The collision of India with the Eurasian plate and the subsequent uplift of the Himalayas and Tibetan Plateau (HTP) have been implicated in the development of the Asian monsoon system (Molnar et al., 1993) and the consequent increased drawdown of atmospheric CO 2 through enhanced silicate weathering or organic carbon burial (France-Lanord & Derry, 1997; Raymo & Ruddiman, 1992). A reduction of atmospheric CO 2 associated with HTP uplift has been invoked as a cause of major global cooling and establishment of permanent Antarctic ice sheets that characterized the transition from the Cenozoic greenhouse to the present icehouse climate (Raymo & Ruddiman, 1992). The development of the monsoon has even been suggested to have itself influenced HTP tectonics by increased erosion and exhumation (e.g., Clift et al., 2008; Harris, 2007; Iaffaldano et al., 2011). The timing of Asian monsoon development is debated with proposed ages clustering around the Late Miocene (∼8-11 Myrs ago) (Molnar et al., 1993) and Late Oligocene/Early Miocene (∼25−22 Myrs ago) (Clift et al., 2008; Guo, 2002) but there is even evidence for a strong seasonality of precipitation in the region as early as ∼39 Myrs ago (Licht et al., 2014). The elevation histories of the Himalayas and the Tibetan Plateau are poorly constrained and most likely distinct with data suggesting significant elevation of parts of Tibet prior to collision with India and a well-developed proto-plateau by the Eocene (see review by Wang et al., 2014). There are even fewer paleo-elevation data for the Himalayas with recent studies suggesting that the mountains just south of the Yarlung-Tsangpo suture were higher than 2 km in the early Miocene and at a similar elevation to today for at least the past 15 Myrs (Ding et al., 2017; Gébelin et al., 2013). The uplift and exhumation histories of different regions within the Himalayas were also likely asynchronous with the age of exposed leucogranites decreasing from west to east along the central Himalaya (Harris, 2007; Webb et al., 2017). The orographic insulation caused by the Himalayas is thought to have been an important driver of monsoon evolution (Boos & Kuang, 2010) but our understanding of the interaction of tectonics, monsoon-driven erosion, silicate weathering and global

The Late Quaternary variability of the South Asian (or Indian) monsoon has been linked with glacial-interglacial and millennial scale climatic changes but past rainfall intensity in the river catchments draining into the Andaman Sea remains poorly constrained. Here we use radiogenic Sr, Nd, and Pb isotope compositions of the detrital clay-size fraction and clay mineral assemblages obtained from sediment core NGHP Site 17 in the Andaman Sea to reconstruct the variability of the South Asian monsoon during the past 60 kyr. Over this time interval eNd values changed little, generally oscillating between 27.3 and 25.3 and the Pb isotope signatures are essentially invariable, which is in contrast to a record located further northeast in the Andaman Sea. This indicates that the source of the detrital clays did not change significantly during the last glacial and deglaciation suggesting the monsoon was spatially stable. The most likely source region is the Irrawaddy river catchment including the Indo-Burman Ranges with a possible minor contribution from the Andaman Islands. High smectite/(illite 1 chlorite) ratios (up to 14), as well as low 87 Sr/ 86 Sr ratios (0.711) for the Holocene period indicate enhanced chemical weathering and a stronger South Asian monsoon compared to marine oxygen isotope stages 2 and 3. Short, smectite-poor intervals exhibit markedly radiogenic Sr isotope compositions and document weakening of the South Asian monsoon, which may have been linked to short-term northern Atlantic climate variability on millennial time scales.

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The demand for fresh spring water recently increased due to intensive domestic, industrial irrigation practices which typically caused depletion of water resources and deterioration of water quality. The spring water quality was analyzed for its major hydrochemistry and hydrochemical evolution of the spring water in the study area. A total of 60 spring water samples were collected from the three kinds of terrain (mountainous, hilly and plain) and analyzed for pH, electrical conductivity (EC), total dissolved solids (TDS), total hardness (TH), calcium (Ca 2þ), magnesium (Mg 2þ), sodium (Na þ), potassium (K þ), bicarbonate (HCO 3 À), sulphate (SO 4 2À), chloride (Cl À), nitrate (NO 3 À), and fluoride (F À). The water quality of drinking purposes was plotted in the Piper trilinear diagram which reveals that spring hydrochemistry is dominated by the alkaline earth and weak acids. Gibbs diagram reveals that the spring water chemistry is primarily controlled by rock-water interaction in the investigated region. The water quality index (WQI), 45% of samples fall in the excellent category, 50% of spring samples fall in good categories for drinking purposes. The pH and TDS are within the permissible limit ranges from 7 to 8.4 and 123to 793 respectively. Based on chemical analysis of the various parameters such as non-carbonate hardness, sodium percentage sodium absorption ratio, residual sodium carbonate were calculated to define the quality of spring water for irrigation purposes. The discharge of spring water was also calculated during the pre-monsoon season and found that 70% of samples have discharge more than 20 L per second (Lps).