Neotectonic and modern stresses of South Sakhalin

Tectonophysical studies are conducted in South Sakhalin for identification of temporal–spatial changes in the geodynamic settings of the formation of the local structures. Analysis of the field data reveals 11 local stress state (LSS) in the large newest megastructures, which were formed on geological basement of different ages. The parameters of the tectonic stresses are significantly distinct in each LSS, especially the orientations (up to reindexation) of the compression and extension axes in different fault wings. Tectonic stresses of two ages and constant latitudinal and horizontal compression axis are reconstructed. The earlier cofold shear stress field with a horizontal and longitudinal extension axis is post-Miocene and the later stress field of the reversed fault with a vertical extension axis is orogenic. The LSSs reconstructed for the first time by the displacement vectors on slickensides, along with the data on the earthquake mechanisms, substantiate the reindexation of the horizontal extension axis with the vertical intermediate axis of major normal stresses at the postfold orogenic stage of evolution of the territory. These results are in agreement with previous data on the transformation of the dextral to reverse thrust displacements along the longitudinal fault systems. The young stress field is more confidently interpreted in the activation fault zones, which limit the orogenic blocks, whereas the traces of cofold deformations without younger orogenic stress fields better remain inside the blocks which are composed of older and strongly dislocated Mesozoic rocks.     

Petrology of titanian clinohumite and olivine at the high-pressure breakdown of antigorite serpentinite to chlorite harzburgite (Almirez Massif,S. Spain)

Rocks of the Cerro del Almirez ultramafic massif (Sierra Nevada, Betic Cordillera, S. Spain) record the high-pressure dehydration of antigorite–olivine serpentinite to form chlorite harzburgite (ol + opx + chl). In the field, these two rock types are separated by a well-defined isograd. Titanian clinohumite (TiCl) and olivine show textural and compositional differences depending on the rock type. OH–TiCl occurs in the serpentinite as disseminated grains and in veins. F–OH–TiCl is observed exclusively in the chlorite harzburgite, where it occurs as porphyroblastic grains and within prograde olivine as irregular and lamellar, planar intergrowths at microscopic and submicroscopic scales. Petrological evidence of partial to complete breakdown of TiCl to olivine + ilmenite is preserved in both rock types. Chlorite harzburgite is characterized by a brown pleochroic olivine with abundantally oriented microscopic to submicroscopic oxide particles. The mean Ti-content of the brown olivine is 144 ppm. The brown olivine preserves TiCl lamellae that sometimes grade into ghost lamellae outlined by the oxide trails. This observation suggests that some of the oxide inclusions in the brown olivine are derived from the breakdown of TiCl intergrowths. Thermodynamic modelling of selected Almirez bulk rock compositions indicates a temperature increase from 635°C to 695°C, at pressures ranging from 1.7 GPa to 2.0 GPa, as the cause for the compositional adjustment of TiCl between the Almirez antigorite serpentinite and chlorite harzburgite. These P–T estimates are in good agreement with the sequence of phase relations observed in the field. The computed phase diagrams in conjunction with the geothermal conditions envisaged for different subduction settings indicate that TiCl is stable in the vicinity of the antigorite serpentinite/chlorite harzburgite phase boundary in some subduction settings. In these circumstances, clinohumite–olivine intergrowths in chlorite harzburgite may act as a sink for high field strength elements, and probably other elements, that are present in the mantle–wedge fluids.     

Distribution of arsenic and other minor trace elements in the groundwater of Ischia Island (southern Italy)

The island of Ischia belongs to the active volcanic area of Naples. It is formed from Quaternary volcanic rocks and exhibits intense hydrothermal activity, which is manifested through numerous springs, fumaroles and sporadic geysers. The content of minor and trace elements in groundwater has been analyzed, including some elements that are considered toxic for humans. Mean concentrations of As, B, Fe, Mn, Sb, and Se in samples from 43 aquifer points exceed the WHO recommended values and the limits set by European and Italian legislation (98/83/CE and DM 471, respectively). In general, the spatial distribution of the elements follows a common pattern: it is governed by a marked structural control, which favors hydrochemical processes that liberate the elements into the water.     

Quantification of vertical water fluxes in the vadose zone using particle‐size distribution and pedology‐based approaches to model soil heterogeneities

One‐dimensional flow simulations were conducted at four locations of the shallow alluvial aquifer of the upper Rhine River (at the Erstein polder) to quantify the time‐dependent moisture distribution, the water flux and the water volume infiltrated in the unsaturated zone as a function of soil heterogeneities during a five‐day‐long flooding event. Three methods of estimating the hydraulic parameters of soil in the vadose zone were tested. They are based on the following: (1) experimental data, (2) soil particle‐size distribution and (3) pedology information on soils. Water fluxes calculated from modelling approaches 2 and 3 were compared with those of the experiment‐based values and the effect of these differences on the arrival time and velocity of water at the water table were analysed. Major differences in water fluxes were found among the methods of estimating the hydrodynamic parameters. At the Terrace location, the groundwater recharge predicted using soil data from methods 1 and 2 are approximately 4500 and 2400 mm, respectively. Flow simulations using soil data and the experiment‐based method show the highest velocities of infiltrating water at the soil surface and largest volume of groundwater infiltration but result in the lowest centres of the moisture content mass. The results obtained using soil data based on the pedological method are similar to those calculated using soil parameters based on the particle‐size distribution of extracted soil samples. Water pressure profiles calculated on Terrace and Channel location, 3 and 7 days after the inundation event agreed reasonably well with those observed when using hydrodynamic parameters from the experiment‐based method. However, the flow model using the pedology‐based parameters largely underestimates the time needed to achieve hydrostatic conditions of the soil water profile once water flooding at the soil surface stops. This can be mainly attributed to the low values of estimated van Genuchten parameter α. Copyright © 2012 John Wiley & Sons, Ltd.     

Dating recent floodplain sediments in the Hawkesbury‐Nepean River system,eastern Australia using single‐grain quartz OSL

Two fluvial sediment cores taken from a floodplain of the Hawkesbury‐Nepean River system in the Sydney region, eastern Australia are dated using Optically Stimulated Luminescence (OSL) to provide a reliable chronology essential for the management and planning of water resources. Nine charcoal ¹⁴C (AMS) dates constrain these OSL ages. Quartz extracted from seven OSL samples from each of the cores was measured using both single‐grain and multi‐grain OSL techniques. Three of the single‐grain natural dose distributions appear to be well bleached, but the others appear to be incompletely bleached to various degrees. Three minimum‐age models (MAM, MAM_UL and IEU) are applied to the single‐grain dose distributions. We conclude that these models give consistent age estimates. For one of the cores it appears to be necessary to use a minimum‐age model to obtain accurate ages, but in the other core incomplete bleaching is probably less important than postdepositional mixing and mixing during sampling. As a result, the burial age is probably best estimated using the weighted average of the individual single‐grain dose estimates. The application of multi‐grain OSL techniques to these samples results in an average apparent age overestimation of ～200 years, which is significant for these samples, but negligible for sediments older than a few thousand years. The intention is that the chronology obtained in this study will be used in conjunction with a proxy flood record, derived from floodplain sediments, to gain an understanding of the long‐term variability in periods of high and low rainfall in eastern Australia.     

Presence of fluoroquinolones and sulfonamides in urban sewage sludge and their degradation as a result of composting

The concentrations of some widely used pharmaceuticals, namely fluoroquinolones (ciprofloxacin C₁₇ H₁₈FN₃O₃, norfloxacin C₁₇ H₁₈FN₃O₃ and ofloxacin C₁₈ H₂₀FN₃O₄ and sulfonamides (sulfadimethoxine C₁₂ H₁₄N₄O₄s and sulfamethoxazole C₁₀ H₁₁N₃O₃S were determined in urban sewage sludge utilized for making compost. The levels of degradation of these pharmaceuticals resulting from sludge treatment were assessed. The concentrations of the studied pharmaceuticals sufficiently varied both in sewage sludge and in compost and due to this phenomenon the possible danger resulting from the presence of pharmaceuticals in sewage sludge, used for composting, can not be ignored. The concentrations of the studied pharmaceuticals were lower in compost, if compared to the relevant concentrations in sewage sludge. The highest pharmaceutical concentration in sewage sludge — 426 μg/kg — was detected in the case of ciprofloxacin. The highest concentrations present in compost were 22 μg/kg of norfloxacin and 20 μg/kg of ciprofloxacin. Results show that before using the sewage sludge for making compost or before using the compost a fertilizer for food plants, they should be carefully tested against the content of commonly used pharmaceuticals.     

Fault tectonics,neotectonic stresses,and hidden uranium mineralization in the area adjacent to the Strel’tsovka Caldera

The scheme of recent fault tectonics and neotectonic stresses of the area adjacent to the Strel’tsovka Caldera in the southeastern Transbaikal region has been compiled for the first time on the basis of structural and geomorphic study. The faults were ranked by criteria of slip direction stability along separate segments and their expression in topography. Neotectonic stresses of corresponding ranks were ascertained as well. The heterogeneity of neotectonic stress field is related to the mosaic development of compression, extension, and the three-axial stress state. Comparison of morphogenetic features of recent and older faults shows the different character of the deformation mechanism and orientation of tectonic displacements. It has been established that the Strel’tsovka Caldera and its northwestern segment, in particular, developed as an echeloned system of pull-apart grabens, but the caldera itself is situated in a recent rise, whereas the northwestern segment is located in a neotectonic depression corresponding to the Dry Urulyungui Basin filled with volcanic and sedimentary rocks. Such a structure markedly expands the outlook for discovery of hidden uranium mineralization in the studied area. The elaborated scheme of neotectonic faults and stresses reflects the postore geodynamic setting and completes the reconstruction of geodynamic conditions pertaining to the periods of preore preparation and ore-forming tectonomagmatic reactivation.     

Origin of boron from a complex aquifer in southeast of Spain

A study of the boron content alongside Cl ^-, SO ₄ ^2-, and NO ₃ ^- ions has enabled the factors that determine its origin to be distinguished. In carbonate rocks, with their higher saline content, boron is associated with marine intrusion. In the Plioquaternary aquifer, its origin is complex and is associated with three processes: marine intrusion, where there is a high Cl ^- content and the B/Cl ^- ratio is close to that of seawater; anthropogenic pollution, at points with high B and NO ₃ ^- concentrations and where the B/Cl ^- ratio is higher than that of seawater; and the dissolution of evaporite deposits present in the Plioquaternary strata, at a series of sampling points where the SO ₄ ^2-/Cl ^- ratio is elevated and B content is high.