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 Bükk 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 Bükk 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.

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 Gyõrszemere-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 formations were encountered, from base upward: Arács Marl Fm. (3,249.5–3,030 m), silty marl with ooids, bivalves, gastropods and ostracode shells. Occasionally layers of angular quartz grains in large quantities appear. Postcladella kahlori and Spirobis phlyctaena indicates Induan (Early Triassic) age. Köveskál Dolomite Fm. (3,030–2,790 m), rich in ooids and also containing anhydrite. The Glomospira and Glomospirella dominance indicates an age interval between Olenekian and earliest Anisian age. Fault breccia (2,790–2,690 m) separating the Köveskál and overlying dolomites. Upper dolomite (2,690–2,200 m): homogeneous, saccharoidal, and totally recrystallized. The age is unknown. The low TOC values of the supposed source rock interval (marl between 3,249.5 and 3,030 m) indicate poor hydrocarbon potential

A triász zátonyok fejlődése a Tethys északi peremén = Evolution of the Triassic Reefs on the Northern Part of the Tethys

Elkészítettük az Aggteleki platform 10 000-es térképét. Két zátonyt különítettünk el. Leírtuk faunájukat és flórájukat, összesen 98 fajt. Egy új fajt (Aggtecella hungarica) és egy új ásványt (nonstrandit) írtunk le. Rekonstruáltuk a platform fejlődését az anisusi-ladin-ban. Egész pontosan meghatároztuk a zátony kialakulás korát: Trinodosus subzona. Az első zátony a Trinososus subzóna kezdetétől a Curionii subzónáig létezett, majd a zátony ÉK-re progradált. Bebizonyítottuk, hogy a Neotethys riftesedése és az Aggteleki zátony kialakulása között ok-okozati összefüggés van. Kimutattuk, hogy minden neptúni telér három időszakban keletkezett: Binodosus-, Trinodosus-, Avisianum subzone. | We finished the 1:10 000 map about the Aggtelek platform. We distinguished two reefs, described their fauna and flora, all together 98 species. We described a new species (Aggtecella hungarica) and a new mineral (nonstrandit). We reconstructed the evolution of the platform during the Anisian-Ladinian. We determined the exact age of the reef forming: Trinodosus subzone. The first reef existed from the beginning of the Trinososus subzone until the Curionii subzone, than the reef prograded to the NE. We proved, that there is a causal relation between the rifting of the Neotethys and the forming of the Aggtelek reef. We justified, that every neptunian dykes originated during three interval: Binodosus-, Trinodosus-, Avisianum subzone

CT Based Analysis Of Pore Network Of Reservoir Rocks

High-resolution X-ray Computed Tomography (CT) is a novel technique suited to a wide range of geological investigations. It is a quick and non-destructive method to produce images that correspond closely to serial sections through an object. Sequential contiguous images are compiled to create three-dimensional representations that can be manipulated digitally to perform efficiently a large array of measurements and visualizations. In this study we combined conventional core analysis technique with micro-scale Computed Tomography imaging technique to extract pore network properties of carbonate rocks. In order to detect pore properties from the CT images different filtering algorithms and various segmentation techniques were applied to obtain robust data, which were compared with those of mercury injection texts carried out in the laboratory on the same samples. The methodology is applied to a set of real porous media and the resulting pore network statistics showed great variability compared to lab results due to limitations in voxel resolution. Despite this, useful information about the pore constituents could be extracted

Stratigraphy, facies and geodynamic settings of Jurassic formations in the Bükk Mountains, North Hungary: its relations with the other areas of the Neotethyan realm.

Jurassic mélange complexes related to the subduction of the Neotethys Ocean occur in the Bükk Mountains, North Hungary. This paper characterizes the sedimentary sequence of basin and slope facies that occur in the southwestern part of the Bükk Mountains, placing special emphasis on the redeposited sedimentary rocks (olistostromes, olistoliths: Mónosbél Group) in order to obtain information on the provenance of the clasts, and the mode and time of their redeposition. The series of formations studied shows a general coarsening-upwards trend. Based on radiolarians and foraminifera, the Mónosbél Group formed in Early to Late Bathonian time. The lower part of the complex is typified by a predominance of pelagic carbonates, shale and radiolarite with andesitic volcaniclastic intercalations. The higher part of the succession is characterized by polymictic olistostromes. Large olistoliths that are predominantly blocks of Bathonian shallow marine limestone (Bükkzsérc Limestone) appear in the upper part of the sequence. Based on the biostratigraphic and sedimentological data, results of analyses of the redeposited clasts and taking into consideration the concepts of the development of the western Neotethys domain, the evolutionary stages of the sedimentary basins were defined. The onset of the compressional stage led to initiation of nappe stacking that led to the formation of polymict olistostromes and then to the redeposition of large blocks derived from out-of-sequence nappes of the former platform foreland

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.