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1

Facies architecture of the Cambrian deposits of the Baltica shelf in the Lublin Basin, SE Poland

Stadnik Renata, Bębenek Sławomir, Waśkowska Anna

Annales Societatis Geologorum Poloniae

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2019

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Vol. 89, No. 2

105--120

EN

In the Cambrian, the Lublin Basin was a shallow-water area, located on the western edge of the Baltica palaeocontinent. The Cambrian sedimentary sequence, forming the lower part of the sedimentary cover of the North European Platform, is lithologically diversified and reflects dynamic variation in depositional environment. This paper presents the distribution of palaeofacies and sedimentary environments in the early Lublin Basin, including changes in their lateral extent during its evolution in the Cambrian. In order to evaluate the facies architecture of the Lublin Basin, a sedimentological analysis was carried out. On the basis of the detailed logging of drill cores, lithofacies made up of conglomerates, sandstones, mudstones and heterolithic deposits were distinguished; 16 lower-rank sublithofacies were identified. Their specific assemblages are indicative of shelf-type lithofacies associations, i.e. (1) tidal flat with muddy, mixed and sandy tidal plain sublithofacies including subtidal channels; (2) barrier-lagoon; (3) shoreface with lower, middle and upper shoreface subassociations; and (4) offshore with upper and lower offshore subassociations, including sandy tidal ridges. During the early Cambrian, the lateral variability and environmental succession indicate a transgressive, long-term trend and the migration of a lagoonal environment across wide tidal plains and the shoreface up to an offshore environment. The Lublin Basin reached its greatest lateral extent and maximum depth in the upper lower Cambrian. Next, an opposite trend began and during the middle Cambrian a regression cycle is recorded in successive changes in sedimentary environments that reflect a progressive shallowing. Multiple changes in adjacent environments indicate repeated and cyclical, lower-rank ingressions.

2

Recent studies on the Silurian of the western part of Ukraine

Łuczyński P., Skompski S., Kozłowski W.

Acta Geologica Polonica

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2016

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Vol. 66, no. 3

281--297

EN

The paper summarises the effects of recent studies carried out by a team from the Department of Historical and Regional Geology of the Faculty of Geology, University of Warsaw on the upper Silurian of Podolia (western part of Ukraine). The sedimentary history of the Silurian succession of Podolia is characterised by its cyclic pattern, with shallowing-upward cyclothems. In the traditional interpretation, the occurrence of stromatoporoid beds within each cyclothem marks the deepest (or most open-marine) sedimentary environment within the cycle. According to the results of recent studies, their occurrence is connected rather with a relatively shallow-water environment and with high energy phenomena. A substantial reinterpretation of the main sedimentary processes governing the deposition and facies distribution on the shelf is presented. Particularly, there are recognised and described high-energy sedimentary events repeatedly punctuating the generally calm sedimentation that prevailed in the lagoonal settings, some of which are interpreted as tsunami induced. Further perspectives for studies on the Silurian successions of Podolia are also discussed. The main problem is the precise correlation of particular sections that are scattered over vast distances and developed in similar facies associations.

3

Środowiska sedymentacji i palinofacje kredy dolnej w otworach wiertniczych Ciechocinek IG 3, Mszczonów IG 1 i Korabiewice PIG 1

Leszczyński K., Waksmundzka M.

Biuletyn Państwowego Instytutu Geologicznego

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2014

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nr 457

1--14

PL

Na podstawie badań litologicznych, profilowań sedymentologicznych oraz analiz palinologicznych rozpoznano środowiska sedymentacji i palinofacje kredy dolnej w otworach wiertniczych Ciechocinek IG 3, Mszczonów IG 1 i Korabiewice PIG 1. Wykonano dokładną analizę spektrum palinologicznego – stosunku zawartości planktonu do całości palinomorf, ilości fitoklastów w całkowitym kerogenie oraz zawartości materii organicznej. W celu scharakteryzowania palinofacji w analizowanych otworach przeprowadzono korelacje danych palinologicznych z wynikami profilowań sedymentologicznych oraz z obserwacjami litofacjalnymi i paleogeograficznymi. Wyniki badań pozwoliły na ogólne rozpoznanie środowisk sedymentacji i palinofacji w strefie depozycji węglanowo-silikoklastycznej oraz w strefie aktywnej poduszki solnej. Na podstawie zebranego materiału, w nawiązaniu do określonego w badaniach palinofacjalnych spektrum palinologicznego, w profilu kredy dolnej wydzielono następujące środowiska morskie: odbrzeża, przybrzeża dolnego–środkowego, płytkiej zatoki morskiej, laguny i płytkiego szelfu węglanowo-silikoklastycznego. W przypadku braku jednoznacznych cech diagnostycznych środowisko sedymentacji określono jako ogólnie morskie.

EN

Based on lithological and sedimentological logging and palynological analysis, sedimentary environments and palynofacies were identified in the Lower Cretaceous of the Ciechocinek IG 3, Mszczonów IG 1 and Korabiewice PIG 1 boreholes. A thorough analysis of the palynological spectrum was performed, determining the ratio between the amount of palynomorphs and the total of plankton, the amount of phytoclasts in the total kerogen, and the content of organic matter. Palynological data were correlated with sedimentological, lithofacies and paleogeographical data. The research resulted in a general recognition of sedimentary environments and palynofacies in the carbonate-clastic deposition zone and in a zone of an active salt pillow. The following sedimentary environments were identified in the Lower Cretaceous sediments, based on the analysed material and with regard to the palynological spectrum: offshore, lower–middle shoreface, embayment, lagoon and shallow carbonate-siliciclastic shelf. In case of the absence of diagnostic features for exact determination of sedimentary environments, the environments were defined as generally marine.

4

Possibilities and restrictions of heavy-mineral analysis for the reconstruction of sedimentary environments and source areas

Derkachev A.N., Nikolaeva N. A.

Geologos

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2013

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Vol. 19, No. 1-2

147--158

EN

The possible reconstruction of ancient sedimentary environments on the basis of heavy-minerals assemblages is presented by means of discriminant lithogeodynamic diagrams that compare modern and ancient sedimentary environments. This is exemplified by Mesozoic-Cenozoic deposits recovered from ODP cores obtained from the Philippine and Japan Seas, the Japan Trench and the North Atlantic, as well as by deposits from folded areas onshore. On the basis of the comparative analysis, it can be deduced that the main tendencies in mineral assemblages of modern deposits that depend on the structural-tectonic conditions, are fairly well preserved in Cenozoic deposits (including the deposits recovered by ODP drilling). On the other hand, the environmental reconstruction of folded and faulted pre-Cenozoic continental areas on the basis of their heavy-mineral assemblages, by comparing them with supposed modern analogs, is not always possible with much certainty. The main reasons may be either a considerable change in the composition of the initial (primary) mineral assemblages as a result of intralayer solution or the absence, at the time of deposition, of geodynamic environments that closely resembled modern ones.

5

The palynofacies pattern for the Lower Cretaceous of central Poland

Leszczyński K., Waksmundzka M.

Geological Quarterly

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2013

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Vol. 57, No. 1

101–-112

EN

Sedimentary environments and palynofacies were identified in the Lower Cretaceous of central Poland. The study was based on lithological observations, sedimentological logging and palynological investigations in the following boreholes: Poddębice PIG2, Koło IG3 and IG4, Wągrowiec IG1, Sarnów IG1, Ciechocinek IG3, Mszczonów IG1, Korabiewice PIG1, Człuchów IG2, Klosnowo IG1 and Tuchola IG1. Palynological observations were correlated with sedimentological, lithofacies and paleogeographical data. Sedimentary environments and palynofacies were analysed in the vertical section, and spatially in different areas: in the central basin area, in the carbonate-clastic deposition zone, in the transitional zone (deltaic sedimentation) and in a zone of an active salt pillow. The following sedimentary environments were identified in the Lower Cretaceous: upper shoreface and lower-middle shoreface with transitions to an offshore-open marine shelf, delta (?delta front) passing up into distributary channel fills on a delta plain, presumed barrier and shallow-marine embayment, lagoon and shallow carbonate-siliciclastic shelf. In case of the absence of diagnostic features for exact determination of sedimentary environments, the environments were defined as generally marine or transitional (probably deltaic). A maximum flooding surface has been identified in the Poddębice PIG2 section, represented by a thin dark-grey marl bed which seems to be dated at the Berriasian/Lower Valanginian transition. The relationships between sedimentary environments and the characteristics of the palynofacies spectrum were determined, and a palynofacies pattern for the Lower Cretaceous of central Poland was proposed in a tabular form.

6

Wskaźniki środowiskowe badeńskich skał siarczanowych w zapadlisku przedkarpackim

Kasprzyk A.

Biuletyn Państwowego Instytutu Geologicznego

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2008

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nr 432

71-97

PL

Skały siarczanowe (gipsy i anhydryty) mogą tworzyć się w bardzo zróżnicowanych środowiskach depozycyjnych i diagenetycznych od subaeralnych do subakwalnyh (płytko- i głębokowodnych), w warunkach powierzchniowych lub pogrzebania. Rozpoznanie tych środowisk w starszych osadach siarczanowych jest możliwe na podstawie wskaźników środowiskowych, tj. ich cech sedymentacyjnych (np. laminacja, struktury prądowe, struktury mikrobialne, powierzchnie rozpuszczania i erozji, struktury krystaliczne, gruzły siarczanowe), mineralogiczno-petrograficznych (skład mineralogiczny, paragenezy mineralne, mikrostruktura) i geochemicznych (np. pierwiastki główne i śladowe, izotopy siarki, tlenu i strontu). Wyniki badań sedymentologicznych, petrograficznych i geochemicznych badeńskich skał siarczanowych z rdzeni otworów wiertniczych, zlokalizowanych w różnych obszarach zapadliska przedkarpackiego, wskazują na zróżnicowane warunki sedymentacji w zbiorniku ewaporacyjnym przedpola Karpat. Warunki te, zrekonstruowane na podstawie wskaźników środowiskowych osadów i analogii facjalnych do dobrze rozpoznanych współczesnych i kopalnych środowisk ewaporacyjnych, reprezentują główne systemy depozycyjne (subaeralne, płytko- i głębokowodne) basenu saliny. Osady powstałe w tych środowiskach uległy po depozycji przeobrażeniom i przeszły różną ewolucję diagenetyczną w warunkach zarówno płytkiego, jak i głębokiego pogrzebania. W peryferyjnej części basenu tworzyły się głównie litofacje selenitowe i mikrobialne, następnie poddane przemianie diagenetycznej (anhydrytyzacji) w warunkach syndepozycyjnych i wczesnodiagenetycznych. Anhydryty laminowane i brekcje to głębokowodne, redeponowane osady klastyczne, pierwotnie gipsowe, poddane anhydrytyzacji w warunkach wgłębnych w różnych stadiach diagenezy. Charakter osadów w spągowej części sukcesji basenowych, ich cechy sedymentacyjno-petrograficzne i skład izotopowy wskazują na euksyniczne warunki depozycji w środkowej części basenu. Wskaźniki środowiskowe skał siarczanowych świadczą o wyraźnym zróżnicowaniu warunków depozycji w strefie peryferyjnej i środkowej basenu oraz sugerują duży udział wód niemorskiego pochodzenia w tworzeniu się tych utworów.

EN

Ca-sulphate rocks (gypsum and anhydrite) form in a wide-range of environmental settings from marginal (subaerial and very shallow subaqueous) through shallow to deep subaqueous, at the subsurface and in burial. Based on modern analogues, environmental markers: (i) sedimentary (e.g., lamination, current marks, mikrobial structures, dissolution and erosion surfaces, crystalline structures, sulphate nodules), (ii) petrographic and mineralogical (mineral composition and paragenesis, fabrics), and (iii) geochemical (e.g, major and minor elemental composition, isotopic composition of sulphur, oxygen and strontium) provide useful information an the depositional and diagenetic environment for the ancient sulphate deposits. The results of the complex sedimentological, pettrographic and geochemical studies of Badenian sulphate deposits from different parts of the Capathian Foredeep basin indicate distinct sedimentary conditions, which represent the main depositional systems (subaerial, shallow and deep subaqueous) of the salina basin. Gypsum deposits formed in these settings underwent a particular pathways of diagenetic evolution and an alteration into anhydrite. In the marginal settings selenite and microbial faciesi formed, that underwent synsedimentary and early-diagenetic anhydritization (via nodule formation) at the surface. In deeper, central parts of the basin mainly clastic gypsum deposits formed. Laminated anhydrite and breccias are deep-water, redeposited clastic deposits (originally gypsum), that were transformed into anhydrite under burial in different stages of diagenesius. In the basin centre anhydrite shows features characteristic of basinal facies formed in euxynic conditions. The results suggest the different depositional and diagenetic regimes between the basin margin and central part, and large non-marine (riverine, groundwater) inputs to the basin during sulphate formation.

7

Środowiska sedymentacji i palinofacje kredy dolnej w kilku otworach wiertniczych centralnej Polski

Leszczyński K., Waksmundzka M.

Biuletyn Państwowego Instytutu Geologicznego

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2008

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nr 432

99-121

PL

Na podstawie badań litologicznych i profilowań sedymentologicznych, dokonano wstępnego rozpoznania środowisk sedymentacyjnych i palinofacji kredy dolnej centralnej części Niżu Polskiego w otworach wiertniczych Sarnów IG 1, Wągrowiec IG 1 i Poddębice PIG 2. Wykonano dokładną analizę spektrum palinologicznego: stosunku zawartości planktonu do całości palinomorf, ilości fitoklastów w całkowitym kerogenie oraz zawartości materii organicznej. Przeprowadzono korelacje danych palinologicznych z danymi sedymentologicznymi (profilowania sedymentologiczne rdzeni wiertniczych), litofacjalnymi i paleogeograficznymi. Na podstawie analizowanego materiału, i w nawiązaniu do określonego w badaniach palinofacjalnych spektrum palinologicznego, wydzielono w osadach kredy dolnej następujące środowiska morskie: przybrzeża górnego (upper shoreface) i przybrzeża dolnego-środkowego (lower-midle shoreface) z przejściem do odbrzeża (offshore) do zbiornika otwartego szelfu (open marine szelf), deltowe (?czoło delty, delta front) z wyżej występującymi osadami ?kanałów rozprowadzających (distributary channels) równi deltowej oraz prawdopodobnie barier i płytkiej zatoki morskiej (embayment). W otworze wiertniczym Poddębice PIG 2 zidentyfikowano powierzchnię maksymalnego zalewu (maximum flooding surface) reprezentowaną przez warstewkę ciemnoszarego marglu, która wydaje się być datowana na przełom beriasu i walanżsau dolnego. Przeprowadzone badania są pierwszym i wstępnym podejściem do podjętej problematyki związku palinofacji ze środowiskami sedymentacyjnymi w kredzie dolnej.

EN

The paper presents a preliminary recognition of sedimentary environments and palynofacies in Lower Cretaceous deposits of the Sarnów IG 1, Wągrowiec IG 1 and Poddębice PIG 2 boreholes of central part of the Polish Lowland, central Poland, based on lithological and sedimentological investigations. A detailed analysis of palynological spectrum included determination of the contents of plankton (in relation to total frequency of palynomorphs), phytoclast in total kerogen, and organic matter. Palynological data were subsequently correlated with the results of sedimentological logging of drill cores, as well as with lithological observations and overall palaeogeographical research. Based on the material analysed, and referring to the identified palynological spectrum, the following sedimentary environments have been distinguished in the Lower Cretaceous sections: upper shoreface and lower-middle shoreface with transitions to an offshore-open marine shelf, delta (?delta front) passing up into distributary channel fills on a delta plain, and presumed barrier and shallow-marine embayment. A maximum flooding surface has been identified in the Poddębice PIG 2 section, represented by a thin dark-grey marl bed which seems to be dated at the Berriasian/Lower Valanginian transition. The investigations are the first, preliminary approach to the problem of relationship between palynofacies and sedimentary environments in the Lower Cretaceous of Poland.

8

Facies development and sedimentary environments of the Carpathian Keuper deposits from the Tatra Mountains, Poland and Slovakia

Rychliński T.

Annales Societatis Geologorum Poloniae

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2008

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Vol. 78, No 1

1-18

EN

The lower-middle Upper Triassic succession of the Fatricum domain from the Tatra Mts is commonly called the Carpathian Keuper. During Late Triassic, the Fatricum Basin was a proximal part of the central Inner Carpathian Basin. In early Carnian times, carbonate sedimentation stopped. Emersion of the Middle Triassic carbonate platform resulted in development of palaeokarst and pedogenic fabrics and deposition of conglomerates. Typical Carpathian Keuper sediments – variegated shales with intercalations of sandstones and dolomites represent mixed continental/shallow marine environments. Variegated mudstones with pedogenic carbonate concretions and intercalations of thin sandstone beds originated in mudflat environment under the semi-arid climate condition. Thick-bedded, cross-stratified sandstones with common plant debris represent fluvial deposits. They were deposited during the periods of climate pluvialisation. According to ?13C and ?18O data, thick, continuous dolomitic sediments containing local cherts represent marine sediments of perilittoral environments, which were commonly emerged as evidenced by common palaeokarst and palaeosols featuring these complexes. Cyclicity in the lower part of the Carpathian Keuper resulted from climatic changes, whereas dolomite-clastic cycles from the upper part of the succession were generated probably by sea level fluctuations. Moreover, deposition of the Keuper succession was controlled by synsedimentary tectonic which resulted in big facies variability.

9

Sedimentary environments of the Middle Jurassic epicontinental deposits from the central part of the Polish Basin (Kuiavian Region)

Feldman-Olszewska A.

Volumina Jurassica

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2006

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Vol. 4, no. 1

86-86

EN

The Polish Basin was the eastern part of the Jurassic European epicontinental basin. The zone of maximum thickness of the Middle Jurassic deposits runs along the so called Mid-Polish Trough which extends from the West Pomerania (NW) to the Holy Cross Mountains (SE), generally along the Teisseyre-Tornquist Zone. The complete litological profile of the Middle Jurassic deposits exceeds 1100 m in the depocentre of the Mid-Polish Trough (in the Kuiavian Region). Sediments are represented by sandstones, mudstones, heteroliths and claystones with intercalations of siderites, dolomites and coquina beds. Subordinately, crinoidal limestones, arenaceous limestones, gaizes and oolitic ironstones occur. Sedimentological studies were based on investigation of cores from ten deep boreholes. Nineteen lithofacies were distinguished: black shales, massive mudstones, bioturbated mudstones, lenticular bedded mudstones, heteroliths, wavy bedded sandstones, flaser bedded sandstones, sandstones with clay drapes, structureless sandstones (massive and bioturbated), parallel bedded sandstones, cross bedded sandstones, HCS (hummocky cross stratification) cross bedded sandstones, ripple bedded sandstones, herringbone cross bedded sandstones, chamosite sandstones, calcareous sandstones and arenaceous limestones, crinoidal limestones, conglomerates, condensed bed. Additionally, 15 ichnogenera of trace fossils: Asterosoma isp., Bergaueria isp., Chondrites isp., Diplocraterion isp., Gyrochorte isp., Lockeia isp., Ophiomorpha isp., Palaeophycus isp., Planolites isp., Rosselia isp., Skolithos isp., (?)Spongeliomorpha isp., Teichichnus isp., Terebellina isp. and Thalassinoides isp. were recognized in the Middle Jurassic deposits of Kuiavian Region. They point to sedimentation in the transition zone - foreshore environments. Based on the geochemical and palaeoecological investigations, four biofacies connected with different oxygenation of the bottom waters during sedimentation of the black shales have been proposed. The Upper Aalenian - Lower Bajocian deposits represent clayey sedimentation which occurred in dysoxic to anoxic environment. On the other hand, the Upper Bajocian - Lower Bathonian deposits represent dysoxic to oxic conditions. Sedimentation of the Middle Jurassic deposits in the central part of the Polish Basin took place in the shallow epicontinental sea, in environment spanning offshore to foreshore zones of a shallow siliciclastic shelf. Precise sedimentological studies point that the Middle Jurassic succession can be divided into 8 transgressive-regressive cycles. The oldest (Lower Aalenian) one begins with estuarine/foreshore sediments, sharply covered with offshore black shale facies. The Upper Aalenian, Bajocian and Lower Bathonian cycles are built of the transgressive offshore black shales and progradational regressive successions composed of mudstones and heteroliths and topped by shallow or middle shoreface sandstones. The Middle and Upper Bathonian cycles begin with transition zone sediments or lower shoreface deposits. The uppermost part of these cycles are built of sandstones and limestones representing the upper shoreface, foreshore and lagoon environments. The transgressive part of the last (Callovian) cycle is documented by carbonate-siliciclastic shoreface deposits which pass upwards into limestones of the Upper Jurassic. At the boundary between the Middle and the Upper Jurassic a condensed bed occurs.

10

Representative geosites of the Roztocze Hills

Wysocka A., Roniewicz P.

Polish Geological Institute Special Papers

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2004

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Vol. 13

137-144

EN

The paper is an overview of the geological structure of Roztocze and its geological history. It is especially concentrated on the Miocene deposits. The lithology, sedimentary structures and microfacies of these deposits indicate a high-energy, shallow-water, normal marine environment which is mainly connected with the shore zone. Moreover, during the Badenian in the Roztocze area the deposition was connected with the evolution of the Carpathian Foredeep. Brusno, Huta Różaniecka, Nowiny, Józefów, Żelebsko and Łysaków present the most interesting and the most representative geosites of Roztocze. These geosites allow to observe different types of rocks, sedimentary and biogenic structures. Due to this fact, it is possible for pupils, students and other people to learn about the geology of the Roztocze Hills.

PL

Praca prezentuje przegląd wiedzy na temat budowy i historii geologicznej Roztocza. Koncentruje się przede wszystkim na utworach mioceńskich. Litologia, struktury sedymentacyjne i mikrofacje tych utworów wskazują na wysokoenergetyczne, płytkomorskie środowisko sedymentacji, związane ze strefą brzegową. Przebieg sedymentacji w badenie wykazywał na tym obszarze silny związek z ewolucją zapadliska przedkarpackiego. Najbardziej interesujące i reprezentatywne dla utworów mioceńskich geostanowiska to: Brusno, Huta Różaniecka, Nowiny, Józefów, Żelebsko i Łysaków. W tych geostanowiskach możliwe jest prowadzenie obserwacji różnych typów skał, struktur sedymentacyjnych i biogenicznych. W związku z tym dla uczniów, studentów i innych stanowią one doskonałe punkty do nauki geologii obszaru Roztocza.

11

Additional notes ON geosites of the Ukrainian Roztocze

Wysocka A.

Polish Geological Institute Special Papers

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2004

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Vol. 13

145-148

EN

Geological investigations allowed to reconstruct sedimentary environments of the Miocene deposits from the Ukrainian part of the Roztocze Hills area. Moreover, three localities Stradc, Lozyna and Gleboviti are proposed as representative geosites of the Ukrainian Roztocze, which are spectacular from the geological point of view.

PL

Badania geologiczne pozwoliły na zrekonstruowanie mioceńskich środowisk sedymentacji z obszaru ukraińskiej części Roztocza. Zaproponowano trzy lokalizacje na obszarze Ukraińskiego Roztocza: Stradc, Lozyna i Gleboviti, jako wybrane geostanowiska, unikatowe z geologicznego punktu widzenia.

12

Środowiska sedymentacji i rozwój depozycji osadów górnego czerwonego spągowca w rejonie Poznania

Aksamitowska A.

Przegląd Geologiczny

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2003

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Vol. 51, nr 2

168-174

PL

W obrębie osadów górnego czerwonego spągowca wydzielono kilkanaście litofacji oraz określono środowiska ich depozycji. Na podstawie przestrzennej analizy powiązanych ze sobą genetycznie litofacji opisano następstwo środowisk sedymentacyjnych w czasie i przestrzeni oraz czynników warunkujących ich rozwój. Było to podstawą do scharakteryzowania systemów depozycyjnych oraz opisu rozwoju sedymentacji górnego czerwonego spągowca na badanym obszarze. Rozpoznano dwa systemy depozycyjne: eoliczny i fluwialny. Ich rozwój i rozprzestrzenienie były kontrolowane przez procesy o charakterze tektonicznym oraz zmiany klimatyczne. Przeprowadzone badania pozwalają na dokładniejsze przeanalizowanie paleogeografii permskiej w trakcie sedymentacji osadów górnego czerwonego spągowca.

EN

Several lithofacies and their sedimentary environments were recognised within Upper Rotliegend deposits. Spatial analysis of genetically related lithofacies, allowed to descrite the sequence of sedimentary environments and factors controlling their evolution. It was the basis to characterise the depositional systems of the Upper Rotliegendes in the eastern Wielkopolska area. Two depositional systems were recognised: aeolian and fluvial. Their evolution was controlled by tectonic and climatic factors. This study permits a refinement ofpaleogeographic interpretation of the Upper Rotliegendes deposits.

13

Zastosowania skamieniałości śladowych w analizie facjalnej i wysokorozdzielczej stratygrafii sekwencji - przykład z kambru polskiej części kratonu wschodnioeuropejskiego

Pacześna J.

Przegląd Geologiczny

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2001

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Vol. 49 nr 12

1137-11

EN

Trace fossils are a good tool for identification and interpretation of sedimentary environments. The basic procedure of ichnofacies analysis is to define the interactions between the ecological structure of trace fossil assemblage and the abiotic factors of environment. The ichnologic criteria are very good and easily recognizable indicators of the environmental architecture of parasequences and their bounding surfaces. Furthermore, the trace fossil assemblages can be used as indicators ofpaleobathymetric trends in geological sequences, thus indicating contrasting stacking patterns of packages of parasequences. The Middle Cambrian parasequence package of the Podlasie Depression (central part of the Polish segment of the East European Craton) shows a distinctly upward shallowing trend interfingering between upper offshore, lower and upper shoreface environmental zones. These parasequences are arranged into a regressive, progradational parasequence set of highstand system tract. Another trend appears in the retrogradational parasequence set of transgressive system tract in the Lower Cambrian deepening upward succession of the Podlasie Depression. In the upper parts of the sequence, parasequences with more deep-water assemblages of trace fossils, indicating the upper offshore environments, prevail. Based on the ichnologic criteria, stratigraphically significant discontinuities can be delineated. The more readable in an ichnologic record are the flooding surface bounding parasequences, parasequence sets and transgressive or regressive surfaces of coastal erosion. Discontinuity surfaces are marked by substrate-controlled Glossifungites assemblage of trace fossil excavated in semiconsolidated, flrmground substrates previously highly biolurbated by a softground ichnofossil assemblage.