Carpathian Journal of Earth and Environmental Sciences, May 2012, Vol. 7, No. 2, p. 239 - 248 GEOMORPHOMETRICAL METHOD FOR DELINEATION OF PLAINS - CASE STUDY OF THE SOUTH-EASTERN (SERBIAN) SEGMENT OF THE PANNONIAN PLAIN Jelena ĆALIĆ, Tivadar GAUDENYI, Marko V. MILOŠEVIĆ, Dragoljub ŠTRBAC & Milovan MILIVOJEVIĆ Geographical Institute “Jovan Cvijić” of the Serbian Academy of Sciences and Arts, Đure Jakšića 9, 11000 Belgrade, Serbia, e-mail: [email protected] Abstract: Usage of the terms Pannonian Basin and Pannonian Plain in physical and regional geography is often characterised by vague spatial extent, especially in Serbian geographical literature. The aims of this paper are directed towards establishing a method which would define a plain in geomorphological and geomorphometrical sense. Although the case study is focused on definition of the actual boundary of the Pannonian Plain in Serbia, the method of delineation can be used on other locations as well, especially in the wider area of the Pannonian (Carpathian) Basin. The method relies on the numerical analysis of a digital terrain model, which produced the value of the surface roughness coefficient. By combining the geomorphometrical analysis with spatial extent of characteristic lithologies (Quaternary) and morphological processes (dominant fluvial aggradation and eolian process), the exact delineation of the Pannonian Plain in Serbia was carried out. As opposed to some earlier opinions, the Pannonian Plain extends further to the south from the Sava and the Danube Rivers, encompassing also the lower parts of the Drina, Kolubara, Velika Morava and Mlava basins. Within Serbia, the Pannonian Plain occupies 24,450 km2, which is 27.6% of the territory of the country. The elevation ranges from minimal 68.5 m a.s.l. to the maximum of 155 m a.s.l. The mean elevation of the Pannonian Plain in Serbia is 83.5 m a.s.l. Key words: Pannonian Basin, Pannonian Plain, geomorphology, geomorphometry, relief roughness, Serbia 1. INTRODUCTION ancient Roman province Pannonia, which existed in the Roman Empire from 1st to 4th century A.D, encompassing The term Pannonian Basin is often used in the areas from the Vienna Basin on the north to the Sava geosciences, referring to the low land and hilly area River on the south, while the eastern border in central and south-eastern Europe. While the approximately followed the course of the Danube River. usage of the term in palaeogeography, In the paper named “The surface of the Alföld” palaeontology, sedimentology/stratigraphy and (“Az Alföld felszíne”), Cholnoky (1910) discussed the structural geology is mostly clear and general features of the Great Hungarian Plain (Alföld), unambiguous, in physical and regional geography realizing that the plain continues further from the southern of the countries at its southern rim, there are many parts of Hungary of that time, to Serbia, Croatia and inconsistencies and imprecise definitions (e.g. northernmost parts of Bosnia (Fig. 1). He stressed the need Marković, 1970; Milanović et al., 2011). In for more precise delineation of the southern boundary of regional-geographical literature, the term the plain, stating that such studies will be “the task of the Pannonian Basin is often interchanged with the Serbian colleagues” (Cholnoky, 1910, p. 420). term Pannonian Plain, but without the clear The aims of this paper address both semantic and spatial delineation. forementioned problems: (a) to determine the Introduction of the term Pannonian Basin into geomorphological definition of a plain, within a case geological literature took place when the Pannonian study of the Pannonian Plain (through definition of stage was defined in stratigraphical references by topography, forms and active processes), to be used in Róth von Telegd (Róth, 1879; Róth von Telegd, physical geography; (b) to outline the Serbian part of the 1879). The term originated from the name of the Pannonian Plain (i.e. its south-eastern boundary). 239 Figure 1. One of the first maps of the Alföld (Great Hungarian Plain), by Cholnoky (1910), indicating that the plain stretches further to the south from the Danube River (1 – alluvial plains in Alföld, 2 – upper Dilluvial areas in Alföld, 3 – lower Dilluvial areas in Alföld, 4 – area not belonging to Alföld). Present state borders added for easier orientation. 2. STRUCTURAL-TECTONIC Quaternary caused the so-called “basin inversion” DEFINITION OF THE PANNONIAN which marks the neotectonic phase characterized by BASIN SYSTEM compression and differential vertical movements. The compression resulted from the continuous The basement of the Pannonian Basin is a counter-clockwise rotation and northward complex of several tectonic units (terranes). complex indentation of the Adria microplate (e.g. Bada et al, of several tectonic units (terranes). The greatest part 1999; Dombardi et al., 2010). Complex tectonic of the area is divided between the units ALCAPA, to pattern and evolution led to the introduction of the the north-west of the Mid-Hungarian Shear Zone term Pannonian Basin System, which was used for (MHSZ), and the unit Tisza (e.g. Fodor et al., 2005) the first time by Royden et al. (1983a,b). or Tisza-Dacia (e.g. Dombardi et al., 2010), to the Although some parts of the basin were subject south-east of the MHSZ. This zone is even to uplifting during the neotectonic phase, several flat- nowadays characterised by intense tectonic activity lying, low altitude areas were subject to continuous (Marótiné Kiszely, 2010). Apart from these two subsiding since the early Miocene and filled with units, the south-eastern part of the basin consists of thick sequences of sediments (Bada et al., 2006). The two more units – the Vardar Zone and Serbian- most conspicuous of such areas are the Great Macedonian Massif (Fig. 2). Hungarian Plain, Little Hungarian Plain, Sava and The basin formation within the Alpine Drava throughs. Flat-lying plain in the south-eastern orogenic belt began in the early Miocene, through (Serbian) part of the Pannonian Basin System has not the extension and subsidence in the back-arc basin been thoroughly geomorphologically studied. In due to the collision between the Adria microplate Serbian literature references, it is usually called the and the European continent (Bada et al., 1999). Pannonian Plain (e.g. Marković, 1970), but its precise Changes in the regional stress field in Pliocene and definition and extent have not been defined yet. 240 Figure 2. Main structural elements of the Pannonian Basin and the distribution of Neogene sediments, (compiled after the data of Haas et al., 2001; Royden & Horváth, 1988; Fodor et al., 1999; Dombárdi et al., 2010; Dimitrijević, 1992) In the basement, this part of the plain is the spatial extent of the Lake Pannon and its sediments. formed of three main tectonic units: Tisza-Dacia, Under the name Great Pannonian Basin (in the Vardar Zone and the Serbian-Macedonian German: grossen pannonischen Becken; in Hungarian: Massif. The Vardar Zone is characterized by nagy pannoniai medencze), Róth von Telegd (Róth, ophiolithic geology (Karamata et al., 1998) and 1879; Róth von Telegd, 1879) presented the one of its uplifted outcrops is Mt.Fruška Gora, sedimentation basin in which the following facies were situated between the river courses of the Danube deposited: Pontian (Congeria beds), Levantine (Paludina on the north and the Sava on the south. The beds) and Trachian (Belvedere beds; restricted to the Northern Unit of the Serbian-Macedonian Massif Vienna Basin). The reason for the birth of this term was was affected by a Miocene extension in the to unite the above mentioned beds, which could not be Pannonian Basin (Psilovikos, 1984). Tisza-Dacia clearly separated one from another. At that time, this unit is separated from the Vardar Zone by a deep term perfectly fitted because it encompassed the areas to system of ruptures known as the Drava Fault the east of the Danube course in the Carpathian Basin (Prelogović et al., 1997). In the Serbian part of the (Middle-Danube Basin) and the Vienna Basin – Pannonian Plain, this fault does not have the locations where the Pannonian sediments are distributed. surface morphological expressions (Vukašinović, In the later research, Lőrenthey (1900) excluded 1973). Detailed elaboration of neotectonics in the the freshwater Pliocene Levantine beds from the southern part of the Pannonian Basin System can Pannonian stage. Consequently, the final phase of the be found in Marović (2002, 2007). Pannonian was represented by caspibrackish Pliocene sediments. The Lake Pannon evolved from the Central 3. PALAEOGEOGRAPHICAL AND Paratethys (or Paratethyan Sarmatian Sea, after STRATIGRAPHICAL DEFINITION Harzhauser & Mandic, 2008), with salinity change OF THE PANNONIAN BASIN from mesohaline to (caspi)brackish environment. Neither the Pannonian Basin System Pannonian Basin is a palaeogeographical (structurally) nor the Lake Pannon (hydrologically) were term related to the area of the Lake Pannon or uniform, “dish-like” features during their evolution. On Pannonian Lake (in German: Pannonische See). the contrary, they functioned as dynamic systems, Some authors use the term Pannonian Sea (e.g. divided on many locations by islands and peninsulas Eremija, 1975, p. 195; Gábris, 1994). Pannonian (Magyar et al., 1999). Basin is a palaeogeographical term connected to The time frame of the Lake Pannon genesis and 241 evolution varies across different sedimentation geomorphology which should give a clear definition of realms. It is considered