Anoop Kumar Singh

Recent Wetting and Glacier Expansion in the Northwest Himalaya and Karakoram

Hydroclimatic variability driven by global warming in the climatically vulnerable cold semi-arid to arid northwest (NW) Himalaya is poorly constrained due to paucity of continuous weather records and annually resolved proxies. Applying a network of annually resolved tree-ring-width chronologies from semi-arid region of Kishtwar, Jammu and Kashmir, India, we reconstructed April-May standardized precipitation index extending back to A.D. 1439 (576 years). The reconstructed series is featured by the most conspicuous long-term droughts during the 15th to early 17th centuries followed by a general wetting, with 1984–2014 being the wettest interval in the past 576 years. The data, consistent with other independently developed tree-ring-based hydrological records from cold semi-arid to arid NW Himalaya and Karakoram, point to an increased regional wetting in the recent decades. Such an increased wetting might have led to the anomalous behaviour of glaciers in the NW Himalaya and Karakoram in contrast to the general receding trends in the central and eastern Himalaya.

Structural Overview and Morphotectonic Evolution of a Strike-Slip Fault in the Zone of North Almora Thrust, Central Kumaun Himalaya, India

The aim of the present research is to provide the base line details of the NNW-SSE trending Raintoli fault (RF) which is running parallel to the North Almora Thrust (NAT) along the Saryu valley from Seraghat-Naichun to Seri in the central sector of the Uttarakhand Himalaya, India. The RF is characterized as dextral strike slip fault and behaves as a ductile shear zone within the zone of NAT. The dextral sense of shear movement of RF is delineated by the fabric of the shear zone rocks including microscopically observed indicators such as sigma and delta porphyroclasts, quartz c-axis, and the field structural data. Additionally, in the quaternary period the dextral strike slip fault is reactivated with oblique slip component as characterized by various geomorphic indicators, for example, triangular facets, abandoned river channels, unpaired fluvial terraces, and V-shaped valleys with recurrent seismicity. Further, the morphometric parameters including Valley Floor Width to Valley Height ( ), asymmetry factor (AF), and gradient index (GI) further prove active nature of RF as suggested by low values of hypsometric integration, V-shaped valley, higher gradient index, and tilting of Saryu basin.

Stalagmite Inferred High Resolution Climatic Changes throughPleistocene-Holocene Transition in Northwest Indian Himalaya

Investigated for d18O and d13C isotopes, mineralogy and growth rate, a 20 cm long and 230Th-dated calcite stalagmite from Kalakot (Jammu and Kashmir Himalaya), has recorded high resolution precipitation variability during the Pleistocene-Holocene transition. At present, the study area is influenced by both the Indian Summer Monsoon (ISM) and Westerlies. The StalAge model indicates that the stalagmite grew between 16.3 ka to 9.5 ka BP under the ideal isotopic equilibrium conditions as revealed by the Hendy test results. The d18O and d13C values range from -5.41 to -8.82% and -7.09 to -10.84% respectively. Although the U/Th chronology is poor due to low Uranium content in the samples resulting in relatively large errors, the first stalagmite inferred precipitation variability reconstructed from NW Indian Himalaya makes this study significant. The near footprints of three global events, e.g., Older Dryas (OD), Allerod period and Younger Drays (YD) can be noticed at ~14.3-13.9, 13.9-12.7 and 12.7-12.2 ka BP. The precipitation strength was weaker during the OD and YD, but was stronger during the Allerod interstadial. By the termination of YD interval, the climate seems fluctuating in the NW Himalaya. There seems variation in commencement, duration and termination of the above mentioned events in different parts of the globe due to latitude location and response time.

Rivers of Uttarakhand Himalaya: Impact of Floods in the Pindar and Saryu Valleys

The Uttarakhand Himalaya is frequently rocked by cloud burst-/heavy rainfall-induced floods during monsoon period. The resultant of the events is not only loss of million dollar properties but also toll of local inhabitants as well as pilgrimages as the state have various shrines. Several rivers originate from the Himalayan region and provide the drinking water to millions of people in India. Whereas, the behaviours of the rivers seems to be very precarious and carry floods in downstream region sometime due to excessive precipitation. Considering the significance of the rivers of the region, the present investigation focused on flood events along Pindar and Saryu valleys and its cause and impact on inhabitant. Both the valleys are criss-crossed by numbers of thrusts/faults, which makes the region more prone to disasters. Various geomorphic features e.g. immature topography, deflecting river courses, ponding of ancient drainage, development of cascades, formation of unpaired fluvial terraces and series of triangular fault facets suggested the tectonic modification within the valleys along thrusts/faults. Thus, the fragile lithology, torrential rainfall, accelerating erosion and incision with higher uplift due to tectonic upheaval along the active faults play a significant role in destabilizing of the river valleys and responsible for rainfall-induced catastrophes in the region. Moreover, the anthropogenic disturbance with increased pressure of urbanization, ignorance and poor understanding of geological structures pulverizing the river dynamics as well. Therefore, it is suggested that the impact and human causality can be minimized along the river valleys through detail investigations of geological structure, proper guidelines for sustainable development and awareness of processes of landslides-/cloudburst-induced floods. Further, it needs to relocate the people to safer side on the flat and gentler slopes without waiting for next disaster as relocation is much better than rehabilitation.

Speleothems and Climate

The Karst topography describes the dissolution of underlying soluble rocks by surface water or ground water. This is commonly found in carbonate terrain (limestone and dolomite) in mountainous regions. The rain water infiltrates through the cracks of the rocks in the vertical manner until it reaches the water table and thereafter, it moves horizontally below the surface of water table. The conditions of this process are, (1) exposure of thick limestone cover the ground surface, and (2) limestone cover overlain by non soluble rocks. The discernible character of the karst topography is simply known as caves and sinkholes.

Studied Speleothems and Methodology

Considering the vast expansion of limestone host rock throughout the Himalaya, we studied six caves in the different sectors (Fig. 3.1) under varying precipitation regimes. These are, Kalakot Cave (33°13′19″ N: 74°25′33″ E; altitude, 826 m) from Jammu and Kashmir; Borar Cave (30°38′18″ N: 77°39′09″ E; altitude, 1622 m) and Tityana Cave (30°38′30.7″ N: 77° 39′07.4″ E; altitude, 1470 m) from Himachal Pradesh; Dharamjali Cave (29°31′27.8″ N: 80°12′40.3″ E; altitude, 2200 m), Sainji Cave (30°16′07″ N: 79°18′14″ E; altitude, 1478 m) and Chulerasim Cave (29°53′08″ N: 79°21′06″ E; altitude, 1254 m) from Uttarakhand.