Polish Basin Research Articles

Ultrastructure of the Jurassic serpulid tubes-phylogenetic and paleoecological implications.

The ultrastructural diversity of the Middle and Late Jurassic serpulid tubes from the Polish Basin has been investigated. The inspection of 12 taxa representing the two major serpulid clades allowed for the identification of three ultrastructure types-irregularly oriented prismatic structure (IOP), spherulitic prismatic structure (SPHP), and simple prismatic structure (SP). Six of the studied species are single-layered and six species possess two distinct layers. Ultrastructural diversity corresponds to certain serpulid clades. The members of Filograninae have single-layered tube walls composed of possibly plesiomorphic, irregularly oriented prismatic structure (IOP). Two-layered tubes occur solely within the clade Serpulinae, where the external, denser layer is built of either the ordered spherulitic (SPHP) or simple prismatic microstructure (SP), and the internal layer is composed of irregularly oriented prismatic structure (IOP). Apart from phylogenetic signals provided by the tube ultrastructure, it can be used in analyzing paleoecological aspects of tube-dwelling polychaetes. Compared to the more primitive, irregularly oriented microstructures of Filograninae, the regularly oriented microstructures of Serpulinae need a higher level of biological control over biomineralization. The advent of the dense outer protective layer (DOL) in serpulids, as well as the general increase in ultrastructure diversity, was likely a result of the evolutionary importance of the tubes for serpulids. Such diversity of the tube ultrastructural fabrics allowed for maximizing functionality by utilizing a variety of morphogenetic programs. The biomineralization system of serpulids remains more complex compared to other tube-dwelling polychaetes. Physiologically more expensive tube formation allows for mechanical strengthening of the tube by building robust, strongly ornamented tubes and firm attachment to the substrate. Contrary to sabellids, which perform a fugitive strategy, an increased tube durability allows serpulids a competitive advantage over other encrusters.

Salt-pillow formation during inversion of evaporite-filled half graben – Insights from seismic data interpretation and integrated analogue-numerical modelling

The Mid-Polish Anticlinorium is a regional structure that formed during Late Cretaceous inversion of the Permian-Mesozoic Polish Basin. Within the anticlinorium, local salt pillows built of the Upper Permian (Zechstein) evaporites are often located above reverse faults that accommodated basement inversion. Seismic data from the Szubin area in central Poland were used to guide a combined analogue and numerical modelling study to test whether locally thicker evaporites deposited within a half-graben, could indeed give rise to a salt pillow formed above the half-graben's hanging wall during its inversion. The results of the two approaches are internally consistent and prove that such a genetic relationship is fully viable, with the most important variables being the size of the half-graben, the viscosity of the salt, and the presence of any erosion of the pillow structure. Thus, the existence of salt pillows along the major inversion zones of the Mid-Polish Anticlinorium could possibly be used as indicators for the location of syn-depositional half-grabens during deposition of the Zechstein evaporites. This in turn might suggest that even in the basin center, shallower areas might have existed above the footwalls of such half-graben during Zechstein deposition, characterized by smaller thicknesses and somewhat different facies arrangement. Similar concepts likely apply to other intracontinental salt basins that experienced rifting and then inversion.

Upper Cretaceous contourites from northwestern Poland in the vicinity of the Szamotuły salt diapir

This paper presents the results of seismostratigraphic interpretation of the Upper Cretaceous sedimentary succession preserved within two synclines flanking the Szamotuły diapir in northwestern Poland. This succession is characterized by a complex Santonian–Campanian internal geometry characteristic of contourites – that is, deposits formed by contour (bottom) currents. The aim of the present paper is to document these contourites using 2D seismic reflection profiles calibrated by the Obrzycko 1 well. The contourite drifts in the immediate vicinity of the Szamotuły structure exhibit elongated mounded shapes, with adjacent concave moats. At greater distances from the diapir, gradual aggradational patterns are observed. The formation of these Santonian– Campanian contourites was associated with growth of the Szamotuły diapir during regional compression and Polish Basin inversion. These contour currents and associated contourites formed an integral part of a regional axial depositional system developed within the flanks of the Mid-Polish Anticlinorium. Furthermore, this paper discusses the potential role of contourites as palaeomorphological indicators of palaeoslopes in varied geodynamics settings, such as inverting sedimentary basins, as opposed to the passive margins upon which they have been most commonly documented.

Triassic and Jurassic possible planktonic foraminifera and the assemblages recovered from the Ogrodzieniec Glauconitic Marls Formation (uppermost Callovian and lowermost Oxfordian, Jurassic) of the Polish Basin

Abstract. In the 1960s and 1970s Werner Fuchs of the Austrian Geological Survey (Vienna) described a significant number of new foraminiferal taxa that he considered ancestral to the planktonic foraminifera. All these taxa are well-curated in the collections of the Austrian Geological Survey and have been studied by one of us (Malcolm B. Hart). Some of these taxa, from the Triassic and lowermost Jurassic strata of Austria and northern Italy, are poorly preserved, possibly the result of having an original aragonitic wall structure. None of these taxa possess characters which give the appearance of a planktonic mode of life, although some of them (e.g. Oberhauserella, Praegubkinella) may well have been ancestral to the holoplanktonic foraminifera that appeared in the Toarcian and younger strata. Other taxa in the collections of the Austrian Geological Survey (part of GeoSphere Austria), from the Jurassic of Poland, are preserved as glauconitic steinkerns and are either unidentifiable as foraminifera or suspect in terms of their stratigraphical and evolutionary significance.

Geotectonic setting of Permian polymetallic deposits in the Polish Basin

Geotectonic setting of Permian polymetallic deposits in the Polish Basin

Diverse magma evolution recorded in trace element composition of zircon from Permo-Carboniferous rhyolites (NE German Basin, NW Polish Basin)

Permo-Carboniferous rhyolitic rocks are widespread in the NE German Basin and NW Polish Basin. Hafnium (Hf) and oxygen (O) isotopes analysed in zircon from these rocks suggest diverse sources and processes involved in the formation of rhyolitic magmas. In this study, detailed core-to-rim trace element compositions were analyzed in zircon from four localities that were previously analyzed for Hf and O isotopes. The trace element analyses, in particular Hf concentrations as well as Eu/Eu*, Ce/U, Yb/Gd, and Th/U ratios, are consistent with prolonged magma evolution in three localities from the NE German Basin (Fehmarn, Slazwedel and Penkun). The fourth locality within the NW Polish Basin (Wysoka Kamieńska) is consistent with a shorter period of magma evolution. Similar stages were distinguished in zircon from the three NE German Basin localities that include: early crystallization followed by rejuvenation with more primitive magma (stage A), subsequent fractional crystallization (stage B) and finally late crystallization in a saturated system or alternatively late rejuvenation with a more primitive magma (stage C). Interestingly magmatic rims on inherited zircon grains have compositions typical for late stage B and stage C, which is consistent with their late addition to evolving rhyolitic magma, most probably during assimilation and not during source melting. The zircon from the fourth, NW Polish Basin locality shows limited compositional variability consistent with the eruption of hot magma not long after the zircon started crystallizing. Thus trace element analyses in zircon provide a record of magmatic processes complementary to that of Hf and O isotope analysis, in that, a detailed analyses of core-to-rim compositional variations are particularly useful in distinguishing respective stages of magma evolution and can pinpoint the relative timing of inherited grains being incorporated into magma.

Influence of the diagenetic oxidation and allochthonous organic matter input on geochemical and petrological results – Insights from the Upper/Middle Triassic strata, Polish Basin

Set of 24 Lower Keuperian (Upper Ladinian) and Grabfeld Formation (Lower Carnian) grey/black claystones core samples from the central part of the Polish Basin was examined by geochemical (Rock-Eval and Gas Chromatography-Mass Spectrometry) and petrological analyses. The Rock-Eval and petrological analyses revealed that the analysed organic matter is mostly mature/overmature (1.0–2.5%Ro). A combination of biomarker maturity indicators and petrological analyses suggest that autochthonous organic matter did not reach 0.9%Ro, and the higher mature organic matter particles have an allochthonous origin. Most samples contain significant input of allochthonous organic matter, which influenced the results of some geochemical indicators describing the origin of organic matter and palaeoenvironmental conditions.Investigated strata contain mostly mixed planktonic-bacterial and terrigenous organic matter. A higher contribution of terrigenous organic matter was observed within the Grabfeld Fm., where geochemical traces of fluvial-deltaic palaeoenvironment was recorded. Deposition of both strata occurred mostly under anoxic bottom waters in brackish or normal-saline marine conditions. However, an elevated salinity level was observed within Grabfeld Fm. sample from Byczyna 1 borehole.All samples contain phenylnaphthalenes (PhN), phenylphenanthrenes (PhP), and aromatic ketones, widely used as diagenetic oxidation indicators. The juxtaposition of two ratios based on phenanthrene (P), methylphenanthrenes (MP), and PhP was proposed to define the degree of organic matter diagenetic oxidation. Combined results of ƩMP/(ƩMP + ƩPhP) and P/(P + ƩPhP) revealed that Grabfeld Fm. contains more oxidised organic matter than Lower Keuperian strata. Moreover, the distribution of the PhN isomers – 1-PhN and 2-PhN – is controlled mainly by maturity level only in the least oxidised samples, where P/(P + ƩPhP) values range from 0.8 to 1.0. In other samples, the PhN distribution is controlled by the diagenetic oxidation degree. For this reason, the distribution of 1-PhN versus 2-PhN should not be used as a maturity indicator within more oxidised samples.

Hydrocarbon generation modelling in the Permian and Triassic strata of the Polish Basin: implications for hydrocarbon potential assessment

Hydrocarbon generation modelling in the Permian and Triassic strata of the Polish Basin: implications for hydrocarbon potential assessment

Geochemical fingerprint—inter-basin chemostratigraphic correlation allowed for a more detailed stratigraphic subdivision of the Pliensbachian–Bathonian strata from the Carpathian Foredeep basement (Ukraine)

In this study, we combined the geochemical characteristics based on Rock-Eval pyrolysis and gas chromatography – mass spectrometry (GC–MS) results with the facies analysis. These surveys were conducted within grey to black claystones/mudstones intervals of the Podil’tsi and Kokhanivka formations, related to the Pliensbachian and Toarcian–Bathonian ages, respectively. The geochemical results revealed that the Podil’tsi Formation contains mixed marine/terrigenous, early-mature to mature organic matter. The deposition of this formation took place in dysoxic redox conditions of a sulphate-poor marine palaeoenvironment, with oxygen scarcity within the photic zone, as documented by green- and brown-pigmented Chlorobiaceae. Oleanane is present within the samples from the Podil’tsi Formation, which is uncommon within Lower Jurassic sedimentary rocks. The Kokhanivka Formation contains mostly early-mature, terrestrial organic matter, deposited in suboxic conditions of a sulphate-poor, fluvial–deltaic palaeoenvironment. The absence of aliphatic diterpenoids within the Middle Jurassic strata points to the low significance of conifers in the sediment supply area at this time. All of the Podil’tsi and most of the Kokhanivka formations are characterised by poor hydrocarbon potential. Only the middle part of the Kokhanivka Formation, built by brown, organic-rich claystones, shows fair-to-good hydrocarbon potential. Based on our results, a chemostratigraphic correlation of the Toarcian–Bathonian strata from the Carpathian Foredeep with the same strata from the neighbouring Polish Basin was performed. The juxtaposition of the geochemical and facies results suggests that the interval of brown organic-rich claystones, from the middle part of the Kokhanivka Formation can be related to the Middle–Upper Aalenian Age.

The Late Cretaceous tectono-sedimentary evolution of northern Poland – A seismic perspective on the role of transverse and axial depositional systems during basin inversion

This paper describes a new tectono-sedimentary model of the Late Cretaceous evolution of the northern, peripheral part of the Polish Basin, strongly influenced by inversion tectonics and fed by transverse and parallel depositional systems. The study area is located in northern Poland, in the boundary zone between the southeastern marginal part of the East European Craton and the northeastern margin of the Mid-Polish Anticlinorium, a regional inversion structure that runs northwest-southeast across the entirety of Poland. Traditionally, a “layer-cake” geological model, mainly based on borehole data, has been employed to characterize the regional depositional architecture of the Upper Cretaceous succession. Our new interpretation is based on regional geo-seismic transects, including the unique, regional high-resolution PolandSPAN™ seismic survey, calibrated by deep wells. The upper Albian – Upper Cretaceous succession was subdivided into five regional seismic stratigraphic units. Within these units, seismic facies and corresponding lithofacies representing siliciclastic and carbonate-siliceous depositional systems are described. The relative role of transverse and parallel depositional systems, including bottom currents, was recognized. Bottom current activity was documented by numerous, previously unknown seismostratigraphic features such as changes in lateral thickness, unconformities, and incisions. Two recognized contour current systems (N–S and NW–SE) operated along the edges of inversion structures that were uplifted in the Late Cretaceous – Palaeogene. A very significant rearrangement of this part of the Polish Basin, highlighted by a regional unconformity mappable over the entire study area, took place in the Campanian – Maastrichtian.

The application of archival borehole data to recognizing the primary mineral composition and diagenetic changes in Jurassic sandy rocks of the Polish Basin

With emphasis being placed on the re-examining of mature petroleum basins and reduction of the negative impact of the industry on the environment, the use of archival data in geological exploration is essential. This is especially important in regions where the old, Soviet-type tools were used in the past and which are now using modern, western logging equipment. The application of archival geological, geochemical and geophysical data allows recognition of reservoir formations without the use of modern measurements. For the purpose of this research, Jurassic sandy rocks identified in the archival borehole Z-GN4 were analysed. They appear to be a perfect target for further petroleum and geothermal exploration in the Polish Basin; however, variable mineral composition and diagenetic features can cause difficulties while estimating their reservoir properties. The difference between gamma ray and spontaneous potential shale volume parameter (clay difference) was applied together with gamma ray measurement to determine the impact of primary and diagenetic features on each sandy petrofacies. Based on an integration of detailed petrographic analysis of available core samples from Z-GN4 borehole with archival borehole logs, four different sandy petrofacies were distinguished. Moreover, deep resistivity and sonic logs were used to highlight the carbonate-cemented intervals. This study shows how the application of petrofacies analysis in archival datasets can support the interpretation of uncored intervals and upgrade the level of reservoir characterization.

Lower Jurassic in the central part of the Polish Basin - Geochemical and petrological approach

Lower Jurassic grey/black horizons composed of mudstones and claystones can be found in the Polish Basin area. These horizons are interbedded in thick sandstone packets, which to date have been mostly recognised as good geothermal reservoirs. In this paper, we examined the hydrocarbon potential of the Lower Jurassic claystones and mudstones from the central part of the Polish Basin. To properly evaluate these, we described in detail the organic matter's origin and maturity, as well as the palaeoenvironmental conditions. The collected core samples were examined by geochemical (Rock-Eval pyrolysis and GC-MS) and petrological (macerals content, vitrinite, and fusinite reflectance values) analyses. The obtained results revealed that the Lower Jurassic strata have poor hydrocarbon potential and contain mostly early-mature, terrigenous organic matter. Deposition took place under dysoxic conditions of the epicontinental sea, with the serious influence of deltaic/estuarine systems. Some samples contained mature, marine organic matter dominated mostly by bacterial input. One Sinemurian/Hettangian sample contained a high contribution of algal organic matter, which can be linked with the diatoms or diatom-related organisms as C25HBI, 24-norcholestane and 4-desmethyl-23,24-dimethyl steranes were detected. This might represent some of the oldest geochemical evidence of diatoms or diatom-related organisms. A wide spectrum of plant-derived biomarkers was marked in most of the samples, which allowed us to find traces of conifers, bryophytes, and fungi. Evidence of palaeo-wildfires was also noted. Newly introduced Pyrolytic Input Ratio (PIR) and Fire Maceral Index (FMI) were also examined. The use of PIR in samples with higher marine organic matter input indicated that PIR is not suitable for these samples, as the obtained results were overestimated. The PIR and FMI results obtained from the Lower Jurassic samples dominated by terrigenous organic matter suggested that both indicators gave proper results, as well as those samples with lesser paleo-wildfire product input.

Palaeoecological implications of stable isotope analyses of late Valanginian ammonites from central Poland

Analyses of δ18O and δ13C of original shells of late Valanginian (verrucosum to triptychoides ammonite zones) ammonites preserved in clay at localities in central Poland, and of some Berriasian samples from well cores have been carried out for the first time. Analyses of carbon stable isotope composition have revealed diverse values, representing vital effects rather than recording the palaeoenvironment. In turn, analyses of oxygen stable isotope composition in samples from the verrucosum and triptychoides ammonite zones clearly indicates the connection between particular species and stable isotope ratios, and thus palaeotemperature. The interpretation of ammonite palaeoecology in the present paper is based on estimated palaeotemperatures and supports other interpretations of ammonite behaviour, mainly based on functional morphology of shells. There are two main groups of ammonites associated with lower and higher temperatures. The first group of δ18 O values indicates lower palaeotemperatures. Genera analysed include Bochianites, Dichotomites and Prodichotomites; a nekto-benthic (demersal) habitat is suggested for these. The second group, characterised by higher palaeotemperatures, includes Saynoceras, Valanginites and Olcostephanus, with a suggested nektonic (or planktic) habitat (free-floating), Neohoploceras and Neocomites with a suggested nektonic habitat (free-swimming) and a seasonal migration from warmer (Tethys) to cooler waters of the Polish Basin or lived in the Polish Basin for several summer and winter seasons. Co-occurring bivalves, echinoid spines and scaphopods were analysed for comparison with results obtained from ammonites for a better overview of the palaeoenvironment. The estimated palaeotemperatures for the Polish Basin are between 12 and 13 °C (at the sea floor) to 21–24 °C (in the upper water column), while for the Tethys or summer surface waters of the Polish basin, these were in the range of 26–30 °C.

Geochemical and petrological characteristics of the Middle Jurassic organic-rich siliciclastic sediments from the central part of the Polish Basin

Organic-rich claystones and mudstones can be very good source rocks for hydrocarbons. Middle Jurassic organic-rich siliciclastic horizons are known from the Polish Basin area, however, there are no hydrocarbon accumulations associated with these horizons. The main scientific goal of this paper is to propose why these horizons did not produce significant hydrocarbons quantities. To deal with it, we characterised organic matter origin, maturity level, and hydrocarbon potential of Middle Jurassic strata. Palaeoenvironmental conditions of the Middle Jurassic Polish Basin were also described. The samples were examined by geochemical (Rock-Eval and GC–MS) and petrological (macerals content, vitrinite, and fusinite reflectance values) analyses. The analyses revealed that the Middle Jurassic strata at the study area, in general, contain mixed terrigenous/aquatic organic matter with a significant content of pyrogenic origin polycyclic aromatic hydrocarbons (PAHs). Inertinite and liptinite group macerals dominate in maceral composition. This suggests that analysed samples contain a mixture of type IV and II kerogens. Most of the analysed samples contain immature or early-mature organic matter. In general, the maturity level is higher in the southern part of the study area, where higher subsidence of Polish Through allowed to reach greater burial depths. Sediments were deposited in anoxic basement conditions of the epicontinental sea with the serious influence of deltaic/estuarine systems. The water and air transport are responsible for significant input of terrigenous organic matter, mostly reworked in frequent palaeo-wildfire events. The high content of charred organic matter is the main reason why despite high total organic carbon (TOC) values, the hydrocarbon potential of analysed horizons is poor/fair. Fire maceral index (FMI) was proposed and juxtaposed with pyrolytic input ratio (PIR) to propose that PIR is sensitive mostly to higher-temperature palaeo-wildfires products.

Deep vs. shallow – two contrasting theories? A tectonically activated Late Cretaceous deltaic system in the axial part of the Mid-Polish Trough: a case study from southeast Poland

Abstract. The Polish Basin is a part of a trans-European sedimentary basin comprising the Central European Basin System and stretching from Denmark through Germany to southeastern Poland, and even further to the south into Ukraine. It experienced uplift during the Late Cretaceous, which consequently resulted in the inversion of its axial part (i.e., the Mid-Polish Trough) and development into the Mid-Polish Anticlinorium. In many existing paleotectonic interpretations, southeast Poland – i.e., the subsurface San Anticlinorium and the present-day Roztocze Hills – was included in the Mid-Polish Trough during the Late Cretaceous, representing its axial, most subsiding part. This paleotectonic model was the basis for facies and bathymetric interpretations that assumed Upper Cretaceous sediments, deposited close to the axial part of the Mid-Polish Trough (e.g., in the Roztocze Hills), constituted the deepest facies. In recent years, several studies have contradicted this notion. A growing body of data suggests that this area (southeast Poland) was already a landmass by the Coniacian and Santonian – and certainly in the Campanian and Maastrichtian – rather than forming the deepest part of the Polish Basin. The shallow marginal marine, cyclic middle Campanian, marly to sandy deposits, recently discovered in the Roztocze Hills, were interpreted to be of deltaic origin. This has led to the adoption of new facies and bathymetric models, which – notably – are in stark opposition to most previous interpretations. Notably, the new interpretation implies the presence of a landmass in the place where, in prior frameworks, the deepest and most subsiding part of the Polish Basin (i.e., Mid-Polish Trough) was located during the Cretaceous. Here, we document this Late Cretaceous depositional system – the Szozdy delta developed in the axial part of the Mid-Polish Trough. These middle Campanian deposits crop out extensively in the Roztocze Hills region, close to the village of Szozdy, and exhibit coarsening-upward tripartite cyclothems. Three facies associations have been distinguished: (1) dark grey calcareous mudstones, (2) a yellow calcareous sandstone, and (3) calcareous gaize lithofacies. The sequence, as a whole, was accumulated via the repeated progradation and abandonment of deltaic complexes on the delta front platform setting, with the primary transport direction originating from the axis of the inverting Mid-Polish Trough (thus from the subsurface San Anticlinorium) toward the northeast. This interpretation is supported by a suite of sedimentological, palynofacies, and heavy mineral data. The development of the Szozdy delta system is framed in the context of the dynamic tectonic processes operating contemporaneously in southeast Poland: that is, tectonic inversion (uplift) on one hand, and the generation of new accommodation space via enhanced subsidence on the other. This discovery sheds new light on our understanding of Late Cretaceous facies distribution, bathymetry, and paleogeography and might potentially suggest a different burial history than assumed so far.

Together but separate: decoupled Variscan (late Carboniferous) and Alpine (Late Cretaceous–Paleogene) inversion tectonics in NW Poland

Abstract. In Europe, formation of the Palaeozoic Variscan orogenic belt, and the Mesozoic–Cenozoic Alpine–Carpathian orogenic belt led to a widespread inversion events within forelands of both orogenic domains. We used legacy 2-D seismic data together with the newly acquired 3-D seismic data that, for the first time, precisely imaged sub-Zechstein (i.e. sub-evaporitic) upper Palaeozoic successions in NW Poland in order to develop a quantitative, balanced 2-D model of the late Palaeozoic–recent evolution of this area, characterised by a complex pattern of repeated extension and inversion. Four main tectonic phases have been determined: (1) Late Devonian–early Carboniferous extension and subsidence possibly related to extensional reactivation of Caledonian thrusts, (2) late Carboniferous inversion caused by the Variscan orogeny, (3) Permo-Mesozoic subsidence related to the development of the Polish Basin and (4) its Late Cretaceous–Paleogene inversion. Variscan and Alpine structures form a superimposed multilayer inversion system, mechanically decoupled by the Zechstein evaporites.

Middle and Late Jurassic tube-dwelling polychaetes from the Polish Basin: diversity, palaeoecology and comparisons with other assemblages

Middle and Late Jurassic tube-dwelling polychaetes from the Polish Basin: diversity, palaeoecology and comparisons with other assemblages

Tectonics of the Wysoka Kamieńska Graben (NW Poland) and implications for fault sealing potential

Reservoir confinement by faults is important for safe storage of liquid waste or hydrocarbons. Having access to 3D seismic and borehole data, we have interpreted the tectonic setting of the Wysoka Kamieńska Graben (WKG) in the NW part of the Polish Basin and subsequently made an interpretation of the sealing potential of the graben-bounding faults. The formation and development of the graben in the Late Triassic and Early Jurassic was controlled by mechanical decoupling in the salts of the Zechstein Group. The primary tectonic factor triggering the graben origin was dextral strike-slip movement along the regional fault zone in the Paleozoic basement, transtensional accommodation of which in the Zechstein-Mesozoic cover led to development of a horse-tail pattern of grabens. During the Late Cretaceous, the graben underwent minor tectonic inversion. Sealing potential analysis of the graben-bounding faults was performed for the Triassic–Jurassic sequence including juxtaposition seal and fault gouge seal components. Finally, we have focussed our interpretation on the Jurassic sequence where the best reservoirs have been recognized. Our results indicate good to moderate sealing potential of the Hettangian reservoir, poor to moderate sealing of the Pliensbachian reservoir and lack of sealing of the Bajocian reservoir. Hence, the Hettangian reservoir, characterized by large thickness, low clay content and a large regional extent, acts as a potential storage formation, being confined by the graben-bounding faults of the WKG

Impact of palaeo-wildfires on higher plant parameter revealed by new biomarker indicator

Palaeo-wildfires were a common phenomenon in the Earth history. Their products can influence on some biomarker indicators characterising palaeo-environment conditions. Selected plant-derived aromatic biomarkers and polycyclic aromatic hydrocarbons (PAHs) were analysed in the Jurassic strata from the Polish Basin, Jurassic strata from the Mesozoic basement of the Carpathian Foredeep and Neogene strata from the Carpathian Foredeep. Marked compounds recorded varied input from palaeoflora families and the variable intensity of palaeo-wildfires. Retene (Ret), cadalene (Cad), 6-isopropyl-1-isohexyl-2-methylnaphthalene (ip-iHMN), dehydroabietic acid methyl ester (DAME), simonellite (Sim), fluoranthene (Fl), benz[α]anthracene (BaA), benzo[α]pyrene (BaP), benzo[ghi]perylene (BgP), coronene (Cor) were identified in the analysed samples. Based on mentioned compounds, pyrolytic input ratio (PIR) defined as (Cad + Sim + TDHA+ip-iHMN+Fl + BaA + BaP + BgP + Cor)/(Cad + Sim + TDHA+ip-iHMN) was proposed. To provide broader possibility of use, the total dehydroabietic acid (TDHA) counted as sum of DAME and free dehydroabietic acid was used in PIR equation. PIR manage to define pyrolytic organic matter input. Combination of PIR with higher plant parameter (HPP) results, defined as Ret/(Cad + Ret), enables the distinction of samples deposited in a warm/hot and humid palaeo-climate from these deposited in more arid conditions, which were affected by palaeo-wildfires. Heretofore, high HPP values have been interpreted as an evidence of a warm/hot and humid palaeo-climate. This interpretation is true when PIR values are low. If the PIR values were higher, then the palaeo-wildfires influence on HPP was more significant and palaeo-climate misinterpretation was more probable. The new indicator can be used in case of immature or early mature and mostly terrestrial organic matter.

Investigation of Old Exploration Boreholes in the Lublin Basin with Regard to Potential Rotary-Percussion Drilling of Shale Gas Wells

The rotary-percussion drilling method is a prospective way to decrease drilling costs. It is obvious, based on literature analyses and finished geothermal drilling, that the Lublin Basin can be perceived as the one where rotary-percussion drilling can be used to drill an overburden of shale rocks. The paper explained the geology of the Lublin Basin, its’ geological structures, and the possibility of the use of drilling with a down-the-hole hammer, which could significantly decrease the cost of the whole shale gas drilling investment. Data collected from the wells drilled in the Lublin Basin were compared and analyzed to determine the viability of rotary-percussion drilling. Provided analyses showed that using the rotary-percussion drilling method in the Lublin Basin had a greater possibility of application than in other Polish shale basins (Baltic and Podlasie).