The South Alpine-Dinaridic realm was affected by igneous activity in the Middle Triassic; the marine carbonate platforms and the adjacent basins contain highly variable intrusive-volcanic assemblages. We studied the petrography and determined the zircon U-Pb ages of the Triassic volcanic products in the Transdanubian Range. The geochemical features and thus the geodynamic context of the magmatism are badly known, as the rocks experienced variable chemical alteration. The exact duration of the igneous activity is also poorly constrained, as the geochronological data of the former studies were obtained mostly by the weathering-sensitive K-Ar and Rb-Sr methods and thus some data even being younger than the age of the stratigraphic cover. The presence of andesite dikes and of pebbles and cobbles (< 20 cm) of basalt, andesite, rhyolite and of rhyolitic tuff in the Triassic carbonate platform deposits indicates that within the Transdanubian Range formed a volcanic complex in Triassic. The major mineralogical and geochemical features of the Transdanubian igneous suite are similar to the Triassic formations in the Southern Alps. However, dissimilar zircon composition excludes the immediate relationship of the zircon-bearing silicic formations in the two tectonic units. New U-Pb ages show that the beginning of the volcanic activity is probably coeval with the eruption of the widespread "pietra verde" trachytic tuffs in the Upper Anisian-Ladinian successions, but the majority of the ages are younger than those ash layers. The new age constraints give a benchmark for the termination of the volcanic activity in Carnian time in the Transdanubian Range.

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In sedimentary rocks, Fe-Al phosphate minerals occur in different rocks and depositional environments. Herein, we present microcrystals of wavellite, crandallite, and cacoxenite from pedogenic goethite pisoliths and nodules. Pisoliths and nodules are generally dominated by Fe oxides and oxihydroxides. Frequently, pisoliths and nodules demonstrate high phosphatization and a substantial contribution of allogenic detritus. The aim of our study is to present these remarkable crystals found in goethites. We describe the geochemistry and mineralogy of the pisoliths and try to interpret the possible paragenesis of the minerals. Loose ferruginous pisoliths and nodules are separated from the red paleosol and analyzed using field emission scanning electron microscope (FE-SEM) coupled with the energy dispersive X-ray detector (EDS), X-ray fluorescence spectroscopy (XRF), and X-ray powder diffraction (XRD) methods. The studied paleosols are weathered in a subtropical climate and the newly formed precipitation products, such as crandallite, wavellite, cacoxenite, and goethite, accumulate during the weathering of apatite.

A Middle and Late Triassic (Ladinian -Lower Carnian) volcanogenic clastic succession can be found in the Eastern Bakony, in the Transdanubian Range of Hungary. The aim of this study is to present and evaluate the petrographic characteristics of the rocks of this succession and compare them to some coeval volcanic formations of the Transdanubian and Southern Alps. The rocks can be investigated in the surface outcrops of the Hideg Valley of Inota as well as in the boreholes of Bakonykúti Bút-2 and Várpalota Vpt-3. The volcanogenic succession can be subdivided into two main parts with reference to the the boreholes. Its lower, fine-grained part contains predominantly volcanic rocks, numerous carbonized plant remnants, and a few crinoidea fragments. Its upper, coarse-grained part contains a lot of volcanic and limestone pebbles and Daonella fragments. The following rock types have been identified by macroscopic, polarization and electron microscopic investigations: a large amount of intermediate volcanic rocks (andesite), mafic volcanic rocks (scoria basalt, basalt and microdolerite), a smaller amount of silicic volcanic rocks (rhyolite / rhyolite tuff, aplite), and some related crystal fragments.The source area probably consisted of some kind of Middle and Late Triassic volcanic rocks (mafic-intermediate lava rocks and depositions from a phreatomagmatic explosion); today, the related representatives of the latter are located in the Transdanubian Range (the closest location is the area of Balatonfő) and in the Southern Alps (especially the Dolomites). At this time the Southern Alps were located close to the area of the Transdanubian Range Unit and the volcanic event was the most intensive and extensive to occur there. The upper part of the volcanogenic conglomerate/pebbly sandstone was formed in a similar way to the Wengen and Marmolada Formation in the Southern Alps. The volcanic material originated from nearby terrestric sources and these consist of mostly intermediate and mafic rocks. It was transported under sea by mass movements and was deposited in the surrounding basin of platforms. The formation of the lower part of the succession was different from the above. The first step was a phreatomagmatic explosion which resulted in a mafic-intermediate deposit in a shallow marine / terrestrial environment. Immediately after this event the volcanic material was re-deposited in a basin by mass movements.Keywords: Eastern Bakony, volcanogenic sandstone, petrography, ladin volcanism, Southern Alps, palaeogeography Összefoglalás A Tethys közép-európai triász időszaki fejlődéstörténetének nyomozása az egymástól távolabbi területeken található nem vulkanogén üledékes kőzetek összehasonlító vizsgálatával régóta eredményesen zajlik. A térben és időben is sokkal változatosabb kifejlődésű vulkanogén képződmények ezirányú vizsgálatában rejlő lehetőségek még messze nincsenek kihasználva. Ennek leginkább az lehet az oka, hogy ezeknek a hazai kőzeteknek a részletes kőzettani leírása még nem történt meg. Ladin vulkanogén tö...