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Wykorzystanie sejsmostratygrafii do rozpoznania rozkładu mioceńskich facji zbiornikowych w północno-wschodniej części zapadliska przedkarpackiego

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Pietsch K. , Porębski S. J. , Marzec P.

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tom T. 36, z. 2

173-186

PL

Interpretacja sedymentologiczna i sejsmostratygraficzna, wykonana dla przekroju usytuowanego w północno-wschodniej części rowu Wielkich Oczu i przebiegającego poprzez wyniesienie Markowice - Lubliniec oraz dalej na NE, umożliwiła identyfikację spągowej niezgodności kątowej sarmatu (UN0) oraz wydzielenie w formacji z Machowa nie mniej niż siedmiu sekwencji genetycznych zbudowanych głównie z osadów deltowych. Niezgodność UN0 odzwierciedla epizod ekstensyjny nałożony na regionalną, fleksuralną rotację dna basenu w kierunku SW i jest przykryta zespołem frontalnych, podnoszących się w przeciwnym kierunku wyklinowań litosomów deltowych zasilanych ze źródła orogenicznego. Wyklinowania te mogą stanowić pułapki dla gazu generowanego i akumulowanego w heterolitach czoła delty i prodelty. W kierunku SE niezgodność ta przykryta jest lokalnie przez gazonośne, gruboławicowe arenity kwarcowe o proweniencji platformowej. Jest możliwe, iż podobne piaskowce występują także lokalnie na wyniesieniu Markowice - Lubliniec na powierzchni UNO, poniżej zespołu wspomnianych wyklinowań.

EN

Sedimentological and seismostratigraphic interpretation of a dip cross-section located in the northwestern part of the Wielkie Oczy Graben, across the Markowice - Lubliniec elevation and farther to the NE resulted in the identification of the base-Sarmatian angular unconformity (UNO) and allowed to subdivide the Machów Formation into seven genetic sequences composed mainly of deltaic deposits. The unconformity reflects extension episode superimposed on regional south-westward rotation of the basin floor and is overstepped and upplapped towards the NE by deltaic bodies fed from an southerly (orogenic) source. The upplaping pinchouts may form combined, structural-stratigraphic traps for methane generated in delta front-prodelta heteroliths. Unconformity UNO is farther to the SE overlain locally by gas-bearing massive sandstones of intrabasinal or northerly provenience, and similar sandstones may be expected to occur in the study area below the belt of upplapping pinch-outs.

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Cenomanian Acanthoceratoidea (Cretaceous Ammonoidea) from the Koppeh Dagh, NE Iran : taxonomy and stratigraphic implications

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Mosavinia A. , Wilmsen M.

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tom Vol. 61, no. 2

175-192

EN

Seven species of the acanthoceratoidean genera Forbesiceras Kossmat, 1897, Mantelliceras Hyatt, 1903, Acanthoceras Neumayr, 1875 and Cunningtoniceras Collignon, 1937 are described and illustrated from the upper (i.e., Cenomanian) part of the Aitamir Formation of the Koppeh Dagh, northeast Iran. The mantelliceratines were collected from Lower Cenomanian silty shales while the rest of the fauna stems from lower Middle Cenomanian glauconitic sandstones in the upper part of the formation. The ammonite association allows recognition of the lower Lower Cenomanian Mantelliceras mantelli and the lower Middle Cenomanian Acanthoceras rhotomagense zones. The upper Lower Cenomanian M. dixoni Zone is not proven by its index but is most likely represented by a unit of fossil-poor shales intercalated between the two above-mentioned zones. The lowermost Middle Cenomanian Cunningtoniceras inerme Zone, however, is potentially at least partly missing due to a major sea-level fall and lowstand in the latest Early to earliest Middle Cenomanian. A preliminary sequence stratigraphic interpretation of the successions suggests the presence of Lower Cenomanian sequence boundaries Sb Ce 1-3. The Aitamir Formation is truncated along a major regional unconformity at the base of the overlying Abderaz Formation (Turonian.Coniacian). The Upper Cenomanian and most likely also (parts of) the Lower Turonian are missing. This major unconformity has a tectonic origin as it deviates from the eustatic sea-level trend which was very high at this time. Furthermore, contemporaneous tectonic unconformities are also known from Central Iran and may have their origins in rotational movements of the Central-East Iranian Microcontinent.

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Integrated stratigraphy of the Upper Hauterivian to Lower Barremian Agua de la Mula Member of the Agrio Formation, Neuquen Basin, Argentina

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Archuby F. , Wilmsen M. , Leanza H.

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tom Vol. 61, no. 1

1-26

EN

The Upper Hauterivian to Lower Barremian Agua de la Mula Member of the Agrio Formation (Neuquen Basin, Argentina) was studied applying an integrated stratigraphic approach and facies analysis. The ammonite biostratigraphy of the member has been improved based on bed-by-bed collecting. The already defined biozones (Spitidiscus riccardii, Crioceratites schlagintweiti, Crioceratites diamantensis and Paraspiticeras groeberi) were recognized, precisely related to the succession, and further refinement was proposed. Sequences of different order are built by stacked starvation/dilution (s/d) sequences, regarded here as sixth-order sequences with only two components that can be unequivocally distinguished: the lower starvation hemisequence and the upper dilution hemisequence. Pro- and retrogradational stacking pattern of s/d sequences define supra-ordinate sequences. The sequence-stratigraphic analysis resulted in the subdivision of the member into four main depositional sequences (dsAM-1 to -4) and several subordinate sequences. Previously published sequence stratigraphic charts of the Neuquen Basin did not relate sedimentary sequences to biozones, and are hence not comparable to the scheme presented here and other charts. Our study shows a good agreement with the sequence-chronostratigraphic scheme of european basins, thus arguing in favour of a predominantly eustatic control on sequence development during the Late Hauterivian to early Barremian. A latest early Barremian age is proposed for the almost ammonite-barren upper part of the Agrio Formation, based on correlations of sequence boundaries.

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A putative Tournaisian and Visean volcanic-sedimentary succession in the Lublin Basin, SE Poland: depositional processes, petrological characteristics and sequence stratigraphy

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Waksmundzka M. I. , Kozłowska A. , Pańczyk M.

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tom Vol. 71, no. 3

305--344

EN

The aim of this study was to establish the stratigraphic extent of a putative Tournaisian Stage within the Carboniferous succession in the Lublin Basin. The oldest part of the succession, known as the Huczwa Formation and comprising depositional sequences 1-4, was investigated based on lithofacies analysis, sequence stratigraphy and petrographic studies. The article provides descriptions of depositional sequences, parasequences (cyclothems) and lithofacies that were formed in a range of environments (elements of depositional architecture) and as a result of volcanic processes - lava and pyroclastic eruptions and chemical weathering of their products. Correlation of the sequence stratigraphy to the West European and global Carboniferous chronostratigraphic divisions, as well as to the Khoriv suite in the Lviv-Volyn Basin in adjacent Ukraine, indicates a putative late Tournaisian age for sequence 1, and a late Visean age for sequences 2-4. There is a stratigraphic gap between sequences 1 and 2, spanning probably the uppermost Tournaisian and the lower and middle Visean. The upper Tournaisian is represented by the FRST-LST deposits of sequence 1, comprising mainly volcaniclastic conglomerates and sandstones developed in braided-river channels and incised valleys with hyperconcentrated flow processes. These deposits are represented by polymictic paraconglomerate and lithic/sublithic/subarkose arenites or sublithic wackes, and contain predominantly grains of acidic and alkaline volcanic and igneous rocks. This material probably came from the Łuków-Wisznice Elevation and the Volynian Polesia region, located to the NE and E of the Lublin Basin. In the uppermost part of sequence 1, volcanic rocks and tuffs appear which developed during the activity of at least three volcanic cones in the Lublin Basin. The volcanoes were the source of alkaline lavas in the central and SW areas of the basin, and of acidic lavas in the SE area, previously undescribed. The Visean sequences 2-4 consist of the FRST-LST sediments deposited within incised valleys. The TST and HST deposits accumulated mainly in a shallow ramp-type carbonate shelf, shallow clayey shelf and deltaic environments.

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The evolution of late Ediacaran riverine-estuarine system in the Lublin-Podlasie slope of the East European Craton, southeastern Poland

80%

Pacześna J.

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tom Vol. 27

1-96

EN

A model of evolution and destruction of the late Ediacaran riverine-estuarine system that developed in the Podlasie Depression and Lublin-Podlasie slope of the East European Craton is presented based on the identification and definition of facies associations, depositional systems and the framework of high-resolution sequence stratigraphy. Two groups of depositional systems have been identified - alluvial, estuarine, and one open coast system. The alluvial system was initially represented in the northeastern and western synrift depocentres by alluvial fans. Distal parts of the fans were areas of fluvial deposition. Large, sand-bed braided rivers flowed transverse to the sedimentary basin axis. During final stages of the alluvial basin evolution, the levelling of the rift topography and the increase in subsidence rate in the south-east of the basin resulted in the development of anastomosed system rivers. The rivers flowed along the basin axis from north to south. A change in the braided-river flow type from ephemeral during the early stage of the alluvial basin evolution to perennial in the later stages, development of anastomosed system river floodplains and the change in the colour of accumulated fluvial deposits indicate a climate change from arid and desert to more humid and moderate conditions. The late Ediacaran siliciclastic succession of the Lublin basin is a record of the transgressive stage of estuary development. It is manifested by five successive parasequences composing the transgressive systems tract. During the earliest evolutionary stages, the Lublin estuary was a mixed wave-and tide-dominated. In its peak development, as the influence of tides significantly increased, it turned into a macrotidal, hypersynchronous estuary of funnel-shaped geometry. Regression of the Lublin estuary, resulting in its ultimate decline, started along with the highstand development at the Ediacaran/Cambrian transition. The estuary became transformed into a mixed-energy wave-and tide-dominated estuarine system and subsequently into a wave-dominated open coast.

PL

Na podstawie zdefiniowania asocjacji facjalnych i systemów depozycyjnych oraz przedstawienia ram wydzieleń wysokorozdzielczej stratygrafii sekwencji sformułowano model rozwoju i destrukcji późnoediakarskiego systemu fluwialno-estuariowego, rozprzestrzenionego w obniżeniu podlaskim i lubelskim skłonie kratonu wschodnioeuropejskiego. Wyróżniono dwie grupy systemów depozycyjnych - aluwialne i estuariowe oraz system otwartego wybrzeża. System aluwialny był początkowo reprezentowany w północno-wschodnich i zachodnich depocentrach synryftowych przez stożki aluwialne. Dystalne części stożków były obszarami depozycji fluwialnej. Duże, piaskodenne rzeki roztokowe spływały poprzecznie do osi basenu sedymentacyjnego. W końcowych stadiach ewolucji basenu aluwialnego wyrównanie topografii ryftowej i wzrost tempa subsydencji w jego południowo-wschodniej części spowodowały rozwój rzek systemu anastomozującego. Spływały one wzdłuż osi basenu z północy na południe. Zmiana rodzaju przepływu rzek roztokowych z okresowego we wczesnych etapach rozwoju basenu aluwialnego na ciągły w późniejszych stadiach, rozwój równi zalewowych rzek systemu anastomozującego i zmiana koloru osadów akumulowanych przez rzeki świadczą o zmianie klimatu suchego, pustynnego na bardziej wilgotny, umiarkowany. Późnoediakarska sukcesja silikoklastyczna basenu lubelskiego jest zapisem transgresywnego etapu ewolucji estuarium. Jej przebieg odzwierciedla pięć kolejnych parasekwencji budujących transgresywny ciąg systemowy. W najwcześniejszych etapach rozwoju estuarium lubelskie miało charakter mieszany, falowo-pływowy. W fazie maksymalnego rozwoju, w miarę znaczącego wzrostu oddziaływania pływów, było to makropływowe, hypersynchroniczne estuarium o kominowej geometrii. Na przełomie ediakaru i kambru wraz z rozwojem ciągu systemowego wysokiego stanu względnego poziomu morza rozpoczął się regres i stopniowa likwidacja estuarium lubelskiego, które przekształciło się w estuarium o mieszanej energii falowo-pływowej i następnie w otwarte wybrzeże z udziałem falowania.