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Czwartorzędowe piaskowce i zlepieńce wapniste na Niżu Polskim : zarys problematyki i znaczenie geologiczne

Kulus Bogusz

Przegląd Geologiczny

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2025

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Vol. 73, nr 4

405--408

EN

The products of carbonate cementation of Quaternary sediments in the Polish Lowlands are sandstones and calcareous conglomerates. Various concepts of their origin are suggested in the literature: from the leaching of calcium carbonate by meteoric waters down the profile under interglacial or Holocene conditions, to the cementation of sediments under the ice sheet or in the Pleistocene periglacial environment. Genetic reconstructions must take into account many factors influencing calcium carbonate precipitation in interglacial environments (activity of living organisms, water table fluctuations) and glacial environments (transgression and ablation of ice sheets, migration of glacial waters). This requires the use of research methods such as analysis of cements and detrital grains in thin sections, analysis of isotopic composition and dating of cements. Analysis of Quaternary sandstones and conglomerates as early diagenetic forms can be an important element in the interpretation of the diagenetic history of older formations.

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Analiza petrograficzna próbek rdzeni wiertniczych na przykładzie skał miocenu z otworu wiertniczego Bielowicko IG

Kuberska Marta, Kozłowska Aleksandra

Przegląd Geologiczny

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2025

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Vol. 73, nr 4

398--404

EN

The paper presents the results of a detailed petrographic study of rock samples from the Dębowiec Beds, obtained using a number of different analytical methods (microscopic analysis, CL, SEM, EDS ISIS, XRD). The Bielowicko IG 1 borehole, one of many located in the south-western part of the Upper Silesian Coal Basin margin, was subjected to detailed analysis due to the need for geological exploration of potential CO2 storage sites. The samples represent fine-grained conglomerates and predominantly medium-grained sandstones classified as subarkose and sublithic arenites. The conglomerates are polymictic with a predominance of clasts of sedimentary origin. Carbonate minerals (calcite, dolomite), authigenic quartz, clay minerals (illite, chlorite, kaolinite) and iron hydroxides have been identified as cement of these rocks. There is also pseudomatrix formedfrom the grinding of soft clasts of clay rocks. Sandstones and conglomerates were subjected to numerous diagenetic processes, such as mechanical and chemical compaction, cementation, replacement, dissolution and alteration of unstable components. The effects of dissolution and alteration are observed as secondary intragranular and intercrystalline porosity. The sediments are characterized by modest porosity (average about 10%) and very poor permeability. The pre-selected Cieszyn-Skoczów-Czechowice reservoir, within which the Bielowicko IG 1 borehole is located, was ranked as having the highest potential for CO2 storage in the Upper Silesian Coal Basin margin.

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Petrographic and mineralogical characteristics of diagenetic overprinting in Neoproterozoic diamictites from Murchisonfjorden, Nordaustlandet, Svalbard

Bal Szczepan, Nejbert Krzysztof, Michalski Krzysztof, Domańska-Siuda Justyna, Manby Geoffrey, Hołda-Michalska Aleksandra, Sláma Jiří

Mineralogia

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2025

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Vol. 56, iss. 1

23--33

EN

The diagenetic processes exhibited by the Neoproterozoic diamictites from Murchisonfjorden (Nordaustlandet, NE Svalbard) are presented. Diamictite samples from the Cryogene Polarisbreen Group - the Petrovbreen Member of the Elbobreen Formation and the Wilsonbreen Formation were analysed. The mineralogical associations composed of chlorite group minerals (chamosite), albite, calcite, Fe-dolomite, clay minerals (illite) and quartz, recognized by integrated optical microscopy, scanning electron microscopy (SEM) and Raman spectroscopy techniques are typical for an advanced stage of mesogenetic diagenesis. Low-grade burial mineral associations were not identified. Our investigations indicate that during diagenesis increased heat flux accompanied fluid migration and remineralization. Identified Fe-Ti – oxides, anatase in thin sections and magnetite identified by rock-magnetic experiments are the products of the secondary diagenetic mineralization. The ferromagnetic carriers representing primary depositional remanence magnetization (DRM) were not preserved.

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The impact of diagenesis on the reservoir properties of Mesozoic sedimentary rocks of the Łódź and Miechów troughs, central Poland

Kozłowska Aleksandra, Kuberska Marta, Feldman-Olszewska Anna, Maliszewska Anna, Połońska Małgorzata, Wołkowicz Krystyna

Geological Quarterly

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2025

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Vol. 69, No. 3

art., no. 28

EN

Mesozoic siliciclastic and carbonate strata, analysed in 28 boreholes located in the Łódź and Miechów troughs, Poland, comprise Triassic and Jurassic rocks accumulated under terrestrial and marine conditions, and Cretaceous deposits of marine origin. Siliciclastic rocks (sandstones, siltstones, mudstones and claystones, with subordinate conglomerates) are the main lithofacies in the Lower and Upper Triassic, Lower and Middle Jurassic, and in the Lower Cretaceous. Carbonate rocks dominate in the Middle Triassic and Upper Jurassic. The Upper Cretaceous succession is represented by siliceous-carbonate deposits. These sedimentary rocks were studied in terms of sedimentary basin analysis and in particular as regards their reservoir characteristics, with detailed petrographic and porosity studies of these rocks and special emphasis on the sandstones and limestones. The focus was on the effects of diagenetic processes and their influence on reservoir properties. The most important diagenetic processes that affected the reservoir properties of the rocks were compaction, cementation and dissolution, and also replacement in carbonate rocks. Compaction and cementation have reduced the porosity of the sandstones by an average of ~44% and 29%, respectively. The effects of dissolution, mainly of feldspar grains and bioclasts, contributed to the development of secondary porosity in the rocks. Replacement processes – dolomitization of limestones – also increased the porosity of the rocks. Sandstones with good reservoir properties (porosity >15%, permeability >100 mD) are found in the Lower Triassic (Buntsandstein), Lower Jurassic and Lower Cretaceous. Among the carbonates, the Middle Triassic (Muschelkalk) deposits show the best reservoir properties, but most of the porous (>10%) carbonate and carbonate-marly rocks are impermeable. The Miechów Trough, by comparison with the Łódź Trough, includes better reservoir properties.

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Silica diagenesis in Eocene carbonates of the Okçular Formation, Turkey : inferences from field observations and petrography

Yeşilot Kaplan Meryem

Geological Quarterly

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2025

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Vol. 69, No. 3

art., no. 30

EN

The silica diagenesis of limestones depends on the environmental conditions and the presence of a silica source. Microstructural features, cracking, porosity, crystal/grain size and the chemical composition of the limestones and chert nodules and layers in the Okçular Formation are parameters controlling silica diagenesis. Cherts are observed in three forms (1) chert nodules with/without a rim, (2) fractured cherts, and (3) layered cherts. Authigenic quartz crystals, chertified foraminifers, microlaminations in the limestones and the chert-limestone grain size relation indicate diagenetic replacement. There is a positive correlation between the size of the microquartz crystals and the colour of the cherts, according to fluid circulation, the trace element content, and the degree of silicification. As the size of microquartz crystals increases due to all these factors, the colour changes from brown to grey-black. Crack widening due to nodule growth, the generally parallel arrangement of chert nodules in carbonates to cracks, and the presence of diagenetic stylolites indicate that both tectonic and diagenetic fractures played a role in silicification. The presence of Cl, P, Ti, Mn and Mo in the chertified zones in limestones indicates inorganic silicification in a marine environment.

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Principles of calcite macrofossil sampling and analysis for geochemical studies on Mesozoic palaeoenvironments

Ullmann Clemens V.

Volumina Jurassica

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2024

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Vol. 22

35--58

EN

Macrofossil carbonate is extensively used for palaeoenvironmental and chemostratigraphic research, especially for the reconstruction of Mesozoic and Paleozoic environments, climates and Earth system evolution. Work on such materials has allowed to chart geochemical signatures of biomineralisation and diagenetic overprints. This information, in conjunction with studies on modern analogues, allows placement of newly obtained results into a well-established conceptual framework of geochemical and structural overprints on macrofossils.The reliability of geochemical research using Mesozoic macrofossils can be optimized by taking into account these general patterns of fossil diagenesis and tendency for exhibiting metabolic effects that bias palaeoenvironmental proxy incorporation into biominerals. Such biases are specific to individual taxa and successions and have to be tested in each study to provide quantitative constraints on preservation. Due to the large potential range of the expression of post-depositional alteration, analysis of relevant diagenetic phases and altered fossil materials should always complement study of the best-preserved material. This contribution outlines principles behind this screening approach and provides guidance on general sampling and sample evaluation strategies. These strategies improve the confidence in the validity of analytical data from macrofossil carbonate for palaeoenvironmental interpretation, including for novel and easily altered geochemical proxies.

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Submarine groundwater discharge into a semi-enclosed coastal bay of the southern Baltic Sea : a multi-method approach

Ehlert von Ahn Cátia Milene, Dellwig Olaf, Szymczycha Beata, Kotwicki Lech, Rooze Jurjen, Endler Rudolf, Escher Peter, Schmiedinger Iris, Sültenfuß Jürgen, Diak Magdalena, Gehre Matthias, Struck Ulrich, Vogler Susan, Böttcher Michael Ernst

Oceanologia

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2024

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No. 66 (1)

111--138

EN

The present study aims to understand the impact of submarine groundwater discharge (SGD) on a coastal area with different lithology and degrees of SGD. Sampling campaigns took place in Puck Bay and the Gulf of Gdańsk, southern Baltic Sea encompassing years between 2009 and 2021. The methodological approach combined geophysical characterization of the surface sediments with detailed spatial and temporal (isotope) biogeochemical investigations of pore and surface waters, and was supported by nearshore groundwater and river surveys. Acoustic investigations identified areas of disturbance that may indicate zones of preferential SGD release. The composition of porewater and the differences in the bay's surface waters disclosed SGD as common phenomenon in the study area. Regional SGD was estimated through a radium mass balance. Local estimation of SGD, based on porewater profiles, revealed highest SGD fluxes at the sandy shoreline, but relatively low elemental fluxes. Though SGD was low at the muddy sites corresponding elemental fluxes of nutrients and dissolved carbon exceeded those determined at the sandy sites due to intense diagenesis in the top sediments. SGD appears to be sourced from different freshwater endmembers; however, diagenesis in surface sediments substantially modified the composition of the mixed solutions that are finally discharged to coastal waters. Overall, this study provides a better understanding of the SGD dynamics in the region by a multi-approach and emphasizes the need to understand the processes occurring at the sediment-water interface when estimating SGD.

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Wstępne badania diagenezy utworów wapienia muszlowego w północnej części regionu śląsko-krakowskiego (otwór 25-BN Biskupice)

Dymowski Witold

Przegląd Geologiczny

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2023

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Vol. 71, nr 5

274--278

EN

The paper presents investigation on diagenesis of Muschelkalk carbonates in the 25-BN Biskupice borehole, NE part of the Silesian-Cracow region. A cycle of dissolution and neomorphic alterations has been identified in the dolomites, Fe-dolomites and calcites occurring at the medium and late stages of diagenesis based on the analytical results of petrographic, cathodoluminescence and SEM methods.

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Wpływ więźby skały na mechanizm deformacji : studium przypadku wstęg deformacyjnych w piaskowcach otryckich (Bieszczady)

Strzelecki Piotr Jan, Świerczewska Anna

Przegląd Geologiczny

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2023

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Vol. 71, nr 4

231--234

EN

Compaction is one of the fundamental modes of strain localization. Pure compaction bands are deformation structures that develop in granular rocks. The Otryt sandstone, a flysch sandstone, hosts naturally formed pure compaction bands that originated due to tectonic shortening. The pure compaction bands formed when the host rock was poorly indurated. The deformation bands are of the disaggregation or cataclastic type, with cataclasis occurring more frequently in coarser-grained sandstones. Additionally, in laminated fine-grained sandstones, disaggregation takes the form of micro-folding. Textural features of the host rock appear to control the microstructural type of pure compaction band.

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Mikrofacje i diageneza wapieni oolitowych najniższego triasu w profilu Gorzów Wielkopolski IG 1 (zachodnia Polska)

Jasionowski Marek, Becker Anna

Przegląd Geologiczny

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2023

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Vol. 71, nr 5

292--297

EN

Lowermost Triassic oolitic limestones occur in the Gorzów Wielkopolski IG 1 borehole as thin intercalations (mostly less than 1 m thick) within laminated or massive reddish brown mudstones or sandy mudstones of the Baltic and Pomerania formations of the Lowerand Middle Buntsandstein, respectively. In order to characterize the microfacies and diagenesis of the limestones, 46 thin sections from 44 core specimens were investigated. The limestone intercalations are poorly diversified in terms of microfacies, especially in the lower part of the section (Baltic Formation), where almost exclusively fine-grained, well-sorted ooid grainstones occur. The upper part of the section (Pomerania Formation) is more diverse. In addition to grainstones similar to those of the Baltic Formation, coarse-grained and/or poorly sorted ooid grainstones, subordinate stromatolites, oncoid grainstones, and mudstones are present. The limestones are almost completely devoid of bioclasts. The only organic remains present in the thin sections are single rounded plates composed of apatite (possibly fish scales) and, even rarer, snail shells and small shells of other organisms (bivalves?, ostracods?), now dissolved (probably originally aragonitic) and visible only due to the preserved coatings of micritic calcite cement previously precipitated on them. The diagenesis of these deposits has not been very intensive and involves mainly cementation by calcite and subordinately by anhydrite, recrystallization of some ooids and other grains (including carbonate bioclasts), and to alesser extent by dissolution under pressure.

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Depositional environment, geochemistry and diagenetic control of the reservoir quality of the Oligo-Miocene Asmari Formation, a carbonate platform in SW Iran

Omidpour Armin, Moussavi-Harami Reza, Loon van Antonius Johannes, Mahboubi Asadollah, Rahimpour-Bonab Hossain

Geological Quarterly

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2021

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Vol. 65, No. 2

art. no. 27

EN

The Oligo-Miocene Asmari Formation in SW Iran represents sedimentation on a carbonate platform. Thin-section analysis allowed distinguishing 26 microfacies, which can be grouped into twelve microfacies associations that represent four main depositional environments: open-marine, outer-ramp, middle-ramp and inner-ramp settings. The carbonates have undergone a complex diagenetic history, from penecontemporaneous shallow-marine consolidation to deep-burial diagenesis. The most important processes that affected the carbonates are dolomitization (in different stages), cementation (by anhydrite and calcite), dissolution (fabric-selective and fabric-destructive), fracturing, stylolitization and neomorphism. Minor diagenetic processes that modified the sediments are pyritization, silicification, glauconitization, micritization and bioturbation. Diagenetic processes such as dolomitization, dissolution and fracturing improved the reservoir quality, whereas cementation and compaction have reduced the reservoir quality of the Asmari Formation. Whole-rock oxygen and carbon isotope analyses of limestone samples show that the isotopic composition of the carbonates was hardly affected by diagenesis and that the carbonates remained roughly in isotopic equilibrium with the Paleogene seawater. Some samples have, however, been affected significantly by diagenesis during deep burial in a closed to semi-closed diagenetic system.

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Diagenesis, sequence stratigraphy and reservoir quality of the Carboniferous deposits of the southeastern Lublin Basin (SE Poland)

Kozłowska Aleksandra, Waksmundzka Maria I.

Geological Quarterly

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2020

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Vol. 64, No. 2

422--459

EN

This study estimates the reservoir properties of the Carboniferous deposits in the southeastern part of the Lublin Basin based on diagenetic and sequence stratigraphic patterns. Depositional sequences distinguished represent the following environments/processes: shallow clay and carbonate shelves, deltaic, fluvial, and hyperconcentrated flow while para-sequences (cyclothems), maximum regression-initial transgression surfaces (T), maximum flooding surfaces (MFS) and also lowstand (LST), transgressive (TST) and highstand (HST) systems tracts have been recognised. Sequences recognized may be linked to the global stratigraphic division of the Carboniferous, thus providing a time framework and environmental context for petrographic and petrophysical examinations. The reservoir properties were found to be clearly controlled by depositional environment, diagenetic history and burial. The best properties were recognized in sandstone lithosomes formed in braided, meandering and anastomosed fluvial channels and hyperconcentrated flows which fill the incised valleys and belong to the LST. They are characterized by good porosity reaching up to 15.1%. The TST and HST deposits are represented chiefly by claystones, mudstones and limestones that formed in a shallow shelf and deltaic environment, being sealing intervals. The diagenetic history of sandstones comprises eo-, meso- and telodiagenetic phases. The major processes acting during the first of these were mechanical compaction, dissolution of mineral grains, formation of predominantly quartz overgrowths around the quartz grains, and crysialiizaton of kaolinite. During mesodiagenesis, cementation with quartz, kaolinite and carbonates continued along with the formation of dickite and fibrous illite; moreover, mineral grains were dissolved and chemical compaction set in. The effects of telodiagenetic processes were feldspar dissolution and precipitation of kaolinite. During diagenesis the maximum temperature affecting the Carboniferous deposits was ~120°C. Compaction and cementation were the main factors responsible for the reduction of porosity by approximately 55 and 38%, respectively. One of the major diagenetic processes was dissolution resulting in the formation of secondary porosity. The Serpukhovian and Bashkirian sandstones from sequence 11 show good reservoir potential, while those from sequences 6, 9, 10, 12-14 only fair potential.

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Warunki temperaturowe w czasie diagenezy piaskowców pensylwanu w rejonie Morza Bałtyckiego

Kozłowska Aleksandra

Przegląd Geologiczny

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2019

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Vol. 67, nr 3

167--168

EN

The purpose of this study is to reconstruct the temperature conditions in the sediment during the diagenesis history of Pennsylvanian sandstones drilled in three deep boreholes in the Baltic Sea. These sandstones are represented by quartz and sublithic arenites and wackes, cemented by matrix and autigenic minerals. Among the autigenic minerals: quartz, clay minerals (kaolinite, dickite, illite) and carbonates (calcite, dolomite, ankerite) are the temperature indicators. The presence of dickite in the sediments indicates a temperature of about 120°C. Quartz and carbonate crystallization temperatures, based on the analysis of fluid inclusions, are estimated to be in the range of 70-180°C. The K/Ar age of the fibrous illite thatforms at the final stage of diagenesis (above 100° C), was determined at 262 ±2 to 247 ±4 My, i.e. from the Middle Permian to the Early Triassic. It determines a length of the post-deposition period, when the deposits were permeable for pore fluids.

14

Porównanie petrografii i diagenezy piaskowców karpackich z różnych jednostek litostratygraficznych

Leśniak Grzegorz

Przegląd Geologiczny

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2019

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Vol. 67, nr 3

175--178

EN

Petrographic research was carried out on 549 thin sections representing Carpathian sandstones of the Lower Cretaceous to Miocene sediments from the Silesian and Skole units (east of Gorlice town). They represented the Lgota, Spass, Inoceramian, Stryj, Istebna, Jamna, Ciężkowice, Menilite, Polanica, Boryslav, Kliwa, and Krosno sandstones. The first goal of the study was to determine the composition of rockframework as well as the types, quantities and distribution of cements. The granulometric composition of sandstones is very diversified, varying from very fine-grained (similar to mudstones) to fine-grained or coarse-grained sandstones. Sorting of detrital grains is rather poor. Only fine-grained sandstones exhibit the better sorting. The investigated rocks can be described as arenites and wackes, sublitharenites, lithoarenites, subarkoses and arkoses. In the next step of research, analyses of diagenetic processes and their influence on the change ofporosity were also carried out. Results of the study of rock framework composition and the type and amount of cements allowed me to compare similarities and differences of the Carpathian sandstones from various lithostratigraphic units.

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The impact of fossils on diagenetically controlled reservoir quality : the Zechstein Brońsko Reef

Fheed Adam

Annales Societatis Geologorum Poloniae

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2019

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Vol. 89, No. 1

47--81

EN

Although the sedimentation and diagenesis of the Polish Zechstein Limestone strata (Ca1, Permian) already have been investigated, relatively little has been done to resolve their petrophysical potential. Therefore, the gap between sedimentological and petrophysical studies was bridged through an integrated analysis of geological and geophysical data. The results of core description, polarized-light microscopy, well log interpretations and laboratory measurements on core samples were combined with previously published nuclear magnetic resonance (NMR) and X-ray microtomography (μCT) data, especially helpful in the recognition of pore geometry. The Ca1 strata of the Brońsko-1 and Brońsko-2 wells, located on the Zechstein Brońsko Reef (West Poland), were studied to determine the influence of fossils on porosity and permeability. It was concluded that greater diversification of the original biota led to an increase in porosity and variation in pore geometry. While encrusting organisms such as foraminifers promoted the development of channel and fracture porosity, the dissolution of the primarily aragonitic bivalve and gastropod shells and the shells of terebratulid brachiopods often gave rise to the formation of cavernous and mouldic porosity. The channels appear to be most common in the bryozoan-foraminifer biofacies, representing a shallowing of the depositional environment. Caverns, in turn, corresponded to the organisms of the brachiopod-bryozoan and the lightly karstified bivalve-gastropod biofacies, both of which probably experienced the influence of sabkha conditions, leading to a general decrease in porosity. The bryozoan zoecia tended to enhance both primary intraparticle voids, and after their dissolution, secondary intraparticle pores, which showed limited connectivity in the high-energy Acanthocladia biofacies, where considerable fragmentation of fossils took place, hence decreasing the permeability. Anhydrite cementation was found to be the most pronounced factor controlling porosity destruction, while dolomitization enhanced it significantly, especially for the stromatolitic biofacies, where small, unconnected vugs were formed owing to this process. The permeability is typically below 100 mD, and this is caused by the rich diagenetic history of the reef, that recorded marine, sabkha-related and burial cementation, now represented by the different fabrics of anhydrite, calcite, and dolomite.

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Skały syderytowe jury środkowej Kujaw : studium petrologiczne

Maliszewska A., Kozłowska A., Kuberska M.

Przegląd Geologiczny

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2018

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Vol. 66, nr 4

240--251

EN

The paper presents the results of new mineralogical and petrographic analyses of Middle Jurassic sideritic rocks in the Kujawy area. The scope of the research has been extended to the Ciechocinek-Brześć Kujawski-Wojszyce zone, where clayey and sandy siderites and sideritic coquina form only inserts in siliciclastic rocks. Early diagenetic sideroplesite and mesodiagenetic sideroplesite, Fe-dolomite, ankerite, pistomestite and calcite occur among carbonate minerals. They are accompanied by an early diagenetic green mineral called chamosite and identified as berthierine in the XRD analysis. The richest mineral composition occurs in the sideritic coquina containing various shell elements, often also ooids. It is suggested that the formation of the coquina in the Klodawa-Łęczyca anticline area was caused by saline movements of the Cimmerian orogeny. The start-up and blending of salt masses and the rockfracture contributed to the intensive circulation of mineralizing solutions and the development of diagenetic processes, especially the replacement of unstable components and the cementation of Jurassic sediments throughout the Kujawy area.

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Solution-collapse breccias in the upper Olenekian–Ladinian succession, Tatra Mts, Poland

Jaglarz P., Rychliński T.

Annales Societatis Geologorum Poloniae

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2018

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Vol. 88, No. 4

303--319

EN

The upper Olenekian-Middle Triassic succession of the Tatricum domain (Central Western Carpathians, southern Poland) includes a few horizons of breccias, which are intercalated with early-diagenetic dolostones. On the basis of macroscopic and microscopic (including cathodoluminescence) observations, the paper presents a new interpretation of the genesis of the breccias and their diagenetic history. The rocks studied range from monomictic, cemented mosaic packbreccias to chaotic, unsorted, monomictic, particulate rubble floatbreccias. The processes that preceded the formation of the breccias encompassed the precipitation of evaporites and the early-diagenetic dolomitization of lime muds. The solution-collapse breccias were formed during episodes of cyclic sediment emersions in the upper Olenekian and Middle Triassic, as the result of gradual sediment collapse after karstic dissolution of the intercalated evaporites. After the brecciation process, during diagenesis the rocks were subjected to cementation by sulphate minerals and next, to multi-stage dolomitization. Later tectonic processes led to fracturing and even re-brecciation of the previously formed solution-collapse breccias.

18

Skały permu dolnego (czerwonego spągowca) zachodniej Polski : monografia petrograficzna

Maliszewska A., Jackowicz E., Kuberska M., Kiersnowski H.

Prace Państwowego Instytutu Geologicznego

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2016

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T. 204

5--115

PL

Praca zawiera wyniki interdyscyplinarnych badań petrologicznych skał czerwonego spągowca, występujących na obszarze zachodniej części Niżu Polskiego. Materiał badawczy pochodził z rdzeni głębokich otworów wiertniczych Polskiego Górnictwa Naftowego i Gazownictwa oraz Państwowego Instytutu Geologicznego – Państwowego Instytutu Badawczego. W zachodniej części Niżu Polskiego na kompleks litologiczny czerwonego spągowca dolnego składają się głównie skały wulkaniczne, subwulkaniczne i wulkanogeniczne, obejmujące nierozdzielone utwory piroklastyczno-epiklastyczne i epiklastyczno-piroklastyczne. Mniej licznie występują skały epiklastyczne, w których dość pospolite są składniki pochodzenia wulkanicznego. Na obszarze monokliny przedsudeckiej i jej północnego obrzeżenia kompleksy wulkaniczne składają się głównie z andezytów i trachyandezytów, w mniejszej ilości z ryolitów, dacytów, trachitów, a tylko lokalnie z bazaltów. Miejscami występują tu kwaśne skały piroklastyczne, lecz objętościowo ustępują one miejsca skałom subwulkanicznym – mikrodiorytom, gabrom, mikromonzonitom, mikrogranitom, granitom i sjenitom. Do rzadkości należą utwory piroklastyczne o charakterze obojętnym. Na obszarze Pomorza serię wulkaniczną reprezentują przede wszystkim ryolity i dacyty, a podrzędnie – trachyandezyty, andezyty i trachity. Dość często występują tu kwaśne skały piroklastyczne, lecz ze względu na raczej niewielkie miąższości ich sumaryczny udział objętościowy jest niewielki. Skały subwulkaniczne mają zazwyczaj skład mikrodiorytu i mikromonzonitu. Wiek posadowienia skał wulkanicznych wynosi 293,0 (±2,0) - 307,9 (±4,6) mln lat, natomiast wiek ich anatektycznego składnika wykazuje dwa maksima: 800-1100 i 1500-1600 mln lat. Pokrywy wulkaniczne z zachodniej Polski uległy głębokim, wielokrotnym przemianom, które spowodowały przeobrażenia minerałów pierwotnych i szkliwa oraz wypełnienie pęcherzyków pogazowych minerałami wtórnymi. Pierwszy etap przeobrażeń wiązał się z działalnością ekshalacji wulkanicznych i gorących źródeł, drugi etap – z cyrkulacją ciepłych wód porowych podczas postępującego pogrzebania, aż do osiągnięcia warunków metamorfizmu bardzo niskiego stopnia w trzecim etapie przemian. Zawartość pierwiastków niedopasowanych oraz zmienność lateralna i wertykalna wskaźników geochemicznych sugeruje, że skały andezytowo-trachyandezytowo-bazaltowe wywodzą się z komór magmowych usytuowanych w górnym płaszczu, a w ewolucji składu ich stopów istotną rolę pełniła intensywność wytapiania źródła i kontaminacja magm materiałem skorupy kontynentalnej, o zróżnicowanej regionalnie litologii. Środowisko tektoniczne generacji magm określono jako wewnątrzpłytowe, lokalnie z cechami kontynentalnego łuku wysp. Podobne wyniki dała dyskryminacja środowiska tektonomagmowego skał kwaśnych, reprezentujących w zmiennym stopniu wytopiony materiał skorupy kontynentalnej o zróżnicowanym lateralnie składzie, poza niektórymi dacytami, będącymi najprawdopodobniej dyferencjałami magm obojętnych. Skały określane jako „wulkanogeniczne” występują przeważnie w kompleksach fluwialnych, rzadziej jeziornych, wśród osadów stożków aluwialnych i równi aluwialnej oraz spływów rumoszu (Kiersnowski, 2003b). Wyróżniono tu litofacje: lapillową, aglomeratowo-lapillową oraz grubo- i drobnopopiołową. Osadowe skały epiklastyczne czerwonego spągowca dolnego są reprezentowane głównie przez piaskowce i zlepieńce, w mniejszym stopniu przez mułowce i iłowce. Skały złożone głównie z ziaren frakcji psamitowej i psefitowej, oprócz kwarcu, zawierają liczne klasty pochodzenia wulkanicznego. Ich spoiwo zawiera minerały ilaste, wodorotlenki żelaza, miejscami także kalcyt, kwarc autigeniczny i anhydryt. Ze zróżnicowania wskaźników geochemicznych skał wulkanogenicznych wynika, że tworzące je osady podczas transportu ulegały frakcjonowaniu związanym z degradacją ziarna i wzbogaceniem w klasty terygeniczne, a po depozycji były w stanie jeszcze stosunkowo świeżym. Sugeruje to, że zarówno dezintegracja ich skał macierzystych, jak i transport miały charakter mechaniczny (erupcje freatomagmowe, a następnie lawiny gruzowe, lahary lub osuwiska wulkaniczne). Środowiska tektoniczne depozycji utworów wulkanogenicznych określono jako aktywną krawędź kontynentalną oraz kontynentalny łuk wysp. Osady czerwonego spągowca górnego są głównie reprezentowane przez różnorodne utwory fluwialne i eoliczne, w części także przez jeziorne utwory plai (Kiersnowski, 1998). Miejscami (w przystropowych odcinkach profilów czerwonego spągowca) występują osady brzegowej strefy płytkiego morza, określane jako biały lub szary spągowiec. Charakterystyczną cechą skał litofacji zlepieńcowej czerwonego spągowca jest znaczna ilość okruchów skał wulkanicznych, które niemal zawsze dominują nad klastami skał osadowych. Zlepieńce oligomiktyczne, złożone z litoklastów osadowych pojawiają się miejscami, głównie na Pomorzu. Litofacja piaskowcowa jest reprezentowana przez arenity i waki kwarcowe oraz sublityczne. Wśród piaskowców eolicznych bardzo licznie występują arenity i waki subarkozowe. Najlepsze właściwości zbiornikowe stwierdzono wśród piaskowców eolicznych, zwłaszcza wydmowych, a najgorsze – w osadach plai (Darłak i in., 1998). W spoiwie piaskowców oprócz matriksu występują liczne składniki ortochemiczne, takie jak: minerały węglanowe, kwarc autigeniczny, anhydryt, chloryty, illit i kaolinit. Oznaczenia wieku K-Ar illitu i δ18O wykazały, że krystalizował on z zasolonych wód porowych, w przedziale 113,6-187,1 mln lat (głównie wczesna i środkowa jura). Oznaczenia δ18O w cementach kalcytowych i dolomitowych wskazują na związek ich wód krystalizacyjnych z wodami zasolonymi, częściowo mieszanymi ze słodkimi. Na obecne wykształcenie litologiczne osadów czerwonego spągowca olbrzymi wpływ miały procesy diagenetyczne, zwłaszcza kompakcja i cementacja. Na rozwój właściwości zbiornikowych skał największy wpływ miało rozpuszczanie diagenetyczne, prowadzące do wytwarzania wtórnej porowatości w obrębie szkieletu ziarnowego i cementów. Z kolei rozwój diagenetycznego illitu, tworzącego włókniste struktury typu sieci, ograniczał zdolności filtracyjne osadów. Większość wymienionych procesów postsedymentacyjnych miała miejsce na etapie mezodiagenezy.

EN

The paper presents the results of interdisciplinary petrologic research of Rotliegend rocks from the western part of the Polish Lowlands. The research material comes from cores of deep boreholes drilled by the Polish Oil and Gas Company and the Polish Geological Institute - National Research Institute. In the western part of the Polish Lowlands, the Lower Rotliegend lithologic complex consists mainly of volcanic, subvolcanic and volcanogenic rocks represented by undivided pyroclastic-epiclastic and epiclastic-pyroclastic rocks. Less abundant are epiclastic rocks containing fairly common constituents of volcanic origin. In the Fore-Sudetic Monocline and its northern margin, the volcanic complexes consist mainly of andesites and trachyandesites with minor proportions of rhyolites, dacites, trachytes and local basalts. Relatively common are acidic pyroclastic rocks, but they are minor in volume as compared to subvolcanic rocks - microdiorites, micromonzonites, microgranites, granites and syenites. Pyroclastic rocks of intermediate composition are rare. In Pomerania, the volcanic series is represented mainly by rhyolites and dacites with subordinate trachyandesites, andesites and trachytes. Acidic pyroclastic rocks are relatively abundant, but their total volume proportion is small because of their small thicknesses Subvolcanic rocks usually have a composition of microdiorite, gabbro and micromonzonite. The emplacement ages of volcanic rocks were from 293.0 (±2.0) to 307.9 (±4.6) million years. Inherited ages of their anatectic component display two maxima: 800-1100 and 1500-1600 million years. The volcanic covers of western Poland have undergone strong multiple alterations that resulted in the transformation of primary minerals and volcanic glass, and in the filling of gas bubbles with secondary minerals. The first stage of alterations was associated with the activity of volcanic exhalations and hot springs, the second stage - with the circulation of warm pore waters during progressive burial until the conditions of very lowgrade metamorphism in the third stage of alterations. The content of incompatible elements as well as lateral and vertical variations of geochemical indexes suggest that the andesite-trachyandesite-basaltic rocks are derived from magma chambers in the upper mantle, and the intensity of source melting and contamination of magmas by continental crust material of regionally variable lithology played an important role in the evolution of the composition of their melts. Tectonic setting of magma generations has been defined as intraplate, locally with the characteristics of continental island arc Similar results were obtained by the discrimination of tectonomagmatic setting of acidic rocks, representing variably melted continental crust material of laterally varied compositions, which most likely represents differentiates of intermediate magmas, except for some dacites. Rocks referred to as “volcanogenic” occur mostly in fluvial complexes, more rarely in lacustrine ones, among deposits of alluvial fans, alluvial plain and debris flows (Kiersnowski, 2003). The lapilli, agglomerate-lapilli, coarse-ash and fine-ash lithofacies have been distinguished here. Lower Rotliegend sedimentary epiclastic rocks are represented mainly by sandstones and conglomerates, with minor siltstones and claystones. Rocks consisting primarily of psammitic and psephitic grains contain quartz and numerous clasts of volcanic origin. The cement contains clay minerals, iron hydroxides, locally calcite, quartz and authigenic anhydrite. The diversity of geochemical indexes of volcanogenic rocks indicates that these deposits underwent fractionation during transport, associated with the degradation of grains and enrichment in terrigenous clasts. After deposition they were still relatively fresh. It suggests that both the disintegration of the parent rocks and the transport were mechanical in nature (phreatomagmatic eruptions followed by debris flows, lahars or volcanic landslides). Tectonic settings of volcanogenic deposition have been determined as an active continental margin and a continental island arc. The Upper Rotliegend rocks are represented mainly by a variety of fluvial and aeolian deposits, in part also by lacustrine playa sediments (Kiersnowski, 1998). In some places (near-top Rotliegend sections), there are shallow-marine, nearshore deposits, referred to as the Weissliegend. A characteristic feature of the Rotliegend conglomerate lithofacies is a considerable amount of fragments of volcanic rocks, which usually dominate over clasts of sedimentary rocks Oligomictic conglomerates composed of lithoclasts of sedimentary rocks are locally observed mainly in Pomerania. The sandstone lithofacies is represented by arenites as well as quartz and sublithic wackes. Among the aeolian sandstones, very numerous are arenites and subarkosic wackes. The best reservoir properties are found among aeolian sandstones, particularly of dunes, and the worst properties are typical of playa sediments (Darłak et al., 1998). In addition to the matrix, the sandstones also contain numerous ortochemical constituents, such as carbonate minerals, authigenic quartz, anhydrite, chlorite, illite and kaolinite. Age determinations (K-Ar of illite and δ18O) show that illite crystallized 113.6-187.1 million years ago (mainly the Early and Middle Jurassic) from saline pore waters. The δ18O determinations in calcite and dolomite cements show the relationship of their crystallization waters with saline waters, partly mixed with fresh waters. The present lithology of the Rotliegend deposits is mainly the result of diagenetic processes, especially compaction and cementation. Reservoir properties of the rocks developed primarily due to diagenetic dissolution that led to the production of secondary porosity within the grain framework and cements. The development of diagenetic illite, forming fibrous structures of network type, reduced the permeability of the sediments. Most of these post-sedimentary processes took place during mesodiagenesis.

19

Sulfur isotope patterns of iron sulfide and barite nodules in the Upper Cretaceous Chalk of England and their regional significance in the origin of coloured chalks

Jeans C. V., Turchyn A. V., Hu X.-F.

Acta Geologica Polonica

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2016

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Vol. 66, no. 2

227--256

EN

The relationship between the development of iron sulfide and barite nodules in the Cenomanian Chalk of England and the presence of a red hematitic pigment has been investigated using sulfur isotopes. In southern England where red and pink chalks are absent, iron sulfide nodules are widespread. Two typical large iron sulfide nodules exhibit δ34S ranging from -48.6‰ at their core to -32.6‰ at their outer margins. In eastern England, where red and pink chalks occur in three main bands, there is an antipathetic relationship between the coloured chalks and the occurrence of iron sulfide or barite nodules. Here iron sulfide, or its oxidised remnants, are restricted to two situations: (1) in association with hard grounds that developed originally in chalks that contained the hematite pigment or its postulated precursor FeOH3, or (2) in regional sulfidization zones that cut across the stratigraphy. In the Cenomanian Chalk exposed in the cliffs at Speeton, Yorkshire, pyrite and marcasite (both iron sulfide) nodules range in δ34S from -34.7‰ to +40.0‰. In the lower part of the section δ34S vary from -34.8‰ to +7.8‰, a single barite nodule has δ34S between +26.9‰ and +29.9‰. In the middle part of the section δ34S ranges from +23.8‰ to +40.0‰. In the sulfidization zones that cut across the Cenomanian Chalk of Lincolnshire the iron sulfide nodules are typically heavily weathered but these may contain patches of unoxidised pyrite. In these zones, δ34S ranges from -32.9‰ to +7.9‰. The cross-cutting zones of sulfidization in eastern England are linked to three basement faults – the Flamborough Head Fault Zone, the Caistor Fault and the postulated Wash Line of Jeans (1980) – that have affected the deposition of the Chalk. It is argued that these faults have been both the conduits by which allochthonous fluids – rich in hydrogen sulfide/sulfate, hydrocarbons and possibly charged with sulfate-reducing bacteria – have penetrated the Cenomanian Chalk as the result of movement during the Late Cretaceous or Cenozoic. These invasive fluids are associated with (1) the reduction of the red hematite pigment or its praecursor, (2) the subsequent development of both iron sulfides and barite, and (3) the loss of overpressure in the Cenomanian Chalk and its late diagenetic hardening by anoxic cementation. Evidence is reviewed for the origin of the red hematite pigment of the coloured chalks and for the iron involved in the development of iron sulfides, a hydrothermal or volcanogenic origin is favoured.

20

Analiza petrograficzna surowców skalnych za pomocą katodoluminescencji na przykładzie piaskowców cergowskich (Karpaty zewnętrzne)

Pszonka J.

Zeszyty Naukowe Instytutu Gospodarki Surowcami Mineralnymi i Energią PAN

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2015

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nr 89

5--18

PL

W artykule scharakteryzowano zjawisko katodoluminescencji, jego zastosowanie w petrologii oraz główne cele analizy obrazu i widm katodoluminescencyjnych: identyfikcję pierwiastków śladowych w minerałach i identyfikację natury defektów oraz genetycznych warunków minerałów. Następnie przedstawiono wyniki badań laboratoryjnych przy użyciu katodoluminescencji z tzw. zimną katodą. Badania z wykorzystaniem katodoluminescencji służą określeniu pierwotnych cech tekstualnych (wielkość ziaren, upakowanie, obtoczenie, kontakty międzygranularne) i identyfikacji struktur wewnętrznych składników (przemiany mineralne, zonacja), które w przypadku piaskowców cergowskich pozwoliły na zaproponowanie kilku wniosków: a) Na podstawie intensywności i koloru luminescencji wyróżniono trzy generacje cementu węglanowego. Tego typu wyróżnienia nie umożliwiają inne metody. b) Na podstawie wzajemnych relacji geometrycznych wyróżnionych generacji cementu oraz charakterystycznych dla nich cech zaproponowano najbardziej prawdopodobną sekwencję rozwoju diagenezy cementu. c) Przy pomocy katodoluminescencji bardzo wyraźnie zobrazowano proces zastępowania skaleni przez cement węglanowy, co w znacznym stopniu wyjaśnia wyjątkowo wysokie parametry technologiczne piaskowców cergowskich. Przeprowadzone badania oraz wyciągnięte wnioski pokazują duże, często niezastąpione możliwości badawcze katodoluminescencji z zimną katodą i jednocześnie podkreślają, że metoda ta powinna być uzupełniana badaniami geochemicznymi identyfikującymi skład chemiczny minerałów, np. za pomocą elektronowego mikroskopu skaningowego (SEM).

EN

The article describes the phenomenon of cathodoluminescence, its use in petrology and the main aims of image and cathodoluminecence spectra analysis: identification of trace elements in minerals, the nature of defects and conditions of their origin. This publication is related to laboratory studies with catchodoluminescence (CL) with cold cathode. Cathodoluminescence studies were used to identify the primary textural features and the internal structures of component grains of the Cergowa sandstones. The following conclusions were drawn on this basis: a) several generations of carbonate cements have been detected none of which is visible under the polarizing microscope, b) the most probable sequence of carbonate cement generations is proposed on the basis of their geometric relationships, c) partial or total replacement of feldspar grains by calcite is a common diagenetic phenomenon in the Cergowa sandstones and resulted in very strong cementation of detrital components, which is manifested by their high hardness and resistance. This study also emphasizes that it is difficult to determine the nature of diagenetic changes by means of cold cathode CL without additional studies that would reveal the chemical composition of minerals, e.g. by the scanning electron microscope (SEM).