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Trees outside forest (TOF) play an important role in global carbon cycling, since they are large pools of carbon as well as potential carbon sinks and sources to the atmosphere. In view of the importance of biomass estimates in the global carbon (C) cycle, the present study demonstrates the potential of the standwise tree outside forest inventory data and finer spatial resolution of IRS-P6 LISS-IV satellite data to classify TOF, to estimate above-ground TOF phytomass and the carbon content of TOF in a semi-arid region of the southern Haryana, India. The study reports that above-ground TOF phytomass varied from 1.26 tons/ha in the scattered trees in the rural/urban area to 91.5 tons/ha in the dense linear TOF along the canal. The total above-ground TOF phytomass and carbon content was calculated as 367.04 and 174.34 tons/ha, respectively in the study area. The study results conclude that the classification of TOF and estimation of phytomass and carbon content in TOF can be successfully achieved through the combined approach of Remote Sensing and GIS based spatial technique with the supplement of field data. The present approach will help to find out the potential carbon sequestration zone in the semi-arid region of southern Haryana, India. [ABSTRACT FROM AUTHOR]

Each geomorphic hazard involves a degree of risk which incorporates quantification of the probability that a hazard will be harmful. At present, the categorization of sub-watersheds into erosion risk is considered as the fundamental step to conserve the soil loss. Development of badlands over the laterites of Birbhum district is an indicative of excessive soil loss in the monsoonal wet-dry type of climate. Slope erosion and channel erosion have generated huge amount of sediment from the small watersheds during intense monsoonal rainfall (June-September). The adjoining areas of Rampurhat I Block, Birbhum (West Bengal) and Shikaripara Block, Dumka (Jharkhand) have lost the lateritic soil cover at a rate of 20-40 ton/ha/year (Sarkar et al.). In order to estimate the progressive removal of soil particles from the gully-catchments of the above-mentioned area, different morphometric parameters, soil parameters, hydrologic parameters and empirical models are employed. Side by side, the study is carried out to categorize the gully-catchments into different magnitude of erosion risk using several multivariate statistical techniques. [ABSTRACT FROM AUTHOR]

Simultaneous photometric measurements of the OI 557.7 nm and OH (7, 2) band from a low latitude station, Kolhapur (16.8°N, 74.2°E) during the period 2004-2007 are analyzed to study the dominant waves present in the 80-100 km altitude region of the atmosphere. The nocturnal intensity variations of different airglow emissions are observed using scanning temperature controlled filter photometers. Waves having period lying between 2 and 12 hours have been recorded. Some of these waves having subharmonic tidal oscillation periods 4, 6, 8 and 12 hours propagate upward with velocity lying in the range 1.6-11.3 m/s and the vertical wave length lying between 28.6 and 163 kms. The other waves may be the upward propagating gravity waves or waves resulting from the interaction of inter-mode tidal oscillations, interaction of tidal waves with planetary waves and gravity waves. Some times, the second harmonic wave has higher vertical velocity than the corresponding fundamental wave. Application of these waves in studying the thermal structure of the region is discussed. [ABSTRACT FROM AUTHOR]

A critical analysis made on the long-term monthly, seasonal, yearly variation and annual cycle of total column ozone (TCO) concentration at New Delhi (29°N, 77°E), India and Halley Bay (76°S, 27°W), a British Antarctic Service Station reveals more decline in yearly mean ozone concentration at Halley Bay than at New Delhi from 1979 to 2005. The nature of variations of monthly mean TCO during the months of August and September was the most identical with that of yearly mean ozone values at New Delhi and Halley Bay, respectively, for the same period. Annual cycles of TCO over these stations are completely different for the above period. The effect of O depletion on night airglow emission of OH(8, 3) line at New Delhi and Halley Bay has been studied. Calculations based on chemical kinetics show that the airglow intensity of OH(8, 3) has also been affected due to the depletion of O concentration. The yearly variations and annual cycle of intensities of OH(8, 3) line for the above two stations are depicted and compared. It has been shown that the rate of decrease of intensity of OH(8, 3) line was comparatively more at Halley Bay due to dramatic decrease of Antarctic O concentration. [ABSTRACT FROM AUTHOR]

The entire 606 m-thick sedimentary sequence in borecore MCP-7 from Chintalapudi area, Chintalapudi sub-basin has been lithologically designated as Kamthi Formation. However, the palynological investigation revealed five distinct palynoassemblages, which essentially fall under two groups, one group (Palynoassemblage-I, II and III) having dominance of striate disaccates along with presence of some stratigraphically significant taxa, belongs to Late Permian (Raniganj) palynoflora, while the other group (Palynoassemblages IV and V) shows sharp decline in percentage of characteristic taxa of first group, i.e., striate disaccates, and consequent rise or dominance of taeniate and cingulate cavate spores, belongs to Early Triassic (Panchet) palynoflora. Palynoassemblage-I, II and III (Group I) are characterized by dominance of striate disaccates chiefly, Striatopodocarpites spp. and Faunipollenites spp. along with presence of rare but stratigraphically significant taxa, viz., Gondisporites raniganjensis, Falcisporites nuthaliensis, Klausipollenites schaubergeri, Chordasporites sp., Striomonosaccites, ovatus, Crescentipollenites multistriatus, Verticipollenites debiles, Strotersporites crassiletus, Guttulapollenites hannonicus, G. gondwanensis, Hamiapollenites insolitus, Corisaccites alutus, Lunatisporites ovatus, Weylandites spp. and Vitreisporites pallidus. Palynoassemblage-I is distinguished by significant presence of Densipollenites spp. while Palynoassemblage-II shows significant presence of Crescentipollenites spp. and Palynoassemblage-III differs from the above two assemblages in having significant presence of Guttulapollenites hannonicus. Palynoassemblage-IV (Group II) is characterized by high percentage of taeniate disaccates chiefly Lunatisporites spp., while Palynoassemblage-V (Group II) is characterized by cingulate-cavate trilete spores chiefly, Lundbladispora spp. and Densoisporites spp. Striate disaccates show a sharp decline in these two assemblages. In Chintalapudi area Late Permian and Early Triassic palynoflora has been recorded for the first time indicating existence of Raniganj and Panchet sediments as well. The study further supports the earlier studies of Jha and Srivastava () that Kamthi Formation represents Early Triassic (=Panchet Formation) overlying Raniganj equivalent sediments with a gradational contact. [ABSTRACT FROM AUTHOR]

Glaciers are widely recognized as sensitive indicators for regional climate change. Very few studies have been conducted to investigate the long term deglaciation status in the Himalaya. In the present study, glaciers in the Beas basin, Himachal Pradesh, India were mapped by interpretation of various glacio-morphological features using the Landsat and IRS images. The mapping of 224 glaciers during the period 1972-2006 reveals that the glacier cover reduced from 419 to 371 km, witnessing approximately 11.6% deglaciation in the Beas basin. A higher rate of retreat of the glaciers was observed during 1989-2006 as compared to the retreat during 1972-1989. Also, the loss has been more prominent in the glaciers with an areal extent of 2-5 km. The number of glaciers increased from 224 to 236 due to fragmentation in this period. The average elevation of the ablation zone basin showed an upward shift from 3898 m (1972) to 4171 m (2006) which may be a consequence of a shift in Equilibrium Line Altitude (ELA) reflecting imbalance. [ABSTRACT FROM AUTHOR]

The geochemical characteristics of abyssal peridotite samples from one dredge station (27°49.74S, 65°02.14E, water depth 4473 m) on the super slow-spreading Southwest Indian Ridge (SWIR) near 65°E were investigated. Abyssal peridotites recovered from this site were comprised mainly of lizardite, chlorite, carbonate and magnetite with minor amounts of talc, pyroxene phenocrysts and sparse olivines. Serpentinites exhibit talc veins and major serpentine derived from serpentinization with relict olivine granuloblasts. Olivine grains in serpentinites display exsolution lamellae, indicating the occurrence of talc reduction or decompression during seawater-rock interaction. Pyroxene shows clear cleavage in two directions, with clinopyroxene or orthopyroxene exsolution lamellae. By contrast, bulk rock trace element patterns of serpentinites reveal depletion in most incompatible elements, similarly to the depleted mid-ocean ridge basalt mantle composition, indicating that the SWIR peridotites originated from a depleted mantle source magma and have experienced partial melting. Meanwhile, Rb, Ba, U, Pb, Sr, Li anomalies and the Ce/Pb ratio suggest that these serpentinites have been strongly altered by seawater. [ABSTRACT FROM AUTHOR]

Palynological investigations of five borecores, viz., GAM-3, GAM-6, GAM-7, GAM-8 and GAM-10 from Mailaram area have suggested the occurrence of complete Lower Gondwana succession in Mailaram area. Total nine palynozones have been identified on the basis of dominance, sub-dominance and appearance of various palynotaxa. These palynozones belong to Talchir, Upper Karharbari and Barakar (Early Permian), Raniganj (Late Permian) and Panchet (Early Triassic) palynofloras of Indian Gondwana. The oldest Palynozone-1 demonstrated in borecore GAM-6 (331.4-500 m) and borecore GAM-10 (505.66-581.55 m), is characterized by the dominance of Parasaccites and sub-dominance of Plicatipollenites belongs to Talchir Palynoflora; Palynozone-2 identified in borecore GAM-7 (667-749 m) and borecore GAM-8 (89.75 m) is characterized by the dominance of Parasaccites and sub-dominance of Scheuringipollenites which belongs to Upper Karharbari Palynoflora. Palynozone-3, identified in borecore GAM-6 (149.7-240.05 m) and borecore GAM-8 (84.95 m), is characterized by the dominance of Scheuringipollenites akin to Scheuringipollenites zone of Barakar palynoflora; Palynozone-4, recorded in borecores GAM-3 (294-437.98 m), GAM-7 (453-640.5 m) and GAM-8 (35.35 m) is characterized by the dominance of Faunipollenites and sub-dominance of Striatopodocarpites along with certain stratigraphically significant taxa, viz., Weylandites, Guttulapollenites, Corisaccites, Aurangapollenites and Osmundacidites. Palynozone-5, demarcated in borecore GAM-3 (144.86-221.3 m) and borecore GAM-10 (35.35 m), is distinguished by the dominance of striate disaccates along with at least 30% pollen assigned to Striasulcites; Palynozone-6, identified in borecore GAM-3 (35.1-73.08 m) and borecore GAM-7 (231-423 m), is characterized by the dominance of striate disaccates along with 20-30% of Densipollenites; Palynozone-7, recorded in borecore GAM-7 (206 m), is distinguished by the dominance of Crescentipollenites along with striate disaccates; Palynozone-8, identified in borecore GAM-7 (178.4 m), is characterized by the distinguished presence of taeniate pollen Guttulapollenites. Palynozones 4-8 belong to Raniganj Palynoflora. Palynozone-9, identified in borecore GAM-7 (166 m), is discriminated by the dominance of trilete spore Verrucosisporites and sub-dominance of taeniate pollen Lunatisporites which belongs to Triassic palynoflora. On the basis of palynological data Palynozone-1 (= Talchir palynoflora), Palynozone-2 and Palynozone-3 have been assigned to Early Permian age; Palynozones 4-8 (= Raniganj palynoflora) have been assigned to Late Permian age and Palynozone-9 (= Triassic palynoflora) has been assigned to Early Triassic age. With the aim of correlating the Permian and Triassic sediments of Mailaram area palynological investigations of five borecores were carried out. [ABSTRACT FROM AUTHOR]

Carbon dioxide, water vapour, air temperature and wind measurements at 10 Hz sampling rate were carried out over the coast of Arabian Sea, Goa (15°21′N, 73°51′E) in India. These observations were collected, in association with the surface layer turbulent parameters for the Arabian Sea Monsoon Experiment (ARMEX). In the summer monsoon period, concentration of CO was in the range of 550-790 mg m whereas the water vapour was in the range of 17.5-24.5 g m. The Fast Fourier Transform (FFT) analysis has been performed on these observations to investigate the spectral behaviour of CO and water vapour. The relation between CO and water vapour on various atmospheric scales has been proposed. CO and water vapour observations confirmed the existence of periodicities of large (11, 8 days), meso (5 days) and micrometeorological (20 min) scales. [ABSTRACT FROM AUTHOR]

The present study reports occurrence of helically coiled microfossil Obruchevella Reitlinger from the Owk Shale of the Kurnool Group from the peninsular India. The age of the Kurnool Group is poorly constrained due to the absence of direct radiometric dating and meager palaeobiological data. Occurrence of Obruchevella is considered as a typical Vendian marker genus recorded mostly from close to the Precambrian-Cambrian boundary successions. Hence, the present assemblage is important to ascertain the age of the basin. In the Owk Shale, four species of Obruchevella, viz., O. delicata, O. parva, O. minor and O. valdaica are recorded as organic walled microfossils. Among them O. valdaica is the largest in terms of size parameters. On the global scale, the recovered species occur in the Late Neoproterozoic to Early Cambrian sediments. Therefore, the occurrence of microfossil Obruchevella in the Owk Shale and known burrow structures in the Narji Limestone suggest Ediacaran age close to the Cambrian for the Kurnool Basin and challenges the recently assigned Mesoproterozoic age of the basin. [ABSTRACT FROM AUTHOR]

A detailed analytical study of major cations (Ca, Mg, Na, K) and anions (SO $_{4}^{2-}$, HCO $_{3}^{-}$, Cl, NO $_{3}^{-})$ of meltwater draining from Gangotri Glacier was carried out to understand major ion chemistry and to get an insight into geochemical weathering processes controlling hydrochemistry of the glacier. In the meltwater, the abundance order of cations and anions varied as follows: Ca > Mg > K > Na and SO $_{4}^{2-}$ > HCO $_{3}^{-}$ > Cl > NO $_{3}^{-}$, respectively. Calcium and magnesium are dominant cations while sulphate and bicarbonate are dominant anions. Weathering of rocks is the dominant mechanism controlling the hydrochemistry of drainage basin. The relative high contribution of (Ca+Mg) to the total cations (TZ), high (Ca+Mg)/(Na+K) ratio (2.63) and low (Na+K)/TZ ratio (0.29) indicate the dominance of carbonate weathering as a major source for dissolved ions in the glacier meltwater. Sulphide oxidation and carbonation are the main proton supplying geochemical reactions controlling the rock weathering in the study area. Statistical analysis was done to identify various factors controlling the dissolved ionic strength of Gangotri Glacier meltwater. [ABSTRACT FROM AUTHOR]

Investigations of aerosol optical and physical characteristics using the application of Ångström formula and second order polynomial fit were carried out from April 2006 to March 2009 at Mohal in the Kullu valley. The measurements of spectral aerosol optical depths (AODs) were conducted using multi-wavelength radiometer (MWR). The AOD at 0.5 μm wavelength on daily basis (mean ± standard deviation) for the entire three-year study period is obtained as 0.24 ± 0.08. Seasonal variations show the highest AOD at 0.5 μm wavelength with ~0.34 ± 0.08 during pre-monsoon (April-July), followed by ~0.26 ± 0.08 during monsoon (August-September), ~0.21 ± 0.05 during post-monsoon (October-November) and ~0.20 ± 0.07 during winter (December-March). The seasonal values indicate that the AOD at 0.5 μm wavelength is decreasing from pre-monsoon to winter with a notable reduction around 41%. The Ångström parameters using least square method is not found appropriate for size distribution particularly when coarse mode aerosols dominate. The coefficients of second order polynomial fit are more appropriate for the discrimination of aerosol size or irrespective to the dominance of either of the aerosols size. The difference in coefficient of polynomial fit is used to get confirmation on the dominant mode during different seasons. Study reveals that about 93%, 72% and 59% of AOD spectra are dominated by a wide range of fine mode fractions or mixture of modes during post-monsoon, winter and monsoon, respectively. On the other hand, during pre-monsoon, 72% of AOD spectra are found to be dominated by coarse mode aerosols. [ABSTRACT FROM AUTHOR]

The most used temperature and salinity climatology for the world ocean, including the Indian Ocean, is the World Ocean Atlas (WOA) (Antonov et al 2006, 2010; Locarnini et al 2006, 2010) because of the vast amount of data used in its preparation. The WOA climatology does not, however, include all the available hydrographic data from the Indian Exclusive Economic Zone (EEZ), leading to the potential for improvement if the data from this region are included to prepare a new climatology. We use all the data that went into the preparation of the WOA ( Antonov et al 2010; Locarnini et al 2010), but add considerable data from Indian sources, to prepare new annual, seasonal, and monthly climatologies of temperature and salinity for the Indian Ocean. The addition of data improves the climatology considerably in the Indian EEZ, the differences between the new North Indian Ocean Atlas (NIOA) and WOA being most significant in the Bay of Bengal, where the patchiness seen in WOA, an artifact of the sparsity of data, was eliminated in NIOA. The significance of the new climatology is that it presents a more stable climatological value for the temperature and salinity fields in the Indian EEZ. [ABSTRACT FROM AUTHOR]

The failure of atmospheric general circulation models (AGCMs) forced by prescribed SST to simulate and predict the interannual variability of Indian/Asian monsoon has been widely attributed to their inability to reproduce the actual sea surface temperature (SST)-rainfall relationship in the warm Indo-Pacific oceans. This assessment is based on a comparison of the observed and simulated correlation between the rainfall and local SST. However, the observed SSTconvection/rainfall relationship is nonlinear and for this a linear measure such as the correlation is not an appropriate measure. We show that the SST-rainfall relationship simulated by atmospheric and coupled general circulation models in IPCC AR4 is nonlinear, as observed, and realistic over the tropical West Pacific (WPO) and the Indian Ocean (IO). The SST-rainfall pattern simulated by the coupled versions of these models is rather similar to that from the corresponding atmospheric one, except for a shift of the entire pattern to colder/warmer SSTs when there is a cold/warm bias in the coupled version. [ABSTRACT FROM AUTHOR]

Two new palm leaf impressions, cf. Iguanura wallichiana and Palmacites makumensis sp. nov. are described from the Makum Coalfield, Tinsukia District, Assam. They belong to the Tikak Parbat Formation being considered as Late Oligocene (Chattian 28-23 Myr) in age. Their presence, along with the other known fossil records indicates that CMMT (cold month mean temperature) was not less than 18°C with plenty of rainfall, in the region during the period of deposition. [ABSTRACT FROM AUTHOR]

The reef and associated beachrock from certain Gulf of Mannar islands (Rameswaram, Kurusadai, Shingle and Appa Island) were studied to assess the diagenetic evidences. Sixty samples were collected from marine terraces and reef platforms. The samples comprised of coral rubbles, shell fragments and lithic fractions. The presence of corals in the form of framework or isolated patches on the reef flat suggests the rapid increase of accommodation and probably absence of terrigenous and siliciclastic inputs. Moreover, the massive coral heads above the transgressive phase suggest the maximum flooding and relatively deepest facies. The freshwater dissolution, association of marine and meteoric cements suggest the semi-arid climatic condition with marine diagenesis during sea level lowstands and recharge of freshwater lenses during periodic rainfalls. In addition, the interaction of these mixed carbonate, siliciclastic sediments results in silicification of carbonate components. The reef associated beachrock were deposited in low energy environment with some amount of terrigenous matters derived from Precambrian basement rocks and transported into reef area by ephemeral streams and longshore sediment transport. The incorporation of coral fragments within the siliciclastic sediments are most probably due to the erosion and re-deposition of the sediments. [ABSTRACT FROM AUTHOR]

Two sediment types were found in five gravity cores collected from water depths between 56 m and 121 m along the northwestern continental margin of India: lime muds were abundant in the lower section while siliciclastic sediments dominated the upper section. Lime mud-dominated sediments in shelf cores contained 60%-75% carbonate, 0.3%-0.6% Sr and terrigenous minerals, whereas those at the shelf break were found to have >90% carbonate, 0.6%-0.8% Sr and traces of terrigenous minerals. Aragonite needles showing blunt edges, jointed needles and needles wrapped in smooth aragonite cement were found to be common. Stable (O and C) isotopes of lime mud indicate a potentially freshwater contribution for shelf cores and purely marine contribution for those at the shelf break. Calibrated radiocarbon ages of the lime muds ranged from 17.6-11.9 ka in different cores. The results reported here suggest that the lime muds in the shallow shelf are probably reworked from the Gulf of Kachchh, whereas those at the shelf break were biodetrital, initially formed on the carbonate platform during low stands of sea level and then exported. The change in lime mud-dominated to siliciclastic-dominated sediments in the cores may be due to climate change and rapid rise in sea level during the early Holocene. [ABSTRACT FROM AUTHOR]

Spectral reflectance data derived from Moon Mineralogy Mapper (M) onboard India's Chandrayaan-1 has revealed Fe bearing Mg-spinel-rich lithology on central peaks of the crater Theophilus. These newly identified Fe bearing Mg-spinel-rich rock types are defined by their strong 2-μm absorption and lack of 1-μm absorptions in spectral reflectance response. Such lithology has been reported previously along the inner ring of Moscoviense Basin on the lunar far side. The Modified Gaussian Modeling (MGM) analysis of the Fe bearing Mg-spinel reflectance spectra has been done and the results of the analysis clearly bring out a strong spectral absorption at 1872 nm with no significant absortion around 1000 nm. The presence of spinel group of minerals in the Theophilus central peak and the fact that central peaks mostly represent uplifted mass of deep crustal material confirm that central peaks can be used as a window to study the deep crustal and/or upper mantle composition and may lead to a fresh perspective about the crustal composition of Moon. [ABSTRACT FROM AUTHOR]

Marine Oligocene sequences in India outcrop only in western part of Kachchh. Earlier researchers have recognized the Oligocene strata under the Nari Series (Nagappa 1959; Chatterji and Mathur 1966). The Nari Series has a type area in Pakistan. It has two subdivisions - the Lower Nari (Lower Oligocene) and the Upper Nari (Upper Oligocene). It seems that there is no valid proof about the age of the Lower Nari due to lack of proper fauna (Eames 1975), and according to Pascoe (1962), the Upper Nari slightly transgress into Aquitanian (Lower Miocene), therefore, one has to be very cautious. Biswas and Raju (1971) reclassified the Oligocene strata of Kachchh and lithostratigraphically clubbed them as the Maniyara Fort Formation with type section along the Bermoti stream. This Formation has four members. The lower three members correspond to the Ramanian Stage (Lower Oligocene, Biswas 1971, 1973) while the uppermost to the Waiorian Stage (Upper Oligocene, Biswas 1965, 1971, 1973). The Ramanian Stage is characterized by large forams especially Nummulites fichteli, Nummulites fichteli intermedius, Lepidocyclina ( Eulepidina) dialata and Operculina sp. Several ostracods are also known to occur. Megafauna include bivalves, gastropods, echinoids, corals, mammals and reptiles. Concerning bivalves earlier researchers have recorded a few taxa namely Trisidos semitorta (Lamarck), Cubitostrea angulata (J de C Sowerby), Pecten ( Amussiopecten) labadyei d'Archiac and Haime, Periglypta puerpera (Linne') var. aglaurae Brongniart, Ostrea fraasi Mayer Eymer and listed Pecten laevicostatus J de C Sowerby, Callista pseudoumbonella Vredenburg and Clementia papyracea (Gray) from Kachchh as against overall 42 forms from the Nari Series as a whole (Vredenburg 1928). This tempted us to make an attempt to collect bivalve fauna systematically which are occurring prolifically in the Ramanian Stage. In the present work, for this purpose, sections are worked out around Lakhpat (23°50N; 68°47E), Maniyara Fort (23°2805N; 68°37E) Rakhdi Dam (23°2726N; 68°4010E) and Waior (23°2505N; 68°4137E) with a view to highlight the entombed bivalve taxa. Authors have encountered 53 species of which 23 are restricted to the Ramanian Stage. [ABSTRACT FROM AUTHOR]

A number of mafic intrusive bodies (mostly dykes) are exposed in the Chhotanagpur Gneissic Terrain (CGT). Most dykes trend in ENE-WSW to E-W following major structural trends of the region. These metabasite dykes show granoblastic to grano-nematoblastic textures and contain hornblende, plagioclase, chlorite, quartz and epidote which suggest their metamorphism under amphibolite grade P-T conditions. Although no radiometric age is available for the metabasite dykes, field relationships with host rock and available geochronology on granitoids suggest their emplacement during Mesoproterozoic. Geochemical characteristics of these dykes classify them as low-K tholeiite to medium-K calc-alkaline type. At least two types of metabasite dykes are recognized on the basis of their HFSE contents; one group shows entirely calc-alkaline nature, whereas the other group has rocks of tholeiite-calc-alkaline series. High Mg# observed in a number of samples indicates their derivation from primary melt. Multi-element spidergrams and rare-earth element patterns observed in these samples also corroborate their derivation from different magma batches. Trace element patterns observed for Nb-Ta, Hf-Zr, Sr and Y suggesting involvement of subduction related processes in the genesis of CGT metabasite dykes. Perceived geochemical characteristics suggest that metamorphism did not affect much on the chemistry of metabasites but source region, responsible for the generation of CGT metabasites, was possibly modified during subduction process. This study suggests that magma generated in a destructive plate setting fed the Mesoproterozoic mafic dykes of the CGT. [ABSTRACT FROM AUTHOR]

Addressing the geologic significance of lineaments and their correlation with joints/fractures is still unclear. The present study attempts to analyse the lineament swarms developed in a Precambrian metamorphic terrain in India using both unfiltered and filtered techniques. The unfiltered analysis technique shows that the major lineament and fracture trends are oriented along EW and NS directions respectively, thus failing to provide any correlation between them. The application of domain-based filtering techniques identifies a highly predominant fracture-correlated lineaments in mica schist constituting the EW trending shear zone in the area. This correlation is not evident in the areas north and south of the shear zone, where the lineaments are consistently oriented along the foliation planes of the rocks and are designated as 'foliation correlated'. The present analysis indicates that the fracture frequency and the strain history may have played significant roles for the formation of fracture-correlated lineaments in the metamorphic terrain. [ABSTRACT FROM AUTHOR]

A prediction model based on the perfect prognosis method was developed to predict the probability of lightning and probable time of its occurrence over the south-east Indian region. In the perfect prognosis method, statistical relationships are established using past observed data. For real time applications, the predictors are derived from a numerical weather prediction model. In the present study, we have developed the statistical model based on Binary Logistic Regression technique. For developing the statistical model, 115 cases of lightning that occurred over the south-east Indian region during the period 2006-2009 were considered. The probability of lightning (yes or no) occurring during the 12-hour period 0900-2100 UTC over the region was considered as the predictand. The thermodynamic and dynamic variables derived from the NCEP Final Analysis were used as the predictors. A three-stage strategy based on Spearman Rank Correlation, Cumulative Probability Distribution and Principal Component Analysis was used to objectively select the model predictors from a pool of 61 potential predictors considered for the analysis. The final list of six predictors used in the model consists of the parameters representing atmospheric instability, total moisture content in the atmosphere, low level moisture convergence and lower tropospheric temperature advection. For the independent verifications, the probabilistic model was tested for 92 days during the months of May, June and August 2010. The six predictors were derived from the 24-h predictions using a high resolution Weather Research and Forecasting model initialized with 00 UTC conditions. During the independent period, the probabilistic model showed a probability of detection of 77% with a false alarm rate of 35%. The Brier Skill Score during the independent period was 0.233, suggesting that the prediction scheme is skillful in predicting the lightning probability over the south-east region with a reasonable accuracy. [ABSTRACT FROM AUTHOR]

Pterospermumocarpon (Type: P. kalviwadiensis), a new morphogenus of fossil fruits showing resemblance with fruits of extant Pterospermum Schreb. (Malvaceae s.l.), is described from the Sindhudurg Formation (Miocene) at the Kalviwadi Village, Sindhudurg District, Maharashtra, India. Diagnostic feature of the fossil taxon is the dehiscent pentalocular capsule with five distinct sutures and imprints of winged seed-like structures in the locules. Recent modifications in the systematics of the Malvales, their fossil record, and the distribution and migration of Pterospermum and other malvalean taxa in the context of the Indian subcontinent are discussed. [ABSTRACT FROM AUTHOR]

The frontal part of the active, wedge-shaped Indo-Eurasian collision boundary is defined by the Himalayan fold-and-thrust belt whose foreland basin accumulated sediments that eventually became part of the thrust belt and is presently exposed as the sedimentary rocks of the Siwalik Group. The rocks of the Siwalik Group have been extensively studied in the western and Nepal Himalaya and have been divided into the Lower, Middle and Upper Subgroups. In the Darjiling-Sikkim Himalaya, the Upper Siwalik sequence is not exposed and the Middle Siwalik Subgroup exposed in the Tista river valley of Darjiling Himalaya preserves a ~325 m thick sequence of sandstone, conglomerate and shale. The Middle Siwalik section has been repeated by a number of north dipping thrusts. The sedimentary facies and facies associations within the lithostratigraphic column of the Middle Siwalik rocks show temporal repetition of sedimentary facies associations suggesting oscillation between proximal-, mid- and distal fan setups within a palaeo-alluvial fan depositional environment similar to the depositional setup of the Siwalik sediments in other parts of the Himalaya. These oscillations are probably due to a combination of foreland-ward movement of Himalayan thrusts, climatic variations and mountain-ward shift of fan-apex due to erosion. The Middle Siwalik sediments were derived from Higher- and Lesser Himalayan rocks. Mineral characteristics and modal analysis suggest that sedimentation occurred in humid climatic conditions similar to the moist humid climate of the present day Eastern Himalaya. [ABSTRACT FROM AUTHOR]

Field geomorphology and remote sensing data, supported by Optical Stimulated Luminescence (OSL) dating from the Mandakini river valley of the Garhwal Himalaya enabled identification of four major glacial events; Rambara Glacial Stage (RGS) (13 ± 2 ka), Ghindurpani Glacial Stage (GhGS) (9 ± 1 ka), Garuriya Glacial Stage (GGS) (7 ± 1 ka) and Kedarnath Glacial Stage (KGS) (5 ± 1 ka). RGS was the most extensive glaciation extending for ~6 km down the valley from the present day snout and lowered to an altitude of 2800 m asl at Rambara covering around ~31 km area of the Mandakini river valley. Compared to this, the other three glaciations (viz., GhGS, GGS and KGS) were of lower magnitudes terminating around ~3000, ~3300 and ~3500 m asl, respectively. It was also observed that the mean equilibrium line altitude (ELA) during RGS was lowered to 4747 m asl compared to the present level of 5120 m asl. This implies an ELA depression of ~373 m during the RGS which would correspond to a lowering of ~2°C summer temperature during the RGS. The results are comparable to that of the adjacent western and central Himalaya implying a common forcing factor that we attribute to the insolation-driven monsoon precipitation in the western and central Himalaya. [ABSTRACT FROM AUTHOR]

The Malari Leucogranite in the Garhwal Himalaya is cut across by a continental-scale normal fault system called the South Tibetan Detachment (STD). A mineralogical, geochemical and fluid inclusion study of samples from the fault zone of the Malari Granite was performed to reveal the imprints of fluid-rock interaction. Fluid inclusion assemblages observed in the alteration zone indicate the presence of NaCl-dominated aqueous fluids with varied salinity of 6-16 wt.% of NaCl equivalent. Mineralogical changes include the alteration of feldspar to muscovite and muscovite to chlorite. This alteration took place at temperatures of 275°-335°C and pressures between 1.9 and 4.2 kbars as revealed by the application of chlorite thermometry, fluid isochores, and presence of K-feldspar+muscovite+chlorite+quartz mineral assemblage. Geochemical mass-balance estimates predict 32% volume loss during alteration. An estimated fluid/rock ratio of 82 is based on loss of silica during alteration, and reveals presence of a moderately low amount of fluid at the time of faulting. Results of fluid inclusion and alteration mineralogy indicate that the Malari Leucogranites were exhumed due to normal faulting along the STD and erosion from mid-crustal levels. Most of the leucogranites in the Himalayas occur along the STD and possibly a regional-scale fluid flow all along the STD might have caused similar alteration of leucogranites along this tectonic break. Regional fluid flow was probably concentrated along the STD and channelized through mesoscopic fractures, microcracks and grain boundaries. [ABSTRACT FROM AUTHOR]

Several basaltic lava flows have been identified in the study area in and around Linga, in the Eastern Deccan Volcanic Province (EDVP) on the basis of distinctly developed structural zones defined by primary volcanic structures such as columnar joints and vesicles. These basaltic lava flows are spatially distributed in four different sectors, viz., (i) Bargona-Gadarwara (BG) sector (ii) Shikarpur-Linga (SL) sector (iii) Arjunvari-Survir Hill (AS) sector and (iv) Kukrachiman-Morand Hill (KM) sector. A three-tier classification scheme has been adopted for the characterization and classification of individual lava flows. Each lava flow consists of a Lower Colonnade Zone (LCZ) overlain by the Entablature Zone (EZ) and Upper Colonnade Zone (UCZ). The LCZ and UCZ grade into a distinct/indistinct Lower Vesicular Zone (LVZ) and Upper Vesicular Zone (UVZ), respectively. The LCZ and UCZ of the flows are characterized by columnar joints while the EZ is marked by multi-directional hackly jointing. The geometry of different joint patterns corresponds to different styles of cooling during solidification of lava flows. Detailed petrographic studies of the investigated lava flows reveal inequigranular phenocrystal basalts characterized by development of phenocrystal phases including plagioclase, clinopyroxene and olivine, whereas groundmass composition is marked by tiny plagioclase, clinopyroxene, opaque mineral and glass. Electron microprobe analyses indicate that the olivine has a wide range ∼Fo to Fo revealing a wide spectrum of compositional variation. Pyroxene compositions are distinctly designated as Quad pyroxenes. Phenocrystal pyroxenes are mostly diopsidic, while the groundmass pyroxenes mainly correspond to augite with a minor pigeonite component. Pyroxene phenocrysts are characterized by a prominent Ti-enrichment. Phenocrystal plagioclase grains are calcic (An-An), whereas groundmass plagioclase are relatively sodic (An-An). Groundmass opaque minerals are characteristically found to be Ti-magnetite/ilmenite/pyrophanite. Pyroxene thermometry reveals a temperature span of 850°C to 1280°C for the studied lavas while olivine-clinopyroxene thermometry yields a temperature range from 1040°-1160°C. The variation of temperature for the lava flows is ascribed to their normal cooling history after eruption. [ABSTRACT FROM AUTHOR]

A new fossil fruit wing of Shorea Roxb. belonging to the family Dipterocarpaceae is described from the Early Miocene sediments of Kachchh, Gujarat. It resembles best the extant species Shorea macroptera Dyer, which is a prominent member of the tropical evergreen forests of the Malayan Peninsula. The present finding, along with the other megafossil records described from the same area, indicates a typical tropical vegetation with a warm and humid climate at the time of deposition in contrast to the present day xeric vegetation in the area. As the family Dipterocarpaceae no longer exists in western India, it is essential to discuss the time of its extinction and possible causes, which may include drastic changes in the climate of the region. The present finding also supports the theory of a Malaysian origin for the family in contrast to the hypothesis of a Gondwanan origin. [ABSTRACT FROM AUTHOR]

Mawpyut igneous suite in Jaintia Hills of Meghalaya plateau comprises differentiated suite of ultramafic-mafic rocks. The complex differs from other ultramafic-alkaline-carbonatite igneous emplacements of Shillong plateau and Mikir Hills like Jesra, Sung, Samchampi complexes, by the absence of alkaline-carbonatite rocks as major litho-units. Melanite garnet-bearing nepheline syenite, occurs as late phase minor intrusion in Mawpyut igneous complex, posseses alkaline character and shows inubiquitous relation with the host ultramafic-mafic rocks. On the other hand, this alkaline intrusive bodies of the Mawpyut igneous complex shows chemico-mineralogical resemblance with garnet-bearing nepheline syenite, ijolite litho-members of Jesra, Sung, Samchampi complexes of the region. It is interpreted that melanite garnet-bearing nepheline syenite intrusion in Mawpyut is contemporaneous with Jesra, Sung, Samchampi ultramafic-alkaline-carbonatite complexes and the host rocks of Mawpyut complex is an earlier magmatic activity possibly from a comparatively least enriched source. [ABSTRACT FROM AUTHOR]

The Kachchh Mainland Fault (KMF) is a major E-W trending seismically active fault of the Kachchh palaeorift basin whose neotectonic evolution is not known. The present study deals with the eastern part of the KMF zone where the fault is morphologically expressed as steep north facing scarps and is divisible into five morphotectonic segments. The Quaternary sediments occurring in a narrow zone between the E-W trending KMF scarps and the flat Banni plain to the north are documented. The sediments show considerable heterogeneity vertically as well as laterally along the KMF zone. (The Quaternary sediments for a northward sloping and are exposed along the north flowing streams which also show rapid decrease in the depth of incision in the same direction.) The deposits, in general, comprise coarse as well as finer gravelly deposits, sands and aeolian and fluvial miliolites. The Quaternary sediments of the KMF zone show three major aggradation phases. The oldest phase includes the colluvio-fluvial sediments occurring below the miliolites. These deposits are strikingly coarse grained and show poor sorting and large angular clasts of Mesozoic rocks. The sedimentary characteristics indicate deposition, dominantly by debris flows and sediment gravity flows, as small coalescing alluvial fans in front of the scarps. These deposits suggest pre-miliolite neotectonic activity along the KMF. The second aggradation phase comprises aeolian miliolites and fluvially reworked miliolites that have been previously dated from middle to late Pleistocene. The youngest phase is the post-miliolite phase that includes all deposits younger than miliolite. These are represented by comparatively finer sandy gravels, gravelly sands and sand. The sediment characteristics suggest deposition in shallow braided stream channels under reduced level of neotectonic activity along the KMF during post-miliolite time evidenced by vertical dips of miliolites and tilting of gravels near the scarps. The tectonically controlled incision and dissection of the Quaternary deposits is the result of neotectonic activity that continues at present day. The overall nature, sedimentary characteristics and geomorphic setting of the sediments suggest that the KMF remained neotectonically active throughout the Quaternary period. [ABSTRACT FROM AUTHOR]

The saturation index of clay minerals like Gibbsite, Kaolinite, Illite, Montmorillonite and Chlorite in groundwater were studied in detail by collecting 29 groundwater samples from the shallow coastal aquifers in and around Kalpakkam. The samples collected were analysed for major cations, anions and trace elements by using standard procedures. The study reveals that pH has a significant role in the saturation index (SI) of minerals. It also shows that the relationship of electrical conductivity to the SI of these minerals is not significant than that of the ionic strength, log pCO values, and alumina silica ratio have significant relation to the SI of these clay minerals. The SI of these clay minerals was spatially distributed to identify the areas of higher SI. Silica has good correlation to SI of Kaolinite, Gibbsite and Montmorillonite and Al has good correlation to SI of all the minerals except to that of Chlorite. [ABSTRACT FROM AUTHOR]

In this study, environmental magnetic, heavy metal and statistical analyses were conducted on 21 surface sediments collected from Chennai coast, India, to examine the feasibility of heavy metal pollution using magnetic susceptibility. The Chennai coastal sediment samples are dominated by ferrimagnetic minerals corresponding to magnetite-like minerals. The percentage of frequency dependent magnetic susceptibility reflects the presence of super-paramagnetic/single domain magnetic minerals in Chennai harbour, Cooum and Adayar rivers sediments. High pollution load index in sample E1, E2, CH7, C11, C12 and A16 is mainly due to anthropogenic activities such as, harbour activities, Cooum and Adayar rivers input and industrial effluent. Factor analysis shows that the magnetic concentration dependent parameters ( χ, χ and SIRM) covary with the heavy metal concentrations, suggesting that the input of magnetic minerals and heavy metals in Chennai coastal sediments are derived from the same anthropogenic sources. Strong correlation obtained between pollution load index (PLI) and concentration dependent parameters ( χ, χ and SIRM) for the polluted samples with magnetic susceptibility excess of 50×10 mkg. Significant correlations between heavy metals and magnetic susceptibility point out the potential of magnetic screening/monitoring for simple and rapid proxy indicator of heavy metal pollution in marine sediments. [ABSTRACT FROM AUTHOR]

Written history's limitation becomes apparent when attempting to document the predecessors of extreme coastal events in the Indian Ocean, from 550-700 years in Thailand and 1000 years in Indonesia. Detailed ground-penetrating radar (GPR) surveys in Mahabalipuram, southeast India, complemented with sedimentological analyses, magnetic susceptibility measurements, and optical dating provide strong evidence of extreme wave events during the past 3700 years. The diagnostic event signatures include the extent and elevation of the deposits, as well as morphologic similarity of buried erosional scarps to those reported in northern Sumatra region. Optical ages immediately overlying the imaged discontinuities that coincides with high concentration of heavy minerals date the erosional events to 340 ± 35, 350 ± 20, 490 ± 30, 880 ± 40, 1080 ± 60, 1175 ± 188, 2193 ± 266, 2235 ± 881, 2489 ± 293, 2450 ± 130, 2585 ± 609, 3710 ± 200 years ago. These evidences are crucial in reconstructing paleo extreme wave events and will pave the way for regional correlation of erosional horizons along the northern margin of Indian Ocean. [ABSTRACT FROM AUTHOR]

Relationship of outgoing long-wave radiation (OLR) with convective available potential energy (CAPE) and temperature at the 100-hPa pressure level is examined using daily radiosonde data for a period 1980-2006 over Delhi (28.3°N, 77.1°E) and Kolkata (22.3°N, 88.2°E), and during 1989-2005 over Cochin (10°N, 77°E) and Trivandrum (8.5°N, 77.0°E), India. Correlation coefficient ( R) between monthly OLR and CAPE shows a significant (~ − 0.45) anti-correlation at Delhi and Kolkata suggesting low OLR associated with high convective activity during summer (seasonal variation). Though, no significant correlation was found between OLR and CAPE at Cochin and Trivandrum (low latitude region); analysis of OLR and temperature (at 100-hPa) association suggests that low OLR peaks appear corresponding to low temperature at Delhi ( R~ 0.30) and Kolkata ( R ~ 0.25) during summer. However, R between OLR and temperature becomes opposite as we move towards low latitudes (~8°-10°N) due to strong solar cycle influence. Large scale components mainly ENSO and quasi-biennial oscillaton (QBO) that contributed to the 100-hPa temperature variability were also analyzed, which showed that ENSO variance is larger by a factor of two in comparison to QBO over Indian region. ENSO warm conditions cause warming at 100-hPa over Delhi and Darwin. However, due to strong QBO and solar signals in the equatorial region, ENSO signal seems less effective. QBO, ENSO, and solar cycle contribution in temperature are found location-dependent (latitudinal variability) responding in consonance with shifting in convective activity regime during El Niño, seasonal variability in the tropical easterly jet, and the solar irradiance. [ABSTRACT FROM AUTHOR]

This study investigates the impact of monthly Ganges-Brahmaputra river discharge variations on Bay of Bengal salinity and temperature during the period 1992-1999. The Ganges-Brahmaputra river discharge is characterized by a well-defined seasonal cycle with strong interannual variations. The highest/lowest yearly peak discharge occurs in summer 1998/summer 1992, with 1998 value amounting to twice that of 1992. This river discharge is then used to force an ocean general circulation model. Our main result is that the impact of these rivers on the variability of Bay of Bengal sea surface salinity is strong in the northern part, with excess run-off forcing fresh anomalies, and vice versa. Most of the years, the influence of the interannual variability of river discharge on the Bay salinity does not extend south of ~10°N. This stands in contrast with the available observations and is probably linked to the relatively coarse resolution of our model. However, the extreme discharge anomaly of 1998 is exported through the southern boundary of the Bay and penetrates the south-eastern Arabian Sea a few months after the discharge peak. In response to the discharge anomalies, the model simulates significant mixed-layer temperature anomalies in the northern Bay of Bengal. This has the potential to influence the climate of the area. From our conclusions, it appears necessary to use a numerical model with higher resolution (both on the horizontal and vertical) to quantitatively investigate the upper Bay of Bengal salinity structure. [ABSTRACT FROM AUTHOR]

A small isolated mafic body occurs to the south of Sirohi near village Daba within the Neoproterozoic Erinpura Granite in the southern sector of the Proterozoic Delhi Fold Belt in NW India. This mafic body occurs close to a 100 m wide NE-SW trending shear zone (Daba Shear Zone) which overprints the felsic rock fabrics. Further south, a small mafic body near village Kui was also sampled which forms the southern limit of the Phulad Ophiolite Suite which is a 300 km long major NE-SW trending lineament, described as Western Margin Fault. Some of the lithological components of the Daba mafic body show locally preserved magmatic fabric but completely transformed mineralogies under lower amphibolites facies metamorphic conditions where two-stage deformation has been inferred. Magnetic fabric analysis underlines a general correspondence of structural elements in both felsic and mafic lithologies. Binary correlations of Zr with other high field strength elements underline fractionation as the main process in the evolution of Daba and Kui rocks. Geochemical characteristics indicate subalkaline tholeiitic basalt affinity for these mafic rocks. The trace element characteristics, such as enriched LIL elements, high Th, absence of negative Nb anomalies and depletion in compatible elements in Daba samples suggest an enriched mantle source and lower degree of melting. The trace and rare earth element characteristics for Kui (Th anomaly, Nb-Ta trough and less spiked patterns, flat REE trends) indicate derivation from a refractory mantle source affected by fluids derived from subduction. Distinct differences in trace and REE characteristics between Daba and Kui can be interpreted in terms of different stages of ophiolite development. [ABSTRACT FROM AUTHOR]

The Okha Shell Limestone Member of Chaya Formation is the coarse grained, shell rich deposit commonly recognized as the beach rocks. It has been age bracketed between Late Pleistocene and Holocene. Late Quaternary sea level changes have been studied with beach rocks along the Saurashtra coastal region. The present study has been carried out in the Okhamandal area of the Saurashtra peninsula especially on the Okha Shell Limestone Member as exposed at various locations along the coast from north to south. Temporal and spatial correlations of the observations have revealed three events in the Okha Shell Limestone Member of Chaya Formation that are correlated laterally. The events show depositional breaks represented by discontinuity surfaces, the taphofacies varieties and ichnological variations. The present study in the context of available geochrnological data of the region suggests a prominent depositional break representing low sea level stand (regression) during an Early Holocene during the deposition of Okha Shell Limestone Member. [ABSTRACT FROM AUTHOR]

Stable carbon isotope analysis of fossil leaves from the Bhuj Formation, western India was carried out to infer the prevailing environmental conditions. Compression fossil leaves such as Pachypteris indica, Otozamite kachchhensis, Brachyphyllum royii and Dictyozamites sp. were recovered from three sedimentary successions of the Bhuj Formation, Early Cretaceous in age. A chronology was established based on faunal assemblage and palyno-stratigraphy and further constrained by carbon isotope stratigraphy. The three sampling sites were the Karawadi river bank near Dharesi; the Chawad river bank near Mathal; and the Pur river section near Trambau village in Gujarat. The Dharesi sample was also analyzed to investigate intra-leaf δC variability. The mean δC of the leaf was − 24.6 ± 0.4‰ which implied negligible systematic change along the leaf axis. The Mathal sample was fragmented in nature and showed considerable variation in carbon isotopic composition. The Trambau sample considered to be the oldest, dating to the middle of Aptian ( ca. 116 Ma), shows the most depleted value in δC among all of them. The overall δC trend ranging from mid Aptian ( ca. 116 Ma) to early Albian ( ca. 110 Ma) shows a progressive increase in δC from −26.8 to −20.5‰. Based on these measurements the carbon isotopic composition of atmospheric carbon dioxide of the Aptian-Albian period is estimated to be between −7.4 and −1.7‰. The ratio of the partial pressure of carbon dioxide in leaf to that of the ambient atmosphere calculated based on a model is estimated to be similar to that of the modern plants. This indicates that the Early-Cretaceous plants adapted to the prevailing high carbon dioxide regime by increasing their photosynthetic uptake. [ABSTRACT FROM AUTHOR]

We developed a ring-width chronology of teak ( Tectona grandis L.) from a moisture stressed area in Maharashtra, India. Bootstrapped correlation analysis indicated that moisture index (MI) and Palmer Drought Severity Index (PDSI) showed better performance rather than same year rainfall over the region. Tree-ring variations were most correlated positively with PDSI during different seasons compared with MI. Significant strong positive correlation with MI, and negative association with temperature and potential evapotranspiration (PET) were found during previous and current year post-monsoon (ON). This study shows that the moisture availability during the post-monsoon of the previous year has a significant role in the development of annual growth rings. The reconstructed previous year post-monsoon (−ON) moisture index for the period 1866-1996 indicates 3.5 and 29.3 years periodicities. [ABSTRACT FROM AUTHOR]

Continuous measurements of aerosol size distributions in the mid-point diameter range 20.5-500 nm were made from October 2005 to March 2006 at Pune (18°32′N, 73°51′E), India using Scanning Mobility Particle Sizer (SMPS). Volatilities of atmospheric aerosols were also measured at 40°, 125°, 175°, 300° and 350°C temperatures with Thermodenuder-SMPS coupled system to determine aerosol volatile fractions. Aerosols in nucleated, CCN and accumulated modes are characterized from the measured percentage of particles volatized at 40°, 125°, 175°, 300° and 350°C temperatures. Averaged monthly aerosol concentration is at its maximum in November and gradually decreases to its minimum at the end of March. The diurnal variations of aerosol concentrations gradually decrease in the night and in early morning hours (0400-0800 hr). However, concentration attains minimum in its variations in the noon (1400-1600 hr) due to higher ventilation factor (product of mixing height and wind speed). The half an hour averaged diurnal variation of aerosol number concentration shows about 5 to 10-fold increase despite the ventilation factor at higher side before 1200 hr. This sudden increase in aerosol concentrations is linked with prevailing conditions for nucleation bursts. The measurement of volatile fraction of ambient aerosols reveals that there are large number of highly volatile particles in the Aitken mode in the morning hours and these volatile fractions of aerosols at temperatures <150°C are of ammonium chloride and ammonium sulfate, acetic and formic acids. [ABSTRACT FROM AUTHOR]

Monthly scenarios of relative humidity ( R) were obtained for the Malaprabha river basin in India using a statistical downscaling technique. Large-scale atmospheric variables (air temperature and specific humidity at 925 mb, surface air temperature and latent heat flux) were chosen as predictors. The predictor variables are extracted from the (1) National Centers for Environmental Prediction reanalysis dataset for the period 1978-2000, and (2) simulations of the third generation Canadian Coupled Global Climate Model for the period 1978-2100. The objective of this study was to investigate the uncertainties in regional scenarios developed for R due to the choice of emission scenarios (A1B, A2, B1 and COMMIT) and the predictors selected. Multi-linear regression with stepwise screening is the downscaling technique used in this study. To study the uncertainty in the regional scenarios of R, due to the selected predictors, eight sets of predictors were chosen and a downscaling model was developed for each set. Performance of the downscaling models in the baseline period (1978-2000) was studied using three measures (1) Nash-Sutcliffe error estimate ( E), (2) mean absolute error (MAE), and (3) product moment correlation ( P). Results show that the performances vary between 0.59 and 0.68, 0.42 and 0.50 and 0.77 and 0.82 for E, MAE and P. Cumulative distribution functions were prepared from the regional scenarios of R developed for combinations of predictors and emission scenarios. Results show a variation of 1 to 6% R in the scenarios developed for combination of predictor sets for baseline period. For a future period (2001-2100), a variation of 6 to 15% R was observed for the combination of emission scenarios and predictors. The variation was highest for A2 scenario and least for COMMIT and B1 scenario. [ABSTRACT FROM AUTHOR]

The objective of this study is to apply and test a simple parametric water balance model for prediction of soil moisture regime in the presence of vegetation. The intention was to evaluate the differences in model parameterization and performance when applied to small watersheds under three different types of land covers ( Acacia, degraded forest and natural forest). The watersheds selected for this purpose are located in the sub-humid climate within the Western Ghats, Karnataka, India. Model calibration and validation were performed using a dataset comprising depth-averaged soil moisture content measurements made at weekly time steps from October 2004 to December 2008. In addition to this, a sensitivity analysis was carried out with respect to the water-holding capacity of the soils with the aim of explaining the suitability and adaptation of exotic vegetation types under the prevailing climatic conditions. Results indicated reasonably good performance of the model in simulating the pattern and magnitude of weekly average soil moisture content in 150 cm deep soil layer under all three land covers. This study demonstrates that a simple, robust and parametrically parsimonious model is capable of simulating the temporal dynamics of soil moisture content under distinctly different land covers. Also, results of sensitivity analysis revealed that exotic plant species such as Acacia have adapted themselves effectively to the local climate. [ABSTRACT FROM AUTHOR]

Land degradation reduces the ability of the land to perform many biophysical and chemical functions. The main aim of this study was to determine the status of land degradation in the Budgam area of Kashmir Himalaya using remote sensing and geographic information system. The satellite data together with other geospatial datasets were used to quantify different categories of land degradation. The results were validated in the field and an accuracy of 85% was observed. Land use/land cover of the study area was determined in order to know the effect of land use on the rate of land degradation. Normalized differential vegetation index (NDVI) and slope of the area were determined using LANDSAT-enhanced thematic mapper plus (ETM+) data, advanced space borne thermal emission and reflection radiometer, and digital elevation model along with other secondary data were analysed to create various thematic maps, viz., land use/land cover, geology, NDVI and slopes used in modelling land degradation in the Kashmir Himalayan region. The vegetation condition, elevation and land use/land cover information of the area were integrated to assess the land degradation scenario in the area using the ArcGIS 'Spatial Analyst Module'. The results reveal that about 13.19% of the study area has undergone moderate to high degradation, whereas about 44.12% of the area has undergone slight degradation. [ABSTRACT FROM AUTHOR]

The occurrence of exceptionally heavy rainfall events and associated flash floods in many areas during recent years motivate us to study long-term changes in extreme rainfall over India. The analysis of the frequency of rainy days, rain days and heavy rainfall days as well as one-day extreme rainfall and return period has been carried out in this study to observe the impact of climate change on extreme rainfall events and flood risk in India. The frequency of heavy rainfall events are decreasing in major parts of central and north India while they are increasing in peninsular, east and north east India. The study tries to bring out some of the interesting findings which are very useful for hydrological planning and disaster managements. Extreme rainfall and flood risk are increasing significantly in the country except some parts of central India. [ABSTRACT FROM AUTHOR]

Tephra, emplaced as a result of Pleistocene eruption of the Indonesian 'supervolcano' Toba, occurs at many localities in India. However, the ages of these deposits have hitherto been contentious; some workers have argued that these deposits mark the most recent eruption (eruption A, ca 75 ka), although at some sites they are stratigraphically associated with Acheulian (Lower Palaeolithic) artefacts. Careful examination of the geochemical composition of the tephras, which are composed predominantly of shards of rhyolitic glass, indicates that discrimination between the products of eruption A and eruption D (ca 790 ka) of Toba is difficult. Nonetheless, this comparison favours eruption D as the source of the tephra deposits at some sites in India, supporting the long-held view that the Lower Palaeolithic of India spans the late Early Pleistocene. In principle, these tephra deposits should be dateable using the K-Ar system; however, previous experience indicates contamination by a small proportion of ancient material, resulting in apparent ages that exceed the true ages of the tephras. We have established the optimum size-fraction in which the material from Toba is concentrated, 53-61 μm, and have considered possible origins for the observed contamination. We also demonstrate that Ar-Ar analysis of four out of five of our samples has yielded material with an apparent age similar to that expected for eruption D. These numerical ages, of 809 ± 51, 714 ± 62, 797 ± 45 and 827 ± 39 ka for the tephras at Morgaon, Bori, Gandhigram and Simbhora, provide a weighted mean age for this eruption of 799 ± 24 ka (plus-or-minus two standard deviations). However, these numerical ages are each derived from no more than 10-20% of the argon release in each sample, which is not ideal. Nonetheless, our results demonstrate that it is feasible, in principle, to date this difficult material using the Ar-Ar technique; future follow-up studies will therefore be able to refine our preparation and analysis procedures to better optimize the dating. [ABSTRACT FROM AUTHOR]

The Jaduguda U (-Cu-Fe) deposit in the Singhbhum shear zone has been the most productive uranium deposit in India. Pyrite occurs as disseminated grains or in sulphide stringers and veins in the ore zone. Veins, both concordant and discordant to the pervasive foliation, are mineralogically either simple comprising pyrite ± chalcopyrite or complex comprising pyrite + chalcopyrite + pentlandite + millerite. Nickel-sulphide minerals, though fairly common in concordant veins, are very rare in the discordant veins. Pyrite in Ni-sulphide association is commonly replaced by pentlandite at the grain boundary or along micro-cracks. Based on concentrations of Co and Ni, pyrite is classified as: type-A - high Co (up to 30800 ppm), no/low Ni; type-B - moderate Co (up to 16500 ppm) and moderate to high Ni (up to 32700 ppm); type-C - no/low Co and high Ni (up to 43000 ppm); type-D - neither Co nor Ni. Textural and compositional data of pyrites suggest that the hydrothermal fluid responsible for pre-/early-shearing mineralization evolved from Co-rich to Ni-rich and the late-/post-shearing fluid was largely depleted in minor elements. Sulphur isotope compositions of pyrite mostly furnish positive values ranging between −0.33 and 12.06‰. Composite samples of pyrites with only type-A compositions and mixed samples of type-A and type-B are consistently positive. However, pyrite with mixed type-A and type-C and pyrite with type-D compositions have negative values but close to 0‰. By integrating minor element and sulphur isotope compositions of pyrite in conjunction with other published data on the Jaduguda deposit, it is proposed that reduced sulphur for the precipitation of most pyrites (type-A, type-B) was likely derived from isotopically heavy modified seawater. However, some later sulphur might be magmatic in origin remobilized from existing sulphides in the mafic volcanic rocks in the shear zone. [ABSTRACT FROM AUTHOR]

The concentration of ultrafine aerosol particles of aitken and nucleation mode having size in the range of 1-20 nm was monitored with water-based Condensation Particle Counter. The monitoring was carried out from midnight-to-midnight in every alternate day on a fortnightly basis to represent summer, monsoon and winter (autumn) seasons of 2008 at Mohal (1154 m amsl) and Kothi (2530 m amsl) in Kullu-Manali area of the northwestern Himalayan region of India. The results indicate that diurnal pattern has faint bimodal structure with two peaks, one in morning and the other in evening at both the sites but it is not as distinct as found in plains. There is rather a constant particle density pattern of large magnitude consistent with vehicular movement from morning till evening. The monthly 24 h average particle density gradually picks up from January, increases rapidly in summer months and then decreases in monsoon season at Mohal but at Kothi it keeps on rising from April to October with a slight more increase in September. The particle density is more in summer than in monsoon season at Mohal, a trend opposite to plains. It may be due to the development of warm thermal layer on valley floor while a cold layer develops along snowy hilltops in winter leading to convection of fine particle up the slopes of valley during daytime. At Kothi, the trend is same as it is in continental plains but opposite to Mohal. The relatively more value of particle density in September and October at both the sites may be due to month long International Kullu Dussehra fair in the valley. The vehicular survey conducted agrees well with entire study period averaged diurnal variations and monthly 24 h averaged value of fine particle density. The average value of ultrafine particle density at each hour of a day for entire study period is 20369 ± 1230 Ncm and 14389 ± 1464 Ncm at Mohal and Kothi sites, respectively. The comparison with earlier results shows a significant increase indicating impact of vehicular onslaught on pure air of this hilly region. [ABSTRACT FROM AUTHOR]

critical analysis has been made on the long-term yearly and seasonal variations of ozone concentration at Varanasi (25°N, 83°E), India and Halley Bay (76°S, 27°W), a British Antarctic Service Station. The effect of O depletion on night airglow emission of Li 6708 Å line at Varanasi and Halley Bay has been studied. Calculations based on chemical kinetics show that the airglow intensity of Li 6708 Å line has also been affected due to the depletion of O concentration. The yearly variations and seasonal variations of intensities of Li 6708 Å line for the above two stations are shown and compared. It has been shown that the rate of decrease of intensity of Li 6708 Å line was comparatively more at Halley Bay due to dramatic decrease of Antarctic O concentration. [ABSTRACT FROM AUTHOR]

Saddle-shaped reticulate Nummulites from the Early Oligocene rocks of Khari area, SW Kutch, India is reported here for the first time. Unusual shape of this Nummulites is due to the curved nature of the coiling plane, indicating space constrained postembryonic test growth. With regular development of chambers, septa and septal filaments, the saddle-shaped Nummulites constitutes the third morphotype of N. cf. fichteli Michelotti form A. Other morphotypes of the species reported earlier include inflated lenticular and conical tests. Multiple morphotypes of N. cf. fichteli form A indicates varied test growth in response to substrate conditions. Morphological variability exhibited by N. cf. fichteli form A from Kutch and some Early Oligocene reticulate Nummulites from the Far East are comparable. This faunal suite is morphologically distinct from the contemporary reticulate Nummulites of the European localities. [ABSTRACT FROM AUTHOR]

new fossil leaf impression is described from the Early Miocene sediments of Kasauli-Kalka road section, Himachal Pradesh. The characteristic leaf venation pattern suggests that it has a close affinity with Ficus L., particularly with F. racemosa L. (= F. glomerata Roxb.). Its presence indicates a warm and humid climate in the region during the deposition of sediments, in contrast to the present day cooler and less humid climate. [ABSTRACT FROM AUTHOR]