Dear Variscan researchers, dear friends of Bohemian Massif,
We are pleased to announce that the 5th Bohemian Massif Symposium will be held from June 7th – 10th 2023 at Smolenice Castle in the Slovakia near Bratislava (the Malé Karpaty Mts.).
This symposium follows the successful Variscan meetings organized by Austrian, Czech, and German friends of Bohemian Massif in the Šumava/Böhmerwald in 2014 and 2016, in Presseck in 2018, and in Freistadt in 2021.
The aim of the Symposium of the Bohemian Massif is to bring together geoscientists to discuss the latest data from the research of classical Variscan terrains such as the Bohemian Massif and data from adjacent areas in order to obtain new ideas for possible future correlation research.
The meeting is without a registration fee, the participants will pay only for their accommodation and meals on-site. We look forward to meet you at Smolenice Castle – a Congress Centre for the Slovak Academy of Sciences.
Program:
(download in PDF)
- June 7th arrival in the afternoon, introductory lectures in the late afternoon
- June 8th talks and posters
- June 9th excursion to the Variscan core of the Malé Karpaty Mts. The excursion will be organized by bus/buses and various topics such as magmatic, metamorphic, and tectonic lithologies will be discussed. Various Variscan rocks in the Malé Karpaty Mts. will be shown during the field trip – granites including diorite body, calc-silicate contact rocks, metasedimentary Paleozoic rocks but also product of large post-Variscan Permian mafic magmatism.
- June 10th half-day excursion will be organized individually by cars in the Tribeč Mts. for the presentation of an Alpine granite duplex by two Variscan magmatic blocks. The trip will terminate around 2 PM in order to return home that evening/night.
5th Bohemian Massif Symposium
Smolenice Castle, Slovakia
June 7th – 10th 2023
Contact:
RNDr. Igor Broska, DrCs.
Earth Science Institute
Slovak Academy of Sciences
Bratislava, Slovakia
Organizers:
Igor Broska
Milan Kohút
Silvia Antolíková
Tomáš Sobocký
Ľubica Puškelová
Book of abstracts (pdf, 2.4 MB)
Report on the 5th Bohemian Massif Symposium
The 5th Bohemian Massif Symposium was held from June 7th – 10th 2023 at the Congress Centre of the Slovak Academy of Sciences in the Smolenice castle located near Bratislava in the mountain range of Malé Karpaty. This symposium followed the successful Variscan meetings organized by Austrian, Czech, and German geologists – friends of Bohemian Massif:
2014 (Böhmerwald / Šumava – meeting organised by Friedrich Finger), 2016 (Annín – by Kryštof Verner), 2018 (Presseck – by Gernold Zulauf), 2021 (Freistadt – by Friedrich Finger).
In general, the aim of the 5th Bohemian Massif Symposium was to bring together geoscientists working in the Bohemian Massif to discuss their latest data and compare them with similar achievements from other European Variscan terrains. Due to researchers, studying crystalline basement within the Variscan fragments in the Alpine belt namely in the Eastern Alps and Western Carpathians, having problem with alteration of Variscan segments by Alpine overprint – the Bohemian Massif (BM) meeting became good open Central European platform for understanding of the Variscan evolution and basis for correlation research of Variscan fragments within the Central European Alpine edifice. Exchange of the experience on the BM geodynamics can be used for their correlation with the adjacent Variscan areas in the time of piling of new isotopic and bulk rock data.
All lectures presented at the 5th Bohemian Massif Symposium opened friendly but extensive discussion and some of them pointed to their potential for future correlation investigation. The prepared abstract proceeding is available on the website of the conference and can be a good motivation for the problematic Variscan research.
The excursion part of the 5th Bohemian Massif Symposium was aimed to show principles of the structure of the Variscan segments in the Western Carpathians. On the first day, the participants were introduced to the Bratislava Variscan granitic Massif with S-type affinity, which recent age determination shows an age of 359 Ma including several large diorite bodies in origin of the same age. The Bratislava pegmatite field is formed by pegmatites belonging to the LCT family with common beryl, Nb-Ta oxides or columbite and tantalite. The Bratislava granitic Massif also contains frequent low-grade metapelitic and metapsammitic xenoliths, which exhibit typical periplutonic contact metamorphic paragenesis – sillimanite zone on the granite contact, and more distant staurolite-garnet and biotite zones. The metamorphic granite zones point to granite emplacement in the depth of more than 15 km or at 3.5 kbars pressure conditions.
During the excursion, the participants were introduced to the Malá Baňa amphibolitic body, which forms a large roof pendant intruded by the BGM granodiorite and preserving an original metamorphic foliation. Excursion route led to the Modra granitic Massif, which recently showed the age of 353 Ma. The Modra biotite granodiorite is interesting by preservation of the abundant inherited zircons from Cadomian basement. The presence of the flecked hornfels with andalusite and cordierite indicates the intrusion of the Modra granodiorite into the upper crust at a pressure of ca. 1.5 kbars. Roof rocks – Dubová formation was shown in a recumbent fold in the Hrubá dolina Valley. The calk–silicate hornfels of Dubová formation were formed on the contact with the Modra I-(S) type granodiorite. The metamorphosed Devonian limestone and shales in outcrop was shown in abandoned large quarry.
The second day of excursion was focused on the presentation of the Variscan granites with signatures of Alpine overprint. The Krnča locality near Topoľčany became a place where the stacking of the Variscan altered granite over the unaltered Tatric Unit, represented by unmetamorphosed S-type granites, can be well documented. The stacking of metamorphosed and hydrothermally altered granites included also the Lower Triassic quartzite, the Lužná Fm. The last locality was a Nitra-Zobor abandoned quarry with I-type affinity tonalite/granodiorite.
The general slab breakoff model for the origin of the Variscan Western Carpathian granitic rocks was presented at the end of meeting, along with some remarks to geodynamic setting during the Devonian evolution.
The next meeting is planned again in the Bohemian Massif 2025, and we believe that some correlation papers initiated during the Smolenice symposium oriented mainly to comparison of the Variscan granite evolutions will became an important part for future discussion on Variscan tectonic setting, and also some ideas towards the configuration of continental fragments during the Variscan orogeny.
Igor Broska and Milan Kohút
Bratislava, June 12th 2023
