Large Mammals from the Plio-Pleistocene of Kashmir Inter-mountane Basin, India, with Reference to their Status in Magnetic Polarity Time Scale

Reste von Großsäugern (Equus, Elephas, Cervus und Canis) aus der plio-pleistozänen Karewa-Formation des Kashmir-Beckens in NW-Indien werden beschrieben. Da die Fossilien aus paläomagnetisch datierten Schichten stammen, kann hier erstmals eine zeitliche Korrelation für das Auftreten der Großsäuger für das Kashmir-Becken gegeben werden. Equus und Cervus erscheinen erstmals vor etwa 2.0 Mio. Jahren, während Elephas und Canis erst in der Brunhes-Epoche belegt sind. Das Auftreten dieser Gattungen wird mit anderen bekannten biochronologischen Sequenzen des Subkontinentes verglichen und kurz auf die Grenzziehung zwischen Plio- und Pleistozän in Nordindien eingegangen.researc

Evolution of Lamayuru palaeolake in the Trans Himalaya: Palaeoecological implications

Vor etwa 35 000-40 000 Jahren schuf eine Episode neotektonischer Aktivität an der Indus-Sutur bei Lamayuru (Ladakh) einen See, von dem eine über 105 m mächtige Abfolge fluviolakustriner Ablagerungen erhalten ist. Die zwischen Ton/Silt/Sand eingelagerten lakustrinen Horizonte (Kalkschlämme) und karbonatreichen Schichten haben Süßwasser-Ostrakoden, Gastropoden und Charophyten geliefert. Insgesamt wurden 9 Fossilhorizonte angetroffen. Die hauptsächlichen Ostrakodentaxa sind llyocypris (l. gibba und I. bradyi), Eucypris und Candona. Bei den Gastropoden dominieren Lymnaea, Succinea und Gyraulus. Die Charophyten werden durch Chara globularis vertreten. Die paläoökologische Interpretation basiert auf den charakteristischen Faunen- und Florenelementen und auf der Natur der Sedimente. Es wird vermutet, daß der See während seiner ganzen Existenz ziemlich flach war und kaltes, extrem salzarmes, langsam fließendes, pflanzenreiches Wasser führte. Als ein offenes Becken mag er einen kontinuierlichen Abfluß während seiner ganzen Existenz gehabt haben. Die Entleerung des Sees wurde verursacht durch eine strukturelle Zerrüttung des Seebodens und die Ausfüllung durch riesige, durch einen weiteren Impuls tektonischer Aktivität ausgelöste Schuttmassen.researc

Morphotectonic assessment of the Gaula river basin, Kumaun lesser Himalaya, Uttarakhand

Morphotectonics is a discipline of geomorphology that explores how landforms are formed or modified by tectonic action. In the present study we uthe sed application of geospatial technology to evaluate the active deformation owing to Main Boundary Thrust (MBT) and Ramgarh Thrust (RT) in Outer part of Kumaun Lesser Himalaya. Active deformation inside river valleys is ascribed downcuttinging and incision of bedrock, offset of river channel, lateral migration of the river, and development of Knickpoints. Therefore, we used quantitative geo-mathematical analysis of The Gaula river basin using ASTER DEM along with survey of India Toposheet (1:50,000) supplemented by field observations. Four morphotectonic metrics, including the basin elongation ratio, the asymmetry factor, the channel sinuosity, and the hypsometric integral, were derived to examine the relative index of active tectonics (RIAT). We applied Stream Power Incision Model (SPIM) by analysing the steepness index (Ksn) using the stream power law. Additionally, a comprehensive evaluation of tributary streams of the Gaula watershed has been carried out to understand relative tectonic activity. Further we used Chi integral (χ) to measure transience dynamics and geometric disequilibrium of Gaula basin. We conclude that most sub-basins are tectonically enhanced, structurally organized and elongated in nature. The landform in the study area is largely controlled by presence of MBT, RT and subsidiary thrusts spread over in the vicinity. Based on our activity classes we concluded that approximately 31% of the area in Gaula river basin falls in very active whereas ∼34% is potentially active. Furthermore, we suggest that the results will be very useful for estimation of hazard potential zones in sub-Himalayan region of foothill zone of Kumaun Himalaya

Recent freshwater Ostracoda and Bivalvia from Indo-Nepal border (Tethys Himalaya): Ecological implications

We report for the first time Recent ostracods and bivalves from Central Tethys Himalaya, collected from Changru village, which is situated in the Tinker valley of northwestern Nepal near the Indo-Nepal border. The specimens were collected from the surface sediments of a small pond, shaped by a small tributary of the glacier fed Tinker River. The ostracod species belonging to the families Ilyocyprididae, Cyprididae and Candonidae and one bivalve (Pisidium sp., Family Pisidiidae) have been identified. Psychrodromus olivaccus and Potamocypris villosa are being reported for the first time from India and Nepal. Several broken and unidentifiable gyrogonites of charophyta were also recovered. The ostracod sample, as a whole, points to a shallow freshwater lake environment influenced by slowly running carbonate rich waters under cool temperatures, low mineralization and sparse vegetation. This is in accordance with the occurrence of Pisidium, which is commonly associated with ostracods in the freshwater lakes and streams. The ostracod fauna shows affinity with the fossil and extant forms recovered from the Higher and Tethys Himalaya of NW India. This opens a new opportunity for studying ostracods in the Indian Central Himalaya - a region which otherwise has been ignored until now

Climatic variability in Central Indian Himalaya during the last similar to 1800 years: Evidence from a high resolution speleothem record

Stable isotopes from a U/Th dated aragonite stalagmite from the Central Kumaun Himalaya provide evidence of variation in climatic conditions in the last similar to 1800 years. The delta O-18 and delta C-13 values vary from -4.3 parts per thousand to -7.6 parts per thousand and -3.4 parts per thousand to -9.1 parts per thousand respectively, although the stalagmite was not grown in isotopic equilibrium with cave drip water, a clear palaeoclimatic signal in stalagmite delta O-18 values is evident based on the regional climate data. The stalagmite showed a rapid growth rate during 830-910 AD, most likely the lower part of Medieval Warm Period (MWP), and 1600-1640 AD, the middle part of Little Ice Age (LIA). Two distinct phases of reduced precipitation are marked by a 2 parts per thousand shift in 8180 values towards the end of MWP (similar to 1080-1160 AD) and after its termination from similar to 1210 to 1440 AD. The LIA (similar to 1440-1880 AD) is represented by sub-tropical climate similar to modern conditions, whereas the post-LIA was comparatively drier. The Inter Tropical Convergence Zone (ITCZ) was located over the cave location during wetter/warmer conditions. When it shifted southward, precipitation over the study area decreased. A prominent drop in delta O-18 and delta C-13 values during the post-LIA period may also have been additionally influenced by anthropogenic activity in the area. (C) 2013 Elsevier Ltd and INQUA. All rights reserved

Stalagmite based high resolution precipitation variability for past four centuries in the Indian Central Himalaya: Chulerasim cave re-visited and data re-interpretation

Although the variations in δO and δC and the U/Th dating in the speleothems are considered as key proxies, improved dating with better quality resolution as well as composition of stalagmites and growth rate along with the cave monitoring are equally important for understanding the high resolution precipitation variability in the past. With a total of six dates on a 11.5 cm long stalagmite, we re-interpret the decadal to century scale climatic changes with multi-year droughts from the Indian Central Himalaya between ca. 1622 and 1950 AD. The sample is composed of aragonite (both compact sub-layers and porous sub-layers). Although, the age model of this young speleothem may be within age uncertainty owing to the high Th/ Th isotope ratios, yet the distinction of this study lies in recording various historical drought events which are otherwise never reported from the Himalayan foothills. Additionally, the sample consists of reasonable amount of U (>2 ppm), thus the age correction requirement may be minimum. The higher growth rate and comparatively lower values of δO and δC are observed during the Little Ice Age (LIA) until ca. 1820 AD, indicating its being wet in the Himalayan foothills in contrast to the Peninsular India and other regions which are solely influenced by the Indian Summer Monsoon (ISM). This is mainly because the monsoon trough moves from the plains to the Himalayan foothills during break-monsoon conditions and provides more orographic precipitation in form of the Westerlies in the south facing Himalayan slopes. The post-LIA period from ca. 1820 AD onwards is interpreted as comparatively drier than the LIA

Mid-late holocene climatic reconstruction using core sediments from Khajjiar lake, Himachal Pradesh, India

We present results of our investigations on 7.65 m long core sediments from the Khajjiar lake, Himachal Pradesh, aimed at reconstructing palaeoclimate variability in the climatically sensitive region affected by both ISM (Indian Summer Monsoon) and IWM (Indian Winter Monsoon). Based on the multi-proxy approach, including organic geochemistry (carbon isotopes), magnetic susceptibility as primary proxies and inorganic geochemistry (major oxides) with grain size analysis as secondary proxies, climate of the mid-late Holocene (∼4600 yr) has been established on centennial to millennial scale. The chronology of the sediments is constrained by five AMS radiocarbon dates. The sedimentological data reveal variations in sediment grain size related to palaeo-precipitation. The first high resolution multi-proxy record from the Khajjiar lake core indicates less humid conditions during ∼4600–4185 cal yr BP except an extreme peak of dry and arid climate at around ∼4370 cal yr BP. Intensified monsoon with more wet and humid conditions has been interpreted during ∼4185–3790 cal yr BP. ∼3790–3300 cal yr BP, ∼2845–2115 and ∼1555–405 cal yr BP, and ∼2990–2845 cal yr BP and fluctuations are observed from ∼2115 to 1555 cal yr BP. The results suggest two major climatic phases corresponding with the 4.2 ka and Roman Warm Period (RWP). A regional comparison of mid-late Holocene climate records reveals a broad synchronicity, but with considerable spatial variation. The timing and duration of climate events varied across regions