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The Precambrian‐Cambrian (Pc‐C) boundary marks significant biological, atmospheric, and oceanic changes. These changes include extinction of the Ediacaran fauna, initiation of complex lifeforms, and oxygenation of the atmosphere and oceans. In this contribution, elemental and Mo‐S isotopic compositions of organic‐rich shales overlying the Pc‐C boundary from the Tal Formation, Lesser Himalaya, have been investigated. These datasets are used to reconstruct past oceanic redox state and sulfate concentrations. The principal component analysis of the elemental dataset identifies six major factors, with factors associated with organic matter and sulfide phases accounting for about half of the total variance. Iron speciation and Mo/U data suggest that the shales were deposited in anoxic and ferruginous deep water conditions. The δ98Mo data (1.5 ± 0.2‰) and their mass balance calculations indicate that the areal extent of sulfidic waters and pyrite burial rates were about 2–4 times higher during the Pc‐C transition than in the modern ocean. The pyrite‐δ34S values (3.6–8.3‰) for the Tal shales are isotopically heavier compared to modern‐day sedimentary pyrites (∼−21‰). Calculations involving earlier‐reported δ34S values for early Cambrian seawater and our measured pyrite‐δ34S data estimate the seawater sulfate concentration (8 ± 3 mM) during their deposition. This sulfate value for the Tal basin is higher than that reported for the late Neoproterozoic ocean (<5 mM), attributable to increasing oxygen availability and continental supply during this time. The observed basinal conditions and high terrestrial input may have influenced metazoan diversification. Key Points: Chemical and Mo‐S isotopic study of black shales overlying the Pc‐C boundary from the Tal Formation (Lesser Himalaya) was carried outTrace element, Fe‐speciation and Mo isotopic data suggest a stratified basin with anoxic and ferruginous bottom water conditionsHigher seawater sulfate (∼8 mM) during the Pc‐C transition (than Proterozoic) linked to atmospheric oxygenation and enhanced riverine input [ABSTRACT FROM AUTHOR]

Ground vibration is an integral part of the rock blasting process which may cause damage to the nearby structures located surrounding the blasting area. The peak particle velocity (PPV) associated with blast-induced ground vibration is the most suitable parameter for correlating damage potential of blast-induced ground vibration. Thus, its prediction plays important role for smoothly conducting the blasting operations. The PPV largely depends on quantity of charge weight per delay, distance between the blast and observation points and the properties of the transmitting media. In this research work, a comparative study has been carried out for prediction of safe charge weight per delay for various distances by commonly used statistical equations, multiple linear regressions as well as by technique. The blast data collected from a basaltic region in an urban area has been used for testing of the model. In the ANN model, the distance from the blasting site to the monitoring stations, depth of hole and the maximum charge weight per delay were selected as the input parameters of the constructed model, the output parameter was the PPV as the vibration indicator. The ANN model with 10-5-1 configuration, sigmoid transfer function in hidden layer and linear transfer function in output layer gives the best correlation between predicted and actual values, with overall correlation coefficient (R) of 0.95. It can predict the PPV with acceptable mean -squared error (MSE) of 0.0029. The results in this study indicated that ANN is a reliable technique to predict the PPV due to blasting. [ABSTRACT FROM AUTHOR]

Terrestrial geothermal fields and oceanic hydrothermal vents are considered as candidate environments for the emergence of life on Earth. Nevertheless, the ionic strength and salinity of oceans present serious limitations for the self-assembly of amphiphiles, a process that is fundamental for the formation of first protocells. Consequently, we systematically characterized the efficiency of amphiphile assembly, and vesicular stability, in terrestrial geothermal environments, both, under simulated laboratory conditions and in hot spring water samples (collected from Ladakh, India, an Astrobiologically relevant site). Combinations of prebiotically pertinent fatty acids and their derivatives were evaluated for the formation of vesicles in aforesaid scenarios. Additionally, the stability of these vesicles was characterized over multiple dehydration-rehydration cycles, at elevated temperatures. Among the combinations that were tested, mixtures of fatty acid and its glycerol derivatives were found to be the most robust, also resulting in vesicles in all of the hot spring waters that were tested. Importantly, these vesicles were stable at high temperatures, and this fatty acid system retained its vesicle forming propensity, even after multiple cycles of dehydration-rehydration. The remaining systems, however, formed vesicles only in bicine buffer. Our results suggest that certain prebiotic compartments would have had a selective advantage in terrestrial geothermal niches. Significantly, our study highlights the importance of validating results that are obtained under ‘buffered' laboratory conditions, by verifying their plausibility in prebiotically analogous environments. [ABSTRACT FROM AUTHOR]

The article presents a study which analyzed the headwaters of the Ganga for dissolved ions strontium (Sr) and 87Sr86 to determine their temporal variations and the factors contributing to them. The study showed that there was significant seasonal variation in the concentrations of Sr and major ions. It concludes that there is an indication of a higher erosion rate over the Himalaya.