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Fatrzańska przynależność utworów retyku w profilu "Nad Moreną" (rejon Przysłopu Miętusiego) : korekta stratygrafii hronikum w Tatrach

Gaździcki A., Uchman A.

Przegląd Geologiczny

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2012

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Vol. 60, nr 6

333-340

EN

The "Nad Moreną" section (Triassic–Jurassic boundary interval) in the Tatra Mts. was previously ascribed to the Choč Nappe (Hronicum domain) or to the Križna Nappe (Fatricum domain). Microfacies analysis of the Rhaetian limestones proves that they belong to the Fatra Formation, particularly because of the fossil biota assemblages. This study definitely proves the Križna (Fatricum) provenance of the "Nad Moreną" section and corrects stratigraphy of the Choč Nappe (Hronicum domain) in the Tatra Mts.

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The Steinplatte complex (Late Triassic, Northern Calcareous Alps, Austria) - subsidence-controlled development of a carbonate-platform-to-intrashelfbasin-transition

Kaufmann B.

Acta Geologica Polonica

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2009

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Vol. 59, no. 3

341-357

EN

In Rhaetian (Late Triassic) times, the Hauptdolomit/Dachstein carbonate shelf situated at the passive continental margin of the northwestern Tethys was characterized by an extensional tectonic regime. Rifting and spreading movements fragmented this shelf into a loosely fitted mosaic of fault-bounded blocks characterized by a differential subsidence pattern. This is expressed in significant thickness variations of platform carbonates and in the formation of the intrashelf Kossen Basin. In this study, it can be demonstrated that tectonic subsidence triggered the development of a carbonate platform margin and that the influence of eustatic sea-level changes was negligible. The Steinplatte complex developed at the transition of the Kossen Basin to the Dachstein Carbonate Platform. Small-scale isolated carbonate mounds situated on a smoothly inclined homoclinal ramp characterized the initial phase and acted as nuclei of further carbonate buildup growth. However, only the ideal palaeogeographic position far enough away from the carbonate-suppressive terrigenous influence of the Kossen Beds, combined with vigorous carbonate production stimulated by rapid subsidence-caused sea-level rise, favoured continuous mound growth. Once established, the carbonate buildup was characterized by rapid aggradational growth, developing a palaeogeographic high with a steep slope and a depression with decreased sedimentation behind, several kilometres distant from the Dachstein Carbonate Platform. Contemporaneously, isostatic adjustment caused an accommodation minimum on the nearby margin of the Dachstein Carbonate Platform leading to its westward progradation. Fading out of subsidence caused filling of the former depression in the back of the buildup by prograding shallow-water Dachstein Limestones. Thus, a new platform margin was established in the Steinplatte area, elevated almost 200 m above the adjacent Kossen Basin. At the Triassic-Jurassic boundary, the Steinplatte complex was subjected to subaerial exposure by a sudden tectonic uplift followed by a rapid isostatic drop. Emergence is indicated by levels of karstified limestones directly underlying supposed exposure surfaces. Final drowning of the Steinplatte complex as well as of the whole Dachstein Carbonate Platform is indicated by the cover of Early Jurassic (Sinemurian) deeper water, ammonitebearing limestones (Adnet Formation).

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Ślady dinozaurów drapieżnych z osadów retyku w Seebergen (Turyngia, Niemcy)

Niedźwiedzki G.

Przegląd Geologiczny

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2008

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Vol. 56, nr 7

539-539

EN

Four ichnotypes of theropod dinosaur tracks (described in this paper as cf. Grallator isp., Anchisauripus isp., cf. Eubrontes isp., and Theropoda indet.) were identified in the middle-upper Rhaetian deposits exposed in the Seebergen quarry located near Kammerbruch in the Thuringia Basin, Central Germany. This new paleoichnological find is very important for understanding of diversity and composition of the latest Triassic (Rhaetian) vertebrate assemblages (especially dinosaur assemblages), what is essential for studies on the Late Triassic and Early Jurassic faunal change.

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The Triassic-Jurassic transition in Asturias (northern Spain): ammonoids, bivalves and palynomorphs

Barrón E., Gómez J., Goy A., Márquez-Aliaga A.

Volumina Jurassica

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2006

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Vol. 4, no. 1

275-276

EN

A study of the Triassic/Jurassic transition in Asturias (northern Spain) was performed studying 5 surface sections and 2 boreholes (Fig. 1). Four lithological units were differentiated and correlated. The lower unit is composed of lutites and evaporites (equivalent to the Upper Triassic Keuper facies). The middle unit, which contains the Triassic/Jurassic boundary, corresponds to the well-bedded carbonates of the Solis Member of the Gijon Formation (Fig. 2). The upper unit (Barzana Member) is composed of lutites, evaporites and carbonates. The Fabares Member, overlying or representing a time equivalent of the Barzana Member is composed of a carbonate breccia with a lutitic matrix, formed by the dissolution and the collapse of the Barzana Member. The finding of ammonoids and bivalves in the Solis Member allowed refinement of the biostratigraphy and chronostratigraphy of the Rhaetian and the Hettangian. Among the ammonoids, the record of an (?)Arcestidae (Rhaetian) and several Psiloceras (such as Caloceras pirondii (Reyn?s) of the Hettangian, Planorbis Zone, in the upper part of the Solís Member can be stand out. The dominant Rhaetian bivalves are Isocyprina concentrica and Bakevellia praecursor, which together with Isocyprina ewaldi, "Pteromorphus" elongatus, Pteromya longportensis, "Placunopsis" cf. alpina, Modiolus minimus and Paleocardita cf. austriaca, represent a similar assemblage to that found in the Westbury and Lilstok formations of the Late Rhaetian age of the UK. The Hettangian bivalves are represented by the widely distributed species Pteromya tatei, associated with Cuneigervillia rhombica, Parallelodon hettangiensis and Eomiodos menkei. This assemblage is known in the Hettangian Planorbis Zone of France and Germany. The palynological study allowed identification of 20 spores taxa, 24 pollen taxa, 1 acritarch, 2 prasinophytes and 2 dinoflagellate cyst. Three palynological assemblages (PA) have been distinguished. PA1 is typically Rhaetian and corresponds to the Rhaetipollis germanicus Zone. It is characterized by the presence of Corollina meyeriana, Rhaetipollis germanicus, Ovalipollis pseudoalatus and Tsugaepollenites pseudomassulae. PA2, identified in the Solis Member, is dominated by Corollina pollen grains together with a few spores taxa, acritachs and prasinophytes and can be Rhaetian and/or Hettangian in age. PA3 represented in the upper part of Solis Member and in the Barzana Member contains Hettangian pollen assemblages characterized by Corollina meyeriana, C. torosa, Kraeuselisporites reissingeri, Ischyosporites variegatus and Cerebropollenites thiergartii. Both PA2 and PA3 can be related to the Kraeuselisporites reissingeri Zone. The palynology of the Asturian sections can reasonably be correlated with that of St. Audrie's Bay (UK).

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Hettangian ammonite succession and analysis of the Triassic/Jurassic boundary sequence at Black Bear Ridge, Williston Lake, British Columbia

Hall R., Pitaru S., Henderson C.

Volumina Jurassica

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2006

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Vol. 4, no. 1

285-286

EN

The basal Fernie Formation at Black Bear Ridge consists of 22 m of concretionary, brown weathering siltstones containing abundant ammonites which prove the presence of lower, middle, and upper Hettangian strata. Based on over 300 specimens we have recognized 13 ammonite horizons which may be grouped into six local zones. Lower Hettangian faunas are dominated by strongly ribbed psiloceratids associated, in the upper part of their range, with small Kammerkarites; no smooth psiloceratids of the tilmannipacificum-planorbis group have been found. The Middle Hettangian is marked by the appearance of Kammerkarites hircinum associated with Kammerkarites spp., Discamphiceras, and Pleuroacanthites mulleri. Upper parts of the Middle Hettangian yield Sunrisites sunrisense, Saxoceras portlocki, Kammerkarites spp., Discamphiceras and Alsatites. First appearance of schlotheimiids, which marks the base of Upper Hettangian strata, is above the last occurrences of Sunrisites sunrisense. Faunas in higher strata are dominated by Laqueoceras nigroursus, which ranges up into beds containing Badouxia oregonensis; near the top of the section, Pseudaetomoceras doetzkirchneri appears. Lower Hettangian psiloceratid faunas from Black Bear Ridge can best be correlated with European zonations. Elsewhere, first occurrences of Kammerkarites usually mark the base of the Middle Hettangian, and they are not usually associated with psiloceratids as at Black Bear Ridge. However, strata with Kammerkarites in both Alaska and Queen Charlotte Islands have been placed in the Lower Hettangian. Sunrisites here is associated with both Saxoceras portlocki and Alsatites subliasicus, indicating its Middle Hettangian age, while in both Nevada and South America it occurs above intervals with Kammerkarites and Saxoceras, and is associated with Schlotheimia. At Black Bear Ridge the latter genus only appears above the last Sunrisites. In both Nevada and South America, Laqueoceras is also associated with Sunrisites, not succeeding it as here. Occurrences of Badouxia and Pseudaetomoceras clearly indicate correlation of the highest parts of the sequence with the Upper Hettangian. Correlation of the ammonite associations recorded at Black Bear Ridge with a regional zonation scheme proposed for North America is only partially successful due to differing local ranges of key taxa, and the absence of some genera (Euphyllites, Mullerites, Franziceras, Fergusonites, and Eolytoceras) in this section. Between the "Monotis beds", dense coquinas comprising the uppermost Pardonet Formation (Norian), and the first Jurassic ammonites in the base of the Fernie Formation, is a sparsely fossiliferous interval of flaggy-bedded, brown siltstones 2.3 m thick. Fragmented pectiniform and ramiform conodont elements of Norigondolella sp. and Epigondolella sp., obtained by us from two beds 1.5 and 1.7 m above the "Monotis beds", indicate a probable Rhaetian age for part of this interval. Positive carbon- and nitrogen-isotope excursions at the top of the "Monotis beds" have been correlated with the Norian/Rhaetian boundary (Sephton et al. 2002); they interpreted the Rhaetian/Hettangian (Triassic/Jurassic) boundary to occur 9.0 m higher in the section, though the anticipated negative carbon-isotope excursion was not found at this level. Our new ammonite data confirm that strata just 2.3 m above the top of the "Monotis beds" are already of Hettangian age.

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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.

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Nowe znalezisko śladów dinozaurów w górnym triasie Tatr

Niedźwiedzki G.

Przegląd Geologiczny

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2005

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Vol. 53, nr 5

410--413

EN

New material of dinosaur footprints has been found in the Late Triassic fluvial-lacustrine deposits of the Tatra Mountains, Poland. Footprints discovered in a well-known Rhaetian strata of the Tomanová Formation represent pedal ichnites of Kayentapus sp. and Anomoepus sp. These are the second reported record of dinosaur footprints in the Tatra Mountains.

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A new record of Beneckeia tenuis (Seebach, 1857) from the Rhaetian of Piekoszów (Holy Cross Mountains)

Salamon M.A., Nizicki R.

Geologia / Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie

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2004

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T. 30, z. 4

439-444

EN

The ammonoid Beneckeia tenuis (Seebach) is recorded from the Rhaetian (Lower Anisian) of the Holy Cross Mountains. Three specimens were collected from a single rock layer that is typical of epicontinental sea deposition of the time.

PL

Opisano amonity Beneckeia tenuis (Seebach) z retu (dolny anizyk) Gór Świętokrzyskich. Charakteryzowana fauna obejmuje trzy okazy typowo epikontynentalnej formy Beneckeia tenuis, które pochodzą z jednej warstwy skalnej.