FACIES ASSOCIATIONS AND MICROFOSSILS FROM THE MIDDLE-UPPER TRIASSIC LIMESTONES OF THE TRANSILVANIAN NAPPES (PERȘANI MOUNTAINS, EASTERN CARPATHIANS, ROMANIA)

Triassic limestones that belong to the Transilvanian Nappe system, form extensive outcrops in the central part of the Persani Mountains, near Racos locality, on the southern and northern sides of the Olt Gorges. Triassic carbonate olistoliths were sampled in four distinct locations belonging to the Transilvanian Nappe: the Old Racos Quarry, Olt Gorges, Tipia Racosului Hill and Tipia Ormenisului Hill. The identified facies types include brecciated limestones with encrusting organisms and cyanobacteria, packstone-grainstone with sponges and encrusting organisms, boundstone with grainstone internal sediment, peloidal wackestone-packstone, peloidal packstone-grainstone, intraclastic grainstone-rudstone. Such microfacies characterize reefal bioconstructions or fore-reef domains located in the vicinity of shelf crest areas. They share common features with similar Wetterstein facies carbonates from Italy, Austria or Hungary. The micropaleontological assemblage indicates the Anisian-Ladinian to Carnian ages for the studied limestones, the present study bringing new data concerning the age of these carbonates. In addition, the presence of some foraminifera and dasycladalean algae are mentioned for the first time in this area.

Sectioning of radiolarians under continuous observation

A new method to study the internal structure of fossil radiolarians in presented. The core of the method is (1) freezing the radiolarian in a drop of water using a Peltier module and (2) slicing the radiolarian with a specially equipped electric tooth-brush under an optical microscope. With this method the internal structure of diagenetically altered radiolarians can be studied even if internal sediment cannot be removed. <br><br> Eine neue Methode zur Analyse der Internstrukturen von Radiolarien wird vorgestellt. Die Methode beinhaltet (1) Einfrieren einzelner Radiolarien in einem Wassertropfen mit Hilfe eine Peltier-Elements und (2) Schleifen der Radiolarien mit Hilfe eine modifizierten elektrischen Zahnbürste unter einem Binokular. Mit dieser Methode ist es möglich Internstrukturen von Radiolarien zu untersuchen, selbst wenn diese diagenetisch verändert sind oder fest verbackenes Internsediment aufweisen. <br><br> doi:<a href="http://dx.doi.org/10.1002/mmng.20020050104" target="_blank">10.1002/mmng.20020050104</a>