fructose, peptone, 20 °C and pH 8.0 respectively. Further, the enzyme was purified using ammonium sulphate precipitation followed by dialysis. Later, DEAE Sepharose (Sigma) resin was used for ion exchange chromatography and the protein was eluted using NaCl gradients from 0.1 M – 0.6 M. Enzyme kinetics assessment of the purified amylase with the Lineweaver Burk plot showed values of maximum rate; Vmax (10.869 μmoL/min), and Michaelis-Menten constant Km to be around (14.91 mg/mL). To determine its potential application, analysis of this purified amylase in cleaning the tomato and chocolate stained cotton fabrics after comparing its compatibility with different detergents were executed. Further analysis of the washed stained fabrics via Scanning Electron Microscopy was carried out.

Seasonal variation in the physico-chemical characteristics of lake Gyakar Sinyik (Ganga Lake): A wetland of eastern Himalayas, India

Seasonal variation in the physico-chemical characteristics of lake Gyakar Sinyik (Ganga Lake): A wetland of eastern Himalayas, India

Cenozoic faulting of the Ganzi-Yushu (Xianshuihe) fault from apatite (U-Th)/He ages and its implications for the tectonic reorganization in the southeastern Tibetan plateau

The Ganzi-Yushu-Xianshuihe fault that lies along the northeastern boundary of the Chuan-Dian crustal fragment provides the opportunity to study the tectonic evolution and geodynamic mechanisms of the southeastern Tibetan Plateau. Apatite (U-Th)/He data from an elevation transect provide robust evidence for the initiation of the Ganzi-Yushu fault. The consistent AHe ages of the lower samples constrain the onset of fault activity to 9.4 ± 1.5 Ma. Moreover, the zircon U-Pb dating and rare earth element (REE) analysis confirm that the Queer Shan and Gaogong granitic plutons were emplaced as a whole and then displaced by the Ganzi-Yushu fault. Combining the total offset of these two plutons and the onset timing of the fault activity yields a long-term average left-lateral strike-slip rate of 7.3–10.8 mm/yr for the Ganzi-Yushu fault. Based on the summarized synchronous deformation in the southeastern Tibetan Plateau, including the initiation of fault activity along the whole Ganzi-Yushu-Xianshuihe fault, the slip reversal of the Red River fault, and the fault activity along a series of left-slip faults in the Indochina block, we suggest that the southward extrusion of the Chuan-Dian crustal fragment and clockwise rotation around the Eastern Himalayan Syntaxis initiated at the middle-late Miocene (15-10 Ma).

Crustal Heterogeneity of the Bhutan Himalaya: Insights from PgQ Tomography

Abstract We present the results of a seismic investigation conducted in Bhutan using data from the Geodynamics and Seismic Structure of the Eastern Himalaya Region broadband network, focusing on variations in crustal structure and seismic attenuation properties. Through analysis of seismic data from 56 events recorded between 2013 and 2014, with magnitudes exceeding 4.5 and depths shallower than 50 km, we examined 1 Hz PgQ (Q0)-values among multiple station pairs using the two-station method. Our findings reveal significant disparities in PgQ0-values across Bhutan. The western region exhibits low PgQ0 values, indicating high seismic attenuation, whereas the central region shows medium-to-high PgQ0 values, suggesting lower attenuation. Notably, these results are consistent with the geometry of the Moho, providing valuable insights into crustal geometry and rheology. This study contributes to a deeper understanding of Bhutan’s complex crustal structure, offering insights into crustal properties and seismic attenuation mechanisms in this geologically significant region.

Investigation of land–atmosphere interaction at a high altitude (5330 m a.s.l.) snow covered station of East Himalaya

Investigation of land–atmosphere interaction at a high altitude (5330 m a.s.l.) snow covered station of East Himalaya

New photographic and distribution records of the Beautiful Nuthatch Sitta formosa (Blyth, 1843) and Lesser Adjutant Leptoptilos javanicus (Horsfield, 1821) from the Tsirang District landscape in Bhutan

The distribution records with photographic evidence of the Beautiful Nuthatch Sitta formosa (Blyth, 1843) and Lesser Adjutant Leptoptilos javanicus (Horsfield, 1821) from the Tsirang District landscape in Bhutan. S. formosa, under Sittidae family, was first described in 1843 and is native to the eastern Himalaya, northeastern India, and extending into southeastern Asia. L. javanicus being widely distributed is rare and faces threats from deforestation, leading to its vulnerable status. The largest wading bird in the Ciconiidae family, found mainly in southern and southeastern Asia, with a recent sighting in Tsirang District establishing new distribution records for Bhutan. The district’s ecological diversity, including broadleaved forests, and riverine landscapes, supports a rich avifauna, making it a hotspot for bird enthusiasts. Separate studies are required to ensure the long-term conservation of Beautiful Nuthatch, and to confirm whether Lesser Adjutant is a regular visitor in Tsirang.

Resurgent diversity: upland agriculture, indigenous crops and foodways in Eastern Himalayas

ABSTRACT In this article, we are concerned with the cultivation of food crops – comparing trajectories of millets and buckwheat in Eastern Himalayas, and the circumstances under which farmers plant or forgo certain crops. Crop choices and how farmers cultivate their crops have far-reaching consequences for society, economy and the environment. With accelerating climate change, present global, corporate food regime based on a handful of genetically identical crops appears as a high-risk venture. For many Indigenous peoples alternatives to and negotiations with these regimes are commonly located in their traditions: the crops, foodways, and diversity-based agricultural systems of their ancestors even as a multitude of factors have conspired to their decline across the Eastern Himalayan Region. Yet, paradoxically, with climate change these crops, agriculture and knowledge systems seem to hold the future, especially for smallholder farmers.

Summer-Time Monitoring And Source Apportionment Study Of Both Coarse, Fine, And Ultra-Fine Particulate Pollution In Eastern Himalayan Darjeeling: A Hint To Health Risk During Peak Tourist Season

Summer-Time Monitoring And Source Apportionment Study Of Both Coarse, Fine, And Ultra-Fine Particulate Pollution In Eastern Himalayan Darjeeling: A Hint To Health Risk During Peak Tourist Season

A new genus of Assamiidae (Opiliones, Grassatores) from Xizang, China.

Knowledge of the family Assamiidae in the Eastern Himalayas is primarily concentrated from Nepal, while Bhutan, Xizang, and northeastern India remain much less studied. Herein, a new genus, Linzhiassamia gen. nov., is described from Xizang, China, along with two new species, Linzhiassamiamedogensis sp. nov. and Linzhiassamiazayuensis sp. nov. These represents the first records of the family Assamiidae from Xizang. A comparative analysis with other continental Asian Assamiidae is undertaken, with a focus on genital morphology. Potential closest relatives are identified, including the genus Dhaulagirius Martens, 1977 from Nepal.