@article{MenzelGayeMishraetal.2014, author = {Menzel, Philip and Gaye, Birgit and Mishra, Praveen Kumar and Anoop, Ambili and Basavaiah, Nathani and Marwan, Norbert and Plessen, Birgit and Prasad, Sushma and Riedel, Nils and Stebich, Martina and Wiesner, Martin G.}, title = {Linking Holocene drying trends from Lonar Lake in monsoonal central India to North Atlantic cooling events}, series = {Palaeogeography, palaeoclimatology, palaeoecology : an international journal for the geo-sciences}, volume = {410}, journal = {Palaeogeography, palaeoclimatology, palaeoecology : an international journal for the geo-sciences}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0031-0182}, doi = {10.1016/j.palaeo.2014.05.044}, pages = {164 -- 178}, year = {2014}, abstract = {We present the results of biogeochemical and mineralogical analyses on a sediment core that covers the Holocene sedimentation history of the climatically sensitive, closed, saline, and alkaline Lonar Lake in the core monsoon zone in central India. We compare our results of C/N ratios, stable carbon and nitrogen isotopes, grain-size, as well as amino acid derived degradation proxies with climatically sensitive proxies of other records from South Asia and the North Atlantic region. The comparison reveals some more or less contemporaneous climate shifts. At Lonar Lake, a general long term climate transition from wet conditions during the early Holocene to drier conditions during the late Holocene, delineating the insolation curve, can be reconstructed. In addition to the previously identified periods of prolonged drought during 4.6-3.9 and 2.0-0.6 cal ka that have been attributed to temperature changes in the Indo Pacific Warm Pool, several additional phases of shorter term climate alteration superimposed upon the general climate trend can be identified. These correlate with cold phases in the North Atlantic region. The most pronounced climate deteriorations indicated by our data occurred during 62-5.2,4.6-3.9, and 2.0-0.6 cal ka BP. The strong dry phase between 4.6 and 3.9 cal ka BP at Lonar Lake corroborates the hypothesis that severe climate deterioration contributed to the decline of the Indus Civilisation about 3.9 ka BP. (C) 2014 Elsevier B.V. All rights reserved.}, language = {en} } @article{BasavaiahWiesnerAnoopetal.2014, author = {Basavaiah, Nathani and Wiesner, M. G. and Anoop, Ambili and Menzel, P. and Nowaczyk, Norbert R. and Deenadayalan, K. and Brauer, Achim and Gaye, Birgit and Naumann, R. and Riedel, N. and Stebich, M. and Prasad, Sushma}, title = {Physicochemical analyses of surface sediments from the Lonar Lake, central India - implications for palaeoenvironmental reconstruction}, series = {Fundamental and applied limnology : official journal of the International Association of Theoretical and Applied Limnology}, volume = {184}, journal = {Fundamental and applied limnology : official journal of the International Association of Theoretical and Applied Limnology}, number = {1}, publisher = {Schweizerbart}, address = {Stuttgart}, issn = {1863-9135}, doi = {10.1127/1863-9135/2014/0515}, pages = {51 -- 68}, year = {2014}, abstract = {We report the results of our investigations on the catchment area, surface sediments, and hydrology of the monsoonal Lonar Lake, central India. Our results indicate that the lake is currently stratified with an anoxic bottom layer, and there is a spatial heterogeneity in the sensitivity of sediment parameters to different environmental processes. In the shallow (0-5 m) near shore oxic-suboxic environments the lithogenic and terrestrial organic content is high and spatially variable, and the organics show degradation in the oxic part. Due to aerial exposure resulting from lake level changes of at least 3m, the evaporitic carbonates are not completely preserved. In the deep water (>5 m) anoxic environment the lithogenics are uniformly distributed and the delta C-13 is an indicator not only for aquatic vs. terrestrial plants but also of lake pH and salinity. The isotopic composition of the evaporites is dependent not only on the isotopic composition of source water (monsoon rainfall and stream inflow) and evaporation, but is also influenced by proximity to the isotopically depleted stream inflow. We conclude that in the deep water environment lithogenic content, and isotopic composition of organic matter can be used for palaeoenvironmental reconstruction.}, language = {en} } @article{MishratAnoopJehangiretal.2014, author = {Mishrat, Praveen K. and Anoop, A. and Jehangir, A. and Prasad, Sushma and Menze, R. and Schettler, Georg and Naumann, R. and Weise, S. and Andersen, N. and Yousuf, A. R. and Gaye, Birgit}, title = {Limnology and modern sedimentation patterns in high altitude Tso Moriri Lake, NW Himalaya - implications for proxy development}, series = {Fundamental and applied limnology : official journal of the International Association of Theoretical and Applied Limnology}, volume = {185}, journal = {Fundamental and applied limnology : official journal of the International Association of Theoretical and Applied Limnology}, number = {3-4}, publisher = {Schweizerbart}, address = {Stuttgart}, issn = {1863-9135}, doi = {10.1127/fal/2014/0664}, pages = {329 -- 348}, year = {2014}, abstract = {We report the results of our investigations on the catchment area, lake surface sediments, and hydrology of the high altitude alpine Tso Moriri Lake, NW Himalayas (India). Our results indicate that the lake is currently alkaline, and thermally stratified with an oxic bottom layer. Results from hydrochemistry and isotopic composition (delta O-18 and delta D) of inflowing streams and lake waters show that Tso Moriri Lake is an evaporative lake with contributions from both westerly source (snow melt) and Indian summer monsoon precipitation. Geochemical and mineralogical investigations on the catchment and lake surface sediments reveal the presence of authigenic aragonite in modern lake sediment. The lithogenic components reflect the inflow and sorting processes during transport into the lake, whereas the authigenic carbonate fraction can be linked to the changes in ([precipitation+meltwater]/evaporation) (I/E) balance within the lake. The spatial variability in grain size distribution within the lake surface sediments shows that the grain size data can be utilised as a proxy for transport energy and shoreline proximity in the lake basin. We have evaluated the applicability of commonly applied environmentally sensitive proxies (isotopes, mineralogy, weathering indices) for palaeoenvironmental reconstruction in the Tso Moriri Lake. Our results show that the commonly used weathering index (Rb/Sr) is not applicable due to Sr contribution from authigenic carbonates. The useful weathering indices in Tso Moriri Lake are the Si/Al and the Chemical Proxy of Alteration (CPA). Since the carbonates are formed by evaporative processes, their presence and isotopic values can be used as indicators of I/E changes in the lake.}, language = {en} } @article{PrasadAnoopRiedeletal.2014, author = {Prasad, Sushma and Anoop, A. and Riedel, N. and Sarkar, Saswati and Menzel, P. and Basavaiah, Nathani and Krishnan, R. and Fuller, D. and Plessen, Birgit and Gaye, B. and Roehl, U. and Wilkes, H. and Sachse, Dirk and Sawant, R. and Wiesner, M. G. and Stebich, M.}, title = {Prolonged monsoon droughts and links to Indo-Pacific warm pool: A Holocene record from Lonar Lake, central India}, series = {Earth \& planetary science letters}, volume = {391}, journal = {Earth \& planetary science letters}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0012-821X}, doi = {10.1016/j.epsl.2014.01.043}, pages = {171 -- 182}, year = {2014}, abstract = {Concerns about the regional impact of global climate change in a warming scenario have highlighted the gaps in our understanding of the Indian Summer Monsoon (ISM, also referred to as the Indian Ocean summer monsoon) and the absence of long term palaeoclimate data from the central Indian core monsoon zone (CMZ). Here we present the first high resolution, well-dated, multiproxy reconstruction of Holocene palaeoclimate from a 10 m long sediment core raised from the Lonar Lake in central India. We show that while the early Holocene onset of-intensified monsoon in the CMZ is similar to that reported from other ISM records, the Lonar data shows two prolonged droughts (PD, multidecadal to centennial periods of weaker monsoon) between 4.6-3.9 and 2-0.6 cal ka. A comparison of our record with available data from other ISM influenced sites shows that the impact of these PD was observed in varying degrees throughout the ISM realm and coincides with intervals of higher solar irradiance. We demonstrate that (i) the regional warming in the Indo-Pacific Warm Pool (IPWP) plays an important role in causing ISM PD through changes in meridional overturning circulation and position of the anomalous Walker cell; (ii) the long term influence of conditions like El Nino-Southern Oscillation (ENSO) on the ISM began only ca. 2 cal ka BP and is coincident with the warming of the southern IPWP; (iii) the first settlements in central India coincided with the onset of the first PD and agricultural populations flourished between the two PD, highlighting the significance of natural climate variability and PD as major environmental factors affecting human settlements.}, language = {en} }