Wyniki wyszukiwania - BazTech

1

Towards a bright future with new anti-corrosion pigments

Götz A., Büttner J.

Farby i Lakiery

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2015

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nr 3

10--16

EN

For the decades micaceus iron oxide has been used in anti-corrosive paints for the protection of steel constructions. Despite its good performance there are some disadvantages while using this anticorrosive pigment eg. strong colour that allows only the formulation of muted colours or damage in nozzles and pump systems in spray applications. The article presents results of the investigation of two pigments – muscovite mica and Boruvit – that can replace MIO in some applications, and their anti-corrosive properties in paints.

2

The Triassic/Jurassic boundary in three contrasting facies in Hungary

Pálfy J., Barbacka M., Császár G., Demeny A., Görög Á., Haas J., Götz A., Oravecz-Scheffer A., Ozsvárt P., Piros O., Ruckwied K., Szeitz P., Zajzon N.

Volumina Jurassica

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2006

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Vol. 4, no. 1

292-293

EN

Using an integrated stratigraphic approach, the Triassic/Jurassic (T/J) boundary has been studied in two different tectonostratigraphic units and three contrasting facies types in Hungary. In the northeasternmost part of the Transdanubian Range unit (part of the Alcapa terrane), the Csövár section has been intensively studied recently. Here a marine carbonate succession represents slope to basinal facies, deposited in an intraplatform basin near the margin of a Late Triassic Dachstein-type platform system. The T/J boundary is defined on the basis of ammonoid, radiolarian, conodont, and foraminiferan faunas. Paleontological data not only contribute to a biostratigraphic subdivision, but are also interpreted in the context of end-Triassic extinction and earliest Jurassic recovery of different fossil groups. A significant negative carbon isotope excursion is recorded in both carbonate and organic matter in the boundary interval. In other parts of the Transdanubian Range, a Late Triassic carbonate platform is preserved as the thick Dachstein Limestone Formation. In the Gerecse Mts. and the Tata horst, a T/J unconformity truncates the topmost Rhaetian part of the Dachstein Fm. and separates it from the overlying Hettangian strata, deposited in a deepening marine environment. Earliest Hettangian deposits and fossils are absent. A potentially more complete succession occurs farther to the west, in the Bakony Mts. Here the shallow marine carbonate deposition continues into the Hettangian, represented by the Kardosrét Limestone Fm. that overlies the Norian-Rhaetian Dachstein Fm. The lithostratigraphic boundary corresponds to the T/J boundary that marks a significant break in platform development. A disconformity and small hiatus is assumed but its duration has not yet been satisfactorily determined. A surface section on Körishegy and core material from boreholes Zt-62 (near Zirc) and Süt-28 (near Sümeg) have been investigated. The T/J boundary is marked by a sharp disappearance of Triasina hantkeni and changes in the accompanying foraminiferan and dasycladacean algal assemblage. A preliminary stable isotope study of the cores has failed to identify a negative δ ¹ ³C excursion, suggesting a hiatus at the boundary. The Mecsek Mts. in southern Hungary is part of the Tisza unit (or Tisza terrane). Here the T/J boundary falls within the coal-bearing, terrestrial to marginal marine, locally more than 1000 m thick Mecsek Formation but its precise placement has been proved difficult. Palynology offers the best potential for biostratigraphic subdivision. New palynological and paleobotanical studies are underway, aimed at a more precise palynostratigraphy and a reconstruction of climate and vegetation history in the boundary interval. In summary, the T/J boundary sections in Hungary occur in terrestrial, shallow marine (carbonate platform), and deeper marine (slope to basinal) facies. Their study provide new data towards a better understanding of the biotic and environmental changes at this critical interval of Earth history.

3

Sedimentary features and palynofacies of the Triassic/Jurassic boundary interval (Csövár section, N Hungary)

Ruckwied K., Götz A., Haas J., Pálfy J.

Volumina Jurassica

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2006

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Vol. 4, no. 1

296-296

EN

The studied Csövár section is situated NE of Budapest (Hungary) and exposes a continuous, marine Triassic/Jurassic boundary section of slope to basinal facies. Late Triassic palaeogeographic reconstructions indicate that this area was located close to the offshore margin of the Dachstein carbonate platform system, which was segmented by intraplatform basins. A predominantly limestone succession is exposed in two outcrops: the Pokol-völgy quarry and the southern slope of the Vár-hegy. Based on ammonites and the last appearance of conodonts, the Triassic/Jurassic boundary can be drawn within the Csövár Formation. Facies analysis of the Rhaetian-Hettangian deposits reveals a long-term change in sea level, superimposed by short-term fluctuations. After a period of highstand platform progradation in the Late Norian, a significant sea-level fall occurred in the Early Rhaetian, exposing large parts of the platform. A renewed transgression led to the formation of smaller buildups fringing the higher parts of the previous foreslope that served as habitat of crinoids, representing the main source of carbonate turbidites. The higher part of the Rhaetian is characterized by proximal turbidites with intercalated lithoclastic debris flows. Distal turbidites and radiolarian basin facies become prevalent upsection, dominating in the earliest Hettangian. The next significant facies change in the Early Hettangian is marked by the appearance of redeposited oncoid-grapestone beds, indicating the end of the Rhaetian to earliest Hettangian sequence. Palynofacies of the sedimentary series exposed in the Pokol-völgy quarry is dominated by terrestrial components, reflecting a high supply from the hinterland. Numerous needle-shaped opaque particles, as well as a high amount of large translucent plant fragments within the phytoclast group, may point to the transport mechanism of sedimentary organic matter, strongly related to the occurrence and frequency of turbidites along the slope. The studied samples of the Pokol-völgy quarry yield a typical Upper Rhaetian palynomorph assemblage, characterized by a high amount of Circumpolles (Classopollis), Rhaetipollis germanicus, Ovalipollis pseudoalatus and numerous trilete spores. The marine fraction is marked by foraminiferal test linings and prasinophytes of the genus Pterospermella; acritarchs are very rare and dinoflagellate cysts are absent. This microplankton assemblage is characteristic of a permanently stratified basin. Palynofacies of the carbonates exposed in the upper part of the Vár-hegy section, dated as Lower Hettangian, is dominated by degraded organic matter, small equidimensional phytoclasts and foraminiferal test linings, pointing to a distal basinal setting. The integrated analysis of sedimentary and organic facies enables one to reconstruct the depositional environment and to detect major sedimentary processes. The dominance of turbidites, together with the preservation and composition of sedimentary organic matter, supports the complex basin topography.

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Palynomorph assemblages of Triassic/Jurassic boundary key sections of the NW Tethyan realm: evidence for climatic change

Ruckwied K., Götz A., Pálfy J., Michalík J.

Volumina Jurassica

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2006

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Vol. 4, no. 1

297-297

EN

The composition and diversity of Late Rhaetian/Hettangian microfloras of the NW Tethyan realm are investigated with respect to the Triassic/Jurassic mass extinction and the processes that may have caused this crisis. Key locations for detailed palynological studies are selected in the Tatra Mountains (Slovakia) and the Mecsek Mountains (Hungary). The Furkaska section (Tatra Mts., Slovakia) exposes a complete succession of a proximal marine setting. The Upper Triassic Fatra Formation is characterized by bioclastic limestones and fine-grained clastics overlain by dark claystones with intercalated sandstones of the lowermost Jurassic Kopieniec Formation. Based on geochemical data and microfacies analyses, the boundary interval is placed near the transition of the two formations. In the area of Pécs and Komló (Mecsek Mts., Hungary) outcrops and core material reveal a fluvial-lacustrine succession continued by paralic coal deposits. The Upper Triassic Karolinavölgy Sandstone Formation is built up by arcosic sandstones and siltstones overlain by the coal-bearing uppermost Triassic to Lower Liassic Mecsek Coal Formation. The palynomorph assemblages of both settings display typical Rhaetian/Liassic microfloras, dominated by bisaccate pollen grains, trilete spores and Circumpolles. Striking quantitative changes in the composition of the palynomorph assemblages are interpreted with respect to climatic changes within this period. Palynology has been proven as a powerful tool for terrestrial to marine correlation. The floral turnover on land can be directly read from changes in the palynomorph assemblages in the investigated marine and terrestrial sections.

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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.

6

Faunal and floral distribution, biostratigraphy, cyclostratigraphy and magnetostratigraphy of the T/J boundary

Michalík J., Soták J., Ruckwied K., Götz A., Grabowski J.

Volumina Jurassica

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2006

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Vol. 4, no. 1

292-292

EN

The Rhaetian and Hettangian sequence in the Zliechov Basin, Western Carpathians, comprises records of several environmental crises which could contributed to the global Triassic/Jurassic Boundary Events. The Upper Triassic Fatra Formation is characterized by bioclastic limestones and fine-grained clastics overlain by dark claystones with intercalated sandstones (Cardinia Sandstein) of the Kopieniec Formation. The diversity of benthic fauna decreased at the base of the "Transition Beds" - the uppermost member of the Fatra Formation. The fauna comprises important index forms of bivalve molluscs (Chlamys valoniensis), corals, brachiopods (Austrirhynchia cornigera) and foraminifers (Triasina hantkeni, etc.). The palynofacies of the entire succession is dominated by terrestrial components and by high amount of phytoclasts. The few marine organic particles indicate a very shallow marine depositional environment. The palynomorph assemblage of the Fatra Formation is characterized by numerous specimens of Ricciisporites tuberculatus. The marine fraction of the lower part of the section is dominated by the dinoflagellate cyst Rhaetogonyaulax rhaetica. The palynomorph assemblage of the Kopieniec Formation is characterized by a significant increase of trilete laevigate spores, mainly Deltoispora 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 and by an important fresh water input. The boundary between the Fatra and the Kopieniec formations is sharp, denoted by sudden termination of carbonate sedimentation followed by non-carbonate Boundary Clay of the Kopieniec Formation. Magnetostratigraphic record is in procession, it is hampered by complicated pattern of geomagnetic reversals at the end of the Triassic and at the beginning of the Jurassic period.