Near‐Surface Geomechanical Properties and Weathering Characteristics Across a Tectonic and Climatic Gradient in the Central Nepal Himalaya

The Lesser Himalayan Sequence of the Taplejung Window in the far eastern Nepal Himalaya can be divided into Taplejung Formation, Mitlung Augen Gneiss and Linkhim Schist (from bottom to top respectively). The window is a large domal shaped anticline plunging to the east. Two-mica granite bodies (Amarpur Granite, Kabeli Khola Granite and Tamor River Granite) have intruded the metasediments of Taplejung Formation. The granite bodies are discordant to subconcordant in relation to the country rocks. Quartz, alkali feldspar, plagioclase, muscovite, biotite and tourmaline are the main constituent minerals of the granite. Generally, the core of granite bodies is undeformed, whereas the marginal part is gneissfied with S-C mylonitic texture showing the top to south sense of shear. This sense of shear is related to the movement along the Main Central Thrust (MCT). All the samples from the granitic bodies fall under the granite field in the normative quartz-alkali feldspar-plagioclase (QAP) triangular diagram. The mineral composition shows that the granite is peraluminous in nature. The Kabeli Khola Granite has yielded a 40Ar/ 39Ar muscovite age older than 1.6 Ga indicating its magmatic age. The granites of the study area can also be correlated with the 1.8 Ga Ulleri type augen gneiss of central Nepal.

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Petrography of the Siwalik sandstones, Amlekhganj-Suparitar area, central Nepal Himalaya

Journal of Nepal Geological Society ◽

10.3126/jngs.v28i0.31722 ◽

2003 ◽

Vol 28 ◽

Author(s):

Naresh Kazi Tamrakar ◽

Shuichiro Yokota ◽

Suresh Das Shrestha

Keyword(s):

Middle Miocene ◽

Foreland Basin ◽

Early Pleistocene ◽

Nepal Himalaya ◽

Central Nepal ◽

Present Study Area ◽

Mean Grain Size ◽

Siwalik Group ◽

Variation Trends ◽

The Himalaya

Middle Miocene to early Pleistocene sedimentary sequence deposited in the foreland basin of the Himalaya is represented by the Siwalik Group. In the present study area the Siwalik Group extends in a NW-SE direction and well-exposed. Fortyfour sandstone samples were studied for texture, fabric and composition in order to assess their petrographic properties and variation trends of these properties in stratigraphic levels. Sandstones were classified into sublitharenite, subarkose, lithic arenite, arkosic arenite and feldspathic graywacke and further thirteen sub-clans. Mean grain size (M) and Trask sorting coefficient (So) increase up-section. Recalculated quartz, matrix, modified maturity index (MMI), total cement (Ct), cement versus matrix index (CMI) and ratio of strong cement over total cement ((Cfc/Cs)/Ct) also increase, whilst packing proximity (PP), packing density (PD) and consolidation factor (Pcc) decrease up-section showing distinct trends, and therefore, these properties are promising in recognizing the older sandstones from the younger ones.

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Distribution of boron in the rocks of central Nepal Himalaya

Journal of Nepal Geological Society ◽

10.3126/jngs.v28i0.31723 ◽

2003 ◽

Vol 28 ◽

Author(s):

Santa Man Rai

Keyword(s):

Partial Melting ◽

Boron Content ◽

Lesser Himalaya ◽

Main Central Thrust ◽

Nepal Himalaya ◽

Metasedimentary Rocks ◽

Central Nepal ◽

Very High

Boron content in the rocks of central Nepal Himalaya depends upon the lithology and the grade of metamorphism. The concentration of boron is abundant (up to 322 ppm) in the metasedimentary rocks of the Lesser Himalaya. There seems to be a rather good correlation between the boron content in the rocks and the grade of metamorphism. The boron content progressively increases from chlorite to garnet isograds, then it systematically decreases in the staurolite±kyanite, kyanite and sillimanite isograds, respectively. This trend may be related to the inverse metamorphism associated with movement along the Main Central Thrust. The Manaslu leucogranite contains very high amount of boron (950 ppm). The enrichment of boron in this rock may be due to the release of boron from the Lesser Himalayan rocks during the partial melting of the Higher Himalayan Crystallines (Tibetan Slab) as a result of the movement along the MCT. Tourmaline from the Manaslu Granite is also highly rich in boron (8460 ppm).

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Assessing the Livelihood Vulnerability of Rural Indigenous Households to Climate Changes in Central Nepal, Himalaya

Sustainability ◽

10.3390/su11102977 ◽

2019 ◽

Vol 11 (10) ◽

pp. 2977 ◽

Cited By ~ 10

Author(s):

Nani Maiya Sujakhu ◽

Sailesh Ranjitkar ◽

Jun He ◽

Dietrich Schmidt-Vogt ◽

Yufang Su ◽

...

Keyword(s):

Climate Change ◽

Vulnerability Index ◽

Financial Assets ◽

Nepal Himalaya ◽

Mountain Communities ◽

Farming Communities ◽

Central Nepal ◽

Gender Based ◽

And Gender ◽

Ethnicity And Gender

Climate change and related hazards affect the livelihoods of people and their vulnerability to shocks and stresses. Though research on the linkages between a changing climate and vulnerability has been increasing, only a few studies have examined the caste/ethnicity and gender dimensions of livelihood vulnerability. In this study, we attempt to explore how cultural and gender-related aspects influence livelihood vulnerability in indigenous farming mountain communities of the Nepal Himalaya in the context of climate change. We applied the Livelihood Vulnerability Index (LVI) to estimate household (social group and gender-based) vulnerability in farming communities in the Melamchi River Valley, Nepal. The results identified female-headed families, and those belonging to disadvantaged social groups as more vulnerable and in need of being preferentially targeted by policy measures. Higher exposure to climatic extremes and related hazards, dependency on natural resources, lack of financial assets, and weak social networking were identified as components that determine overall vulnerability. The study also visualizes complex adaptation pathways and analyzes the influence of gender and ethnicity on the capacities of households and communities to adapt to climate change.

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Lithofacies and depositional environment of the Siwalik Group in Samari-Sukaura River area, Central Nepal

Bulletin of the Department of Geology ◽

10.3126/bdg.v16i0.8884 ◽

2013 ◽

Vol 16 ◽

pp. 53-64 ◽

Cited By ~ 3

Author(s):

Dev Kumar Syangbo ◽

Naresh Kazi Tamrakar

Keyword(s):

Depositional Environment ◽

Foreland Basin ◽

River System ◽

Nepal Himalaya ◽

Meandering River ◽

Fine Grained ◽

Architectural Elements ◽

Central Nepal ◽

Eastern Zone ◽

Siwalik Group

Thick sedimentary sequence deposited in the foreland basin of the Nepal Himalaya is represented by the Siwalik Group. The Siwalik Group is well exposed in the Samari-Sukaura River area. The present study is focused in southern portion of the MBT around the Samari-Sukaura area for its depositional environment. The Middle Siwaliks of the Sukaura Road sections is overlained by the Lower Siwaliks which is separated by the Karki Khola Thrust. Extension of the Lower Siwaliks in the Jyamire Khola and the Bundal Khola becomes wider in the eastern Zone. Repetition of the Lower Siwaliks along the southern margin of the MBT is recognized. Depending on lithofacies assemblage and facies analysis, the two broad facies assemblages FA1 and FA2 have been distinguished. FA1 shows SB, FF, LA, LS and CH architectural elements and is interpreted as a product of the fine-grained meandering river system. FA2 shows SB, FF, LA, DA and CH architectural elements and is interpreted as a product of sandy mixed-load meandering river system. DOI: http://dx.doi.org/10.3126/bdg.v16i0.8884 Bulletin of the Department of Geology Vol. 16, 2013, pp. 53-64

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Distribution pattern and species richness of Liliaceae in the Nepal Himalaya

Our Nature ◽

10.3126/on.v14i1.16437 ◽

2017 ◽

Vol 14 (1) ◽

pp. 22-29 ◽

Cited By ~ 1

Author(s):

Hum Kala Rana ◽

Santosh Kumar Rana ◽

Suresh Kumar Ghimire

Keyword(s):

Species Richness ◽

Potential Distribution ◽

Plant Conservation ◽

Management Program ◽

Nepal Himalaya ◽

Creative Commons ◽

Mountainous Regions ◽

Central Nepal ◽

Richness Pattern ◽

High Species Richness

The most important aspect of plant conservation is to predict the potential distribution and its richness in response to climate change. Contributing to the management program, this study aimed to predict the distribution and richness pattern of Liliaceae in Nepal. The BIOCLIM in DIVA GIS 7.5 model based on distribution records of 19 species belonging to three subfamilies of Liliaceae (Lilioideae, Streptopoideae and Calochortoideae) and 19 climatic variables (derived from Worldclim), revealed that Lilioideae and Streptopoideae are potentially distributed in most of the hilly and mountainous regions of Nepal; whereas Calochortoideae mostly in Eastern and very scanty in Central Nepal. Lilioideae is projected to have high species richness in Central and Western Nepal as compared to other subfamilies. This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License.

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Paleohydrological reconstruction of the Siwalik Group along the Tinau Khola section, west-central Nepal Himalaya

Journal of Nepal Geological Society ◽

10.3126/jngs.v39i0.31485 ◽

2009 ◽

Vol 39 ◽

Author(s):

Prakash Das Ulak

Keyword(s):

Slope Gradient ◽

Nepal Himalaya ◽

Sedimentary Sequences ◽

Central Nepal ◽

Frontal Part ◽

West Central ◽

Channel Slope ◽

Siwalik Group ◽

The Himalaya ◽

Velocity Channel

Neogene fluvial sedimentary sequences of the Siwalik Group are extensively accumulated in the southern frontal part of the Himalaya and well exposed in the Tinau Khola section of the west-central Nepal Himalaya. The group reveals a coarsening upwards succession in general but many fining-upwards fluvial successions on a scale from several to tens of metres is established in each lithological unit. The paleohydrological characteristics have been estimated using thickness of fining upwards fluvial successions, their grain diameters, and bedforms. The paleohydrology suggests an increase in flow velocity, channel slope gradient, and discharge of the fluvial system. Paleovelocity varies from 0.17 to 5.31 m/s, paleochannel gradient and paleodischarge change from l.13x10-5 to 7.33x10-4 m/m and 101 to 104 m3/s, respectively towards the stratigraphic top. These progressively changing paleohydrological characteristics reflect the southward propagation of thrusts caused by the upheaval of the Himalaya.

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