Volume 5, Issue 3

Palaeoenvironmental research is playing an important role in recent archaeological investigations. We present preliminary results of geoarchaeological analyses conducted at a palaeochannel located between two prehistoric archaeological sites in eastern Hungary. The study area lies within the Körös River Basin in Békés County, a region of intensive human occupation beginning in the Neolithic, ca. 7550 BP, and represents only the second palynological analysis done in conjunction with archaeological investigations and adjacent to an archaeological site in the Körös region. Pollen from an environmental monolith was used to reconstruct the local vegetation composition and the human impact on arboreal and non-arboreal vegetation near the archaeological sites. Sediment analyses helped to reconstruct hydrological activity and human impact on the local palaeochannel. Results indicate that activity from the Neolithic onwards played an important role in local environmental change, including increasing sedimentation and deposition of organic matter in the local waterway, some forest clearance and a shift from primarily arboreal vegetation to more grasses on elevated surfaces. The trophic status of the local channel changed several times during the Holocene. In addition, indications that groundwater levels may have been fluctuating during the period of human occupation, when combined with the other changes in the area, provide a possible partial explanation for changing settlement patterns.

The purpose of this paper is to identify areas with high flash-flood potential based on an evaluation of physiographic factors controlling the formation of surface runoff. The research method relies on the use of the Flash Flood Potential Index (FFPI), which incorporates physiographic characteristics from the catchment (terrain slope, profile curvature, land use and soil texture). The spatial distribution of the physiographic factors (which contribute to the creation, control and concentration within the drainage network of the overland flow) and the classified zoning of areas according to their hydrological response were achieved with GIS techniques. The results obtained show that physiographic factors on 227 sq km (29%) favor surface runoff on slopes and its localization towards the drainage network. Notably, the highest values of FFPI belong to the lower part of the catchment, where high human population density can be found, reflecting an increased vulnerability to floods and inundations of this area.

New evidence supported by petrography (including mineral chemistry), lithogeochemistry, U-Pb geochronology by Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS), and physicochemical study of fluid and melt inclusions by LA-ICP-MS and microthermometry, point to an orogenic setting of Lagoa Real (Bahia-Brazil) involving uraniferous mineralization. Unlike the previous models in which uraniferous albitites represent Na-metasomatised 1.75 Ga anorogenic granitic rocks, it is understood here that they correspond to metamorphosed sodium-rich and quartz-free 1.9 Ga late-orogenic syenitic rocks (Na-metasyenites). These syenitic rocks are rich not only in albite, but also in U-rich titanite (source of uranium). The interpretation of geochemical data points to a petrogenetic connection between alkali-diorite (local amphibolite protolith) and sodic syenite by fractional crystallization through a transalkaline series. This magmatic differentiation occurred either before or during shear processes, which in turn led to albitite and amphibolite formation. The metamorphic reactions, which include intense recrystallization of magmatic minerals, led uraninite to precipitate at 1.87 Ga under Oxidation/Reduction control. A second population of uraninites was also generated by the reactivation of shear zones during the 0.6 Ga Brasiliano Orogeny. The geotectonic implications include the importance of the Orosirian event in the Paramirim Block during paleoproterozoic Săo Francisco Craton edification and the influence of the Brasiliano event in the Paramirim Block during the West-Gondwana assembly processes. The regional microcline-gneiss, whose protolith is a 2.0 Ga syn-collisional potassic granite, represents the albitite host rock. The microcilne-gneiss has no petrogenetic association to the syenite (albitite protolith) in magmatic evolutionary terms.

The M1 block is a typically complex fault-block oilfield, whose recovery has reached 30.5% through the twenty years waterflooding development. Remaining oil scatters very widely and the production between layers is in a high degree. However, many problems have been exposed at the same time which hinder improvement of the recovery rate and sustainable development of the reservoir. Hence, it is important to carry out basic geological research and form a comprehensive understanding of reservoir properties. However, few such studies have been conducted in China. In this study, work related to basic geological research was conducted based on high-resolution sequence stratigraphy, seismic interpretation technology and 3D visual geological modeling, and significant results were achieved. Three sequence orders and three types of interfacies in the stratigraphic architecture of M1 block were identified through seismic sections, logging curve characteristics and entropy spectrum analysis. Thirty-two short-term sequence cycles (fifth order), eight mid-term sequence cycles (fourth order) and two long-term sequence cycles (third order) were identified, followed by the establishment of a high-resolution isochronous stratigraphic correlation framework. Finally, a regional 3D geological model was established on the basis of these preliminary studies. The integrated 3D geological model is a valuable tool for reflecting geological bodies accurately, and it can accurately represent and describe reservoir heterogeneity.

Locations and depths to magnetic contacts were estimated from the total intensity magnetic field using the Horizontal Gradient Magnitude (HGM), Analytic Signal Amplitude (ASA) and Local Wavenumber (LWN) methods. Aeromagnetic data from the Ibadan area, in south-western Nigeria, were analyzed to estimate depths to magnetic sources as well as source locations. The minimum/maximum depth limits of the HGM and LWN are relatively close and comparable, while shallow source depths limits are greater than expected in the ASA method when compared with the HGM and LWN functions.

A 42 m thick outcropping portion of the Mamfe Formation is subdivided into Manyu (31 m thick) and Kesham (11m thick) Members on the basis of textural, mineralogical and structural differences. The Manyu Member (Albian) consists of folded and indurated, medium to coarse grained arkosic sandstones and thickly laminated organic-rich shales deposited in a lacustrine environment. The Kesham Member (Cenomanian) consists of subarkoses intercalated with massive green shale and mudstone deposited in a fluvial environment. The change in depositional environment was tectonically controlled. The mid Cretaceous paleogeography of the embayment was governed by the NE-SW trending “Ikom ridge” which prevented marine incursion from adjacent the Benue Sea. Evaporites found within the basin were precipitated from ocean water that was periodically spilled by strong tides and storms across the ridge into the embayment. The filling-up of the embayment to base level in the Cenomanian resulted in a shift in the depositional center downstream to adjoining lower Benue Trough. Similarity in heavy mineral composition and maturity of the Cenomanian sandstones with recent clastics in the embayment indicates their derivation from the same source terrain and relatively stable tectonic and climatic conditions at the source area since the Cenomanian time.

An engineering-geological map of the Western Thessaly basin has been compiled, providing a valuable guide to both urban planning and industrial development of the wider area. This map contributes significantly to the optimization of land use and improved planning of technical work. Additionally, the engineering-geological conditions of the formations encountered in the Western Thessaly basin are examined. The formations are grouped into thirteen (13) engineering-geological entities, with regard to their geotechnical behaviour. This entire study was based on both in situ investigations and geotechnical information extracted from 1,039 boreholes. Furthermore, a landslide inventory map of the Western Thessaly basin has been compiled. In addition, the surface subsidence ruptures, due to ground-water overexploitation, have been examined in the eastern part of the study area.

The Van earthquake (M W 7.1, 23 October 2011) in E-Anatolia is typical representative of intraplate earthquakes. Its thrust focal character and aftershock seismicity pattern indicate the most prominent type of compound earthquakes due to its multifractal dynamic complexity and uneven compressional nature, ever seen all over Turkey. Seismicity pattern of aftershocks appears to be invariably complex in its overall characteristics of aligned clustering events. The population and distribution of the aftershock events clearly exhibit spatial variability, clustering-declustering and intermittency, consistent with multifractal scaling. The sequential growth of events during time scale shows multifractal behavior of seismicity in the focal zone. The results indicate that the extensive heterogeneity and time-dependent strength are considered to generate distinct aftershock events. These factors have structural impacts on intraplate seismicity, suggesting multifractal and unstable nature of the Van event. Multifractal seismicity is controlled by complex evolution of crustal-scale faulting, mechanical heterogeneity and seismic deformation anisotropy. Overall seismicity pattern of aftershocks provides the mechanism for strain softening process to explain the principal thrusting event in the Van earthquake. Strain localization with fault weakening controls the seismic characterization of Van earthquake and contributes to explain the anomalous occurrence of aftershocks and intraplate nature of the Van earthquake.

The Inkaya Cu-Pb-Zn-(Ag) mineralization, located about 20 km west of the Simav (Kütahya-Turkey), is situated in the northern part of the Menderes Massif Metamorphics. The mineralization is located along an E-W trending fault in the Cambrian Simav metamorphics consisting of quartz-muscovite schist, quartz-biotite schist, muscovite schist, biotite schist and the Arıkayası formation composed of marbles. Mineralized veins are 30–35 cm in width. The primary mineralization is represented by abundant galena, sphalerite, chalcopyrite, pyrite, fahlore and minor amounts of cerussite, anglesite, digenite, enargite, chalcocite, covellite, bornite, limonite, hematite and goethite with gangue quartz. Fluid inclusion studies on the quartz samples collected from the mineralized veins indicate that the temperature range of the fluids is 235°C to 340°C and the salinities are 0.7 to 4.49 wt. % NaCl equivalent. The wide range of homogenization temperatures indicates that two different fluid generations were trapped in quartz. Sulfur isotope studies of the sulfide minerals showed that all of the δ 34S values are between −2.1 and 2.6 per mil. These values are a typical range for hydrothermal sulfide minerals that have sulfur derived from a magmatic source. Pyrite-galena and pyrite-chalcopyrite sulfur isotope fractionation is consistent with an approach to isotopic equilibrium, and calculated temperatures are 254.6 and 277.4°C for pyrite-galena and 274.7°C for pyrite-chalcopyrite. The microthermometric data and sulfur isotope thermometry indicate the existence of a hydrothermal fluid that circulated along the fault crossing the Simav metamorphics and Arıkayası formation. Fluid inclusion and sulfur isotope thermometry can be used in combination with ore petrographical and geological information to provide site-specific targets for meso-hypothermal metal concentrations.

Nuclear Magnetic Resonance (NMR) logging provides priceless information about hydrocarbon bearing intervals such as free fluid porosity and permeability. This study focuses on using geostatistics from NMR logging instruments at high depths of investigation to enhance vertical resolution for better understanding of reservoirs. In this study, a NMR log was used such that half of its midpoint data was used for geostatistical model construction using an ordinary kriging technique and the rest of the data points were used for assessing the performance of the constructed model. This strategy enhances the resolution of NMR logging by twofold. Results indicated that the correlation coefficient between measured and predicted permeability and free fluid porosity is equal to 0.976 and 0.970, respectively. This means that geostatistical modeling is capable of enhancing the vertical resolution of NMR logging. This study was successfully applied to carbonate reservoir rocks of the South Pars Gas Field.