A Kárpát-Pannon térség oligocén utáni deformációi mágneses anizotrópia mérések alapján = Post-Oligocen tectonic deformations of the Carpathian-Pannonian region from magnetic anisotropy measurements

A pályázat célja a neogén tektonikai deformációk hatásának tanulmányozása volt a Kárpát-Pannon térségben, üledékek mágneses szövetének vizsgálatával. A finomszemű üledékek jobb indikátornak mutatkoztak mint a homokkövek, ezért agyagos rétegeket vizsgáltunk. A Sziléziai- és Magúra-takarók oligocén korú flis képződményei mind gyenge deformációt szenvedtek, amit a rétegződéssel közel párhuzamos mágneses foliáció (MF) jelez. A mágneses lineációk (ML) véletlen eloszlásúak a Magúra-, ill. a helyi csapásirányokkal korrelálnak a Sziléziai-takaróban. Utóbbi kompressziót jelez. Az ML irányok nem követik a kárpáti ívet, amely kizárja annak oroklinális hajlítási eredetét. Hasonló következtetés volt levonható a Pieniny Klippen Belt kréta korú márgáinak vizsgálatából. A belsőkárpáti flisben gyenge deformációt és az áramlás által nem befolyásolt paleomágneses irányokat mértünk. A Dunántúli-középhegységben (DK) az oligocén és pannon üledékek gyengén deformáltak. Az oligocénen egy középső miocén extenziós deformációt tükröző, regionálisan megegyező ML-eket mértünk. A pannonban viszont ritka a jól definiált ML, valószínűleg azért mert a DK fiatal üledékeit a konszolidált alaphegység, illetve a nagyobb távolság leárnyékolja az É-ra mozgó és elforduló Adria mikrolemez közvetlen deformációs hatásától. Ezt a következtetést erősíti, hogy a Pannon-medence D-i részéből származó, hasonló korú üledékek mágneses szövete jelentős deformációról tanúskodik. | The project aimed at tracing the effect of the Neogene deformation in the Carpatho-Pannonian region by studying the magnetic fabric of sediments. We found that fine grained sediments show more clearly the signs of tectonic deformation than sandstones. Thus we studied claystone beds from Oligocene flysch of the Magura and Silesian nappes. They have bedding parallel magnetic foliation (MF), suggesting weak deformation. Magnetic lineations (ML) in the former are randomly oriented. In the latter ML correlate with local strike (compression). The orientations of ML and the Carpathian arc are not in harmony, thus oroclinal bending of the arc in the Miocene is not supported. Similar conclusion was drawn for late Cretaceous marls from the Pieniny Klippen Belt. For the Central Carpathian flysch we proved that deformation was weak and the paleomagnetic directions are not biased by flow orientation either during deposition. From the Transdanubian Range (TR) both Oligocene and Pannonian sediments show signs of weak deformation. The former exhibit geographically consistent ML related to middle Miocene extension. The latter rarely shows well defined ML. We think that the young sediments of TR were protected by consolidated basement and larger distance from northward moving and rotating Adria microplate, for the magnetic fabric of sediments of similar age from the South Pannonian basin was found to show clear evidence of important deformations

An integrated magnetic susceptibility anisotropy (AMS) and structural geological study on Cenozoic clay rich sediments from the Transdanubian Range

Systematic structural and anisotropy of magnetic susceptibility (AMS) measurements were carried out on Cenozoic clay rich deposits from the Transdanubian Range, central part of the Alcapa Unit. The aim was to improve the knowledge on the Neogene tectonic evolution of the area and on the connection of the stress field and the magnetic fabric of the sediments. The measurements of AMS revealed dominant foliation with weak lineation for Middle Eocene-Lower Miocene sediments. The directions of AMS lineation are aligned either with the direction of NNE-SSW extension of a strike slip phase (30–19 Ma) or with the direction of NE-SW extension of the main rifting phase of the Pannonian Basin (19–14 Ma). The studied Late Miocene sediments have foliated AMS fabric, maximum and intermediate AMS directions are intermixed, and the AMS fabrics do not show any sign of tectonic deformation. In contrast, joints and faults were observed in the same rocks. Detailed structural analysis shows two extensional phases between ca. 10-4 Ma, with E-W to WNW-ESE and with NW-SE extension, respectively and the youngest neotectonic strike-slip phase. The contrast between the presence of markers of brittle deformation and the absence of tectonically induced AMS lineation is striking, since the same types of sediments in the South Pannonian basin show just the opposite. The explanation may be that northward moving and CCW rotating Adria caused strong compression in the southern Pannonian basin, resulting in ductile deformation of the clay-rich sediments and systematic reorganization of AMS texture while in our study area sediments of similar character and age were at a larger distance from the strongly deforming basin part

Magnetic monitoring, geochemical and mineralogical analysis of settled dust from North and Central Transdanubia, Hungary

Ferromagnetic grains in airborne dust are important indicators of vehicle traffic, some industrial sources and combustion/heating. Settled dust consists mainly of diamagnetic material; therefore accessory ferromagnetic grains are readily indicated by magnetic measurements. In this paper settled dust samples collected on a monthly basis in the years 2008–2011 were studied. Non-destructive magnetic measurements were followed by geochemical and mineralogical analyses. In selected samples we identified airborne anthropogenic materials (e.g. silicate and magnetite spherules), minerals from the natural environment and organic material. Seasonally appearing materials (e.g. soot in winter, plant fragments and pollen in summer) increased the mass of the settled dust, but not the magnetic susceptibility. Thus, we realized that the generally interpreted mass susceptibility in environmental magnetic studies would not always appropriately characterize the magnetic pollution. In the interpretation we gave preference to total susceptibility because of its direct connection to the pollution, except in comparison with metal concentrations. Trends in magnetic pollution were eventually analyzed for 19 sampling sites. Irrespective of the degree and source of the pollution the monthly variation curves of magnetic susceptibility exhibit a general maximum (March–April), followed by gradual decrease. A corresponding peak is observed in the amounts of dust. Both can be explained by re-suspension of dust settled in winter. The additional maxima in the mass of the dust (June and August, respectively) are probably due to contribution from vegetation and/or an artifact from algaecide. For three key sampling sites comparison was made between the concentrations of 12 metals and the respective mass susceptibilities and good linear correlation was found for Fe, Mn and Zn for all, for Cr, Cu, Pb, V, Ba, Sr and Zr for two sampling sites. Cd, which is enriched in all samples, does not correlate with the magnetic susceptibility

Zsolcai-halmok földtudományi vizsgálata

Az Alföld északi részén, a Sajó ármentes teraszán emelkedő, 6 méter magas, régészetileg feltáratlan kettős halom vizsgálata volt a célunk, mivel korábban szinte semmilyen kutatás nem zajlott e halmokkal kapcsolatban. Ha egyenként vizsgáljuk e halmokat, akkor a közepes, átlagos méretű hazai halmok csoportjába tartoznak. Az viszont már egyáltalán nem tekinthető magyarországi viszonylatban átlagosnak, hogy két, tájképileg és növénytakaróját tekintve kiemelkedően értékes, szorosan egymás mellé épült prehisztorikus halom mai napig fennmaradt egy intenzíven átalakított kultúrtájban. A rétegtani és kőzettani elemzések alapján a Zsolcai-halmok fő építőanyaga a közeli Bükkből származó mészkő, a Szerencsi-dombságból bányászott riolittufa, a halmok lábánál kitermelt termőtalaj és talajjal kevert sárgásbarna pleisztocén löszös üledék. Mindkét halmot fél méternél nem mélyebb, gyűrűszerű mélyedés vesz körbe jelenleg, amelyek eredetileg közel három méter mély, talajvízzel töltött árkok lehettek. Ezekből termelhették ki a halomtestek magasításához szükséges építőanyagot. Az eltemetett paleotalajok radiokarbon kora alapján (cal BC 950–404 és cal BC 879–542) kijelenthető, hogy a két halom az i.e. 9-6. században épülhetett szinte teljesen egyidőben. A geoelektromos, radiokarbon és kőzettani vizsgálatok alapján épített sírkamrával rendelkező szkíta kurgánnak határoztuk meg a kettős halmot. A mágneses anomália mérések szerint a halmoktól északra elterülő sík térszínen több szarmata körárkos sírt azonosítottunk. Mindez azt bizonyítja, hogy a Zsolcai-halmok az időszámításunk utáni 4. évszázadban is fontos kultikus, szakrális helyszínek voltak

An integrated magnetic susceptibility anisotropy (AMS) and structural geological study on Cenozoic clay rich sediments from the Transdanubian Range

Systematic structural measurements and simultaneous measurements of anisotropy of magnetic susceptibiliy (AMS) were carried out on Cenozoic clay rich deposits from the Transdanubian Range, southern part of the Alcapa Unit. The aim was to reconstruct the structural evolution for the studied area and establish the connection of the stress fields and the fabric of the sediments by studying outcrops with both methods. The measurements of AMS revealed dominant foliation with weak lineation for Oligocene and Eocene sediments. The directions of AMS lineation are aligned with the directions of the extension of the oldest deformation phase having affected the given outcrops. This relatively oldest phase is mostly extensional or strike-slip type deformation with NE-SW to NNE-SSW extensional axis. At present we are working on the problem of establishing a statistical relationship between the AMS lineation and direction of the extension calculated from microtectonic measurements The magnetic fabrics of the studied Late Miocene sediments are foliated without consistent lineations on locality level, which means that they do not reveal any sign of tectonic deformation. However, the brittle structural elements, mainly joints and small-displacement faults without striae, in few late Miocene outcrops indicate more than two stress fields although their direction and character are relatively poorly constrained. All of the localities exhibit pure compression, transpression or a strike-slip stress field (this latest is always the youngest one). This coincide with other independent data (such as morphotectonics, space geodetic data (GPS), recent stress data), which prove the inversion of the Pannonian Basin. Financial support from Hungarian Scientific Research Fund (project no. OTKA K 105245 and 81530) is acknowledged

A Unique Megalithic find from the Great Hungarian Plain : Preliminary Report on the Research of a Stone Stele from Kevermes

Large, complex megalithic monuments erected in great numbers on the Atlantic coast and in northern Europe during the 4th‒2nd millennia BC have never been found in Hungary, and the architectural forms and decorative arts of passage and chamber tombs, dolmens, stone circles, and menhirs have not been linked to the archaeological heritage of the Carpathian Basin. This is what renders a stone stele, with engravings evoking some megaliths in western Europe, found near Kevermes in the southeastern Great Hungarian Plain so extraordinary. In this article, we report the results of our research related to this unique object to clarify the circumstances of its discovery, to examine the possibility of forgery, to specify the raw material and provenance of the stele, and to explore the original context. In our next paper, we will present detailed descriptions of the analytical results and discuss the interactions and networks that may have led to the appearance of the motifs on the Kevermes stele on the Great Hungarian Plain