Environmental impact on coastal wetlands since 4 ka in Cauvery Delta: Palynology and thecamoebian study

Palaeoclimate and Palaeoecological study was carried out in ～2 m sediment core deposited since 4 ka in an estuarine environment along Uppanar River mouth, Cauvery Delta. Palynological and thecamoebian evidences indicate (1) a basal fluvial lacustrine depositional environment (～4–3 ka) characterized by sandy sediment, with low salinity and dominance of non-pollen forms like foraminiferal linings and thecamoebians with a low percentage of pollen and spores and (2) an estuarine environment (since 3 ka) characterized by clayey sediment with high salinity and a good percentage of mangrove and terrestrial pollen along with non-pollen forms. A shift in the depositional environment since ～3 ka indicates monsoonal and geomorphological changes in the coastal wetland. During this period dominance of Avicennia and Cheno/Ams indicate low freshwater runoff from land suggesting a weakened monsoon condition enhanced by anthropogenic activity.     

Geochemical modeling,fate distribution,and risk exposure of potentially toxic metals in the surface sediment of the Shyok suture zone,northern Pakistan

The objective of the current study was to assess the contamination of potentially toxic metals (PTMs) in weathered surface sediment, along stream tributaries, and surrounding area of the river Chitral, Shyok suture zone district Chitral, Pakistan. To understand the geochemical features of 113 sediment, samples were collected from the Mirkhani and Drosh area. Then, different statistical tools including the geo-accumulation index (Igeo), cluster analysis (CA), principal component analysis (PCA), and ecological risk assessment (ERA) were used to unravel the origin, intensity, and exposure level of PTMs to control risk and restore the ecosystem within the study area. The results for the PTMs namely nickle (Ni), chromium (Cr), copper (Cu), cadmium (Cd), lead (Pb), zinc (Zn), and cobalt (Co) in Mirkhani and Drosh were in the following ranges: 10–150, 15–210, 15–250, 0.08–1.00, 10–70, 76–240 and 14–51; and 13–240, 17–210, 15–150, 0.08–0.60, 7–140, 47–150 and 13–36 mg/kg, respectively. In consequence, the potential ecological risk caused by Pb, Ni, Cu, Co, Cr, and Zn is reflected by the percentages of samples with an ecological risk index (ERI) greater than one which were 100%, 91%, 100%, 100%, 92%, and 100%, respectively. However, the overall mean decreasing order of ecological risk of PTMs in the district Chitral was Pb > Ni > Cu > Co > Cr > Zn > Cd. Moreover, the PCA yielded 78% variability which indicated that mineral prospects play an important role in the contamination of sediment. Furthermore, the mineral phases of Pb and Zn suggested supersaturation, while that for Cd revealed unsaturation. The results of Igeo, ERI, and CA indicated contamination of PTMs in the study area. The ERI value of Pb, Ni, Cu, Co, Cr, and Zn was higher than 1 suggesting an ecological risk in the study area. Moreover, the current study showed the dominance of geogenic contamination with major contributions from ultramafic rock and known mineral prospects. Therefore, contaminated sediment of the Shyok suture zone is extremely detrimental to the aquatic ecosystem of the study area.     

Template-based classification of SDSS-<Emphasis Type="BoldItalic">GALEX</Emphasis> point sources

We have classified a sample of 37,492 objects from SDSS into QSOs, galaxies and stars using photometric data over five wave bands (u, g, r, i and z) and UV GALEX data over two wave bands (near-UV and far-UV) based on a template fitting method. The advantage of this method of classification is that it does not require any spectroscopic data and hence the objects for which spectroscopic data is not available can also be studied using this technique. In this study, we have found that our method is consistent by spectroscopic methods given that their UV information is available. Our study shows that the UV colours are especially important for separating quasars and stars, as well as spiral and starburst galaxies. Thus it is evident that the UV bands play a crucial role in the classification and characterization of astronomical objects that emit over a wide range of wavelengths, but especially for those that are bright at UV. We have achieved the efficiency of 89% for the QSOs, 63% for the galaxies and 84% for the stars. This classification is also found to be in agreement with the emission line diagnostic diagrams.     

Geology and petrography of the Nagar Parkar igneous complex,southeastern Sindh,Pakistan: The Kharsar body

Kharsar hill is one of many granitic plutons comprising the Nagar Parkar igneous complex. The eastern part of the hill is occupied by grey-pink granite (earlier) and the western part by pink granite (later). They are composed of perthite, quartz, and plagioclase, with minor opaque oxide, biotite, titanite, local amphibole, and secondary chlorite, epidote, leucoxene/titanite. The pink granite is characterized by the presence of mafic clots. Both the granitoids are intruded by microgranite/aplite, and porphyritic mafic and rhyolite dykes, locally in swarms. These are abundant in a NE trending 200 m wide zone cutting the entire granite hill. The dykes may extend over 1 km in length and >10 m in thickness, but most are < 100 m in length. The felsic dykes are of several generations; some are associated with the two varieties of granite, others are contemporaneous with the rhyolite and mafic dykes. The mafic dykes can be grouped into two types one of which contains hornblende and the other augite as the principal mafic mineral. Major element analyses suggest that the granitic rocks are metaluminous. The Kharsar granites, like the others in Nagar Parkar, may be an extension of the Malani igneous suite of Rajasthan. The occurrence of bimodal mafic-felsic dykes and petrographic variation in the mafic dykes are briefly discussed.     

Rock physics template (RPT) analysis of well logs and seismic data for lithology and fluid classification in Cambay Basin

The Cambay Basin is 450-km-long north–south-trending graben with an average width of 50 km, having maximum depth of about 7 km. The origin of the Cambay and other Basins on the western margin of India are related to the break up of the Gondwana super-continent in the Late-Triassic to Early-Jurassic (215 ma). The structural disposition of the Pre-Cambrian basement—a complex of igneous and metamorphic rocks exposed in the vicinity of the Cambay Basin—controls its architecture. The principal lineaments in the Basin are aligned towards NE-SE, ENE-WSW and NNW-SSE, respectively. Rock physics templates (RPTs) are charts and graphs generated by using rock physics models, constrained by local geology, that serve as tools for lithology and fluid differentiation. RPT can act as a powerful tool in validating hydrocarbon anomalies in undrilled areas and assist in seismic interpretation and prospect evaluation. However, the success of RPT analysis depends on the availability of the local geological information and the use of the proper model. RPT analysis has been performed on well logs and seismic data of a particular study area in mid Cambay Basin. Rock physics diagnostic approach is adopted in the study area placed at mid Cambay Basin to estimate the volume in the reservoir sands from 6 wells (namely; A, B, C, D, E and F) where oil was already encountered in one well, D. In the study area, hydrocarbon prospective zone has been marked through compressional (P wave) and shear wave (S wave) impedance only. In the RPT analysis, we have plotted different kinds of graphical responses of Lame’s parameters, which are the function of P-wave velocity, S-wave velocity and density. The discrete thin sand reservoirs have been delineated through the RPT analysis. The reservoir pay sand thickness map of the study area has also been derived from RPT analysis and fluid characterization. Through this fluid characterization, oil-bearing thin sand layers have been found in well E including well D. The sand distribution results prove that this methodology has able to perform reservoir characterization and seismic data interpretation more quantitatively and efficiently.     

The early phase of multiple proto-stellar system emerging from collapse of molecular cloud under various initial thermal states

We report on the short timescale intensity fluctuations of PSR B1133+16 and PSR B1237+25 due to scintillation at 1.54 GHz. The structure functions of intensity fluctuations are constructed and the linear fittings are applied to the structure regime in log–log plots to get the slope values. The slope of the SFs for PSR B1237+25 are less than that of PSR B1133+16, and both of them are much less than 2. For PSR B1133+16, the slope values agree very well with a Kolmogorov spectrum predicted value 5/3, whereas PSR B1237+25 not. We investigate the dynamic spectrum and obtain its auto-correlation function (ACF). Scintillation parameters are obtained by fitting to the autocorrelation function of the dynamic spectrum. The observed diffractive interstellar scintillation (DISS) timescales agree well with the observations and are consistent with some expected values, but the observed de-correlation frequency bandwidths are much less than predicted ones. The expected refractive interstellar scintillation (RISS) timescales are also estimated by using our derived diffractive scintillation parameters. They are consistent with the timescales of slow pulse intensity fluctuations. We proposed that the short timescale of pulse intensity variations caused by the DISS are modulated by the slow variations due to the effects of RISS.     

Comparison of two forest types using adeos 1-polder data over west coast of India

Parametric kernel-based models for Bi-directional Reflectance Distribution Function (BRDF) of vegetated land surfaces attempt to describe the BRDF as a linear superposition of a set of kernels describing basic angular shapes. The kernels and associated model coefficients are derived as approximations to the underlying theories of radiative transfer as well as geometric-optical scattering within vegetation canopies. In the present study, five kernels viz. Ross-Thick, Li-Sparse, Ross-Thin, Li-Dense and Roujean geometric-optical (GO) kernels along with a purely empirical model were examined for their suitability in describing the angular characteristics of two forest types (semi-evergreen and deciduous) during November 1996-March 1997 using ADEOS-1 POLDER data. The statistically significant kernels and their combinations with respect to red and NIR (near infra-red) wavelengths were determined using correlation analysis. Atmospherically corrected POLDER measured reflectances at red and NIR wavelengths were regressed with different kernels and their combinations. It is found that the best fitting volume and GO kernel combinations depend on forest type, wavelength and date.     

Late pleistocene and early holocene climate of Ny-Alesund,Svalbard (Norway): A study based on biological proxies

Subsurface sediments of a 120 cm deep trench from Ny-Alesund, Svalbard, were analysed for pollenspores and other organic matter contents. This study is supported by two AMS ¹⁴C dates (27, 200 yrs BP and 8,762 yrs BP) at the bottom and topmost litho-unit of the trench, respectively. The pollen record provides an evidence of a warm interval at about 27,200 yr BP (Late Weichselian and MIS 3) and cooling episode around 8,762 yr BP. This is also supported by the amount and type of organic matter as well as sediment type and depositional history of the trench sediments.     

A Proposal for Establishing A Gravitational-Wave Detector Interferometer in Pakistan

The proposed ‘Gravitational-Wave Antenna Detector InteRferometer (GWADIR)’ will be a 3 km × 3 km Fabry-Perot type laser interferometer. The laser oscillator to be used will be a DL excited Nd-YAG laser with a minimum output of 100 Watts. The optical system will consist of 25 cm diameter Recycler, Beam Splitter, and Near/End Mirrors for each of two Ducts. The mirror system will be suspended by fine wires to isolate the system from the seismic noises of the earth. The output light emerging from the interferometer will be split into 8 beams and sent to 8 different interference detectors. These detectors will measure the interference intensities for the recombined light from the separate legs of the interferometer. The effective amplification due to the interferometer cavities will allow measurements of displacements to better than 10 times the wavelength of the laser light. A high vacuum of 10-8 Torrs will be maintained throughout the system, using turbo-molecular and ion pumps. The detector is designed to reach strain sensitivities from gravitational sources of h<10-23 (Hz)- 1/2 with a broad-band and narrow-band measurement capability in the range of frequencies from 50 Hz to 10 ⁴ Hz, thus allowing it to detect ‘standard’ signals from such sources as coalescing neutron stars or black-holes out to the edge of the universe. If enough funding became available, the project is expected to complete by the middle of the next decade. This revised version was published online in July 2006 with corrections to the Cover Date.     

Climate‐induced Late‐Holocene ecological changes in Pichavaram estuary,India

Variation in sedimentology as well as freshwater and marine palynomorphs has been studied in ecological perspective in two 2.5‐ and 5‐m deep sediment cores deposited since 3440 and 3630 cal BP, respectively in the central part of Pichavaram mangrove wetland, Cauvery River delta. The palynological and sedimentological results of the sediments reveal a monsoonal circulation and a climatic shift from warm and humid with strengthened monsoon (3630–3190 cal BP) to dry and arid (~2750–760 cal BP). Since the last millennium (~760 cal BP), Pichavaram estuary has been influenced by a similar cyclicity but with a less wet and humid climate due to weakened monsoon conditions. These ecological changes in turn affect the relative sea level rise and fall which is reflected by the variability/extinction of freshwater and marine palynomorphs. The estuary remained an active water channel between ~3630 and 2750 cal BP, responding to the strengthened monsoon, during which the freshwater algal remains with thecamoebians and marine dinoflagellate cysts and foraminiferal linings both dominated with a ratio of 1.5 for marine/freshwater forms. After this period, since ~2750 cal BP there has been a dominance of marine forms with a ratio of 4.5 for marine/freshwater forms, indicating fluvio‐marine sediment deposition and suggesting the recent landward intrusion of seawater during weakened monsoon conditions. Freshwater thecamoebians are vulnerable to the salinity >3 in the aqueous soil solution of estuarine sediment, and therefore serve as an excellent proxy for monitoring salinity gradient along with short‐term high resolution palaeoecological fluctuations induced by climate and relative sea‐level changes in an estuarine ecosystem.