The conference venue is located just at the boundary of the basement/cover nappe stack of the Austroalpine Central Western Carpathians (CWC, Malá Fatra Mts) and the Pieniny Klippen Belt (PKB) – the most peculiar Carpathian structural zone famous by its spectacular rugged topography and intricate internal structure. It is planned that the field trips will concern both of these principal Carpathian structural zones.
22 September 2021 (Wednesday) 08:30 – 17:00
Cretaceous nappe structure and Variscan basement granitoids of the Malá Fatra Mts
Guided by: Dušan Plašienka & Igor Broska
The excursion will be devoted to the Cretaceous nappe structure of the CWC Malá Fatra Mts. Two routes or sites will be visited:
(1) The Rozsutec round-tour, during which we could observe the cover nappe structure of the CWC – Cretaceous marly limestones and synorogenic flysch deposits (Fatric Krížna Nappe) overridden by the Triassic carbonates of the Hronic Choč Nappe, as well as the important backthrust structure of the Medzirozsutce reverse fault. This trip cannot be performed in full, however, due to the seasonal closure of the touristic paths around the summit of Mount Veľký Rozsutec.
The trip will take about 4–5 hours of relatively easy walking (around 8 km), but the last part (steep downslope) might be problematic in wet conditions. Therefore, please be sure that you wear firm mountain boots and do not forget to take the rain protection equipment.
(2) In the afternoon, we shall visit by bus one locality in the pre-Alpine crystalline basement of the Tatric Superunit – Variscan granitoids exposed in the Kraľovany-Bystrička quarry in the Orava River Valley. The quarry exposes equigranular granodiorite/tonalite rocks with abundant aplites and xenoliths which indicate their position in apical parts of the Kriváň granitic massif. The granitoids are pervasively altered by post-magmatic fluids and penetrated by Alpine quartz-carbonate veins with the galena and sphalerite mineralization.
In a way back, and if we are not too late, a short stop in the Zázrivka River Valley (Biela crossing) will demonstrate the mesoscale, south-vergent asymmetric fold developed in the Lower Cretaceous limestones (Mráznica Fm.) of the Fatric Krížna Nappe that is related to post-Paleogene backthrusting.
25 September 2021 (Saturday) 08:30 – 17:00
Composition and structure of the Pieniny Klippen Belt in the Terchová–Zázrivá area
Guided by: Dušan Plašienka, Ján Soták, Roman Aubrecht & Przemysław Gedl
During this excursion, some structural features and sedimentary-stratigraphic data of the PKB rock complexes will be presented along two sections.
(1) The morning section will concern a steeply north-dipping imbricates of several PKB units on southern slopes of Pupov Hill (Rovná hora Pass). There are outcrops in the Upper Cretaceous variegated marlstones of probably the Subpieniny (Czorsztyn) Unit, strongly sheared Lower Cretaceous limestones with scaly fabrics (Pieniny Unit?), a tightly imbricated zone containing also formations belonging possibly to the Šariš (Grajcarek) Unit, and the Upper Cretaceous calcareous flysch of the Pupov Formation.
(2) In the afternoon, we will observe a number of phenomena along the bedrock exposures of the Zázrivka stream in Zázrivá village. However, accessibility of some exposures might be limited if the water level is high. The section starts with the Upper Eocene turbiditic sequence of the Central Carpathian Paleogene Basin with spectacular south-vergent fold-thrust structures. After an unexposed contact with the PKB, an imbricated zone analogous to the Rovná hora section, of possibly all three Oravic units (Subpieniny, Pieniny a Šariš) is cropping out in occasional exposures. North of the Zázrivá village centre, biostratigraphic data from outcrops in the Pupov Formation indicate its Campanian–Maastrichtian to Early Paleocene age, some of them exhibiting also the fold structures. The northern imbricated zone begins with a narrow “mélange” zone, which follows a transversal dextral strike-slip zone within the PKB, and contains tiny slices of several mutually unrelated rock formations. Continuation of the section in the Končitá Valley exposes outcrops of Jurassic and Cretaceous formations that are tentatively assigned to the PKB Šariš Unit.