The Mesozoic stratigraphic record of northern Eurasia includes a total of 1,739 formations. The proportion of conglomerate, sandstone + siltstone, shale, carbonates, evaporites, siliceous rocks, and volcanics + volcaniclastics among sedimentary complexes are evaluated for each epoch of the Mesozoic. Sandstone, shale, and conglomerate occur in 86%, 71%, and 42% of formations respectively. Less common are carbonates (28%) and volcanics and volcaniclastics (24%), whereas evaporites and siliceous rocks are rare (< 5%). The proportion of particular sedimentary rock types fluctuates throughout the Mesozoic. The proportion of sandstone + siltstone changes quite similarly to that of shale. A comparison of stratigraphic data from northern Eurasia and North America reveals some similarities, including a Lower Triassic increase in the conglomerate proportion, a Middle-Upper Triassic increase in the proportion of siliceous rocks, Upper Triassic-Lower Jurassic and Upper Jurassic-Lower Cretaceous “clastic spikes”, and a Middle-Upper Jurassic “carbonate-evaporite spike”. They may reflect any global-scale processes. Increases in clastic deposition coincided with eustatic lowstands, whereas voluminous accumulation of carbonates and evaporites tended to coincide with global sea-level rises. It remains unclear whether global climate was responsible for changes in the proportion of sedimentary rock types.
Authors:Enikõ K. Magyari, Mihály Braun, Krisztina Buczkó, Zoltán Kern, Péter László, Katalin Hubay and Miklós Bálint
the Retezat Mountains, this study discusses radiocarbon chronology and sediment accumulation rate changes in two sediment profiles in relation to lithostratigraphy, organic content, biogenic silica and major pollenstratigraphic changes. A total of 25 radiocarbon dates were obtained from sediments of two lakes, Lake Brazi (TDB-1; 1740 m a.s.l.) and Lake Gales (Gales-3; 1990 m a.s.l.). Age-depth modeling was performed on TDB-1 using calibrated age ranges from BCal and various curve-fitting methods in psimpoll. Our results suggest that sediment accumulation began between 15,124–15,755 cal yr BP in both lakes and was continuous throughout the Late Glacial and Holocene. We demonstrated that local ecosystem productivity showed delayed response to Late Glacial and Early Holocene climatic changes in the subalpine and alpine zones most likely attributable to the cooling effect of remnant glaciers and meltwater input. However, regional vegetation response was without time lag and indicated forestation and warming at 14,450 and 11,550 cal yr BP, and cooling at ca. 12,800 cal yr BP. In the Holocene one major shift was detected, starting around 6300 cal yr BP and culminating around 5200 cal yr BP. The various proxies suggested summer cooling, shorter duration of the winter ice-cover season and/or increasing size of the water body, probably in response to increasing available moisture.
A single tooth from the locality of Üröm-hegy (Hungary) was designated as the holotype specimen of “Archidiskodon meridionalis ürömensis” by Vörös (1979). The observed morphology of the tooth, with a minimum of 15 molar plates (most likely 17) led to the conclusion that this specimen belongs to Mammuthus trogontherii rather than a subspecies of M. meridionalis. On the basis of rodent biostratigraphy a date in the region of MIS 19-17 seems likely (i.e. c. 0.8 Ma — c. 0.7 Ma). Taking into account the meridionalis-like enamel thickness (3.1 to 3.4 mm, mean 3.2 mm) as well as the intermediate or slightly advanced relative crown height (1.65) and lamellar frequency (6), the specimen shows mosaic morphology, which fits well in the framework of the contemporaneous European mammoth-bearing localities (e.g. Voigtstedt). Taking all the evidence together it seems that this molar is not only a misinterpreted specimen, but a representative of a very important period of mammoth evolution in Eurasia, when M. meridionalis and M. trogontherii occurred together in Europe and when the genetic mixing between the adjacent populations resulted in a hybrid zone, which was responsible for mosaic or intermediate individuals, such as the holotype of “Archidiskodon meridionalis ürömensis”.
Authors:Georgy Nikolaevich Gogonenkov and Ahmet Issakovich Timurziev
Extensive 3D seismic exploration has revealed in much of the West Siberian petroliferous basin area a special type of faults and deformations within the sedimentary cover, caused by low-separation basement strike-slip faults. A geologic phenomenon associated with strike-slip fault structures is something new to the understanding of the subsurface structure of West Siberia. Complex morphology, intense disjunctive faulting, block arrangement and enormously wide stratigraphic range of oil and gas presence are characteristic of numerous hydrocarbon fields within the zones of strike-slip fault structures. It would certainly be a risky endeavor to design field development-andproduction projects, drill production wells and conduct geotechnical surveys without confident geomechanical and kinematic models for structure-forming, fluid-conductive and sealing dislocations caused by strike-slip faults in the basement.
Authors:Sándor Kele, Gyula Scheuer, Attila Demény, Chuan-Cou Shen and Hong-Wei Chiang
Travertine is quite a common formation in the area of Budapest (Hungary) indicating strong hydrothermal activity during the Pliocene and Quaternary. It covers former terraces of the Danube River and older geomorphologic horizons; thus, it is an important archive to date fluvial terraces and tectonic movements. Despite numerous investigations performed on these deposits, only few radiometric data are available so far and the absence of the exact timing information hindered paleoclimatic interpretation. The area of Gellért Hill consists mainly of Upper Triassic dolomite, but Quaternary travertine can also be found. In this study a detailed petrographic and stable isotope geochemical study of four travertine sites (1. Ifjúsági Park; 2. Számadó u. (Street); 3. Kelenhegyi u. (Street); 4. Somlói u. (Street)) of the Gellért Hill area is presented, along with analyses on the recent carbonate deposits of Gellért Hill and Sárosfürdő. The travertine of Ifjúsági Park and Számadó u. are spring cone deposits, while the travertine of the Kelenhegyi u. represents a shallow-water depositional environment. Based on the paleontological studies of Jánossy (in Scheuer and Schweitzer, 1988) the Gellért Hill travertine was thought to have been formed during the Lower Pleistocene; however, no radiometric age dating had been performed on these deposits prior our study. Our U/Th analyses yielded ages of 250±44 ky for the Ifjúsági Park travertine (220 m asl) and 180±49 ky for the Számadó u. travertine (195 m asl). These new U/Th ages are in contradiction with the previously assumed Lower Pleistocene age, implying gradual relative decrease in the paleokarst water-level and proving that the elevation of the individual travertine deposits not necessarily show their relative age. The uplift rates of Gellért Hill calculated from the U/Th age data and elevation of travertine occurrences range between 0.47 and 0.52 mm/yr, which is significantly higher than the uplift rates calculated for the Rózsadomb area (0.20 0.25 mm/yr; Kele et al., submitted). The difference in the incision rates between the individual sub-areas suggests that selective uplift was characteristic for the Buda Hills during the Middle Pleistocene; thus, up-scaling reconstruction of paleokarst waterlevel for the whole area from a given locality is not possible.
Oxygen isotope analyses of recent carbonate deposits of Gellért Hill, Sárosfürdő and Rudas Spa revealed that these calcites precipitated under non-equilibrium conditions, and the measured calcitewater oxygen isotope fractionation show the same positive shift relative to “equilibrium values” as was observed in the case of the recently-forming Egerszalók travertine (Kele et al. 2008). Assuming that the water of the paleo-springs of Gellért Hill derived from precipitation infiltrated during interstadial periods of the Pleistocene and considering non-equilibrium deposition (i.e. using the empirical calcite-water oxygen isotope fractionation of Kele et al. 2008), their calculated paleotemperature could range between 22 (±4) °C and 49 (±6) °C. Based on the δ18Otravertine differences the Ifjúsági Park and the Számadó u. spring cone type travertine was deposited from the highest temperature water, while from the lowest temperature water the travertine of Kelenhegyi u. was formed.
Complex and intelligent life developed on Earth because it has retained sufficient water, primarily in liquid form, for several billion years. The loss of Earth’s water to outer space is limited by a cold trap at the top of its thick troposphere. Earth maintains a thick troposphere because the dipolar geomagnetic field deflects the solar wind, preventing ionized particles from heating the upper atmosphere and lowering the tropopause. Earth’s magnetic field is sustained by the dynamo action of convective motions within the outer core, which require a large flux of heat from core to mantle. Plate-tectonics, which provides the required rate of planetary cooling over billions of years, requires the presence of liquid water to make the plates ductile and to lubricate the plate boundaries. The sustained, coupled interaction of liquid water, atmospheric structure, the geomagnetic field and plate tectonics forms a feedback-loop which maintains Earth’s long-term habitability.
Authors:A. Ádám, P. Bencze, J. Bór, B. Heilig, Á. Kis, A. Koppán, K. Kovács, I. Lemperger, F. Märcz, D. Martini, A. Novák, G. Sátori, S. Szalai, L. Szarka, J. Verő, V. Wesztergom and B. Zieger
The paper describes research in geomagnetism and aeronomy carried out in the framework of a project organized by the Geodetic and Geophysical Research Institute of the Hungarian Academy of Sciences. It includes the development of the instrumentation of the Nagycenk Geophysical Observatory (geomagnetic measuring systems, ionosonde), moreover other instrumental and methodological developments, too. Observatory data are available in a database. Based on results of the Nagycenk and Tihany observatories and on data of permanent and temporal networks, long-term trends of different electromagnetic parameters were investigated. Thus geomagnetic activity was found secularly increasing, a decrease of the atmospheric electric potential gradient and a 11-year modulation of the winter/December attenuation of the geomagnetic pulsation activity were confirmed. Several possibilities (pulsations, whistlers, modelling) were used to improve knowledge about structure and parameters of the magnetosphere. Electromagnetic precursors of earthquakes were looked for. A significant increase of understanding was obtained in connection with Schumann resonances and electromagnetic transients caused by lightning. It was shown that see-coasts influence characteristically changes in ionospheric trends (
F2). When looking for the effect of the global climate changes in the subsurface electric resistivity, an example was discovered for the decrease of the resistivity due to infiltrating water from precipitation. Electromagnetic exploration of tectonically conditioned weak zones was continued, too.
Computational time is an important matter in numerical aspects and it depends on the algorithm and computer that is used. An inappropriate algorithm can increase computation time and cost. The main goal of this paper is to present a vectorization algorithm to speed up the global gradiometric synthesis and analysis. The paper discusses details of this technique and its very high capabilities. Numerical computations show that the global gradiometric synthesis with 0.5° × 0.5° resolution can be done in a few minutes (6 minutes) by vectorization, which is considerable less compared to several hours (9 hours) by an inappropriate algorithm. The global gradiometric analysis of representation by spherical harmonics up to degree and order of 360, can be performed within one hour using vectorization, but if an inconvenient algorithm is used it can be delayed more than 1 day. Here we present the vectorization technique to gradiometric synthesis and analysis, but it can also be used in many other computational aspects and disciplines.
The Poisson’s rate value of the rock mass is one of the most important rock mechanical and rock engineering parameter. This value is used for calculating the deformation of the tunnels or displacement on rock foundations, among the others. Unfortunately, measuring this value is very difficult and time consuming in rock masses. The goal of this paper is to present a simple method for estimating the Poisson’s rate value for rock masses if it is known for the intact rock. Using the well-known equations for determining the earth pressure at rest, the relationship between the internal friction angle and the Poisson’s rate value can be determined. Due to the relationship between the internal friction angle and the rock mass classification (namely GSI) are also determined, from these connections the Poisson’s rate value and the GSI can be calculated. A linear equation was found: decreasing the quality of the rock mass, the Poisson’s rate is increasing. The presented calculation is also good, if the Poisson’s rate of the intact rock is not determinable. In this paper it was assumed that the Poisson’s rate value is a material constant. Note, that theoretically it is not true, however for rock mechanical calculations the changing this value is never investigated.
In the small seismic source zone of Kecskemét 203 earthquakes are known between 1739 and 2006, and about 90 percent of them have a magnitude value not more than 3.0, however the strongest event on July 8, 1911 has 5.6 surface-wave magnitude. Concerning the latter earthquake the maximum (epicentral) intensity I = VIII (EMS) was observed in the area enclosed by Kecskemét, Katonatelep and Hetényegyháza locations. The quake caused significant damage to buildings (I ≥ VI EMS) on about 6 thousands square kilometres and was felt (I ≥ III EMS) on some 85 thousands square kilometres. The focal depth is estimated as 11 km directly from the individual intensity data points. During the earthquake liquefaction (sand crater) occurred in the epicentral area and some electromagnetic effects were also observed. Studying the source dimensions we conclude the rupture area is between 40 and 67 square kilometres and the maximum displacement along the fault is estimated to 14–20 centimetres for the Kecskemét earthquake of July 8, 1911. A probabilistic seismic hazard assessment predicts 1.1–1.5 m/s
peak ground accelerations, and 6.6–7.1 maximum (theoretical) earthquake intensity values with 10% chance of exceedance for an exposure time of 100 years in the studied area.
Authors:N. Das, R. Bhandari, D. Ghose, P. Sen and B. Sinha
Strong anomalies in the concentration of helium, radon and gamma were observed in gases at the geochemical monitoring station, Bakreswar, West Bengal, India, about two weeks before the 7.9 M earthquake at Sichuan, China. The distance between the epicenter of the earthquake and the monitoring site is about 1800 km. This long distance preseismic observation indicates that the radius of influence of large magnitude earthquakes may be substantially large and may cut across plate boundaries. This paper presents the observed geochemical anomalies for the Sichuan earthquake and discusses empirical postulates between earthquake magnitude and its radius of influence.
Authors:János Haas, Fotini Pomoni-Papaioannou and Vassiliki Kostopoulou
For comparative studies of Upper Triassic cyclic platform carbonates, the Transdanubian Range (Hungary) and the Pelagonian Zone (Greece) were chosen. Paleogeographically they represent two distant segments of the passive margin of the Neotethys Ocean. During the Late Triassic, on this wide margin a very extensive tropical carbonate platform domain was developed, referred to as the Dachstein-type carbonate platform system. The Transdanubian Range (TR) represents a segment of a continent-encroaching platform system, whereas the Pelagonian-Subpelagonian Zone (PG) may have been a large isolated platform, surrounded by deep-water basins. The discussed Upper Triassic thick platform carbonates (Fődolomit/Hauptdolomit Formation and Dachstein Limestone in the TR, and Pantokrator Formation in the PG) are made up of cyclically arranged facies deposited under similar environmental conditions in the interior zones of carbonate platforms. Three characteristic major facies types can be distinguished: shallow subtidal-lagoonal, intertidal and supratidal-pedogenic, which correspond to the three typical lithofacies (members C, B and A) of Fischer's (1964) Lofer-cycle. The cycles are usually bounded by discontinuity surfaces related to subaerial exposure and pedogenic alteration. The meter-scale (Lofer) cyclicity is predominant throughout the successions. However, various stacking patterns including symmetric complete, truncated, incomplete, and condensed cycles or even alternating peritidal and subtidal facies without any disconformity are recognized in both areas studied. Pervasive or partial early diagenetic dolomitization affected some parts of the cyclic successions in both areas. However, age-dependence of the early dolomitization was clearly demonstrated only in the TR, where the older part of the platform carbonate succession was subject to pervasive dolomitization, whereas the younger part is non-dolomitized and there is a transitional unit between them. This trend is attributed to the climate changing from semiarid to more humid. The Upper Triassic platform carbonates of the TR and PG show strikingly similar features concerning the litho- and biofacies, the stacking pattern and the thickness of the elementary cycles, despite their distant and different paleogeographic setting within the western Neotethys realm. This suggests a eustatic signal, i.e. the cyclic deposition was essentially controlled by orbitally-forced eustatic sea-level changes, although the contribution of autocyclic mechanisms cannot be excluded either. Definite signatures of subaerial exposure (karstic features and vadose meteoric diagenesis) at and below the cycle boundaries also support allocyclic control. In the northeastern part of the TR the carbonate platform was drowned at the Triassic-Jurassic boundary, whereas platform conditions persisted until the end of the Hettangian in the southwestern part. However, the Hettangian part of the succession is characterized by non-cyclic subtidal limestone, implying an upward-deepening trend. In contrast, in the PG the platform conditions continued until early to middle Liassic, and the Liassic succession is typified by well-developed pedogenic features, suggesting long-lasting subaerial exposure intervals, i.e. an upward-shallowing trend.
A total of 1,514 fossil bones were studied from the Vaskapu II rock shelter (Bükk Mountains, North Hungary). The objective of this study was to investigate those processes of bone modification that were important in the dispersal, destruction and preservation of bone in the deposit. Size-selective taphonomic processes were detected in the accumulation of vertebrate remains. The fossils were transported by water through a 15 m high fissure system above the locality during repeated precipitation and thawing. Size-sorting of the bones occurred within the fissures. During this process the fossils were damaged and fragmented and the remains were eventually emplaced into the Vaskapu II rock shelter. The size-sorting is statistically established by a method based on the chisquare test. This method clearly describes the differences between the life and death assemblages.
Authors:Éva Jankovics, Szabolcs Harangi and Theodoros Ntaflos
The alkaline basalt of the Füzes-tó scoria cone is the youngest volcanic product of the Bakony-Balaton Highland Volcanic Field. The bombs and massive lava fragments are rich in various crystals, such as mantle-derived xenocrysts (olivine, orthopyroxene, clinopyroxene, spinel), high-pressure mineral phases (clinopyroxene) and phenocrysts (olivine, clinopyroxene). Peridotite xenoliths are also common. Ratios of incompatible trace elements (Zr/Nb and Nb/Y) suggest that the primary magma was formed in the transitional spinel-garnet stability field, at the uppermost part of the asthenosphere. Magmatic spinel inclusions with low-Cr# (22–35) in olivine phenocrysts can reflect a fertile peridotite source. The olivine, orthopyroxene, colourless clinopyroxene and spinel xenocrysts are derived from different depths of the subcontinental lithospheric mantle and their compositions resemble the mineral phases of the ultramafic xenoliths found in this region. The rarer green clinopyroxene cores of clinopyroxene phenocrysts could represent high-pressure products of crystallization from a more evolved melt than the host magma, or they could be derived from mafic lower crustal rocks. Crystallization of the basaltic magma resulted in olivine and clinopyroxene phenocrysts. Their compositions reflect polybaric crystallization with a final, strongly oxidized stage. The Füzes-tó basalt does not represent a certain magma composition, but a mixture of mineral phases having various origin and mantle-derived basaltic melt.
The article briefly summarizes the history of research of the Villány Mesozoic, with a focus on the Templom-hegy at Villány, and gives short descriptions of the important outcrops of the area. The geologic sketch of the Templom-hegy and concise descriptions of the Upper Triassic Mészhegy Formation, the Pliensbachian Somssichhegy Formation and the Bathonian-Callovian Villány Formation are also given. Several sedimentary cycles were recognized in the early Mesozoic formations exposed on the Templom-hegy. From among them, three fluvio-lacustrine, fining-upward cycles in the Late Triassic and one (or possibly two), marine, fining and deepening upward in the Early Jurassic, are demonstrated and evaluated in detail. The Late Triassic and Early Jurassic cycles at Villány were deposited in a westward-tilted half-graben structure, where repeated tectonic movements were responsible for the episodic and cyclic nature of the sedimentation. The finingupward trends within the three cycles probably reflect climatic changes from humid to arid conditions. For the Middle Jurassic the paleotectonic regime changed: faulting ceased and the territory began to sink uniformly. The Mesozoic subsidence history of the Villány area has close analogies in the contemporaneous blocks of the European inner shelf domain (Helvetic, Briançonnais, (central Penninic, Czorsztyn), and High Tatric Ridges, and the Bihor Autochthon). Their shared features are intensive subsidence in the Early and Middle Triassic, followed by a long interruption of subsidence in the Late Triassic to Middle Jurassic, then a renewed, rapid subsidence in the Late Jurassic. The interrupted subsidence was accompanied by erosion and formation of half-grabens, starting from the mid-Triassic. From this time on, these areas belonged to a transpression/transtension dominated zone for nearly 70 million years, until the Middle/Late Jurassic opening of the Valais-Magura oceanic belt.
Authors:H. Paudyal, D. Shanker, H. Singh and V. Singh
Time dependent seismicity investigation in six seismogenic sources of Nepal and its adjoining areas in the Central Himalaya reveal that there is intermediate time clustering of the moderate size shallow earthquake in each seismogenic source. The inter-event times, between the successive shallow mainshocks, of the magnitude equal to or larger than certain cut-off magnitudes for each of these sources are used for long-term earthquake hazard prediction corresponding to individual sources of the region. For the hazard estimation, the following relations have been established here as: log
+ 4.32, where
is the inter-event time measured in years;
is the moment magnitude of the smallest mainshock considered;
is the magnitude of preceding main shock,
is the magnitude of the following mainshock and
is the moment rate in each source per year. The value of
= 0.22 and multi-correlation coefficient,
= 0.62 for the first equation and
= 0.30 and
= 0.59 for the second equation are estimated.Based on these relations and using the magnitude and time of occurrence of the last main shocks in each seismogenic source, time dependent conditional probabilities of the next shallow main shocks during the next 10, 20 and 30 years as well as the magnitude of the expected main shocks are forecast.
The Vértes Hills are interesting region in Hungary where small earthquakes with magnitude 2–3 exist among small quarry blasts in a noisy background. A seismological station PKSG (Gánt) works in the middle of Vértes Hills. The main purpose of this paper is to test the different discriminatory elements using the registrations of this single station.The diurnal discrimination of quarry blasts shows a peak time. My purpose is to focus onto these questionable earthquakes — happened in the peak time of the blasts — and be able to identify them.Every discriminant gave “1” if the event was considered to be a blast, and “0” if the event was considered to be an earthquake. The sum of these values shows the level of the separation. The classification of fifteen events was wrong. This is approximately 7 percentage of the dataset.It has been found that the spectral analysis and the correlation of spectra proved to be successful in the discrimination. One type of blast and five types of earthquakes are identified based on the correlation analysis of spectra of S-phases on the horizontal component. The result of the correlation analysis is that most of the spectrum of the blasts were very similar to each others. Correlation analysis has also showed that the big part of earthquakes could be classified into 5 groups. Earthquakes of each group concentrated on different places on the map. The maximum frequency and cepstrum analysis failed.
Possibilities of detection of abrupt lateral conductivity changes are presented by mapping of the surface vertical magnetic field in the vicinity of the borehole. Magnetic field components generated by vertical electric bipole do not exist over a uniform or horizontally layered earth. Vertical magnetic field is caused exclusively by resistivity inhomogeneities. Therefore it is very sensitive to lateral discontinuities. A simplified inversion procedure — searching the anomalous subsurface horizontal current distribution linked with the discontinuity — is discussed and tested on synthetic examples.
The structure of the lithosphere of the ALPACA (Alpine-Pannonian-Carpathian) region is described by a model containing about 200000 rectangular volume elements (prisms) of variable dimensions defined in the mapping system of Hungary. Forward computations show that the contribution of the structural units (topography and upper mantle) of the lithosphere to the disturbing potential
of the Earth may reach several tenths of E unit at 300 km elevation. The contribution from the sediments is less by a factor of ten but even its magnitude exceeds the planned sensitivity of the satellite on board measurements. It is expected that some regional information about the horizontal density variation of the crust can be deduced from the GOCE data, especially for the density contrast between the lower crust and upper mantle. Since the density distribution of either the topographical masses or the sedimentary complex is much better known than the density jump on the Moho, therefore their effect on the second derivatives of
can be removed from the measurements. The residuals can be interpreted by inversion using the closed analytical formulae available for rectangular volume elements. The modelling approach based on the local planar co-ordinate frame was compared to the polyhedron representation of the same crustal model defined in a global rectangular co-ordinate system. No significant effect of the Earths curva- ture could be indicated for the Moho interface.
For two independent Gaussian random variables and for a series of outliers according to the classical formula calculated correlation coefficients (
-s) are given; instead of zero significant distortions occur. — A short note is also given to the meaning of the word “outlier”.
In the western region of Argentina, 30° S Lat., near the Andean Range, two Precambrian large faults or lineaments are present: Ambato (AL) (NE-SW) and Valle Fértil (VFF)(∼NS). They are deep-seated faults in the crust, with extend develop in time, crossing each other in the region where Bermejo Basin and Valle Fértil Range (Sierra de Valle Fértil, SVF) are present. The study of these lineaments is important to better know the tectonic evolution of this region. Three deep magnetotelluric soundings were carried out in this zone using induction coils and a flux-gate magnetic variometer. Principal results show a thickness up to 7000 m and saline character for the Bermejo Basin, with resistivities range frm 3 Ωm to 13 Ωm, and an integrated conductivity of 1600 Siemens. High conductivity is also suggested for the AL from the top of basement to higher depths. Westward of VFF, beneath the Bermejo Basin, a conductive lower crust is suggested with a longitudinal conductance at least of 1600 Siemens and seated at 43 km depth; but this layer does not seem to be present eastward of the fault. A possible phase transition zone at 300 km depth is also suggested. From these conductive layers, a heat flow estimate of 36–40 mW/m
is made for the region, using empirical formulas. Graphite is suspected to be the cause of lower crust conductivity. If correct, it would be suggesting a strong ancient tectonic activity, with probable dipping and lifting of significant amplitude in the region.
The behavior of the horizontal component of the magnetic field obtained by ground magnetometers for three intense magnetic storms that happened during the occurrence of continual auroral activity (HILDCAAs) was studied through a UT-LT analysis. The considered storm periods were August 26–28, 1998, October 21–23, 1999 and April 6–8, 2000. Five minute resolution data were taken from six magnetic observatories, with approximately uniform longitudinal distribution. The results were compared with some interplanetary parameters such as velocity of solar wind, south component of interplanetary magnetic field.
Nettleton’s method is based on the elevation dependence of the surface free-air gravity anomalies and widely used to obtain an optimal average density value by applying e.g. least squares model parameter estimation. Its accuracy, however, strongly depends on how efficiently the regional trends and very local (terrain) effects are removed from the gravity anomalies processed. If the geometry of the topography is fixed then the terrain correction term at the evaluation point
is a linear function of the unknown average topographical density. Therefore it can also be included in the equation system to be solved by adjustment and an estimation of the density can be obtained in one step, without iteration. The results of this simple refinement of Nettleton’s method as well as the distorting effect of the regional trend are demonstrated by a local example. It reviews the gravity survey of a geological structure (known as loess bluff) and its surrounding on the bank of the river Danube. The derived density values increase from
= 1163±543 kg/m
= 1764±113 kg/m
as the gravity anomalies are gradually reduced by regional and local (terrain) effects during data processing. The lab determination of surface loess samples from the area having only 3.5% water content gives 1610 ± 100 kg/m
Sydney Chapman (1888–1970), the English geophysicist had close connections with German scientists both before and after World War II. The most important result of this co-operation is the monumental Chapman-Bartels monography on geomagnetism. The paper includes data on celebrations with Chapman and dedicated to Him.
The 1:75 000 scale Special Map (SM75) series of the Third Military Survey is analysed in this work. Geographic co-ordinates of the sheet corners are computed from the sheet number codes, as well as their grid co-ordinates in the modern Křovák Projection and Czech and Slovak national grid called S-JTSK. Distortions caused by paper drying and shrinkage were analysed and a mathematical algorithm is given to compute their effects. Statistical analysis shows that the shrinkage is direction-dependent at the studied 125 map sheets throughout the Czech Republic. This analysis also verified the usefulness and practical adaptability of the shrinkage correction method to obtain more precisely rectified map sheets for GIS applications.
This paper summarizes the early geological maps about Hungary with special respect to their color codes, surface symbol systems and map projections. The process from the
color usage of the earliest maps, through the influence of the color system proposed by the Bologna Geological Congress of 1881 to the symbol system of the modern maps is shown. Analysing the coordinate grids of these map products, the older ones can be rectified in equidistant conic or Cassini projections while the ones of Böckh and Koch and Lóczy et al. can be interpreted as both conic and Budapest-centered Stereographic projected. The ambiguity is because of the relatively low scale of the maps, enabling projection errors of several hundred meters without practical consequences.
Military considerations in the early 1770s declared the need for a systematic mapping of the eastern regions of Norway along the border to Sweden. After a failed attempt of direct map sketching in the field, the geographical circle was introduced in 1779 to establish a triangular network as a backbone for further positioning of natural and man-made features. The resulting maps were used in preparation of fortresses and planning of defensive field operations. The scale of the triangular network was established by an astronomical baseline supported by linear baselines measured on frozen lakes during winter time. Many stations had latitude determinations from circum-meridian observations of the sun and stars to control the precision of the geodetic triangulation. When discrepancies became too large, a new baseline and a new reference point was selected. The original reference point was the flagpole of the fortress at Kongsvinger, which served as the zero-meridian for mapping in Norway until 1850. Other reference sites, for which accurate latitude and longitude were determined from several years of astronomical observations, were established in Trondheim, Bergen, and Kristiansand as the original triangular arc was expanded around the entire coast of southern Norway to close at Kongsvinger after 3 decades of observations. This allowed astronomical control of the geodetic results.
Detailed sea depth data and hydrological observations for the first printed isobath map were collected by Marsigli in the Gulf of Lion three hundred years ago. This map, an annex to his large and comprehensive volume on the seas, has been considered one of the forerunners of thematic maps. Although the cartographic and oceanographic literature often refers to Marsigli’s map, several authors have misinterpreted the data and information contained in the map. This paper re-examines the map legend and the drawing of the map, compares the first isobath map with a modern map of the area, and finally evaluates Marsigli’s contribution to earth sciences.
Various spatial data sets of high quality and homogeneity allow a higher level of multidisciplinary research. The study is aimed at providing a clearer understanding of the technical and semantic aspects of the quality of historical maps, especially with respect to positional errors, through the georeferencing process. Georeferencing the system of historical map sheets with high precision over a large area is not easily incorporated into the less complicated standardised process. Significant problems may occur in rough mountainous regions, especially as many of the areas were not accessed at that time and therefore not surveyed. The standard process of georeferencing comprises mosaicking of singular map sheets to a seamless map, referencing with identical points, and applying an appropriate transformation method. The quality of georeferenced maps is assessed with statistical and visual parameters. The enhanced process additionally integrates descriptive (textual) information about the mapping processes, derivative georeferenced data sets as land use analysis, and Monte Carlo simulations. This approach allows a more detailed understanding of the quality and consequently improves a georeferencing process for any historical data sets. The First Military Survey maps of the Habsburg Monarchy (Josephine survey), produced between 1763 and 1787, were used as study data and the rugged Julian Alps of the Triglav National Park in Slovenia were employed as the study area.
Lake Balaton is located in the Pannonian Basin, Hungary (46°50′ N, 17°50′ E), and is characterized by its large area (594 km
) and very shallow water depth (avg. 3.5 meters). The main tributary is the Zala River, which enters the western bay, and the only outlet is the Sió River in the East.Sámuel Krieger conducted the first known survey focusing on Lake Balaton in 1776. The original purpose of Sámuel Krieger’s work was to illustrate his plans of draining and canalizing Lake Balaton. This map indicates several proposed canals and bathymetric contour lines according to a water level drop of 1, 2, or 3.33 Viennese fathoms (1 Viennese fathom = 1.89 meters). The map also shows settlements, land use and relief. Krieger measured water input from tributaries, documented the water level fluctuations of the lake, and summed his results in the “Descriptio”, a document with several tables of data and a written description of Lake Balaton, the Sió River, and the possible benefits of his plan of draining the lake.Almost 90 years later, the water level was lowered by approximately 1 meter in 1863, cutting off large marsh areas from the water system of the lake. The first bathymetric map was surveyed in 1895 after the lake was partially drained. The bathymetric survey was carried out with the purpose of estimating the water volume held by the lake. Understanding water balance was important for flood control after the Sió Canal and lock was built in 1863. Water depth was measured in 2884 points, along sections near the shore, and scattered points in areas of low relief. Depth was measured with a sounding line or pole. Horizontal positions were measured optically from military triangulation points, and elevations were leveled from a network of benchmarks placed for this survey. Distances were measured in fathoms but elevations were measured in meters for better accuracy. Reprojection of the scanned map was possible, but we had to correct minor errors by triangulation. Surviving benchmarks, depicted buildings and railway bridges were used as control points. The resulting map was used to create a Digital Elevation Model of the lake floor for investigating sedimentation processes.
The paper deals about significant projects of large scale mapping at the beginning of 19th century in the Habsburg Empire. They have been already based on uniform geodetic horizontal control. Basic parameters and features of Second Military Survey in the territory of the Czech Lands as well as links with project of Stable cadastre are delineated. Technology of establishing the horizontal control (1st order trigonometric networks) is described in detail. Qualitative parameters of geodetically measured data and the survey documentation are analysed. Accuracy analysis of angular measurements and methodology of co-ordinate computations in the Gusterberg coordinate system are also discussed.By means of identical points the horizontal control enables unambiguous transformation from the Gusterberg and St. Stephen co-ordinate systems into the national co-ordinate system (JTSK) or WGS 84 with the accuracy higher than graphical accuracy of original maps. This transformation, published here as the global transformation key (GTK), is of great importance. The results of tests of GTKs compiled separately for Bohemia and Moravia+Silesia together with the analysis of contact zone of both above mentioned historical co-ordinate systems are introduced.As an example of GTK application georeferenced map sheets from Second Military Survey are presented. GTKs are of fundamental importance in unification of heterogeneous geodetic information files of cadastre of real estates in the Czech Republic.
The original map sheets of the Third Military Survey of the Austro-Hungarian Monarchy cannot be mosaicked in their original, printed form because of their uneven trapezoid format. To make a digitized raster mosaic of the individual sheets, they all should be georeferenced. Instead of the original projections, which vary from sheet to sheet, a series of sinusoid projections was defined, one unique projection for each sheet columns. The sinusoid projection provides an appropriate approximation of the original trapezoid forms and size of the sheets. Each sheet were rectified in the respective projection then reprojected to a general conic projection, defined for the final mosaic. After all of those transformations, the transformed digital content of the sheets fits to each other well enough to make a geo-referred mosaic. The location parameters of the geodetic datum used for transformation to modern projection systems are the followings:
= +600 m;
= +205 m;
= +437 m. These figures gives exact fit at the fundamental point of Hermannskogel. Because of the not unified geodetic adjustment of the original base point system, using one unified datum causes a maximum error of 220 meters throughout the whole territory of the Monarchy and the adjacent area on the maps.
Müller’s maps of Moravia and Bohemia are important parts of the cartographic and art history. They are not just beautifully and well made, but also part of the living heritage, which have been attracting the attention of people for centuries. Apart from that, they have significantly contributed to the development of cartography. Processing and cartometric analysis of these maps can open access to them and show their quality. Georeferencing significantly improves the possibilities of comparing the map with the present situation. They show the evolution of the landscape as well as that of human settlements. Moreover, publication of the map on the Internet makes it accessible to academics and to the general public. Thus they make a valuable contribution to the popularization of cartography and increase interest in maps.
The Müller’s map of Bohemia originated in the years 1712 till 1718 as the result of the first systematic topographic mapping of the Czech lands. This map served as a base for the First Military Survey realized 1763–1787 on the area of the whole Habsburg Empire. The paper presents a study of relations between the Müller’s map of Bohemia and the maps from the First Military Survey from the region near the town Kladno in the Central Bohemia. The sections of the above mentioned old maps in electronic form have been used for accuracy analysis of selected points located within the test area. The same area has been investigated on the present topographic map of the Czech Republic (scale: 1:25 000). The centres of 39 settlements have been identified in all compared maps and their rectangular plane co-ordinates have been recorded. For the analysis, affine transformation was applied on the point coordinates. The presented results may contribute to the discussion on the positional accuracy of these old maps and on the way our predecessors used for mapping of the Czech Lands in the 18th century.
This paper presents possible solutions to the problem of interactive digital globe publishing on the Internet in connection with the recently opened Virtual Globes Museum. It describes the processing method of two possible source materials: globe prints and photographs. The visualization of the results is realized in two different ways. The first one is a 3D virtual world created using the VRML language. The second one is a special “globe layer” in KML, which can be used in the Google Earth software. The advantages and disadvantages of each solution are also examined.
(1528), created by Lazarus (Secretarius), is an almost 500 year-old map depicting the whole Pannonian Basin. It has been used for several geographic and regional science studies because of its highly valued information context. From geoscientific point of view this information can also be evaluated. In this contribution an attempt is made to analyse in some extent the paleo-hydrogeography presented in the map, reconsidering the approach of previous authors, assuming that the mapmaker did not make large, intolerable errors and the known problems of the cartographic implementation are rather exceptional.According to the map the major lakes had larger extents in the 16th century than today, even a large lake (Lake Becskerek) ceased to exist. Concerning the fluvial pattern, a detailed analysis is possible for the Danube. Important changes can be implied at the Danube Bend, and there was a stronger tendency of island formation (i.e., tendency towards braided style) downstream from the present day Budapest. In most of the cases the assumption of the depicted islands is feasible. The existence of a few paleo-islands not present today can be validated by historical sources as well. Furthermore, the river Sárvíz, today a less important watercourse, might have had more importance in the transport at that time, probably due to its larger water discharge.Summarizing the observations it seems that these are indications of larger discharge values and/or a wetter climate in the Central Pannonian Basin in the 16th century.
The Second Military Survey of the Habsburg Empire (Franziszeische Landesaufnahme) was based on the first triangulation net of the Empire, ordered by Emperor Francis I in 1806. Eight horizontal control points were later used as projection centers for the different parts of the Empire. However, two provinces, mapped in the very early phase of the survey, have no real terrain objects as projection centers. In spite of the earlier literature items, mainly concerning the cadastral systems, the map sheet systems of the Second Military Survey of Tyrol and Salzburg do not follow the Soldner-Cassini projections centered at Innsbruck and Gusterberg, respectively. Indeed, the design of these sheets is similar to the one of the First Military Survey in cartographic point of view also with respect to their projection. The systems of the 1:28 800 sheets in these provinces are not centered at Vienna (St. Stephen) or Gusterberg as it was indicated in the literature. Projection analysis shows that for these provinces a unified sheet system was introduced. It can be connected to an Innsbruck-Pfarrturm-centered Cassini projection but the projection center is not at any distinct point (sheet center, corner or boundary halving point) of the sheet system. This Cassini projection, however, is not suitable for precise georeferencing of the sheets of Tyrol and Salzburg as it results errors up to one kilometer. The map sheets of these provinces can be rectified using quadratic formulae with remnant errors of maximum 220 meters (Tyrol) and 500 meters (Salzburg), which are much higher values than the fitting accuracy of the sheets in other parts of the Empire. According to the analysis, Liechtenstein is also without definite projection center but it is covered by only one extended sheet and its rectification can be done with an accuracy of 30 meters.
Authors:Mateu Esteban, Tamás Budai, Erika Juhász and Philippe Lapointe
Large, irregular volumes of altered, friable Triassic dolomite with poorly recognizable depositional fabrics crop out in the Buda Mountains, Hungary. These rock volumes are characterized by powder-like, chalky, soft, whitish gray microporous carbonates, referred to as “pulverized dolomite”. This is interpreted as the result of corrosion of carbonates along microfractures. The pulverized dolomite is commonly associated with silica and clay cementation (“silicification”) and “mineralization” of ironrich minerals, barite, sphalerite, galena, fluorite, calcite, dolomite and others, clearly pointing out hydrothermal Mississippi Valley Type (MVT) conditions.
The pulverization, silicification and mineralization are considered to be a diagenetic facies association (PSM facies). Tectonic shear corridors played an important role in the development of PSM facies as carriers of hydrothermal fluids, but the geometry of the altered units is very irregular and cross-cuts different Triassic depositional facies in addition to Eocene limestone and Middle-Upper Miocene sediments. The PSM facies represents the early stages of hydrothermal alteration (i.e. the burial phase) that was later modified by thermal mixing zones. Pulverized dolomite bodies that reached the surface were strongly affected by meteoric fluids; peculiar speleo-concretions were formed by calcite cementation of the powdery dolomite clasts.
The altered carbonates show major porosity development whereas the unaltered carbonates present only minor porosity. The size and lithologic contrast of the altered geobodies makes them detectable by geophysical methods of mineral and hydrocarbon exploration.
Authors:Réka Lukács, Szabolcs Harangi, Paul R. D. Mason and Theodoros Ntaflos
The 13.5 Ma Harsány ignimbrite, in the eastern part of the Bükkalja volcanic field, eastern-central Europe, provides a rare example of mingled rhyolite. It consists of two distinct pumice populations (‘A’- and ‘B’-type) that can be recognized only by detailed geochemical work. The pumice and the host ignimbrite have a similar mineral assemblage involving quartz, plagioclase, biotite and sporadic Kfeldspar. Zircon, allanite, apatite and ilmenite occur as accessory minerals. The distinct pumice types are recognized by their different trace element compositions and the different CaO contents of their groundmass glasses. Plagioclase has an overlapping composition; however, biotite shows bimodal composition. Based on trace element and major element modeling, a derivation of ‘A’-type rhyolite magma from the ‘B’-type magma by fractional crystallization is excluded. Thus, the two pumice types represent two isolated rhyolite magma batches, possibly residing in the same crystal mush. Coeval remobilization of the felsic magmas might be initiated by intrusion of hot basaltic magma into the silicic magma reservoir The rapid ascent of the foaming rhyolite magmas enabled only a short-lived interaction and thus, a syn-eruptive mingling between the two magma batches.
The evolution of sedimentary basins can be explored by analyzing the changes in their lithologies and lithofacies (i.e. predominant lithologies). The Greater Caucasus Basin, which was located at the northern margin of the Neotethys Ocean, represents a complete Sinemurian-Tithonian succession. A quantitative analysis of compiled datasets suggests that principal lithologies and lithofacies are represented by siliciclastics, shale and carbonates. The relative abundance of siliciclastics and shale decreased throughout the Jurassic, whereas that of carbonates increased. Evaporites are known from the Upper Jurassic, while volcaniclastics and volcanics, as well as coals, are known only in the Lower to Middle Jurassic. Siliceous rocks are extremely rare. Lithology and lithofacies proportions change accordingly. The Sinemurian-Bathonian sedimentary complex is siliciclastic-and-shale-dominated, whereas the Callovian-Tithonian sedimentary complex is carbonate-dominated. A major change in the character of sedimentation occurred during the Aalenian-Callovian time interval. Regional transgressions and regressions were more important controls of changes in the sedimentary rock proportions than average basin depth. Landward shoreline shifts were especially favorable for carbonate accumulation, whereas siliciclastics and shale were deposited preferentially in regressive settings. An extended area of the marine basin, its lower average depth, and a sharp bathymetric gradient favored a higher diversity of sedimentation. An orogeny at the Triassic-Jurassic transition was responsible for a large proportion of siliciclastics and extensive conglomerate deposition. An arcarc collision in the Middle Jurassic also enhanced the siliciclastic deposition. Both phases of tectonic activity were linked with an increase in volcanics and volcaniclastics. Volcanism itself might have been an important control on sedimentation. A transition to carbonate-dominated sedimentation occurred in the Late Jurassic, reflecting a tectonically calm period.
Correlation of scattered ignimbrite occurrences is crucial in the context of stratigraphy and the volcanic history of an area. In 2007, two papers were published concerning the classification of the volcanic rocks of the Bükkalja volcanic field. The interpretation of these papers shows an apparent contradiction in the age of the ignimbrite, which crops out at Tibolddaróc and Harsány. This paper attempts to resolve this contradiction. We show that the Harsány ignimbrite defined by Lukács et al. (2007) was indeed formed at 13.5 Ma and is not the same as was described by Márton et al. (2007). We redefine the possible locations of the Harsány and Tibolddaróc samples of Márton et al. (2007). The Tibolddaróc sample could represent the ash flow unit in the middle part of the Tibolddaróc volcanic section, whereas the Harsány sample could be derived from the ‘Harsány-bend’ outcrop. Both rocks have different geochemical character compared to the Harsány ignimbrite. This work emphasizes the usefulness of geochemical correlation of scattered rhyolitic ignimbrites, combined with detailed volcanological field observations.
Authors:Balázs Bradák, Emő Márton, Erzsébet Horváth and Gábor Csillag
Four paleosol layers indicating wet and moderate periods and five loess layers indicating dry and cold climate were separated by different methods. The following climate cycle model, based on the development of the sediment sequence created by the influence of climatic, geologic and geomorphologic phenomena, was established by detailed paleomagnetic studies (e.g. anisotropy of magnetic susceptibility (AMS), isothermal remanent magnetization (IRM), frequency dependence of magnetic susceptibility (κFD), etc.):
–A well-foliated magnetic fabric predominantly built up by multi-domain ferromagnetic minerals (magnetite, maghemite) was developed during the semi-arid (350–400 mm/y) and cold loessification period of the Pleistocene. The magnetic fabric can reflect the direction of dust deposition and/or the paleoslope.
–The accumulation period of dust was followed by the more humid (650 mm/y) pedogenic period indicated by the enrichment of superparamagnetic minerals and by the disturbed or inverse magnetic fabric developed during pedogenesis by different processes (e.g. leaching and/or bioturbation).
–The third period following the pedogenic period is the humid erosional phase indicated by the finely layered reworked loess. The magnetic fabric built up by multi-domain ferro- and superparamagnetic minerals is characterized by better-aligned directions of principal susceptibilities than in the wind blown material. Sheet wash and other waterlogged surface processes appeared in the fabric of these layers. This process is possibly connected to sudden, rare yet significant events with high precipitation and absence of vegetation.
–The cycle was closed by the beginning of the next dust accumulation period.
Recent excavation and sampling in the upper part of the Felsőörs section (Balaton Highland, Hungary) yielded important ammonoid findings, identified as belonging to the genera Nevadites, Chieseiceras, Eoprotrachyceras and Falsanolcites. Several specimens of Chieseiceras chiesense were found in a dm-thick clay layer with limestone nodules, regarded as the equivalent of the “Chiesense Groove“ of the Bagolino and other sections in the Giudicarie area (North Italy). The immediately overlying limestone bed yielded Eoprotrachyceras cf. curionii and Falsanolcites cf. rieberi. Together these reliably prove the base of the Curionii Zone, corresponding to the base of the Ladinian Stage, the GSSP of which was recently established at Bagolino. The new data further improved the excellent correlation between the ammonoid records of the Felsőörs section and the Global Stratotype Section at Bagolino. Felsőörs may be considered the most important reference section for the Anisian to Ladinian boundary interval.
The excellently preserved toad fossil was found the Middle Miocene (Badenian) lower freshwater-brackish diatomite layers in Szurdokpüspöki, Mátra Mountains, northern Hungary. This is the first amphibian fossil of the locality. This specimen is the only toad skeleton from Hungary and possibly from the Miocene of Europe. The toothless premaxilla and maxilla denote the family Bufonidae and the ossification of the frontoparietal, prootic and exooccipital indicates the toad species Bufo viridis. The difference from other bufonid toads is the presence of a small bulge on the ventral side of the well-preserved right ilium; thus it is referred to as Bufo aff. viridis. The size of the bones of the fossil anura suggests it was probably a young specimen. Detailed taxonomic description is given.
Authors:Péter Árkai, Kenneth J. T. Livi and Péter Horváth
Metamorphic mineral assemblages in low-temperature metaclastic rocks often contain paragonite and/or its precursor metastable phase (mixed K-Na-white mica). Relationships between the bulk rock major element chemistries and the formation of paragonite at seven localities from Central and SE-Europe were studied, comparing the bulk chemical characteristics with mineral assemblage, mineral chemical and metamorphic petrological data. Considerable overlaps between the projection fields of bulk chemistries of the Pg-free and Pg-bearing metaclastic rocks indicate significant differences between the actual (as analyzed) and effective bulk chemical compositions. Where inherited, clastic, inert phases/constituents were excluded, it was found that a decrease in Na/(Na+Al*) and in K/(K+Al*) ratios of rocks favors the formation and occurrence of Pg and its precursor phases (Al* denotes here the atomic quantity of aluminum in feldspars, white micas and “pure” hydrous or anhydrous aluminosilicates). In contrast to earlier suggestions, enrichment in Na and/or an increase in Na/K ratio by themselves do not lead to formation of paragonite. Bulk rock chemistries favorable to formation of paragonite and its precursor phases are characterized by enrichment in Al and depletion in Na, K, Ca (and also, Mg and Fe2+). Such bulk rock chemistries are characteristic of chemically “mature” (strongly weathered) source rocks of the pelites and may also be formed by synand post-sedimentary magmatism-related hydrothermal (leaching) activity. What part of the whole rock is active in determining the effective bulk chemistry was investigated by textural examination of diagenetic and anchizone-grade samples. It is hypothesized that although solid phases act as local sources and sinks, transport of elements such as Na through the grain boundaries have much larger communication distances. Sodium-rich white micas nucleate heterogeneously using existing phyllosilicates as templates and are distributed widely on the thin section scale. The results of modeling by THERMOCALC suggest that paragonite preferably forms at higher pressures in low-T metapelites. The stability fields of Pg-bearing assemblages increase, the Pg-in reaction line is shifted towards lower pressures, while the stability field of the Chl-Ms-Ab-Qtz assemblage decreases and is shifted towards higher temperatures with increasing Al* content and decreasing Na/(Na+Al*) and K/(K+Al*) ratios.
Authors:Éva Hartai, Tibor Sasvári, Anna Seres and László Kuti
The Bodrogköz is predominantly a flat area surrounded by the rivers Tisza, Bodrog and Latorica. The Hungarian-Slovakian border cuts it into two parts; consequently, the geologic data in the two countries are different in terms of scale and in approach. The authors harmonized the different data on the two sides and created a unified geologic database for the entire area. The Bodrogköz is part of the depression at the northeastern part of the Great Hungarian Plain. It is covered mostly by Quaternary formations but in the Slovakian part there are smaller outcrops of Permian formations and Miocene volcanics.
Authors:Ziad Salem H. Abu-Hamatteh and Ali F. Al-Shawabkeh
Oil shale is the most abundant fossil energy resource discovered in Jordan, ranking third after the USA and Brazil in terms of oil shale reserves. This asset is considered to be Jordan's most extensive domestic fossil-fuel source. The identified reserves of this oil shale are huge and sufficient to satisfy the national energy needs for hundreds of years. Numerous geologic studies have shown that the country contains several oil shale deposits. These deposits are regarded as the richest in organic bituminous marl and limestone that occur at shallow depth. Jordanian oil shale is generally of a good quality, with relatively low ash and moisture contents, a gross calorific value of 7.5 MJ/kg, and an oil yield of 8 to 12%. The spent shale has residual carbon content that may be burned to produce further energy, and ash that can be used for cement and building materials. The current study summarizes the results of the former feasibility studies and discuses the scope of future usage of Jordanian oil shale. The value of this oil shale and its associated products is highlighted herein.
Authors:Bassey E. Ephraim, Barth N. Ekwueme, Mohssen Moazzen and Monir Modjarrad
Different rock types from the area northeast of Obudu, southeastern Nigeria were investigated in order to place constraints on their metamorphic conditions. Detailed petrographic studies indicate four main rock groups in the studied area, namely migmatitic gneiss, migmatitic schist, granite gneiss and a minor amount of amphibolite, metagabbro and dolerite. The chemistry of minerals in these rocks is used to estimate metamorphic pressure and temperature (P-T) using appropriate geothermometers and geobarometers. The estimated temperature for migmatitic gneiss of the area is ∼600–625 °C and 600–650 °C for migmatitic schist; the pressure is ∼ 8 kbar. For amphibolite the temperature is ∼600–700 °C and pressure is 8–12 kbar. The estimated pressures and temperatures for the northeast Obudu rocks correspond to upper amphibolite to lower granulite facies metamorphism. The metamorphism occurred due to continent-continent collision during the Pan-African orogeny, most likely during the D1 deformational phase of the area. The recorded high pressures possibly resulted from crustal thickening in the area. P-T conditions for Pan-African orogeny in northeast Obudu area are in good agreement with P-T estimations for the Pan-African event in adjacent areas.
Authors:Batoul Taghipour, Mohammad Ali Mackizadeh, Mehdi Pourmoghani, Arthur Kasson and Sedighe Taghipour
The Keshe area is a part of Cenozoic magmatic belt of Central Iran. Some volcanics in this area underwent hydrothermal alteration including kaolinitization and alunitization. The altered rocks are characterized by an assemblage of alunite, kaolinite and quartz, which is typical in advanced argillic alteration. The mineralogical study suggests that the hydrothermal alteration in this area occurred in a magmatic hydrothermal environment.
Authors:Lahcen Zouhri, Daniel Vachard and Christian Lamouroux
The Miocene-Pliocene Rharb Basin has important groundwater and hydrocarbon potential in western Morocco. The Pliocene-Quaternary reservoir rests upon the Miocene-Pliocene marly units. The paleogeographic limits are based on planktonic foraminifera biozones. They contributed to the geometric reconstruction of this basin. The goal of the present study is to establish the paleogeographic evolution of the Rharb Basin and the Hercynian structures deduced from seismic and gravity data interpretation. The Pliocene-Quaternary deposits exhibit thickness and lateral facies variations. The Pliocene bathyal gulf showed several tectonic phases, marked by the westward migration of the paleogeographic limit in its eastern part, and a southward migration from its northern one. During Miocene-Pliocene times, the tectonic activity within the study area is characterized by extensional and compressional structures. The faults affecting the Paleozoic units were reactivated several times. The comparison between the paleogeographic limits and identified Hercynian structures constitutes fresh evidence for reactivation of pre-existing Hercynian faults.
Authors:Katrin Ruckwied, Annette E. Götz, József Pálfy and Ákos Török
Palynology and palynofacies patterns of terrestrial Triassic/Jurassic boundary series of the South Hungarian Mecsek Mountains were studied in search of paleoenvironmental and vegetation changes and climatic signatures related to one of the major mass extinction events in Earth's history. Two selected and studied boreholes comprise continuous boundary sections and yield a diverse Late Rhaetian to Hettangian palynomorph assemblage. The most striking feature within the boundary interval is the series of cyclic short-term paleoenvironmental changes from fluvial/deltaic to swamp settings, as inferred from changes in palynomorph associations. However, increasing humidity is documented by a striking increase in trilete spores. These signatures display the response of terrestrial vegetation to regional and global environmental changes, although we found no clear evidence for a mass extinction as documented in the microflora.
A detailed petrographic and mineral-chemical study on metapelites from the Meliatic accretionary wedge complex (Bôrka Nappe, Western Carpathians, Slovak Republic) reveals the HP character of the samples using quantitative phase diagrams contoured with mineral composition, H2O mode isopleths and garnet-phengite thermometry. The presented PT pseudosections prove that small-scale differences in bulk rock composition are responsible for the variations in the mineral assemblages formed at the same PT conditions. The peak conditions indicate blueschist facies metamorphism (520–620 °C, 11–14 kbar) and are correlated with the 150–165 Ma subduction of the Mesozoic Meliata Oceanic branch of the Neotethys. Continuous decrease of P and T from peak conditions enabled the metapelitic rocks to preserve their HP assemblages. The presented HP conditions and retrograde PT path with decreasing P and T are characteristic of subduction zone tectonic settings which are in agreement with most of the geodynamic and tectonic reconstructions for the area.
From the middle part of the Late Jurassic (Kimmeridgian), the hitherto uniform depositional environment of the Adriatic carbonate platform began to show differentiation. In the central part of the platform two intraplatform troughs were formed, one of which stretched from the Karlovac area southward and is known as the Lemeš Trough. The depositional processes that took place within this trough can be observed in the sedimentary succession of Mt. Svilaja. Based on investigated facies characteristics five lithofacies units were distinguished, representing three paleoenvironmental units: (1) shallow subtidal zone below the fair-weather wave-base; (2) intraplatform trough; (3) shallow subtidal zone above the fair-weather wave-base. The environmental changes are related to the tectonically-controlled retrogradation of the shallow subtidal platform, when the deeper-water intraplatform trough area, connected with the open Tethys realm, spread over the sunken part of the platform. Progressive infilling of the trough with bioclastic material led to the re-establishment of the shallow subtidal environment, and the area of the previously existing intraplatform trough was occupied by coral-hydrozoan reefal buildups.