GEOLOGICAL ANALYSIS OF THE KIS-ALFÖLD BASED ON SATELLITE-PHOTOS L. JAKUCS The research introduced only in its main results in this study is a part óf a five-year scientificic program which was carried out by the Institute of Physical Geography of Attila József University of Sciences within the frame of the theme "Satellite Research of Natural Resources of Hungary" at the commission of the Central Institute of Geology. The members of the team lead by dr. prof László Jakucs are as follows: reader dr. Mihály Andó, senior lecturer dr. József Fehér, Senior lecturer dr. Mrs Ferenc Kevei, lecturer candidate dr. Gábor Mezősi and senior lec- turer dr. Imre Tóth. The available LANDSAT longdistance survaillances show that defining the Kis-Alföld as a physical geographical region is a simple task only with a cursory examination because its margins protrude deeply into the wide valley-plains of the bordering Carpathian and Transdanubian rivers. On the satellitephotos of the LANDSAT-satellites (I; II; III.) these marginal regions, which are quastionable and subjectively treatable, too, stand out clearly and this fact helps making a more exact genetic limitation. Yet during our work of interpretation we overstepped the actual borders of the Kis-Alfpld for we saw comparation standing out at all points which says that the regionmargins drawn on geomorphological or soilgeographycal basis are not at the same time the margins of the natural factors determining the development of a region. For quality and quantityration óf past and recens hydro- logical, climatological, sedimentational and structural many times determinant) factors determining and directing the geographycal and sedimentological develop- ment of the Kis-Alföld are controlled far from the frontier, mainly from the direction of the Alps and the Carpathians. Yet the investigation of these foreign regions did not fall within our sphere of activity. That is why for morphogenetical relations we tried to choose the satellite- photos so that we could study reaches as long as possible of the mountain water- shed areas of the rivers of the Kis-Alföld. Overstepping especially the Austrian and the Czechoslovakian frontiers as well'was absolutely necessary so as to draw a useful comparison between the geographical informations about the foreign parts of this region which is homogeneous as regards the genetics and those of the ones in Hungary. Unfortunately for our modells of interpretation about the regions abroad not even so could we give everywhere the conditions of the field and deep bore controll up to the level of the required scientific efficiency. Our investigational region is the second member — according to size — of the Landsat -1. 1973. nov. 1.St' . Landsat -1. 197». aug. 23.'rd . ///^//j Landsat -II 1979. may. 20.th' Geological Analysis of the "Kis-Alföld" 121 Danube-basins surroundee by the Alpian-Carpathian montainsystem. It is connected with the smaller Wien-basin towards the west along the Danube dividing the area at the middle through the wide Gates of Bruck and Dévény towards east with the ten times bigger Great Plain through the Pass of Visegrád. One half of it is in Czechoslovakia to the north of the Danube and its margins protrude deeply into the wide valleys of the Carpathian rivers. To Hungary belongs the other half of it towards the south of the Danube — approximately 5.500 square kilometres — expect the Pandorfi — plateau in Austria. Its absolute geographycal position is determined by 48 57 33 north latitudes and 16 40 and 1845 west longitudes (L. Góczán). Since the documentations of our research refer to first of all to the Hungarian territory of the Kis-Alföld, it is reasonable to determine more exactly the borders of the Kis-Alföld as known in the technical literature. According to Góczán (1975) the border of the macroregion is the Danube on the north, the west and south edge of the Fertő-basin on the west, then after turning to the south-south east at Vitnyéd it turns again to the east at Répcelak up to the valley of Rába. It crosses the Rába at Várkesző, from there runs along the edge of Kemenesalja. The southest border of the region intrudes into the meridional valley of Vindornya down to Óhid, then going round this it turns towards Sümeg, to the north-east. T o the north of Sümeg the south-east-east border runs towards Csabrendek then to the north-east up to Halimba across Nyirád. From here the border can be drawn towards the north up to Pápakovácsi, from where it turns to the north-east again an d runs in this direction up to the north-north-west along the eastern valley — edge of the creek Sokoro-Bakony, then it goes around the north-western corner of the downs of Pannonhalma. From there it runs toward south-east again along the eastern edge of the downs of Pannonhalma. The south-eastern border is Tápszentmiklós— Kisbér—Szák—Kömlőd—Vértesszőlős. From there it runs to the north along the western feet of Gerecse to the Danube. The border runs to the east along the edge of the Danube riverflats at the feet of the Danube-terraces belonging to the Northern- Gerecse and turns to the north in the direction of Esztergom making a little trough in the basin of Dorog. The new areal distributions (Pécsi, Góczán) regard Esztergom as the eastern border of the Kis-Alföld since in the Slovakina territory Demek and his collaborators close the border with the valleys of the Garam and the Ipoly. Regiongeographycally the basin of Dorog is the south-eastern edge of the Kis-Alföld with lowland type of regional factors characteristic of it. We shaw the regionborders of the Kis-Alföld as well as the present distribution of our middle and micro regions on fig. 5. The above described circumscription of the Kis-Alföld is justified by the geo- morphological potentialities, the borders of climatic, plantogeographical and soil- geographical regions together (see figs 10. and 15.). On the satellite-photos this region circumscription seems to be. really reasonable on most places but on some parts a broarder circumscription could be accepted relying upon the long distance survaillan- ces, for example the LANDSAT-photos there is no difference as regards of the region- characteristics between the Sopron—Vas alluvial cone plain as well as the Kemeneshát and the Kis-Alföld. And if these territories are still attached to the Western-Hungarian areal distrib- ution of our geomorphologists the only reasons for thos can be the characteristics-a little different from that of the Kis-Alföld — of the other regional factors (a climate 122 L. Jakucs with a subalpian — subatlantian effect, vegetation, soilgeography, water-balance) which are reflected less on the satellite-photos. During our work of interpretation we felt that the borders of regional categories can get new aspects hydrogeographically and geologically-petrographycally. The reliefrelations of the basinbed of the area (figs. 22. 23.) the juxtapositional system, the areal parts with nearly the same geophysical characteristics (figs 25. 26.), the dist- ribution of the larger and smaller geostructural and geokinetical regions, but even the special positions of the contactlines of the different subsoil water regions induced us by means of further reasons not to stichto the regional category of the geographical- ly circumscribed Kis-Alföld in the interpretation of the satellite-photos but to make an effort to the wider overlapping. Otherwise the edges of the available satellite- photös made these overlappings easy, for they cover not only the whole territory of the Kis-Alföld but also its neighbouring parts of regions and just from the direction of the regiongenetically most active western, south-western and northern sides. Only one satellite-photo covering the whole Hungarian area of the Kis-Alföld does not exist, because mainly the east-west extension of the region surpasses the scope of cameras of the LANDSAT. So we chose photos made during the time of cloudless atmospheric conditions with a comparatively low vapour-content, which cover the area practically without clearances mosaic-like, even overlap one another many times. While proscsessing we found the photos of the findings of the LANDSAT—I. made on 1st November 1973; the one of those of the LANDSAT—II. made 23rd August, 1978, and the one of those of the LANDSAT—III. made on 20th May 1979 the most suitable for our purposes. It has to be noted that we could not get the spectrums No. 6. of the LANDSAT—I. photo in 1973, otherwise we inter- preted spectrumnegatives and spectrumpositives Nos. 4. 5. 6. 7. from each photo- material and those spectrumcombinations of the integrational variation possibilities the aggravated geological emphasizing ability of which proved during analyzing. Western pictureborders of the LANDSAT—I. photo in November 1973 are approximately in the line of Rajka—Hegyeshalom—Kapuvár—Vasvár so the whole area of our research territory to the east of this line can be seen in the photo. Eastern pictureborder of the LANDSAT—II photo in August 1978 can be identified with the line of Almásfüzitő—Kocs—Császár, i.e. this photo covers the whole area of the Kis-Alföld to the west of this line. Practically it is the same with the LANDSAT—Ill-photo in May 1979, the eastern pictureborders of which almost coincide with the edge of the analyzed satel- lite-photo of LANDSAT—II (this is the line of Szőny—Vérteskéthely) i.e. the photo includes the whole area of the Kis-Alföld to the west of this line. Otherwise the area- covering of the used photos is shown on the sketch-map of fig. 1. in a global form, too. It can be judged by fig.