2. Geological Model of the Danube Basin; Transboundary Correlation of Geological and Geophysical Data
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Slovak Geol. Mag., 14, 2 (2014). 17-35 2. Geological Model of the Danube Basin; Transboundary Correlation of Geological and Geophysical Data BALAZS KRONOME1, IVAN BARATH1, ALEXANDER NAGY1, ANDRAS UHRIN2, GYULA MAROS3, RUDOLF BERKA4 and RADOVAN CERNAK1 'State Geological Institute of Dionyz Stur, Mlynskd dolina 1, 817 04 Bratislava 11, Slovak Republic "Eriksfiord AS, Professor Olav Hanssens vei 7A, 4021 Stavanger, Norway 'Geological and Geophysical Institute of Hungary, Stefania lit 14, 1143 Budapest. Hungary 4Geologische Bundesanstalt, Neulinggasse 38, A-1030 Wien, Austria Abstract. The presented paper comprises the first successful problems, and the detailed geological characteristics of attempt towards compiling the full 3D horizontal and cellular the areas. The areas were the following: Vienna Basin, model of the Danube Basin created in the frame of the Danube Basin, Komarno-Sturovo area, Lutzmannsburg- international TRANSENERGY project. In this article we are presenting only one of the five pilot areas of the TRANS- Zsira area and the Bad Radkersburg-Hodos area (Fig. ENERGY project - the Danube Basin. 2.1). The 3D model is built on a large amount of geological As a starting step we collected all available seismic (mapping, stratigraphic, wells) and geophysical (seismic, geo• (160 sections) and well data (1672 wells). After this step magnetic, gravitational) data, completed by structural and it was necessary to define the technical framework for the geodynamic studies in all participating countries (Slovenia, project (file exchange formats, scale of maps etc.). Austria, Hungary and Slovakia). After gathering and processing all available data a unified stratigraphical framework was Finally the WGS1984 UTM Zone 33N as the common compiled for all participating countries, followed by defining coordinate system and Transverse Mercator as the the main structural features and finally creating the model. common projection were chosen. Our 3D model contains 8 horizons (Quaternary. Upper and The next step was the harmonization of stratigraphic Lower Pannonian, Sarmatian. Badenian, Neogene volcanites. data, e.g. the time-consuming process of correlation of Lower Miocene and Paleogene and the Pre-aienozoic basement) subdivided into 37 formations. The structural pattern of the area different formations. These formations describe some• was simplified after several consultations into a scheme of 7 times the same lithologic and temporal geological units of approximately SW-NE and 4 roughly NW-SE to W-E faults. a partner country with different synonyms, but more often The 3D model is also the first attempt to visualize the the different names can cover slightly different rock Neogene volcanic bodies buried below younger sediments, lithologies as well. The most problematic question was including hypothetical Gabcfkovo volcano. the harmonization of the Post-Oligocene formations of Keywords: Danube Basin, international cooperation, cross- the Paratethys. The most valuable sources for this task border geology, 3D geological model, structural model, buried were the Geological Map of Western Carpathians and volcanoes adjacent areas (Lexa et al. eds., 2000), the DANREG project maps and explanatory notes (Csaszar et al., 2000) 2.1. Introduction and the T-JAM project (Fodor et al., 2011). The complete harmonized stratigraphical chart is published in Maros et The aim of the TRANSENERGY project was to al. (2012). support the harmonized geothermal water and geothermal The 3D geological models for each one of the pilot energy utilization in the western part of the Pannonian areas were made separately: the Vienna Basin in Austria, Basin and its adjacent basins (e.g. Vienna Basin), which the Danube Basin in Slovakia, the Komarno-Sturovo and are situated in the transboundary zone of Austria, Lutzmannsburg-Zsira areas in Hungary and the Bad Hungary, Slovak Republic and Slovenia. The so called Radkersburg-Hodos area in Slovenia. supraregional model includes the entire project area of the NW Pannonian Basin and the adjacent areas, encom• The final products scales of the Supra regional and passes the main geothermal reservoirs and manages the Pilot areas models are the following: complete area in a uniform system approach. The supra- • Supra regional area 1:500 000, Surface geology regional model area was further divided into several sub- 1: 200 000 regions of enhanced hydrogeothermal utilization poten• • Pilot areas: tial, designated as pilot areas, usually forming geological o Danube Basin 1:200,000; or hydrogeological units which have been identified and o Vienna Basin 1:200,000; investigated in a more detailed way. In the Supra regional o Lutzmannsburg-Zsira 1:100,000; area five pilot areas were chosen, where local models had o Bad Radkersburg-Hodos 1:200,000; been developed. They focused on the local transboundary o Komarno-Sturovo 1:200,000. Slovak Geol. Mag., 14, 2 (2014), 17-35 18 nr ,^x m V -/Rachnltz- Koeaahlll. Styrian basin* Fig. 2.1 Localization of the supraregional (orange line) and the pilot areas: 1 - Vienna Basin; 2 - Danube Basin; 3 - Ko• marno-Sturovo area; 4 - Lutzmannsburg-Zsira area; 5 - Bad Radkersburg-Hodos area (modified after Maros et al., 2012) 2.2. Methodology 2.3), as well as other published works. In this phase we had consulted concepts as well as details with experts due The primary aim of the geological model of the to the optimization (simplification in fact) of the later Danube Basin pilot area was to create a 3D geological fault model and stratigraphy. framework accurate enough for hydraulic modelling, 3. Pre-modelling data processing: however we realized, that such a model itself would be • calculation of time-to-depth for the seismic valuable for further research. The model is based on profiles; seismic and borehole data, partially on other sources • redefinition of the borehole data according to the (published results, maps). The Danube Basin pilot area is unified stratigraphic legend; located in three countries (Slovakia, Hungary and • converting and entering the data into the 3D Austria) and was modelled in the frame of geological modelling software. horizon models of the TRANSENERGY territory (Maros et al., 2012). The pilot area covers 1,2340 km2, has a 4. Creation of the 3D model in main steps: slightly elongated shape with length ca. 140 km in SW- • creation of non-faulted horizons; NE and width ca. 110 km in NW-SE direction. • creation of the fault model; The steps of creating the model we can be summa• • combining non-faulted surfaces with fault model rized as follows: into a faulted 3D model; 1. Creation of the common framework for all parti• • input and refining lithological and stratigraphic cipants: since the TRANSENERGY Supra area covers content of 3D "space" between horizons (zones). parts of four states, the work on the model started with 5. Creation of outputs: visual (maps, sections) as well unifying the different local stratigraphic charts for all four as text outputs, presentations. states (Slovakia, Hungary, Austria and Slovenia). In this During the work we used common text and tabular phase we also needed to agree on horizons to be model• editing tools (MS Office, OpenOffice), vector and led, coordinate system and projection, scale of outputs, bitmap-based graphical software (Corel, Inkscape, GIMP), exchange formats to be used etc. Maplnfo and partly also ArcGIS for map and GIS based 2. Data compilation and processing: collecting the tasks. The 3D modelling itself was realized with software existing seismic and well data (Tab. 2.1, Figs. 2.2 and Petrel 2008. 2. Geological Model of the Danube Basin... I 19 Table 2.1 Overview of input data fingerlike protruding among the Male Karpaty, Povaisky Inovec and TribeC Mts. Number Deepest Medium Number Structural evolution of the basin comprises several or wells well [in] depth of of seismic wells [m] profiles temporal phases, depending closely on the evolution of the mountain chain. The major part of the basin started its Slovakia 146 3,303 1,139 19 evolution in the Badenian time. Structurally, this was an Hungary 189 4,517 1,084 63 episode of the finalizing phase of the pullapart type Austria 74 1,860 243 depocentres collapse, gradually changing into extensional grabens of the basin rifting. The extension started along NNESSW trending normal faults which could be rejuve 2.3. Overview of the geological history of the nated displacements along previously reverse faults in the Danube Basin basement and a very complex reversestrike slipnormal The Neogene Danube Basin is the largest subunit of fault deformation history has to be supposed along Raba the Western Carpathian basin system. In the Slovakian and Hurbanovo tectonic zones. The later (Sarmatian and territory it corresponds to the Danube Lowland and in the Pannonian) history is characterized like a backarc basin, area of Hungary it is called Little Hungarian Plain. If s with the depocentres functioning as extensional grabens western margin is bordered by the Eastern Alps with and halfgrabens. The wide rifting at the Sarmatian/Pan Leitha Mts., and northernmore by the Western Carpathian nonian boundary was followed by deep thermal postrift Male Karpaty Mts. In the North, the basin is laterally subsidence phase (Royden et al., 1983, Kovac, 2000). 640000 660000 I , I >270000 >2600O0 >25O0O0 >240000 N .230000 50 km ♦ Fig. 2.2 Localization of seismic profiles Slovak Geol. Mag.. 14. 2 (2014), 17-35 20 680000 1 wm- 5370000 A. a\ 5350000 BR*H!XLM 6340000 ■fiMKBOMSS 5310000 S310000 • • 6270000 • »• * • A---..-..,. -6260000 N I I 720000 740000 ♦ M 50 km Fig. 2.3 Localization of wells 2.4. Results and discussion local data, it is the most useful model with sufficient accuracy for our purposes which covers the whole area. 2.4.1. Stratigraphy Horizon: Pre-Cainozoic basement Because of the geological structure of the pilot area The PreCainozoic basement of the basin at the western the final model comprises zones (formations) in 8 hori and northern boundary is built up of several units of the zons which we defined as base surfaces at chosen strati Central Eastern Alps and Central Western Carpathians, graphic boundaries of the core column (e.g.