Felicitász Velledits

THE OLDEST TRIASSIC PLATFORM MARGIN REEF FROM THE ALPINE - CARPATHIAN REGION (AGGTELEK, NE HUNGARY): PLATFORM EVOLUTION, REEFAL BIOTA AND BIOSTRATIGRAPHIC FRAMEWORK

The 1:10,000 scale mapping of the southern part of the Aggtelek Plateau (Western Carpathians, Silica Nappe, NE Hungary) and the study of five sections revealed two Middle Triassic reef bodies. In the late Pelsonian the uniform Steinalm Platform was drowned and dissected due to the Reifling Event. A connection with the open sea was established, indicated by the appearance of gladigondolellid conodonts from the early Illyrian. Basins and highs were formed. In the NW part of the studied area lower - middle? Illyrian basinal carbonates were followed by a platform margin reef (early?-middle Illyrian; reef stage 1) developed on a morphological high. This is the oldest known Triassic platform margin reef within the Alpine-Carpathian region. The reef association is dominated by sphinctozoans and microproblematics. The fossils are characteristic of the Wetterstein-type reef communities. Differently from this in the SE part of the studied region a basin existed from the late Pelsonian until the early Ladinian. During the late Illyrian- early Ladinian, the reef prograded to the SE, and reef stage 2 was established. Meanwhile, on the NW part of the platform a lagoon was formed behind the reef. Based on our palaeontological study the stratigraphic range of Colospongia catenulata, Follicatena cautica, Solenolmia manon manon, Vesicocaulis oenipontanus must be extended down to the middle Illyrian. Synsedimentary tectonics were detected in the 1. Binodosus Subzone, 2. Trinodosus Zone - the most part of the Reitzi Zone, 3. Avisianum Subzone.

The Büdöskút Olistolith, an exotic limestone block from the Bükk mountains (NE-Hungary)

SummaryThe present paper presents results of stratigraphical, sedimentological and micropalaeontological investigations of an olistolith from the Büdöskút area in the Bükk Mts (NW Hungary). The olistolith consists of Norian sub- and peritidal platform carbonates (Büdöskút lime-stone). During early diagenesis dissolution cavities originated which where filled by ostracodal mudstones. Other cavities first were wallpapered by evinospongial crusts and later filled either by ostracodal mudstones or by brick-red haematitic material (weathered bauxite). The evinospongial crusts show stromatolite-like structures and their forming therefore is supposed to be organically (microbially) induced.During the Early up to the Late Jurassic the host rock was dissected by neptunian dykes. The internal sediments faunal content reveals that the dykes formed during the (?) Hettangian/Sinemurian and the Toarcian— Oxfordian age.A comparison of the Büdöskút limestone neptunian dyke internal sediments with the Bükk parautochthonous and the Szarvasko-Mónosbél nappe complex sedimentary columns shows no similarities. Therefore the Büdöskút olistolith is interpreted as an exotic body within the Bükk Mts.

AXOPORA AGGTELEKENSIS SCHOLZ, 1972, ORIGINALLY DESCRIBED AS HYDROZOA, IS ATTRIBUTED TO THE NEW GENUS ANISOPHYTES (CYANOPHYTA?)

Examination of the calcareous microfossil from the Anisian reef limestones of the Aggtelek Mountains, northern Hungary, described as Axopora aggtelekensis by Scholz, supports the cyanobacterian nature of this organism. It is not a Hydrozoa as originally thought by Scholz. For this microfossils, occuring in Triassic shallow water carbonates the new genus Anisophytes is proposed. The differences between Anisophytes , as gregarious microfossil composed of tubes, and other similar looking organisms, like Tubiphytes , Aeolisaccus kotori Radoicic, Koivaella Tchuvashov or Proaulopora Vologdin is discussed. Anisophytes is attributed tentatively to Cyanophyceans.

Re-evaluation of the Triassic sequence in the subsurface of the Little Plain Basin Hungary: A case study from the Győrszemere-2 well

The Little Plain Basin is one of the largest units in the Pannonian Basin System. Its continuation in Slovakia is called the Danube Basin. The Little Plain Basin is one of the most underexplored areas in Hungary. Based on archival geologic and geophysical data the lithostratigraphic composition of the area is controversial. The significance of the area is increased by the known Neogene and the supposed basement (Paleozoic and Mesozoic) hydrocarbon systems in Hungary and in Slovakia. The purpose of this study is to identify the exact age, facies, geologic formations and possible source rocks of the Triassic section penetrated by the Gyorszemere-2 well in the Little Plain Basin. Based on new facies and paleontological results it can be stated that two Triassic sequences are identified in the well, separated by fault breccia. A carbonate sequence was deposited between the Induan and Early Anisian and above that a homogeneous recrystallized dolomite appears, the age of which is unknown. The following formatio...

ANISIAN TERRESTRIAL SEDIMENTS IN THE BÜKK MOUNTAINS (NE HUNGARY) AND THEIR ROLE IN THE TRIASSIC RIFTING OF THEVARDAR-MELIATA BRANCH OF THE NEO-TETHYS OCEAN

In recent years detailed sedimentological and biostratigraphical investigations have revealed Anisian terrestrial sediments in three sections of the Bukk Mountains. In the northern part of the mountains fluviatile sediments were recognised while in the southern part lake deposits were observed. Based on the stratigraphical position and microfacies analyses of the resedimented grains, two terrestrial events can be reconstructed. The age of the younger is late Pelsonian-early Illyrian?. This can be correlated with the Richthofen Conglomerate in the Dolomites. The age of the older terrestrial event could not be established exactly but it must have happened either in the Pelsonian or in the Aegean-Bithynian; consequently it may correlate either with the Voltago or with the Piz de Peres Conglomerate in the Dolomites. The terrestrial sediments in the Bukk Mountains are parts of a volcano-sedimentary succession, which is characteristic of the updoming part of a rifting area. Terrestrial sediments in the southern part of the mountains represent the deepest part of the half-grabens, which originated during the course of the rifting. The present paper gives an overview of the Anisian-Lower Ladinian terrestrial sediments in the Southern Alps-Dinarides and considers their formation during the Triassic rifting of the Vardar-Meliata branch of the Neo-Tethys.