Structures and morphotectonic evolution of the frontal fold–thrust belt,Kameng river section,Arunachal Himalaya,India

The Neogene–Quaternary Siwalik foreland fold and thrust belt is studied for better understanding of tectonics along the Kameng river section of Arunachal Pradesh, India. The Kimi, Dafla, Subansiri, and the Kimin Formation correspond to Lower, Middle and Upper Siwaliks, respectively. The lithology in the foreland basin is dominantly sandstones, siltstones, claystones, carbonaceous shales, and boulder beds in the upper part. The structural style of the sedimentary sequence from the Main Boundary Thrust southward shows first order ramp-flat geometry. The brittle shear transfers slip across glide horizons to shallower depth. Repeated splay generations from a major regional-scale floor transfers slip from one glide horizon to another that shortens and thickens the crust. In the micro-scale, the lithological response in the structural development is well documented as pressure solution seams and other diagenetic deformation signatures. The basement asperity plays a significant role as the moving thrust front produced a major lateral ramp. The differential movement of the mountain front on both sides of the ramp is decipherable. This is especially true at the western part of the SE flowing Kameng river. The tectonic evolution of the area initiated with slip along the MBT \(\sim \)11 Ma ago along with the deposition of the Siwalik sediments. With southward propagation of the mountain front, the foreland basin shifted towards S, produced splay thrusts from the Himalayan Frontal Thrust-1 (HFT-1), which has been uplifting the Kimin and the older terraces.     

Petrogenesis of S-type Ladakh granite and mafic microgranular enclaves in the southern margin of Ladakh batholith: An evidence of crust–mantle interaction during the collision between Indian and Eurasian plates

The previous studies revealed the I-type Ladakh magmatism in the Andean-type southern margin of the Ladakh batholith (LB) was related to the subduction of the Neotethyan Ocean and India-Eurasia collision. However, LB's S-type granitic magmatism and associated mafic microgranular enclaves (MMEs) are poorly constrained. Here, we present the new data for S-type Ladakh granite (LG) and associated monzodiorite MMEs in the Andean-type orogeny in the southern margin of the Eurasian plate. The low SiO₂ (47.4–53.9 wt%), high K₂O (1.56–3.21 wt%), Mg^# (52–65), continental-arc tracer patterns, and slightly depleted to evolved Sr-Nd isotopic composition ((⁸⁷Sr/⁸⁶Sr)i = 0.7047–0.7166; ℇ_Nd (t = 50 Ma) = (+1.40 to −8.92)) for MME suggest that they were derived from the phlogopite-bearing deep lithospheric mantle-source at a depth of 5.4–10.5 km depth with 810–870°C, 1.4–2.8 kbar, and enriched by sediment-melts addition into the mantle-wedge from subducting Neotethyan Oceanic slab. The mantle-derived ascending hot mafic magma mixing with felsic magma of the ancient northern Indian margin-derived, generates monzodiorite MME by assimilation and magma mixing processes. Plagioclase, amphibole, and biotite chemistry support the magma mixing processes. LG are characterized by high SiO₂ (63.4–75.0 wt%), K₂O (3.93–5.67 wt%), CaO/Na₂O ratio of >0.3, differentiation index (90.27–97.46), normative corundum (1.0–2.8), A/CNK values (1.00–1.18), hypersthene (0.7–5.7), and low Al₂O₃, MgO, TiO₂, Fe₂O₃. They also exhibit peraluminous, variable tracer elemental abundances, variable (⁸⁷Sr/⁸⁶Sr)i ratios (0.6967–0.7191), and high whole rock ℇ_Nd (t = 50 Ma) values of −4.15 to −11.92) and ancient two-stage Nd model age of 1160 and 1858 Ma. These features suggest that S-type Ladakh granites were derived from the melting of ancient metagreywacke-dominated metasedimentary rocks of the northern Indian margin by a large amount of mafic magma underplating after subducted Neotethyan slab-rollback. The formation of LG and MMEs related to the Andean-type orogeny in the southern margin of the Eurasian plate.     

Biotechnological Advances in Detection of Contaminants from Wastewater

Wastewater from industries causes major environmental pollution problems. The urban development and commercialization in developing countries cause deterioration of surface water resources. Hence, for its improvement, it is essential to develop highly sensitive devices with quick response for monitoring of wastewater contamination. In this respect, biotechnological processes such as biosensors can be promising and a robust option for detection of toxic pollutants. Biosensors can be applied in order to acquire real-time quantitative data. Nowadays, the enzymes or whole cell bio-reporters-based biosensors have promising potential due to the possibility of miniaturization and opportunity for development of in situ biosensors. The growing need of convenient, rapid, and efficient biosensing devices explains the current advancement of biosensors with new transduction materials for multiplexed contaminant detection. Considering the extensive range of sensing strategies including immunochemical-based, enzymatic and nonenzymatic signals, different kinds of biosensors can be classified as electrochemical, optical, thermal, etc. For the past few years, more attention has been paid to nanomaterial-based biosensors which exhibit monitoring on the basis of chemical reactions and biological phenomena. Overall, this review focuses on principle and operation (transduction mechanism) of biosensors based on bio-recognition elements, for the early detection of organic and inorganic contaminants existing in wastewater.     

Structure and dynamics of undercurrents in the western boundary current of the Bay of Bengal

Ocean Dynamics - The structure and variability of undercurrents in the East India Coastal Current (EICC), which is the western boundary current system in the Bay of Bengal (BoB), and the mechanisms...     

A multifrequency maximum-entropy joint analysis of COBE and Tenerife data

We use data from the Tenerife 10-, 15- and 33‐GHz beam-switching experiments along with the COBE 53- and 90‐GHz data to separate the cosmic microwave background (CMB) signal from the Galactic signal, and create two maps at high Galactic latitude. The new multi-MEM technique is used to obtain the best reconstruction of the two channels. The two maps are presented, and known features are identified within each. We find that the Galactic contribution to both the 15- and 33-GHz Tenerife data is small enough to be ignored when compared with the errors in the data and the magnitude of the CMB signal.     

Effect of canal on land use/land cover using remote sensing and GIS

The monitoring of land use/land covers (LULCs) is an indispensable exercise for all those involved in executing policies to optimize the use of natural resources and minimize the ill impacts on the environment. The study here aims at analyzing the changes that occurred in LULC over a time span from 1990 to 2005 using multi date data of a part of Punjab. The digital data consisted of two sets of Landsat Thematic Mapper (TM) data and one set of IRS-1C data. Utilizing hybrid classification technique for interpretation and on field validation, it has been found that canal irrigation leads to changes in LULC as there is a change in cropping pattern as well as increase in water logged area.     

Did the Harappan settlement of Dholavira (India) collapse during the onset of Meghalayan stage drought?

Radiocarbon dating of archaeological carbonates from seven cultural stages of Dholavira, Great Rann of Kachchh (GRK), the largest excavated Harappan settlement in India, suggests the beginning of occupation at ~5500 years BP (pre-Harappan), and continuation until ~3800 years BP (early part of the Late Harappan period). The settlement rapidly expanded under favourable monsoonal climate conditions when architectural elements such as the Citadel, Bailey, Lower and Middle Town were added between the Early and mid-Mature Harappan periods. Abundant local mangroves grew around the GRK sustaining prolific populations of the edible gastropod Terebralia palustris. Oxygen isotope (δ¹⁸O) sclerochronology of Early Harappan gastropod shell suggests seasonal mixing of some depleted (δ¹⁸O ~ −12‰) river water in summer/monsoon months (through ancient Saraswati and/or Indus distributary channels) with seawater that periodically inundated the GRK. Evaporation from this semi-enclosed water body during the non-monsoon months enriched the δ¹⁸O of water/shell carbonates. The humid fluvial landscape possibly changed due to a catastrophic drought driving the final collapse of the settlement of Dholavira exactly at the onset of the Meghalayan (Late Holocene) stage (~4300–4100 years BP ). Indeed, Dholavira presents a classic case for understanding how climate change can increase future drought risk as predicted by the IPCC working group. Copyright © 2019 John Wiley & Sons, Ltd.     

Wilkinson Microwave Anisotropy Probe 5-yr constraints on fnl with wavelets

We present a Gaussianity analysis of the Wilkinson Microwave Anisotropy Probe ( WMAP ) 5-yr cosmic microwave background (CMB) temperature anisotropy data maps. We use several third-order estimators based on the spherical Mexican hat wavelet. We impose constraints on the local non-linear coupling parameter f _nl using well-motivated non-Gaussian simulations. We analyse the WMAP maps at resolution of 6.9 arcmin for the Q , V , and W frequency bands. We use the KQ 75 mask recommended by the WMAP team which masks out 28 per cent of the sky. The wavelet coefficients are evaluated at 10 different scales from 6.9 to 150 arcmin. With these coefficients, we compute the third order estimators which are used to perform a  χ²  analysis. The  χ²  statistic is used to test the Gaussianity of the WMAP data as well as to constrain the f _nl parameter. Our results indicate that the WMAP data are compatible with the Gaussian simulations, and the f _nl parameter is constrained to  −8 < f _nl < +111  at 95 per cent confidence level (CL) for the combined   V + W   map. This value has been corrected for the presence of undetected point sources, which add a positive contribution of  Δ f _nl= 3 ± 5  in the   V + W   map. Our results are very similar to those obtained by the WMAP team using the bispectrum.     

Komatiite within Chhotanagpur Gneissic Complex at Semra,Palamau District,Jharkhand: Petrological and geochemical fingerprints

Komatiite near Semra village, southwest of Daltonganj in Palamau District of Jharkhand, occurs within tremolite actinolite schist of ultramafic parentage. The fragmented olivine phenocrysts show mutually parallel as well as angular alignment, representing relict spinifex texture. Mineralogically the Semra ultramafic is lehrzolite in composition. The cumulates lack visible deformation suggesting original magmatic crystallization of these ultramafic rocks. The present occurrence of Spinifex Textured Peridotitic Komatiite (STPK) in Chhotanagpur Gneissic Complex (CGC) at northwestern part of Eastern Indian Shield is of great significance as it opens up a possibility of the presence of Archaean rock in CGC, which is yet to be established.