Panstwowy Instytut Geologiczny

Warsaw, Poland

Panstwowy Instytut Geologiczny

Warsaw, Poland

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Results of sedimentological and petrological studies of drill cores from two boreholes drilled in the northern part of the Carpathian Foredeep by the Polish Geological Institute in 2009-2010, accompanied by the complex palaeontological, geochemical-petro-graphic, isotopic, mineralogical and palaeomagnetic analyses have enabled to characterize the development and depositional history of the Upper Neogene deposits. The Upper Neogene series consists of monotonous clastics (mainly siltstones, claystones and marls) of Upper Badenian and Lower Sarmatian age. The Badenian-Sarmatian transition is a continuous succession without any lithological expression. The well sections represent the more nearshore (Busko (Młyny) PIG-1) and the more offshore (Kazimierza Wielka (Donosy) PIG-1) zones of the Neogene marine basin of the Carpathian Foredeep. A distinct geochemistry change is recorded later in the Kazimierza Wielka (Donosy) PIG-1 section than in the Busko (Młyny) PIG-1 section, there it took place a little bit earlier than the noticed change in the foraminiferal assemblages from the Badenian to the Sarmatian type. Anyway, the new fauna (bivalves and nannoplankton), associated with the Sarmatian transgression, occurred in the sections earlier than the general geochemical transformation of the basin. All observed faunal and geoche-mical changes took place in a deep-marine environment, with a calm deposition from suspension, before the episodes of turbidite activity. Two of numerous tuffte interbeds have been regionally correlated and the upper one is located above the registered normal (C5AAn) to reversed (C5Ar.3r) polarity change (Kazimierza Wielka (Donosy) PIG-1), dated at 12.8 ±0.1 Ma.


The Lower Palaeozoic basin at the western slope of the East European Craton (EEC) (Fig. 1) is currently recognized as one of the most interesting areas for shale gas exploration in Europe. The Upper Ordovician and/or Lower Silurian graptolitic shale is here the major potential reservoir formation (Figs. 2, 3) (Poprawa & Kiersnowski, 2008; Poprawa, 2009). Moreover, the Upper Cambrian to Tremadocian Alum shale is an additional target locally in the northern part of the Baltic Basin. These sediments are often rich in organic matter (Klimuszko, 2002; Poprawa & Kiersnowski, 2008; Wiȩcław et al., 2010; Skŗet & Fabiańska, 2009), as well as silica. Limited data from two wells in the western part of the Baltic Basin show silica contents up to 60-70% (Fig. 4) (Krzemiński & Poprawa, 2006). The advantage of the Lower Palaeozoic shale from the western slope of EEC is its broad lateral extend (Fig. 1) and relatively quiet tectonic setting. The later is particularly true in the case of the Baltic Basin and Podlasie Depression. Structural development becomes to some extent more complex in the case of the Lublin region, where the Lower Palaeozoic shale appears affected by late Famennian to early Visean block tectonics. Development of the organic rich Lower Palaeozoic shale at the western slope of EEC was controlled by several factors. Very important was here the rate of non-organic detritus deposition (Fig. 5). The other factors included organic productivity of the basin, its subsidence, relative sea level changes, basin bathymetry, geochemical conditions at the sea bottom (especially oxygenation), degree of bioturbation, presence of topographic barriers at the sea bottom, leading to development of isolated anoxic zones, sea currents configuration, and climate changes. Organic matter of the Lower Palaeozoic is characterized by presence of II type of kerogen. Appearance of the organic-rich shale within the Lower Palaeozoic section at the western slope of the EEC is diachronic (Fig. 6). From NW towards east and SE, the intervals richest in organic appear related to systematically younger strata, startingfrom the Upper Cambrian to Tremadocian, as well as the Upper Llanvirn and Caradoc in the Leba Elevation (northern onshore Baltic Basin; Fig. 7). In central parts of the Baltic Basin and Podlasie Depression as well as NWpart of the Lublin region, the intervals richest in organic matter are found in the Llandovery section, while in the eastern part of the Baltic Basin and SE part of the Lublin region the highest TOC contents are found in the Wenlock. Therefore, depending on location at the western slope of EEC, different formations are recognized as the targets for shale gas exploration. The Upper Cambrian to Tremadocian shale, present only in the northern part of the Baltic Basin, is characterized by very high contents of organic matter, with average value for individual sections usually ranging from 3 to 12% TOC. This shale formation is, however, of very limited thickness, not higher than several meters in the onshore part of the basin (Szymański, 2008; Wiȩcław et al., 2010). In onshore part of the studied area, thickness of the Caradoc shale changes from a few meters up to more than 50 m (Modliński & Szymański, 1997, 2008). Contents of organic matter in these sediments are the highest in the Leba Elevation zone and the basement of the Plock-Warszawa trough, where average TOC contents in individual well sections range from 1% to nearly 4%. Ashgill rocks are characterized by high TOC contents only in the Leba Elevation zone, where average TOC values for individual well sections rise up to 4,5% at the most. Llandovery shale has high TOC contents, particularly in its lower part, throughout vast parts of the western slope of EEC. The maximum measured TOC contents in those rocks in Podlasie Depression are nearly 20%. Average TOC values for individual sections of the Llandovery are usually equal 1% do 2, 5%, except for the Podlasie Depression, where they may reach as much as 6%. Thickness of the Llandovery shale generally increases from east to west to approximately 70 m at the most. However, in the major part of that area it ranges from 20 to 40 m (Modliński et al., 2006). Thickness of the Wenlock sediments is also highly variable laterally, from less than 100m in SE part of the Lublin region to over 1000 m in western part of the Baltic Basin. Average content of organic matter in individual Wenlock sections in central and western parts of the Baltic Basin and the Podlasie Depression usually ranges from 0,5% to 1,3% TOC. In the eastern part of the Baltic Basin and in the Lublin region it is higher, rising to about 1-1,7% TOC. The above mentioned TOC values show the present day content of organic matter, which is lower than the primary one. The difference between the present and primary TOC contents increases along with increasing thermal maturity. It is also highly dependant on genetic type ofkerogen. Taking into account the II type ofkerogen from the analyzed sediments, it may be stated that in the zones located in the gas window the primary TOC was at least one-half greater than indicated by laboratory measurements. From the shale gas point of view, the basins at the western slope of EEC are characterized by a negative relation between depth at present day burial and thermal maturity (Poprawa & Kiersnowski, 2008). In the zones with burial depth small enough to keep exploration costs at very low level (Fig. 8), thermal maturity of shales is too low for gas generation (Figs. 9, 12a). Maturity increases westwards (Fig. 8) along with depth of burial (Fig. 9). Thus, the potential shale gas accumulations in the western part of the studied area occur at depths too high for commercial gas exploration and exploitation (Fig. 12b). Between of the zone of maturity too low for shale gas development and that where depth of burial is too large for its exploration, there occurs a broad zone of the Lower Palaeozoic shale with increased shale gas exploration potential (Fig. 13) (Poprawa & Kiersnowski, 2008; Poprawa, 2009). In that area, there are shale intervals of relatively high thickness and average TOC exceeding 1-2% TOC (Fig. 7, 10, 12c). Thermal maturity of these rocks appears sufficient for generation of gas (Fig. 9, 10), and results of well tests for deeper-seated conventional reservoirs suggest good quality of dry gas with no nitrogen (Fig. 12c). It should be noted that some gas shows have been recorded in the Lower Palaeozoic shale. Moreover, depth of burial is not too large for commercial shale gas exploration (Fig. 8, 10). Hydrocarbon shows and their composition in the Lower Palaeozoic are strictly related to thermal maturity of the source rock. In the zones of low maturity, these are almost exclusively oil shows documented. Further westwards, in the zone transitional to the gas window area, gas is wet and contains significant contribution of hydrocarbon gases higher than methane. Within the gas window zone, the records are almost exclusively limited to methane shows. Moreover, within the zones of low maturity high nitrogen contents were recorded (Poprawa, 2009). In the zones characterized by thermal maturity in the range from 0,8 to 1,1% Ro and very high TOC contents (over 15% at the most), there is a potential for oil shale exploration. The zones with the highest oil shale potential include eastern Baltic Basin in SW Lithuania and NE part of the Podlasie Depression. Some data necessary for entirely firm estimations of potential shale gas resources of the Lower Palaeozoic complex in Poland are still missing. However, preliminary estimates indicate that these shale gas resources may possibly be classified as gigantic (1,400-3,000 bin m3 ofrecoverable gas; Fig. 15). For comparison, resources of conventional gas in Poland are equal to 140,5 bln m3, and annual domestic gas consumption is at the level of 14 bin m3. However, it should be noted that some characteristics of the Lower Palaeozoic complexes indicate increased exploration risk. The average TOC contents are here lower than in classic examples of gas shales, like e.g. Barnett shale. Moreover, in the zone of optimal burial depth (less than 3000-3500 m) thermal maturity is lower than in the case of the Barnett shale core area. An important risk factor is also both a limited amount and limited resources of conventional gas fields in the Lower Palaeozoic complex (Fig. 13). Amount and intensity of gas shows in the Lower Palaeozoic shale are also relatively low, and there is no evidences for presence of overpressure in this complex. In the eastern part of western slope ofthe EEC, there appears an additional risk factor-a relatively high content of nitrogen in gas.


The last two decades witnessed a significant progress in understanding unconventional hydrocarbon systems, exploration and developments in technology, which led to substantial increase of tight gas and shale gas production. This progress occurred mainly in USA, where unconventional gas production currently stands for ∼50 % of annual domestic gas production, and it is forecast to increase to more than 60 % in 2016. Recoverable shale gas resources of USA and Canada are estimated at present for at least ∼20 trillion m3 (∼750 Tcf). Shale gas is a unique hydrocarbon system in which the same rockformation is a source rock, reservoir rock and seal (Figs. 2, 3). Gas field often appears continuous at a regional scale and does not requires hydrocarbon trap (Fig. 3). For development of shale gas, a high TOC contents (> 1-2 %) is required for relatively thick formation (> 30-70 m). High thermal maturity is essential for gas generation (>1.1-1.3 % Ro), and relatively low depth of burial (3500-4500 m) is necessary for commercial gas production. Gas is accumulated in isolated pores or adsorbed by organic matter (Fig. 5). Gas exploitation requires dense grid of wells with horizontal intervals and multiple fracturing. Shale gas is currently produced in several basins in USA and Canada. American success in unconventional gas production led to intensive shale gas and tight gas exploration across the world, with Europe being one of the priorities (Fig. 7). At the current stage, a couple of European sedimentary basins were selected as the major shale gas exploration targets. This includes predominantly the Lower Jurassic shale in the Lower Saxony Basin in Germany, the Alum shale in Scania (Southern Sweden), and to a lesser degree, the South-Eastern Basin in France with its Lower Jurassic and Lower to Upper Cretaceous shales, the Paris Basin in France with the Lower Jurassic shale, the Upper Jurassic shale in the Vienna Basin, the Lower Cretaceous Wealden shale in England, the Bodensee Trough in SW Germany with the Permian-Carboniferous shale, and the cenozoic Mako Trough in Hungary. In Europe the most intense exploration for shale gas is currently being carried out in Poland. The major target in that exploration is the Lower Palaeozoic shale at the East European Craton (Baltic and Lublin-Podlasie Basin), mainly the Upper Ordovician and/or Lower Silurian graptolitic shale (Fig. 8) (Poprawa & Kiersnowski, 2008; Poprawa, 2010). For that formation, Wood Mackenzie and Advanced Resources International estimated recoverable gas resources as equal to 1,400 mld m3 and to 3,000 mld m3, respectively. Also the Lower Carboniferous shale of the south-western Poland (area of Fore-Sudetic Homocline; Fig. 8) could potentially accumulate gas, however in this case a limitation to potential for shale gas is a complex tectonic setting. Other black shale formations in Poland appear to have lower potential for shale gas exploration due to insufficient thermal maturity, low TOC, or low thickness.


The paper presents the characteristics of the oldest groups of organic microfossils found in two new boreholes (Trojanowice 2 and Cianowice 2) located on the opposite sides of the Kraków-Lubliniec fault zone separating the Upper Silesian and Małopolska blocks. Detailed palynological research allowed determining the age of clastic sediments drilled under the Jurassic and Devonian. Two characteristic microfossil assemblages have been documented: the Late Ediacaran assemblage dating the age of the Małopolska Block basement, and the Terreneuvian assemblage, known from the oldest Cambrian sediments of the Upper Silesian Block. The se associations of organic microfossils include the oldest representatives of bacteria, algae, fungi and animals.


Seven prospective areas have been delineated for gold deposits of vein and metasomatic types in the Sudetes (Kłodzko-Złoty Stok, Southern Kaczawa Mountains and Rudawy Janowickie prospective areas), on the Fore-Sudetic Block (Wądroże Wielkie) and in the contact zone of the Małopolska Block with the Upper Silesia Block (Dolina Będkowska, Pilica and Mysłów prospective areas). In total they are covering ca. 285.5 km2, (ca.252 km2 in the Sudetes and ca. 22 km2 on the Fore-Sudetic Block). The prospective areas were recognized on the basis of current regulations, which defined marginal parameters of specific deposit and delineated its borders together with application of adequate quantitative Au deposit models supported by ore parameters from the old mining records. Total predicted/estimated gold resources (prognostic + prospective resources), which are depending on the applied parameters, are from ca. 9.4 Mg (for n = 16 ore bodies) to 21.5 Mg (for n = 64 o.b.). The auriferous ores of the vein and metasomatic types (blind bodies) are associated with the metamorphosed volcanic-sedimentary Paleozoic formation in Lower Silesia and with contact-metasomatic zones around Variscan granitoid intrusions in southern Poland. The greatest estimated Au resources were recognized in the following areas: Klodzko-Zloty Stokca. 6.3 Mg Au (for n = 7 o.b. -skarns, veins and beresites), Southern Kaczawa Mountains - ca. 4.8 Mg Au (forn = 15 o.b.) and Rudawy Janowickie - ca. 4.5 Mg Au (for n -20 o.b. of vein and/or skarn types). In the contact zone of the Malopolska Block with the Upper Silesia Block the prospective areas are associated with the marginal zones (epithermal Au veins) around the granitoid/porphyry-related mineralization of the Mo-Cu-W type. The limited ore prospecting causes difficulties in estimation of Au resources in that area. The available data has allowed for a rough estimation of Au resources from ca. 1 to 3.5 Mg (for n = 5-21 o.b.). In most of the recognized Au prospective areas, auriferous mineralization is in paragenetic association with refractory gold sulfides and only sporadically appears as native gold or electrum mineralization (mainly in quartz veins). A new stage of gold prospection is highly recommended especially within the abandoned gold mining areas in the Sudetes. An application of modern geophysics (VLF and IP) followed by shallow drillings should bring new discoveries of gold deposits. In the report, environmental and spatial conflicts have also been pointed out within the specific gold prospective areas in relation to the presence of National Parks, NATURE 2000 areas, underground water reservoirs, etc.


The results of detailed analysis of calcareous nannoplankton in Miocene deposits from the northern part of the Carpathian Fore-deep enabled stratigraphic conclusions. Marly clays of the uppermost part of the Skawina Formation in the Busko (Młyny) PIG-1 borehole section are correlated with the NN5 Sphenolithus heteromorphus Zone that corresponds with the Middle Badenian in the Paratethys and the upper Langhian/Lower Serravalianinthe Mediterranean region. The Krzyżanowice Formation, which includes evaporites (gypsum and clay intercalations), and the Machów Formation represent the NN6 Discoaster exilis Zone. By a comparison with other Paratethyan basins, the Badenian/Sarmatian boundary is proposed just below a 20-metres thick set of diatomaceous siltstone layers. Among the calcareous nannofossil species, the appearance of Rhabdosphaera poculi Bóna et Kernerne and Rhabdosphaera procera Martini may point to the Lower Sarmatian transgression. Clayey sequences of the Machów Formation in the Kazimierza Wielka (Donosy) PIG-1 borehole correspond with the NN6 Discoaster exilisZone. Abundanceofdiatom floras observedinthe Busko (Młyny) PIG-1 borehole suggests aproximity of a river mouth that supplied water with nitrates, phosphates and silica. Preservation of delicate siliceous diatom frustules was possible due to rapid deposition of clastic sediments above diatomaceous siltstone.


Micropaleontological study of Miocene deposits from the Busko (Młyny) PIG-1 and Kazimierza Wielka (Donosy) PIG-1 boreholes, located in the northern part of the Carpathian Foredeep, has allowed taxonomic and biostratigraphic characteristics of foraminiferal assemblages. The samples were taken from clay and clay-marly interbeds in sub-evaporitic, evaporitic and supra-evaporitc complexes. In the Busko (Młyny) PIG-1 borehole, five foraminiferal assemblages have been defined (Z.b.I-Z.s.V), corresponding with the following foraminiferal zones: Orbulina suturalis/Praeorbulina - Z.b.I (Moravian substage of the Early Badenian), Neobulimina longa - Z.b.II; Velapertina indigena - Z.b.III, Hanzawaia crassiseptata - Z.b.IV (Kosovian substage of the Late Badenian) and Anomalinoides dividens - Z.b.V (Volhynian substage of the Early Sarmatian). In the Kazimierza Wielka (Donosy) PIG-1 borehole, two foraminiferal assemblages have been identified (Z.b.I and Z.s.II), correlated with following foraminiferal zones Velapertina indigena - Z.b.I (Kosovian substage of the Late Badenian) and Varidentella sarmatica - Z.s.II (Volhynian substage of the Early Sarmatian). The third assemblage (Z.s.III), because of poor preservation of foraminifers has been attributed to the Sarmatian stage in general. Lateral replacement of planktonic and benthonic foraminiferal assemblages confirms a significant facies variability of the Late Badenian deposits that accumulated in the northern margin of marine basin in the Carpathian Foredeep.


The Middle Miocene evaporite horizon of the Carpathian Foredeep is overlain by thick marine clastic series. This lithologically monotonous complex records continuous sedimentation in most of the area and is of Badenian and Sarmatian age. The Badenian-Sarmatian boundary is ambiguous with respect to biostratigraphic subdivision and comprises a relatively long interval depending on locality within the Carpathian Foredeep. Chemostratigraphic analyses, comprising isotopic (carbon and oxygen) as well as major and trace elemental compositions of the Badenian-Sarmatian transition zone in the Busko (Młyny) PIG-1 and Kazimierza Wielka (Donosy) PIG-1 boreholes from the northern part of the foredeep, accordingly indicate that distinct geochemical changes occur at depths of c. 104 m and c. 136 m, respectively. The geochemical changes recorded in this transitional boundary zone refect wider, regional changes in sediment material composition in both the regions, where the boreholes are located. These changes may be linked to the Badenian/Sarmatian chemo-stratigraphic boundary in the northern part of the Carpathian Foredeep.


The paper presents the results of grain size and mineral content studies of six samples taken from Middle Miocene deposits (Machów Formation) in the Kazimierza Wielka (Donosy) PIG-1 borehole. The distinguished garnet association with zirconium, tourmaline, staurolite, and biotite suggests the Carpathian Flysch Belt as the most possible source area of the detrital minerals in the formation.


One of the elements of the mineral deposit prospectivity analysis is the evaluation of land surface in terms of the conditions and possible restrictions on the potential exploitation of ores, which are connected with diverse forms of land use and protecting valuable nature areas. In the article the quantitative method of cartographic environmental analysis of the accessibility of mineral deposit areas is presented, based on the evaluation of land cover (CORINE Land Cover) and legal protected areas by the GIS system application. The core of the method is the point bonitation made in the specially calculated grid of elementary fields. The method was used to show and evaluate both the spatial planning and nature protection conditions for thepotenlial exploitation in prospective areas of selected raw materials, such as: metal ores and gypsum, rocksalt, K-Mg salts and native sulphur in Poland. The prospective areas with estimated resources were presented on maps at scale 1:200 000. The results are presented in the cartographic form, allowing appointing locations for mine investments.

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