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Biostratigraphy, geochemistry and sedimentology of Middle to Late Jurassic strata in the Strážovce section (Strážovské vrchy Mts), Krížna Nappe of the Central Carpathians, Slovakia

Michalík J., Bąk M., Lintnerová O., Méres Š

Volumina Jurassica

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2017

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Vol. 15, no 1

161--178

EN

The Jurassic / Lower Cretaceous sequence of the Strážovce section has been deposited in the central, axial part of the Zliechov Basin. Its most characteristic part – the Ždiar Formation consists of bedded siliceous radiolarian limestones and radiolarites. The radiolar¬ian assemblage typical of the North Tethyan Bioprovince lived during mid Oxfordian – Early Kimmeridgian in a warm upper part of the well stratified water column, partially near to the thermocline. Radiolarian abundance decreases upwards. Productivity decrease is quanti¬fied by the share of biogenic SiO2 as well as by high EFSi values during sedimentation of both the Ždiar and Jasenina formations. The geochemical data indicate relatively stable volume of the siliciclastic component of the rocks and a felsic character comparable to the Average Shale. The chemically homogeneous sedimentary signal indicates values of both CPA and EF ≤ 1 of Ti, Zr, Fe, Na, K, Rb, V and U. The values of EF > 1 signal enrichment of elements with affinity to carbonate minerals (Sr, Mn, P, Y, and Mg). Metal enrichment (Cu, Zn and Ni) indicates metal mobilization from other sources or due to carbonate diagenesis. In comparison to the Average Shale, decreased ΣREE´s and negative Cech and Euch anomalies could be regarded as a typical deep sea water signal. The differentiated REE record of higher calcareous beds of the Jasenina Fm. suggests basinal dysoxic conditions. The “bell-shape” of curves (normalized to shale) indicate that REEs were slightly affected by carbonate diagenesis. The Oxfordian / Kimmeridgian siliceous sedimentation in the Zliechov Basin was influenced probably more by monsoon-controlled input of land derived weathered material than by hydrothermal fluids from the bottom rifts.

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Latest Triassic climate humidification and kaolinite formation (Western Carpathians, Tatric Unit of the Tatra Mts.)

Lintnerová O., Michalik J., Uhlík P., Soták J., Weissová Z.

Geological Quarterly

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2013

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Vol. 57, No. 4

701–-728

EN

The Tomanová Formation, of Rhaetian age, overlying the Norian Carpathian Keuper in the Tatra Mts. is built of cyclic parasequences of mudstones and sandstones. Quartz (15 to 70 wt.%), kaolinite (13 to 46 wt.%) and 2:1 Al dioctahedral phyllosilicates (dioct 2:1: muscovite, illite, illite/smectite: 5 to 39 wt.%) represent the major mineral phase. The kaolinite/dioct 2:1 ratio decreases upwards in the section (from 4.3 to 0.5) and signals variability in weathering/erosion intensity and changing water salinity. Major and trace elements (LILE, HSFS, REE) indicate a uniform source – felsic rocks located probably in the Vindelician Highlands. The sedimentation rate (83 mm/ky) was controlled by climate. Alternation of dry and humid periods is refered by sedimentary textures and by maturity of quartz (aeolian vs. fluvial grains), and organic matter content and composition (Corg and d13Corg). Authigenic siderite or bethierine documents wet and reduced conditions in the upper part of the Tomanová Formation. The sedimention rate of the marine Dudzinec Formation attained 25 mm/ka and the character of cycles preserved in the sequence is similar as that of the Tomanová Formation (fining upwards parasequences). However, the different clay mineralogy, the recycled character of the silicates, the different d13Corg and elevated imput of carbonate detritus with specific C and O isotopic patterns document a discontinuity in the section. The transgressive character of the Dudzinec Fm. was deduced from the stratigraphic distribution and environmental characteristics of the benthic foraminifera present. Involutinids and spirillinids dominate in the lower part, endothyrinids govern the middle part, and in the upper part nodosariids and Ammodiscus-type microfauna occur. These age-diagnostic microfossils indicate a late Rhaetian age. Sea level rise in the Tatric Zone triggered by thermal expansion of the Central Atlantic Rift was gradual, being affected by input of terrestrial clastic sediment both by freshwater and by wind. The Tatric Triassic sequence in the Western Carpathians helps understanding of the development of sedimentation, palaeoclimate (kaolinite weathering), and palaeogeography of the northernmost Tethyan Domain.

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Palynology, T/J boundary microfacies, clay mineralogy, C and O isotopes and other palaeoclimatic indicators from the Tatra Mts.

Götz A., Ruckwied K., Biroń A., Lintnerová O., Michalík J.

Volumina Jurassica

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2006

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Vol. 4, no. 1

282-283

EN

The Furkaska and Kardolina sections expose a complete succesion of the uppermost Fatra Formation and the lowermost Kopienec Formation. The Upper Triassic Fatra Fm. is characterized by bioclastic limestones and fine-grained clastics overlain by dark claystones with intercalated sandstones (Cardinia Sandstein) of the Kopienec Formation. Due to lack of age-diagnostic index fossils, the precise position of the Triassic/Jurassic boundary is not yet known. Based on negative excursion of the δ ¹ ³C carbonate isotopic curve and microfacies analyses the boundary interval was placed near the transition of two formations. Palynological analysis was focused on palaeoenvironmental and stratigraphical aspects. Generally, the continental fraction shows a high amount of phytoclasts. The few marine organic depositional environment indicate a very shallow marine depositional environment. The palynomorph assemblage of the Fatra Fm. is characterized by numerous Ricciisporites tuberculatus. The marine fraction of this part of the sections is dominated by dinoflagellate cyst Rhaetogonyaulax rhaetica. Microflora of the Upper Fatra Formation is very similar to the Ricciisporites tuberculatus Zone of the Polish zonation and Ricciisporites-Polzdiisporites Zone of the SE Nord Sea Basin, both indicating a Middle to Late Rhaetian age. The palynomorph assemblage of the Kopienec Formation is characterized by a significant increase of trilete laevigate spores, mainly Deltoidospora spp. and Concavisporites spp. The dinoflagellate cyst Dapcodinium priscum replaces Rhaetogonyaulax rhaetica in the marine fraction. These changes may be caused by a regression at the Triassic/Jurassic boundary. Quantitative clay minerals analyses documented palaeoclimatic, palaeogeographic and postsedimentary changes in the boundary event and integrated palynological results. Mixed layer illite/smectite (I/S) smectite interlayers take about 80% of the clay fraction and their low content of smectite (10-20%) indicate relatively high diagenetic overprint of the Fatra and Kopienec formations claystones corresponding with burial temperature of 150oC. Varied contents of detrital illite, chlorite and kaolinite were used to demonstrate climatic changes in the hinterland and indicated depositional condition in this semi-restricted basin. Kaolinite and low illite/kaolinite ration indicate more humid climate during earliest Jurassic in comparison with the Rhaetian condition of illite/chlorite dominance. Peak occurrence of kaolinite at the base of the Kopienec Formation recorded different source and strong input of material from weathered and eroded land into proximal part of deltaic plain in comparison with the Fatra Formation.