Compared to coeval successions from the Carpathians, the continuous Jurassic-Cretaceous (J/K) pelagic limestone succession of the Brodno section offers the best possibility to document the J/K passage in a wide area. This section comprises a complete calpionellid, and nannofossil stratigraphic record, that supports the older paleomagnetic data. Moreover, the sequence stratigraphy and stable isotope (δ 18 O, δ 13 C) data gave important results, too, enabling comparison with known key sections from the Mediterranean Tethys area.Key words: J/K boundary, Western Carpathians, regional stratotype, stable isotopes, biostratigraphy, microfossils, pelagic carbonates. Geological context of the Brodno section: an overviewThe Brodno section is situated in an abandoned quarry on the eastern side of the narrow straits of the Kysuca River Valley north of the town of Žilina (known as the "Kysuca Gate", Fig. 1). It yields a record of hemipelagic marine sedimentation in a marginal zone (the Pieniny Klippen Belt) of the Outer Western Carpathians. The lithology, fossil record (including ammonites and aptychi) and stratigraphy were studied by Andrusov (1938Andrusov ( , 1950Andrusov ( , 1959, Scheibner (1961, 1962, 1967), Borza (1969, Scheibnerová (1969), andSamuel et al. (1988). A more detailed description of the Upper Jurassic and Lower Cretaceous litho-and biostratigraphy was provided by Michalík et al. (1990), Vašíček et al. (1992). Houša et al. (1996) introduced the magnetostratigraphy of the Jurassic/Cretaceous (J/K) boundary beds correlated with the microbiostratigraphic data.This paper discusses the results of an integrated biostratigraphic study using three microplankton groups (calpionellids, calcareous dinoflagellates and nannofossils), as well as stable isotope data (δ 18 O, δ 13 C) in the Brodno section, which is proposed here as the candidate for a West Carpathian regional J/K boundary stratotype. The distribution of the stratigraphically important planktonic organisms revealed several coeval calpionellid and nannofossil bioevents recorded in the pelagic carbonate sequence of the Jurassic/Cretaceous boundary age. The stable isotope data underline environmental changes during the interval studied.According to the International Commission on Jurassic Stratigraphy, it is necessary to search for complete sections, which can provide continuous records of both sedimentation and biotic events across stage boundaries. Although the Brodno section lacks ammonite record, it is presented here as a potential candidate considering its continuously well exposed and biostratigraphically properly documented succession, at least for the West Carpathian region. Material and methodsThe Jurassic/Cretaceous boundary succession was studied using an integrated sequence-, bio-and isotope stratigraphy approach from the detailed rock section sampled. A quantitative microfacies analysis was carried in thin sections for the sequence stratigraphic pattern of these pelagic limestones (see Reháková 2000a; Michalík 2007). The calpionellids an...

Magneto-and isotope stratigraphic studies in the Vysoká Nappe (Hlboča section, Fatric Unit, Malé Karpaty Mts, Slovakia) were performed. A generally decreasing δ 13 C isotope curve is interpreted as a primary trend from the Late Oxfordian (3.3 ‰ V-PDB) to the Late Tithonian (1.8-1.4 ‰ V-PDB). Data from the Tithonian part of the Tegernsee Formation probably reflect "local" basin processes connected with the breccia formation in the latest Tithonian/earliest Berriasian and/or with possible diagenetic overprint. The C-isotope record of the Berriasian Padlá Voda Formation is more homogeneous (1.4-1.8 ‰ V-PDB) and assumed to be primary. Magnetostratigraphic investigations were focused on the Jurassic/Cretaceous (J/K) boundary strata. Upper Tithonian nodular limestones of the Tegernsee Formation differ substantially from Lower Berriasian calpionellid limestones of the Padlá Voda Formation in rock magnetic properties. Hematite is present in the Tegernsee Formation, while magnetite is the only magnetic mineral of the Padlá Voda Formation. Additionally, the latter formation contains superparamagnetic magnetite, which significantly influences its magnetic susceptibility. Correlation of normal and reversed magnetic intervals with the Late Tithonian global polarity time scale was supported by microfossil stratigraphy. M21n to M20n magnetozones were distinguished, including the short reversed Kysuca (M20n1r) Subzone within M20n. Interpretation of Lower Berriasian magnetostratigraphy was more complex due to presence of breccia horizons and a stratigraphic gap at the J/K boundary in the lower part of the Padlá Voda Formation embracing M19r and most of M19n magnetozones. This formation was also partially affected by remagnetization. Detailed correlation between the isotope-and magnetic stratigraphy of the Tithonian-Berriasian interval between Hlboča and Brodno sections is also complex due to J/K stratigraphical gap within the Hlboča section. The primary B component accounts for counter-clockwise rotation of the Vysoká Unit with a magnitude of ca. 50°. Since the paleodeclination of Paleogene and Karpatian-Eggenburgian rocks in the area is similar, the rotation must have taken place after Early Miocene. The paleoinclinations of several Upper Tithonian-Berriasian sections of the Central Western Carpathians and western part of the Pieniny Klippen Belt are consistent and indicate paleolatitude of 27-30°N.

No abstract

The Tomanová For ma tion, of Rhaetian age, over ly ing the Norian Carpathian Keuper in the Tatra Mts. is built of cy clic parasequences of mudstones and sand stones. Quartz (15 to 70 wt.%), kaolinite (13 to 46 wt.%) and 2:1 Al dioctahedral phyllosilicates (dioct 2:1: mus co vite, illite, illite/smectite: 5 to 39 wt.%) rep re sent the ma jor min eral phase. The kaolinite/dioct 2:1 ra tio de creases up wards in the sec tion (from 4.3 to 0.5) and sig nals vari abil ity in weath er ing/ero sion in ten sity and changing wa ter sa lin ity. Ma jor and trace el e ments (LILE, HSFS, REE) in di cate a uni form source -fel sic rocks lo cated prob a bly in the Vindelician High lands. The sed i men ta tion rate (83 mm/ky) was con trolled by cli mate. Al ter na tion of dry and hu mid pe riods is refered by sed i men tary tex tures and by ma tu rity of quartz (ae olian vs. flu vial grains), and or ganic mat ter con tent and com po si tion (C org and d 13 C org ). Authigenic sid er ite or bethierine doc u ments wet and re duced con di tions in the up per part of the Tomanová For ma tion. The sedimention rate of the ma rine Dudzinec For ma tion at tained 25 mm/ka and the char ac ter of cy cles pre served in the se quence is sim i lar as that of the Tomanová For ma tion (fin ing up wards parasequences). How ever, the dif fer ent clay min er al ogy, the re cy cled char ac ter of the sil i cates, the dif fer ent d 13 C org and el e vated imput of car bon ate detri tus with spe cific C and O iso to pic pat terns doc u ment a dis con ti nu ity in the sec tion. The transgressive char ac ter of the Dudzinec Fm. was de duced from the strati graphic dis tri bu tion and en vi ron men tal char ac ter is tics of the ben thic foraminifera pres ent. Involutinids and spirillinids dom i nate in the lower part, endothyrinids gov ern the mid dle part, and in the up per part nodosariids and Ammodiscus-type micro fauna oc cur. These age-di ag nos tic microfossils in di cate a late Rhaetian age. Sea level rise in the Tatric Zone trig gered by ther mal ex pan sion of the Cen tral At lan tic Rift was grad ual, be ing af fected by in put of ter res trial clastic sed i ment both by fresh wa ter and by wind. The Tatric Tri as sic se quence in the West ern Carpathians helps un der stand ing of the de vel op ment of sed i men ta tion, palaeoclimate (kaolinite weath er ing), and palaeo ge ogra phy of the north ern most Tethyan Do main.

No abstract