Szekessy Vilmos (szerk.): A Magyar Természettudományi Múzeum évkönyve 41. (Budapest 1948)
Szurovy, G.: Geological structure of the Southern part of the Great Hungarian Plain
//// into the inner part of the Plain with a SE — NW striking trend. Great elevations of the basement rock may also be noticed in the really big basin, which have an exclusively SW — NE trend. The flanks of these elevations are mostly not very steep. The sediments of the Upper Tertiary have been deposited on the basement rock in unconformity. The wells encountered (except thick sand and clay deposits of the Pleistocene, Levantiian and Pannonian) only Miocene and Trias deposits, which due to their composition must be looked upon as a talus. The solid Trias-rocks were only found on the NW slope of the sunken mountain chain which is the continuation of the Transylvanian intermediate chain of mountains descending into the Plain with a SE trend. The crystalline basement rock is only covered by thick Miocene or perhaps also Paleogene deposits in the Kiskunság and Bácska. (Fig. 29). The underground elevations are connected with the orogenic folding periods and were already completed before the deposit of the Tertiary sediments. Therefore, the upper sediments were not involved in any folding. For this reason we may not count with fold structures as regards these younger sediments in the Plain. Only in the southern Bácska, the Save folds may have influenced the younger sediments, but so far this is not supported by any proof. On the other hand, it may be assumed that smaller parts of the basement rocks were blocks formely parted by smaller faults. There is reason to believe that the sinking of the underground is not even quite finished, and it is possible that the above mentioned blocks did not. and do not participate in the sinking movement to the same extent. For this reason we may count on fault structures. On the basis of the extensive gas deposits and more than good oil traces encountered, the presence of commercially productive hydrocarbon deposits is proved. Due to the few weis drilled, it is yet imposible exactly to determine the oil belts in the above mentioned faulty structures. Their extension and the commercial possibilities can not be determined yet either. Although these gases belong to the group of „wet" gases owing to their richess of heavy hydrocarbons, which are always connected with oil deposits, their high content of carbon dioxide is remarkable. The clarification of the origin of this carbon dioxide has to be left to later tests.
