Ichnology of Bhuban and Boka Bil Formations,oligocene-miocene deposits of Manipur Western Hill,Northeast India

Oligocene-Miocene deposits of Bhuban and Boka Bil Formations, Surma Group, Manipur Western Hill consist of well preserved ichnofossil assemblages. These formations are represented by eight lithofacies such as Massive sandstone (Sm), Rippled marked argillaceous sandstone (Sr), Wavy laminated sandstone-siltstone-silty shale (Sw), Laminated shale (Fl), Massive mudstone (Fm), Trough cross-bedded sandstone (St), Lenticular laminated sandstonesiltstonesilty shale (Sll) and Laminated to massive sandstone-siltstone (Ssc). Fifteen ichnospecies were identified, which further categories into Skolithos, Cruziana, and Skolithos/Cruziana ichnofacies. Overall distribution pattern and behavioural nature of the ichnoassemblage and sedimentological attributes suggests that the sediments of Bhuban and Boka Bil Formations were deposited under frequent fluctuating sea level, moderate to strong energy condition, subtidal to lower intertidal environment, rich in organic nutrients.     

Composition and heterogeneity of the microbial community in a coastal microbial mat as revealed by the analysis of pigments and phospholipid-derived fatty acids

The beaches of the North Sea barrier island Schiermonnikoog (The Netherlands) are covered by microbial mats. Five types of microbial mats were distinguished based on a variety of characteristics, located along a transect perpendicular to the coast. Biomass abundance and composition of the microbial community were analyzed in these mats using pigments and phospholipid-derived fatty acids (PLFA) as biomarkers. Biomass per gram sediment increased more than six-fold from the mats at the low water mark to mats found at the edge of the dunes. Microscopic analysis revealed that the increase in biomass was accompanied by a change in species composition. Pigment- and PLFA composition reflected the changes in species composition. The PLFA data could be used to estimate the relative group abundance using the matrix factorization program CHEMTAX., whereas the pigment data were found not to be suitable for this purpose.     

Umbral oscillations and penumbral waves in Hα

We present examples of umbral oscillations observed on Big Bear H filtergram movies and investigate the relation between umbral oscillations and running penumbral waves occurring in the same sunspot. Umbral oscillations near the center of the umbra are probably physically independent of the penumbral waves because the period of these umbral oscillations (150 s) is shorter than the penumbral wave period (270 s) but not a harmonic. We also report dark puffs which emerge from the edge of the umbra and move outward across the penumbra, and which have the same period as the running penumbral waves. We interpret these dark puffs to be the extension of chromospheric umbral oscillations at the edge of the umbra. It is suggested that the dark puffs and the running penumbral waves have a common source: photospheric oscillations just inside the umbra.     

Clustering of groundwater chemistry data with implications for reservoir appraisal in West Siberia

Division of sedimentary strata according to groundwater chemistry is discussed with implications for petroleum reservoir potential. It is suggested to process multiparametric water chemistry data from West Siberia using formalized clustering techniques. The efficiency of this approach has been tested for Neocomian clinoform reservoirs with reference to regional-scale appraisal and subregional petroleum division.     

Organic tracers in sediments from the coastal zone of Ras Abu el-Darag,Gulf of Suez

Sediment samples from the coastal zone of the Gulf of Suez contain a variety of organic compounds from anthropogenic and natural sources. A total of 12 surface samples of bottom sediments were collected with an Ekman grab sampler along an off-shore transect south of Ras Abu el-Darag. The samples were extracted with a mixture of dichloromethane and methanol (3:1 v/v) after drying and sieving through 250 μm mesh. The extracts were derivatized and analyzed by gas chromatography–mass spectrometry in order to characterize the chemical composition and sources of the organic components. Marine with minor terrestrial biota were the major natural sources of organic tracers and included n-alkanoic acids, sterols and saccharides (5.7–76.7%). Anthropogenic sources, from petroleum related activities, detergent usage for spill cleaning and littering, are indicated by the presence of n-alkanes with carbon preference index ≤1.0, hopanes, steranes, unresolved complex mixture of branched and cyclic hydrocarbons, alkyl nitriles, alkamides and plasticizers. Their total relative concentrations ranged from 23.3 to 97.3% of the total extracts. Petroleum residues from natural seepage may also be part of these hydrocarbons. The levels of anthropogenic inputs decrease from about 94% in coastal zone sediments to about 20% in sediments from the reef front.     

Eliminierung und Rückgewinnung von Metallionen aus Abwässern — eine Übersicht

The present state and the trends of the recovery of heavy metals from wastewaters are presented. The classical precipitation techniques are insatisfactory due to increases of solubility in the presence of impurity ions and/or complexing agents. At present, ion-exchange processes constitute the most frequently used method of metal recycling with an effective enrichment of metal ions. For the effective separation of metals from solutions of a low concentration the electrolytic reduction demands large electrode surface areas. In cells with fixed-bed or fluidized cathodes one can obtain specific electrode surface areas of some 10³ m²/m^m3. For the future, processes of extraction and especially membrane separation will gain in importance. In the past few years, a large number of highly selective metal extracting agents as well as the liquid membrane permeation with suitable carriers were developed. Combinations of membrane separation processes with chemical reactions may attain the same importance, as e.g. ultrafiltration in connection with the fixation of metal ions to watersoluble polymers. In the long run, especially techniques will prevail which will not only result in metal enrichment but also in the recovery of the raw material water.     

Magnetometer Array Study in North-Northeast Brazil: Conductivity Image Building and Functional Induction Modes

—Magnetovariational fields recorded by an array of magnetometers in the equatorial region of north-northeast Brazil are analyzed to infer the configuration of internal induced currents in and around the extensive intracratonic Parnaíba basin. Only nighttime magnetovariational fields were used because of the prevailing uniform source field conditions. For periods exceeding 40 min. the vertical fields at all inland sites are dominated by the effects of electric currents originating in the northeast, in the deep Atlantic Ocean. Below this period, although best developed in the 12–15 min. period range, the anomalous signatures are principally controlled by two distinct continental current paths. The first is associated with a N60°E trending graben-like structure in the southeastern part of the basin (named the Parnaíba Basin Conductivity Anomaly—PBCA) and the second appears as a subsurface sedimentary channel, from the NW corner of the array to the central part of the basin. This is named the LINK anomaly, as it connects the northwestern Marajó basin with the Parnaíba basin. While the PBCA is shown to highlight the importance of basement tectonics in the geological evolution of the Parnaíba basin, the LINK anomaly provides strong geophysical evidence of the direction of the sea intrusion into the region of the basin and possibly indicates the connectivity of the Parnaíba basin to the adjoining Amazon basin through the Marajó basin. Frequency and polarization dependence suggest that the induction response of individual structures is not determined by the local conductivity alone but also by their interconnectivity as well as by their linkage to the continental shelf and deep oceanic region.     

Origin,Bulk Chemical Composition And Physical Structure Of The Galilean Satellites Of Jupiter: A Post-Galileo Analysis

The origin of Jupiter and the Galilean satellite system is examinedin the light of the new data that has been obtained by the NASA Galileo Project. In particular, special attention is given to a theory of satellite origin which was put forward at the start of the Galileo Mission and on the basis of which several predictions have now been proven successful (Prentice, 1996a–c). These predictions concern the chemical composition of Jupiter's atmosphere and the physical structure of the satellites. According to the proposed theory of satellite origin, each of the Galilean satellites formed by chemical condensation and gravitational accumulation of solid grains within a concentricfamily of orbiting gas rings. These rings were cast off equatorially by the rotating proto-Jovian cloud (PJC) which contracted gravitationally to form Jupiter some 4 billion years ago. The PJC formed from the gas and grains left over from the gas ring that had been shed at Jupiter's orbit by the contracting proto-solar cloud (PSC). Supersonic turbulentconvection provides the means for shedding discrete gas rings.The temperatures T_n of the system of gas rings shed by the PSCand PJC vary with their respective mean orbital radii R_n (n = 0, 1, 2, Ϊ ) according as T_n ∝ R_n ^-0.9. If the planet Mercury condenses at 1640 K, so accounting for the high density ofthat planet via a process of chemical fractionation between iron and silicates, then T_n at Jupiter's orbit is 158 K. Only 35% of the water vapour condenses out. Thus fractionation between rock and ice, together with an enhancement in the abundance of solids relative to gas which takes place through gravitational sedimentation of solids onto the mean orbit of the gas ring, ensures nearly equal proportions of rock and ice in each of Ganymede and Callisto. Io and Europa condense above the H₂O ice point and consist solely of hydrated rock (h-rock). The Ganymedan condensate consists of h-rock and H₂O ice. For Callisto, NH₃ ice makes up ∼5% of the condensate mass next to h-rock (∼50%) and H₂O ice (∼45%). Detailed thermal and structural models for each of Europa, Ganymedeand Callisto are constructed on the basis of the above initial bulk chemicalcompositions. For Europa (E), a predicted 2-zone model consisting of a dehydrated rock core of mass 0.912M_E and a 150 km thick frozen mantle of salty H₂O yields a moment-of-inertiacoefficient which matches the Galileo Orbiter gravity measurement. For Ganymede (G), a 3-zone model possessing an inner core of solid FeS and mass ∼0.116M_G, and an outer H₂O ice mantle of mass ∼0.502M_G is needed to explain the gravity data.Ganymede's native magnetic field was formed by thermoremanent magnetization of Fe₃O₄. A new Callisto (C) model is proposed consisting of a core of mass 0.826M_C containing a uniform mixture of h-rock (60% by mass) and H₂O and NH₃ ices, and capped by a mantle of pure ice. This model may have the capacity to yield a thin layer of liquid NH₃ċ2H₂O at the core boundary, in line with Galileo's discovery of an induced magnetic field This revised version was published online in July 2006 with corrections to the Cover Date.