Geological Observations from a Palaeolake Basin, Lamayuru, Ladakh, Northwestern Himalaya

A well known Buddhist monastery of Lamayuru is located in a village about 128 Km West of Leh. It is situated on more than 100 m thick Late Quaternary palaeolake deposits which are surrounded by rocks of Lamayuru Formation. Geologically, the Lamayuru Formation includes the Lamayuru and Namikala flysch deposits of Triassic-Jurassic age. This Formation is composed of shales, schist and phyllites. This Lamayuru Formation forms the base and source of palaeolake deposits. In Late-Pleistocene (35 ka B.P.) the Lamayuru River was dammed due to tectonically triggered landslide and the Lamayuru palaeolake came into existence. The sedimentation in the palaeolake basin commenced at 35 ka B.P. and culminated at 1 ka B.P. The deposits of palaeolake consist of carbonaceous mud, sand, silty clay and matrix supported breccia. The palaeolake deposits are a product of complex interplay of lacustrine, fluvio-deltaic to colluvial processes. The research study shows the prevalence of glacio-lacustrine conditions during the major part of depositional history as evidenced by the dominance of varves in these deposits.

Impacts of tourism development on the physical environment of Mussoorie,a hill station in the lower Himalayan range of India

Tourism in mountainous regions is a significant source of revenue generation. However, it has also been associated with many adverse environmental consequences. This study aims at assessing the negative impacts of the incessant upsurge in tourism development on the physical environment of Mussoorie, a well-known mountain tourist destination in India. The impact indicators for the region were identified and assessed by qualitative and quantitative analysis of field observations. The observations indicated the aggravation of traffic congestion, atmospheric pollution, undisposed solid waste, water scarcity and infrastructure unavailability as the prevalent issues, especially during the peak tourist months. The extent of the consequential damage to the environment was evaluated by conducting an assessment of tourism-induced human disturbance on the natural landscape of the town. Slope, slope aspect, vegetation cover, road network and drainage network were incorporated as thedetermining landscape attributes to prepare thematic maps of landscape quality(perceivable intrinsic properties) and landscape fragility(vulnerability to anthropogenic disturbances) using GIS technique. An absorption capacity map was finally prepared to characterize the study area into regions of different conservation needs. The results identified the need for planning appropriate preservation strategies for different tourist places in the town. The study can be used by the policy makers for implementing the regulatory measures against potential disturbances due to mass-tourism.

Active Tectonic Strike-Slip Fault Development near Goran, Samba and Kathua Districts, Jammu and Kashmir

Active tectonic morphometric studies of the sparsely investigated frontal Siwalik terrain around Goran in the Samba district bordering the Kathua district of J&K reveal the presence of NW-SE trending active sinistral strike-slip fault with oblique slip component which is parallel to the Surin-Masatgarh anticline. The Basantar River, the Tarnah stream, the Ujh River, the Sahaar stream and the Ravi River exhibit significant stream offsets where the fault crosses these channels. The values of the morphometric indices viz. stream sinuosity index (S), stream length gradient index (SL), valley floor width to valley height ratio (Vf), mountain front sinuosity index (Smf), hypsometric integral (Hi), basin asymmetry ratio (AF) and basin elongation ratio (Eb) calculated along the linear river offsets with respect to longitudinal River segments of the Rivers Basantar, Tarnah, Ujh, Sahaar and Ravi Rivers reveal that terrain is tectonically active and can be placed in tectonic active class I. The fault has an apparent offset of about 2000 m with it as it crosses the Basantar, the Tarnah, the Ujh, the Sahaar and the Ravi Rivers. The stream offsets upon field and laboratory investigations are developed due to an active sinistral strike slip fault which is being named as Goran fault. This fault has a surface expression of 100 km extending from the Basantar in the northwest up to the Beas River in the southwest whereas the remaining segment may exist as a hidden fault all along the Himalaya.

Machine learning assisted derivation of minimal low-energy models for metallic magnets

We consider the problem of extracting a low-energy spin Hamiltonian from a triangular Kondo Lattice Model(KLM).The non-analytic dependence of the effective spin-spin interactions on the Kondo exchange excludes the use of perturbation theory beyond the second order.We then introduce a Machine Learning(ML)assisted protocol to extract effective two-and four-spin interactions.The resulting spin model reproduces the phase diagram of the original KLM as a function of magnetic field and single-ion anisotropy and reveals the effective four-spin interactions that stabilize the field-induced skyrmion crystal phase.Moreover,this model enables the computation of static and dynamical properties with a much lower numerical cost relative to the original KLM.A comparison of the dynamical spin structure factor in the fully polarized phase computed with both models reveals a good agreement for the magnon dispersion even though this information was not included in the training data set.