Szakáll Sándor - Jánosi Melinda: Minerals of Hungary (Topographia Mineralogica Hungariae 4. Miskolc, 1996)

PLAINS AND HILLY COUNTRYSIDE Although these regions - so characteristic of most of our country - are not particularly well endowed with minerals, microscopic crystals can be found almost everywhere. As there are fewer quarries in this region than in mountainous areas, one has to look very carefully in ditches, canal beds, wells, etc., in order to find minerals. Only here and there do patches or hillocks of Miocene magmatic rocks interrupt the monotony of geologically vast expanses of Quaternary or Recent sedimentary rocks (as on the Bereg flatland). In cavities in these rhyolites or andésites, tridymite, quartz, magnetite, hornblende (rarely epidote, roedderite) may appear, as we have already gathered from previous descriptions of the occurrence of these rocktypes in the mountains (Fig. 81). In argillaceous rocks, quarried for brick-making, pyrite, marcasite and gypsum are quite common. Bog iron ores consisting mainly of goethite, may be covered by a powdery layer of blue vivianite, or small crystals of the latter may occasionally appear in cavities (Great Flungarian Plain, Southwest Transdanubia). Carbonate concretions of calcite may occur in loess and clays. Stream deposits, sandbanks, and barriers are all important localities for minerals carried and deposited by a river from its catchment area. Thus, Danube sands may contain minerals from the mountains of Hungary, from the mountains of Slovakia, or even from Alpine rocks. Alpine gold has been panned for centuries from placers at Ásványráró and Acs. Sands from the Tisza, Maros, and Dráva rivers, or even of Lake Balaton are equally interesting. These banks or barriers contain a veritable collection of tiny minerals, derived from igneous, sedimentary or metamorphic rocks, which are entirely dependent on the geological structure of their catchment area. White and greyish white surface efflorescences appearing on Alkali flats (Great Hungarian Plain: Hortobágy, Kiskunság, Nagykunság, and Little Hungarian Plain) are mainly sulfate minerals (gyp-