Composition and formation conditions of pay zones in the lower Cretaceous Nizhnyaya Kheta and Yakovlevo formations within the Vankor oil-and-gas field (in the Northeast of West Siberia)

Sedimentologic analysis of cores from wells sunk in the Vankor petroleum field allowed refinement of the accumulation conditions producing the sandy strata of the Nizhnyaya Kheta River (Nizhnekhetsky) Formation accumulated in the coastal marine zone and of the Yakovlevo (Yakovlevsky) Formation accumulated under alluvial-deltaic conditions. Petrographic examination of the sandstones added information on the sources, transport, and accumulation conditions of the terrigenous material in the northeastern marginal part of the West Siberian sedimentation basin.     

Effects of sludge pretreatment on sludge reduction in a lab-scale anaerobic/anoxic/oxic system treating domestic wastewater

Excess sludge disposal is one of the serious challenges in biological wastewater treatment. Reduction of sludge production would be an ideal way to solve sludge-associated problems rather than the post-treatment of the sludge produced. In this study, a new wastewater treatment process combining anaerobic/anoxic/oxic system with thermochemical sludge pretreatment was tested in a laboratory scale experiment. In this study, the effects of the sludge pretreatment on the excess sludge production in anaerobic/anoxic/oxic were investigated. The system was operated in two Runs (1 and 2). In Run 1, the system was operated as a reference and in Run 2, a part of the mixed liquid was pretreated thermochemically and was returned to the bioreactor. The average solubilization efficiency of pretreated sludge was found to be about 35 % during the study period of 220 days. Sludge production rate in Run 2 was less than that in Run 1 by about 52 %. Total phosphorous was removed by enhanced biological phosphorous removal with the removal efficiency of 83–87 % and 81–83 % for Run 1 and Run 2, respectively. Total nitrogen removal in Run 2 (79–82 %) was slightly higher than that in Run 1 (68–75 %). The mixed liquor suspended solids/mixed liquor volatile suspended solids ratio was identical after both runs in the range 78–83 %. The effluent water qualities were not significantly affected when operated with thermochemical pretreatment at pH 11 and 60 °C for 3 h during 7 months. From the present study it is concluded that thermochemical sludge pretreatment of anaerobic/anoxic/oxic process plays an important role in reduction of sludge production.     

Fault-line uplifts in the Northeastern Pacific

The nearly latitudinal giant fracture zones in the northeastern Pacific Ocean are accompanied by narrow fault-line uplifts making up tectonic couples that strike for thousands of kilometers. They are especially distinctly expressed in the gravity map of the World Ocean [7]. As is shown in the paper, a compensation mechanism of deep mass displacement operates in the uplift-deepwater trench system. The uplifts have similar asymmetric structures, which reflects the long-term unidirectional effect of the deep geodynamic stress. In my opinion, the system of the fault-line uplifts began to form at the Cretaceous-Cenozoic boundary.     

Structural and magnetic fabric studies of recess structures in the western Himalaya: Implications for 1905 Kangra earthquake

Kinematic information from deformation structures and magnetic fabrics are used to infer recent tectonics around Kangra and Dehradun recesses, western Himalaya. Three types of magnetic fabrics (Type I & II, III, and IV) are identified based on the angle between K3 axis and bedding pole. It was observed that Kangra recess shows more mature fabric type IV as compared to Dehradun recess, where orientation of K3 axes and tectonic fabric reveals dominance of superposed deformation. In the vicinity of Dehradun recess, normal faults occur in un-indurated Quaternary fan deposits confirming their recent formation. The observations are in conformity with earlier studies that during the 1905 Kangra earthquake, the Main Boundary Thrust (MBT) (or one of its subsidiary thrusts) near Kangra showed thrusting whereas the MBT near Dehradun underwent either normal faulting or post seismic adjustments characteristic of normal faulting. The thrusting could be a result of subsurface processes whereas the normal faulting was a result of prevailing surface strains.     

Comparative analysis of marine paleogene sections and biota from West Siberia and the Arctic Region

The analysis of the main biospheric events that took place in West Siberia and the Arctic region during the Early Paleogene revealed the paleogeographic and paleobiogeographic unity of marine sedimentation basins and close biogeographic relations between their separate parts. Most biotic and abiotic events of the first half of the Paleogene in the Arctic region and West Siberia were synchronous, unidirectional, and interrelated. Shelf settings, sedimentation breaks, and microfaunal assemblages characteristic of these basins during the Paleogene are compared. The comparative analysis primarily concerned events of the Paleocene-Eocene thermal maximum (PETM) and beds with Azolla (aquatic fern). The formation of the Eocene Azolla Beds in the Arctic region and West Siberia was asynchronous, although it proceeded in line with a common scenario related to the development of a system of estuarine-type currents in a sea basin partly isolated from the World Ocean.     

Detailed architecture of a compound incised valley system and correlation with forced regressive wedges: Example of Late Quaternary Têt and Agly rivers,western Gulf of Lions,Mediterranean Sea,France

Quaternary incised valley systems are usually characterized by the preservation of a single valley-fill attributed to the last post-glacial period. Moreover, there are very few cases of correlation between incised valley system developed on inner shelf and sedimentary units observed on the mid to outer shelf, mainly forced regressive wedges. The Roussillon shelf, in the western part of the Gulf of Lion, is a particular example of preserved Quaternary compound incised valley system also characterized by a direct correlation with the forced regressive lowstand wedges on the mid-outer shelf. High-resolution seismic data and a borehole, 60 m deep, located on the beach barrier permit an accurate study of the geometry and lithology of the system. Six imbricated and more or less preserved incised valleys and valley-fills are observed up to the inner to mid-shelf. The key surfaces associated to the incised valleys are correlated to the boundaries of the forced regressive wedges. They are assumed to be reworked surfaces. At the borehole location, only few thin layers, less than 1 m thick, of coarse grain and/or floating pebbles, are observed and should correspond to preserved fluvial lowstand deposits reworked under marine influence. The valley fills are mainly composed of estuarine muddy silts. From AMS ¹⁴C age dating it is inferred that the uppermost incised valley system is younger than 45 ky cal BP. Based on those observations, the six preserved incised valley systems are assumed to be controlled by the last six 4th order sea-level cycles — 100 ky — of the middle to late Quaternary. The paleo-topography of the underlying Plio-Quaternary deposits controls the compound incised valley system location. The deep topography of the Messinian Erosionnal Surface is a controlling factor at a lower degree. The partial preservation of the successive valley fill is attributed not only to the differential subsidence but also to the lateral migration of each incision and to the hydrodynamic regime.     

3d transition metal L-edge X-ray absorption studies of the dichalcogenides of Fe, Co and Ni

The X-ray absorption spectra of the transition metal L_3,2-edges of the dichalcogenides FeS₂ (pyrite), FeSe₂, FeTe₂, CoS₂, CoSe₂, CoTe₂, NiS₂, NiSe₂ and NiTe₂ have been studied. These spectra are compared with theoretical simulations make using the atomic multiplet approach assuming on octahedral site for the metal atoms. The Ni spectra can be closely simulated using this approach but the Fe and Co spectra show less good fits to the experimental data. The reasons for this and its implications for the use of L-edge spectra in the study of such minerals are discussed in terms of the covalency and the ground states of the compounds; these results indicate the mixing of the ground states increases in the order Ni<Co<Fe.