Browse Our Earth and Environmental Sciences Journals
Earth and environmental sciences cover all planetary and Earth science aspects, including solid Earth processes, development of Earth, environmental issues, ecology, marine and freshwater systems, as well as the human interaction with these systems.
Earth and Environmental Sciences
Abstract
The Madaras brickyard section found at the northernmost fringe of the Backa loess plateau is one of the thickest and best-developed last glacial loess sequences of Central Europe. In the present work high-resolution magnetic susceptibility measurements (at 2 cm) were implemented on samples from the 10 m-section corresponding to a period between 29 and 11 KY cal b2K. One aim was to compare the findings with the ice core records of northern Greenland in order to establish a high-resolution paleoclimatic record for the last climatic cycle and with findings documented in other biotic and abiotic proxies so far. Our results revealed a strong variability of loess/paleosol formation during MIS 2. Millennial time-scale climatic events that characterize the North Atlantic during the last climatic cycle have been identified. From 29 ka up to the start of the LGM, the recorded MS values show a weak, negative correlation with the temperature proxy, and a weak positive correlation with the dust concentration of Greenland. A strong correlation was observed with the local paleotemperatures. Local climatic factors must have had a more prominent effect here on loess/paleosol development than the climate shifts over Greenland. During the LGM the same pattern is seen with a stronger correlation with the dust concentrations and a weaker correlation with the local temperature. Local climatic factors, plus dust accumulation, must have had a prominent influence on loess/paleosol development here. From the terminal part of the LGM a strong positive correlation of the MS values with the temperature proxy for Greenland accompanied by a strong negative correlation with the dust concentration values is observed. Correlation with local paleotemperatures is positive and moderate, strong. Here climate shifts over Greenland, as well as local endowments equally had an important role on the development of the MS signal.
Abstract
The present article discusses the results of measurements carried out to assess the distribution of different sulfur types in lignite samples deriving from two opencast lignite mines near the villages of Bükkábrány and Visonta. These mines ensure the continuous supply of fuel for one of Hungary's largest thermal power plant. According to our findings no significant differences could be identified between the samples of the two mines based on their total sulfur (St) content. Both lignite types were classified as coals with medium-sulfur content according to the system of Chou (1990). A majority of total sulfur is accumulated in lignite, while in the intercalated carbonaceous shale total sulfur is present in minor amounts. Usually the sequence of the distribution of sulfur among the different bond forms in lignite collected from opencast mine of Visonta is as follows: pyritic sulfur (Sp) > organic sulfur (Sorg) > sulfate sulfur (SSOorg ).
In the samples collected from Visonta and Bükkábrány quantities of total sulfur were similar. However, some difference in their distribution among various sulfur types were noted. Although half of the samples were weathered and the amount of pyrite sulfur must have been higher in the weathered lignite of Bükkábrány preceding the oxidation process, the sequence of the distribution of sulfur was likely as follows Sorg ≥ Sp ≥ SSO4 .
Abstract
The Oligocene clay units in the Budapest area along the new metro (subway) line show different properties than most others. They are denser and of greater strength than most of the unconsolidated ones. This paper provides an overview of their engineering geologic properties using nearly 4700 physical parameter data. These data were obtained from cores representing sampling intervals of the Kiscell Clay, on the Buda side of the Danube River. Seventeen engineering geologic parameters were used in the description of the clay. The parameter analyses show that the clay behaves as a soft rock rather than a soil.
Abstract
The authors carried out geologic investigations in the Kolontár area in connection with the red mud catastrophe of 4 October 2010, and have acquired more detailed knowledge using geologic mapping methods. This study is an evaluation on the basis of the immediate analyses that were made after the accident and are published in this paper.
Based on their research results the authors find that the alluvial deposits of the Torna Brook are highly inhomogeneous, which is manifested in the variability of stability and bearing capacity. Based on the morphology in the area of Kolontár a small, rhombus-shaped pull-apart basin can be outlined, which can be interpreted as a neotectonic event characterized by a right-lateral fault. However, further detailed research is needed in order to understand what kind of role the geologic environment played in the development of the situation that led to the dam failure.
Abstract
Palynological and paleobotanical investigation of bonebeds and other strata of the Csehbánya Formation from the vertebrate locality at Iharkút (Bakony Mts, Hungary) reveals well-preserved Santonian palynological assemblages dominated by the Normapolles group, with a minor component consisting of other angiosperm pollen, some gymnosperm pollen, and spores. Eleven species of Normapolles-type pollen grains belonging to seven genera and fruit remains of a new taxon, Sphaeracostata barbackae gen. et sp. nov., are described. The new species is very abundant in the material, represented by ca. 1000 specimens. The genus Caryanthus Friis and an unnamed form previously reported from Haţeg by Lindfors et al. (2010) are also present.
Plants producing Normapolles-type pollen grains diversified during the Late Cretaceous, with a bloom in the Santonian. The palynostratigraphy of the Upper Cretaceous terrestrial sediments in the studied region is based on Normapolles-related species. The studied assemblage is assigned to the Oculopollis zaklinskaiae-Tetracolporopollenites (Brecolpites) globosus Zone (or Zone C) indicating a late Santonian age. Comparison of the Iharkút palynoflora with other known Upper Cretaceous palynofloras of Central Europe shows diachronous occurrence of Normapolles taxa at different geographic localities and warrants further investigation.
The ecological requirements of the amphibian fauna reflect azonal conditions controlled by the availability of water, which is in agreement with the inferred ecological conditions based on the paleobotanical investigations. The fauna is of entirely non-marine character, further supported by isotope studies, in line with our data showing that the palynological samples contain no marine forms.
Abstract
A fish otolith assemblage consisting of 173 specimens was recovered from littoral sand deposits of the brackish Lake Pannon at Doba, western Hungary. Co-occurring endemic mollusks indicate the Lymnocardium ponticum Zone, thus an age of about 9 million years (Late Miocene) can be assumed. Most of the investigated otoliths belong to the family Sciaenidae. The otoliths are assigned to 6 taxa: Umbrina cirrhosoides, Umbrina aff. cirrosa, Umbrina sp., “genus aff. Umbrina” kokeni, Morone kuehni?, Gadidae indet. This otolith assemblage does not represent the ancient fish fauna of Lake Pannon, because the common prey fish (gobiids) have not been identified. Generally, the Pannonian fish fauna is characterized by a high number of sciaenid otoliths which indicate a shallow estuarine environment. The fish fauna from Doba is a unique otolith assemblage due to the co-occurrence of several Umbrina species.
Abstract
Several main tectonic lineaments originating in the Alps and Dinarides merge in Central Hungary to form the Mid-Hungarian Shear Zone. As these structures are hidden beneath sub-basins of the Neogene Pannonian Basin, it has long been debated whether the tectonic style of the shear zone is mainly contractional or strike-slip. New 3D seismic data allowed a detailed analysis of one of these sub-basins, the Adony Basin, located south of Budapest. Its evolution is linked to the tectonics between the southern Tisza unit of European passive margin affinity, the northern ALCAPA block with Alpine affinity, and sheared remnants of Dinaric units in between. During the Oligocene and Early to Middle Miocene, a flexural basin related to the convergent thrusting of Dinaric- and ALCAPA-derived units was developed. On the southern side, N-NW verging thrust sheets were observed. On the opposite front, Triassic carbonates of ALCAPA were thrust several kilometres above Palaeogene formations to the SW. Dextral transpression is assumed for the Middle Miocene. Local deposition of Middle Miocene salt in the basin formed a detachment surface. Late Miocene sinistral strike-slip faulting resulted in a pull-apart basin above that part of the earlier flexural basin that has not been overthrust. The margins of the basin coincided with the fronts of earlier thrusts. Faults on the basin margins partly detached on the salt, decoupling the supra-salt basin fill from the underlying formations. Within the pull-apart basin, gravity sliding on the steep margins resulted in salt welds, detachment and roll-over folds.
Abstract
Analysis of continental-scale lithostratigraphic data may facilitate an understanding of global sedimentary processes. The number of carbonate-bearing formations established in northern Eurasia (430 in total), northern Africa and Arabia (47 in total), and India (98 in total) is calculated per epochs for the last 145 Ma. The results show maxima in the Late Cretaceous, the Eocene, and the Miocene and minima in the Paleocene, the Oligocene, and the Pliocene. The Quaternary records are somewhat ambiguous. The similarity of the patterns established in the three regions argues for a single globalscale mechanism of carbonate accumulation. The noted patterns also coincide well with some modeled changes in the global amount of carbonates accumulated by epoch. Moreover, increases in the amount of carbonates in the Late Cretaceous and the Eocene, and a decrease in the Paleocene, reflect true changes in the accumulation rates. The global process of carbonate accumulation might have been controlled, at least, by eustatic changes (sea-level rise led to broad transgressions on continental margins and consequently to expansion of shelfal paleoenvironments) and climate dynamics (warm water facilitated carbonate production). Interestingly, no dependence between the global carbonate accumulation and marine biodiversity dynamics is established.
Abstract
The Ab Ask mineral springs are located 85 km northeast of Tehran, in the southern range of the Damavand volcano. Deposits of these calcareous springs are mainly precipitated as travertine. Petrographical, mineralogical, and stable isotope studies were conducted on different types of travertine to determine their genesis and factors that govern carbonate precipitation. Based on sedimentation consequence and lithofacies these travertines are categorized as first type (fresh travertine), second type (fissure-ridge, dam, and cascade), and third type (laminated) travertines, illustrating a specific condition of formation, deposition and diagenesis. Combined XRD and microscopic investigations show that the Ab Ask travertines are is composed of about 95 % calcite and a minor amount of quartz along with iron oxide impurities. The origin and transport of springs water from which travertine was precipitated are elucidated by 13C and 18O isotopic studies of the travertines. δ18O and δ13C values of travertines increase (from −13.0 to −6.3% VPDB and from 6 to 9.8% VPDB, respectively) with increasing distance from the spring orifice. This significant increase is attributed to temperature decrease, rapid degassing of CO2, and biological activities. It seems that CO2 content of these fluids may have originated from limestone decarbonation. Based on the integrated petrographic and stable isotope study, the Ab Ask travertines can could be thermogenic in origin.
Abstract
This paper discusses the assessment methodology of geologic probabilities of success of drillable prospects determined by petroleum exploration geologists. The commonly accepted industry standard assessment methods suggest the probability evaluation of key components of oil and gas accumulation: source rock, reservoir, seal rock and trap, and migration and timing. On the assumption that the risked events resulting in the assembly of the key components are geologically and eventalgebraically independent, the geological probability is computed as the product of the probabilities of each. Without challenging the overall correctness of the approach, this study argues that the presumed independency does not always apply. For these cases, probability evaluation of the actually and truly independent geologic and hydrodynamic processes is advised.
