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With the intent of making data acquisition for fractal geometry-based discrete fracture network (DFN) modeling time-efficient and automatized, a new method was established. For the automation of data retrieval from the images of the studied surfaces, a series of image-processing operations and MATLAB algorithms have been developed. The method allows the retrieval of more than 1,000 fracture-length data/cm2 of one sample in several minutes. This methodology tends to be a useful tool in studies of fracture network geometries. DFN models of a supposed excavated and/or environmental damage zone, designed with the use of data supplied by the above method, are presented in this work as an example.

Open access

Most cities in the world have experienced major developments in the past 20–25 years. However, research has showed that the development aspect of these cities has led to a decrease in green areas. This paper aims to assess the spatiotemporal variations of urban green areas during the period 1990–2015 with special regard to city of Erbil. The study uses a mix of fuzzy functions, linear spectral mixture analysis, and maximum likelihood classification for the classification of Landsat imagery from 1990 to 2015 to extract the four main classes of land use, namely agricultural land, vacant land, built-up land, and green vegetation. Both the classification approaches used in this research produced excellent and reliable results, as an overall accuracy of more than 80% was able to be obtained. The spatiotemporal analysis of land use within the city of Erbil shows a series of major changes between 1990 and 2015. Therefore, the results of the spatiotemporal evolution of urban greenness assessment in the Erbil region can be used both for spatial planning purposes and as an urban greenness assessment method in dry climate areas.

Open access
Central European Geology
Authors:
Zsófia Pálos
,
István János Kovács
,
Dávid Karátson
,
Tamás Biró
,
Judit Sándorné Kovács
,
Éva Bertalan
,
Anikó Besnyi
,
György Falus
,
Tamás Fancsik
,
Martina Tribus
,
László Előd Aradi
,
Csaba Szabó
, and
Viktor Wesztergom

The past decade has seen a great number of studies dealing with magmatic water contents and how these could be retrieved by the nominally anhydrous minerals’ (NAMs) trace structural hydroxyl (water) contents. Constraints have been made to magmatic hygrometry with clinopyroxene and plagioclase. Although results suggest that the method is more flexible and reliable than melt inclusion studies, they also indicate that the trace hydroxyl contents could still be overprinted by syn- and post-eruptive processes. Clinopyroxenes can hold more structural hydroxyl than plagioclases. A comprehensive review is presented with the inclusion of all published results so far to compile the available pieces of information. As a case study, micro-FTIR measurements are made of a representative set of plagioclase phenocrysts from the Börzsöny Mts. (Carpathian–Pannonian Region). The samples were selected to represent the progress of the volcanic activity in time and space, considering the petrologic and geochemical evolution of volcanic products in well-defined volcanostratigraphic positions. The syn- and post-eruptive cooling rate seems to have the greatest effect on water retention. This means that the systematic investigation of water in volcanic phenocrysts can contribute to distinguish the slowly and rapidly cooling parts of the volcanostratigraphic units.

Open access

The aim of this study is to identify the milestones of landscape evolution around the Ecse Mound (Karcag-Kunmadaras, Hortobágy National Park, Hungary) in the Holocene period by sedimentological and malacological analysis of strata underneath and within the body of the kurgan concerned, including that of the same characteristics of the artificially piled layers. An undisturbed core drilling was carried out and the sedimentological properties of both the mound and of the substrate baserock were revealed, analysis of which has been supported by three radiocarbon (AMS) measurements. The baserock formation during the last phase of the Ice Age, Middle and Upper Pleniglacial, and Late Glacial phases was followed by soil development in the Holocene, while the mound was constructed in two phases at the end of the Copper Age by the communities of the Pit Grave (Yamna or Ochre Grave) Culture. By publishing these preliminary data, it is also intended to draw attention to the need of focused research efforts by standardized methodology in kurgan research, in order to make the results of different studies consistent and comparable.

Open access

Many river banks throughout the world are prone to landslides; therefore, serious efforts are made to develop landslide early warning systems. This study presents a method by which the stability changes of the river banks can be continuously monitored; necessary measures can be taken in time to reduce the damage. The method was tested in Dunaszekcső (Hungary), where the high loess bank of the River Danube has been intensively moving since 2007. The tilts of the high bank were measured by two borehole tiltmeters. The connection between tilt values and the river- and groundwater-level variations was investigated by multivariable and moving window regression analyses on the basis of a 6-year-long observation from 2011 to 2016. The results show that increasing regression coefficients mean decreasing stability of the high river bank, so the developed method can be used for continuous supervision of the high bank stability. The method is also suitable for studying the causes of motion processes. Investigations showed clearly that the effect of groundwater table variations is two orders of magnitude higher than the water-level variations of the River Danube. In addition to the erosion of the river, various small tilts of the stable and unstable parts also contribute to the arising of new cracks in the stable part, decreasing its width.

Open access
Central European Geology
Authors:
Máté Zsigmond Leskó
,
Richárd Zoltán Papp
,
Boglárka Anna Topa
,
Ferenc Kristály
,
Tamás Vigh
, and
Norbert Zajzon

The Úrkút manganese ore deposit (Transdanubian Range, Hungary) is one of the largest manganese accumulations to be formed during the Toarcian Oceanic Anoxic Event. In the past 60 years, the area was investigated intensively. The core storage facility of the manganese mine had more than 20,000 sample pieces. Most of these samples have never been investigated. During this study, which is the first widespread clay mineral study in the footwall of the Úrkút manganese ore deposit, we investigated 40 samples from seven boreholes (footwall rocks, black/gray shales below and above the first ore bed, and manganese carbonate ores). Although previous studies assumed that smectite is associated only with the ore beds, our research revealed its appearance in the footwall (Pliensbachian) as well. Simultaneously, tripoli (the local name of completely bleached chert) can also be found in the footwall. Based on the investigated samples, a sharp geochemical difference was detected between Pliensbachian and Toarcian sediments. In this paper, we try to trace the relationship between the smectite content of the footwall and the ore bed and compare these results with the observed geochemical changes. Based on the new data, we assume that the ore accumulation was caused by a flow system (upwelling-controlled ore formation).

Open access

Energy and metals are essential resources in the 21st century and with the economic and technical development are more and more required. The fulfilling of these requirements leads to the need to produce both more ore and energy. Considering these goals, the project CHPM2030 (“Combined Heat, Power and Metal extraction”) was launched in January 2016, focused on the characterization of European mining regions that can be linked to both metal extraction and renewable energy production. The aim of this project is to convert ultra-deep metallic mineral formations into an “orebody-enhanced geothermal system” to co-produce energy and metals. This study will focus on two mining areas (Recsk in Hungary and Neves-Corvo in Portugal), considered CHPM2030 case studies, comparing them regarding mineral (ore) and geothermal potential in terms of heat-flow density values and their implication in temperatures in depth estimations. Especially, when it concerns geothermal energy, the surface demand is an important factor to consider, so wider studies are required.

Open access

The Mecsekalja Zone is a strike-slip fault zone that plays an essential role in the structural framework of South Transdanubia. The metamorphic and deformation history of the crystalline basement of the Mecsekalja Zone has been determined thus far based exclusively on a few surface outcrops and near-surface samples. The Szentlőrinc-1 (Sztl-1) well penetrated the shear zone at a depth of approximately 2 km and brought drilling chips from a 220-m-long section of the basement to the surface. The aim of this study is to reconstruct the metamorphic and deformation history of the Mecsekalja Zone along the Sztl-1 well using these tiny samples. These drilling chips consist of single mineral and rock pieces that are dominated by quartz grains. This study concentrates on the detailed analysis of quartz grains utilizing the physical conditions of metamorphic evolution as well as ductile and brittle deformation to determine the chemical composition and rheology of quartz. The evolution of the studied area can be determined by evaluating analytical data measured by Raman spectroscopy, LA-ICP-MS, and FTIR spectroscopy. These data suggest that the maximum temperature of the early regional metamorphism was 500–575 °C, the temperature of the subsequent ductile deformation was below 500 °C including recrystallization occurred between 400 and 475 °C. During the structural evolution of the study area, two independent, single deformation events occurred. The earlier ductile deformation event was followed by a brittle event through the reactivation of the former ductile shear zone. Our model is in accordance with previous results concerning the evolution of the Mecsekalja Zone, thus, the shear zone, with an identical evolution, can be extended toward the southwest at least to the Sztl-1 well.

Open access

The Late Valanginian–Early Hauterivian iron ore deposit and related formations at Zengővárkony (Mecsek Mts., South Hungary) provided a relatively rich microfauna of foraminifera, crustacean microcoprolites, and sponge spicules. Benthic foraminifera are recognized in decreasing abundance: Glomospira cf. gordialis (Jones and Parker 1860), Lenticulina sp., Spirillina sp., Nodosaria sp., Epistomina sp., and Trocholina sp. A Hedbergella sp. indicates the presence of planktonic foraminifera around the ore deposit. Besides this microfauna, sponge spicules (diactine-type criccorhabds and anactine-type rhax forms) are first recorded from this environment. Rock-forming quantities of various ichnospecies of crustacean microcoprolites are recorded. Favreina hexaochetarius, Palaxius tetraochetarius, and Palaxius decaochetarius isp. provided statistically evaluated quantities in thin sections, which point to a complete crustacean ichnofauna from juveniles to adults. Four different microfossil assemblages are recognized from the Apátvarasd Limestone Fm: (a) Glomospira-dominated foraminifer assemblage, (b) diverse crustacean microcoprolite assemblage dominated by Palaxius, (c) monotypic Favreina assemblage, and (d) diverse sponge-dominated assemblage. These assemblages are similar to that of the Recent Aegean Sea hydrothermal field communities. The remains of an undetermined crinoid from dissolved rock sample may indicate a vivid sea-bottom environment.

Open access

Assessing the uncertainty in reservoir performance is a necessary step during the exploration phase. To examine the uncertainty in flow response, a large set of realizations must be processed. There are several stochastic geostatistical algorithms capable of simulating multiple equiprobable realizations. Although these can show us the possible realities highlighting the spatial uncertainty, their handling is time- and CPU-consuming during the later processes, such as flow simulations. Consequently, only a small number of realizations can be post-processed in industrial practice. The purpose of this work is to develop a method, which will reduce the huge number of realizations in a way that the remaining ones retain the spatial uncertainty of a reservoir’s flow behavior, as would be demonstrated by a larger set of realizations. To solve this problem, ranking methods can be applied. Traditional ranking techniques, such as probability selection, are highly dependent on the applied static properties. In this paper, an alternative selection method is parameterized for measuring the pairwise dissimilarity between geostatistical models, with a distance function based on the hydrodynamic properties of the hydrocarbon reservoirs. The effectivity of the method is highly dependent upon the selected criteria. Thus, the distance function refers to the flow responses and allows visualizing the space of uncertainty through multidimensional scaling. A kernel transformation of the MDS data set is required to obtain a feature space where the K-means algorithm can discover non-linear structures in the basic data set. The final step of the method is the selection of the Earth models closest to the cluster centers. This tool allows for the selection of a subset of representative realizations, containing similar properties to the larger set.

Open access