Shallowing of mafic crust and seismic instability in the high velocity Indian Shield

Indian shield has been frequented by number of large and moderate magnitude damaging earthquakes since historical times, including the recent disastrous ones like Latur Mw 6.3 in 1993, Jabalpur Mw 5.8 in 1997 and Bhuj Mw 7.7 in 2001. Seismogenesis of these events is still not understood well. Detailed study of nine such earthquake localities (as appended in Table 1), indicates quite high P- and S- velocities (6.2–6.7 km/s and 3.65–3.90 km/s respectively) at a shallow depth of almost surface to six kilometers. These seismogenic regions appear to be in a state of continuous uplift and erosion since geological times, which brought mafic (granulitic/amphibolitic) crust to significantly shallow levels in which stresses are accummulated due to ongoing local uplift and a high input of heatflow from the mantle. These stresses act over and above to the regional compressive stresses generated by India-Eurasia collision. As against common belief, the role played by fluids in nucleation of such earthquakes, in the relatively denser and high velocity Indian crust (compared to the other global stable continental regions), appears limited.     

Characterization of Dichotomoceras in the Oxfordian of Kachchh

We report here the first Dichotomoceras of the Indian subcontinent at Kantkote (Wagad) in the proximal most exposed part of the Kachchh Basin. This is further addition to the significant enlargement of the Oxfordian ammonoid record made earlier (Krishna et al. 1994, 1995, 1998, 2000). Near continuous presence of ammonoids has been recorded in ca 55 m thick succession, almost immediately above the Schilli Subzone, that was considered ammonoid devoid earlier. The ammonoid density, diversity and frequency in this just discovered ca 55 m thick column are much scarcer in comparison to the underlying 10 m thick ammonoid abundant Schilli Subzone. Examples of Dichotomoceras are determined almost throughout the said interval which in our preliminary taxonomic evaluation appear identical or close to D. rotoides (Ronch.), D. stenocycloides (Siem.), D. bifurcatus (Quenst.) and D. crassus Enay. It thus suggests the characterization of the Rotoides Subzone of the Transversarium Zone and the superjacent Bifurcatus Zone of the column at least up to the early Late Oxfordian.     

Mathematical analysis of a chaotic model in relevance to monsoon ISO

Mathematical analysis of a predominantly bimodal chaotic attractor, Lu system, was carried out to investigate a possible application of the model as a prototype of monsoon intra-seasonal oscillation (ISO). Bifurcation structures of the system are explored as the system parameter c and the forcing parameter F are varied. Stability criteria of equilibrium points of the forced Lu system are also explored in detail. A sensitivity study is carried out, by changing forcing parameter F, to explore relationships between some of the derived variables of the model and, based on such relationships, an empirical rule is used for extended range prediction. Analogous variables are also derived from the ISO data and prediction results are compared. Application of the prediction rule of regime transition to the observed ISO and chaotic model data is purely based on the bimodal characteristics of ISO and neglects some of the intricate mechanisms therein. We have found that a forced Lu system can be a good prototype in the prediction of peak anomaly of the monsoon ISO when growth rates around a threshold value are taken as predictors.     

Basement tectonics and flexural subsidence along western continental margin of India

The Paleocene-recent post-rift subsidence history recorded in the Mumbai Offshore Basin off western continental margin of India is examined. Results obtained through 2-D flexural backstripping modelling of new seismic data reveal considerable thermo-tectonic subsidence over last ca. 56 Myr. Reverse postrift subsidence modelling with variable β stretching factor predicts residual topography of ca. 2000 m to the west of Shelf Margin Basin and fails to restore late Paleocene horizon and the underlying igneous basement to the sea level. This potentially implies that:(1) either the igneous basement formed during the late Cretaceous was emplaced under open marine environs; or(2) a laterally varying cumulative subsidence occurred within Mumbai Offshore Basin(MOB) during ca. 68 to ca. 56 Ma. Pre-depositional topographic variations at ca. 56 Ma across the basin could be attributed to the extensional processes such as varied lower crustal underplating along Western Continental Margin of India(WCMI). Investigations about basement tectonics after unroofing of sediments since late Paleocene from this region support a transitional and heavily stretched nature of crust with high to very high β factors. Computations of past sediment accumulation rates show that the basin sedimentation peaked during late Miocene concurrently with uplift of Himalayan-Tibetan Plateau and intensification of Indian monsoon system. Results from basin subsidence modelling presented here may have significant implications for further studies attempting to explore tectono-climatic interactions in Asia.     

Biosorption an innovative tool for bioremediation of metal-contaminated municipal solid waste leachate: optimization and mechanisms exploration

Municipal solid waste poses a risk on surrounding environment and public health, mainly because of unscientific disposal and shortage of facilities for proper handling and recycling of leachate. This research article objective is to pinpoint the indigenous fungal isolates of waste leachate samples. Therefore, we carried out biosorption of Cd²⁺ tested the applicability by applying indigenous fungal isolates. The limited number of fungal isolates was found based on their ability for biosorption of Cd²⁺ metal. The fungal strains Trichoderma sp., Aspergillus niger and Aspergillus flavus were reported as potential strains for metal exclusion ability from the leachate. Among them, the Trichoderma sp. was found as excellent fungal agent for Cd²⁺ absorption. The optimum pH was 5.5 ± 1, temperature 45 °C, and spore concentration 10^?5 to achieve the maximum biosorption, and 35 days of incubation period were required by three strains. The maximum metal biosorption achieved was comparable for the three isolates: 56.34% by Trichoderma sp., 44.74 and 42.04% by A. niger and A. flavus, respectively. Concluding, the further intending application to identified potentially fungal isolates is able to improve the efficiency of metal biosorption. These strains are recommended for development of consortia could become a best technique for MSW leachate treatment if its reliability and applicability should be verified prior to technology acceptance.     

Temporal transition analysis of coal mine fire of Jharia coalfield,India, using Landsat satellite imageries

Coal is dominant energy source of world at large and India in particular for several decades and expected to being continued for foreseeable future. However, fire in this fossils fuel is still a global catastrophe for the major coal-producing countries. There are several direct and cascading distress of coal mine fire has been encountered by environment, economy, safety and society. Without knowledge of actual status and extent of coal mine fire, any scope for its better managements may be futile. In India, the coal mine fire of well-known Jharia coalfield (JCF) has been continued since last ten decades and still spreading towards newer areas. The aim of this paper is to highlight the chronological net lateral spatial changes in coal mine fire areas of JCF using Landsat satellite thermal imageries. The mapping of coal mine fire area of JCF during 1988–2013 has been carried out with consecutive 5-year intervals. The lateral changes in surface and subsurface fire areas along with propagation towards new area have been studied. The study also included to evaluate changes of status and extent fire during this time span and effect of its management efforts. On the basis of aforementioned analysis, the study concludes a slow reducing trend in coal mine fire area during last 25 years.     

Accumulation of Heavy Metals by Chickpea Grown in Fly Ash Treated Soil: Effect on Antioxidants

Chickpea grown in fly ash (FA) treated soil (25, 50, and 100% FA) was used to evaluate the effect of FA on antioxidants, metal concentration (Fe, Zn, Cu, Cr, and Cd), photosynthetic pigments (chlorophyll a (chl‐a), chlorophyll b (chl‐b), total chlorophyll (total chl), and carotenoids), growth and yield performance. All antioxidants in roots, shoots and leaves of chickpea increase with increasing FA doses to combat FA stress. The activities of antioxidants were more in the root tissues to cope with stress induced in the plants as compared to shoot and leaf. Concentration of metals was found maximum in roots than the shoots and seeds. The highest concentration of Fe and lowest level of Cd were recorded in all treatments of FA for different parts of the plant. The treated crop showed reduced level of chlorophyll but enhanced level of carotenoids and protein. However, root length, number of nodules and biomass in 25 and 50% FA treatments did not differ significantly in comparison to respective control plants. These results suggest that heavy metals of FA causes oxidative stress in this crop and the antioxidant enzymes could help a pivotal role against oxidative injury.     

Search for and study of photometric variability in magnetic white dwarfs

We report the results of photometric observations of a number of magnetic white dwarfs in order to search for photometric variability in these stars. These V-band observations revealed significant variability in the classical highly magnetized white dwarf GRW+70?8247 with a likely period from several days to several dozen days and a half-amplitude of about 0_. ^m 04. Our observations also revealed the variability of the well-known white dwarf GD229. The half amplitude of its photometric variability is equal to about 0_. ^m 005, and the likely period of this degenerate star lies in the 10–20 day interval. This variability is most likely due to the rotation of the stars considered.We also discuss the peculiarities of the photometric variability in a number of other white dwarfs. We present the updated “magnetic field–rotation period” diagram for the white dwarfs.