Authors:Tibor Zelenka, Pál Gyarmati, and János Kiss
The Tokaj Mts, situated in the northeastern part of the inner arc of the Carpathians, forms a part of a Miocene calc-alkaline andesitic-dacitic-rhyolitic volcanic island arc. The ancient volcanic structures were reconstructed on the basis of the 1:50 000-scale and 22 sheets of the 1:25 000-scale geologicpetrologic maps, as well as the revision of the volcanic facies in 150 boreholes. Multispectral and SAR satellite imagery, aerial photos, data and maps of airborne geophysical surveys (magnetic and radiometric), gravity-filtered anomaly maps, geochemical (soil and stream sediment Au, As, Sb, Hg) concentration distribution maps and the K/Ar dating of 132 samples from 80 paleomagnetic measurements were also used.
The anomalies were only taken into consideration in the interpretation if the coincident results of at least 3 methods indicated the presence of any volcanic structure. In consequence, 91 map-scale volcanic structures were identified by morphology — complex calderas, single lava domes, volcanic fissures, subvolcanic intrusions, diatremes, stratovolcanoes and postvolcanic formations. Conclusions were also drawn regarding the link to the volcanic structures and prospective occurrences of the mineral resources of the Tokaj Mts: andesite, dacite, welded zeolitic tuff, K-metasomatite, perlite, pitchstone, pumice, bentonitic, illitic, kaolinitic, diatom-bearing and silicified lacustrine sediments, hydrothermal Au-Ag and Pb-Zn veins, and Hg stockwerks.
A study is made of the intense storms of March 13–15, 1989 (
= −600nT), October 20–21, 1989 (
= −266 nT) and April 1–2, 1973 (
= −211 nT) in regards to the appearance of positive storm before the beginning of a geomagnetic disturbance in the mid-latitudes and the occurrence of strong negative phase at the equator. F2 region global structure response to the geomagnetic storms was studied using
F2 data obtained during the storms from a global network of ionosonde stations. Investigated phenomena were only observed, on October 20, 1989, in only three of the nineteen plots representing ∼16% occurrence for the case study of March and October 1989 storms: the positive storms at Slough (54.4°N) and Uppsala (59.86°N) and a negative storm at Ouagadougou (12.4°N). These ionospheric storms were caused by the southward turning of
at ∼2100 UT on October 18 which got to a change in
= 12.2 nT at 2300 UT on October 18. In the case of the storm of April 1–2, 1973, the phenomena had ∼69% occurrence: the positive storms at Wakkanai (45.4°N), Akita (39.7°N), Kokubunji (35.7°N), Kiev (50.5°N) Sofia(42.7°N), Ottawa (45.4°N), Boulder (40.0°N) and Point Arguello (35.6°N) and a negative storm at Manila (14.7°N). These ionospheric storms appear to be caused by the southward turning of
at ∼1500 UT which got to a change in
= 13.6 nT at 1900 UT on March 31. The non explanation of these phenomena before now is because in the studies of ionospheric storms it is assumed that the beginning of any particular disturbance is defined by the onset of the magnetic storm. The use of sudden storm commencement (SSC) and main phase onset (MPO) for fixing the beginning of magnetic and ionospheric storms is fraught with problems that render a determination of the exact onset time difficult. The notion of onset of the magnetic storm as a prevailing idea restricted the geoeffectiveness of the solar wind to post onset time thereby foreclosing the explanation of any aspect of the morphology of ionospheric storms whose origin precede the onset reference time.
Authors:Ádám Bede, Roderick B. Salisbury, András István Csathó, Péter Czukor, Dávid Gergely Páll, Gábor Szilágyi, and Pál Sümegi
-Deák , J. , R. Langohr , E.P. Verrecchia
1997 : Small scale secondary CaCO3 accumulations in selected sections of the European loess belt. Morphological forms and potential for paleoenvironmental reconstruction . – Geoderma , 76 , pp. 221
Quaternary thermogene and meteogene travertine occurs globally, both in Hungary and abroad. Size and thickness of the individual deposits are highly variable. They can be classified on the basis of water temperature, morphological setting, depositional environment, microfacies and fabric. All travertine is composed of pure low magnesian calcite and its stable isotopic composition (d13C, d18O) may change according to the facies. Sr and Ba are typical and some places enrichment of heavy metals, U, Th, and REE were also reported. Travertine is generally related to karst water springs; therefore, tectonically-controlled karstification, cave and soil formations are very common. It can be rich in fossils and its water depth varies from some centimeters to tens of meters. Chronology and timing of travertine can be solved by applying numerical, calibrated and correlative methods.