Petrographic-geochemical characterization of the dispersed organic matter in menilite shales from the Silesian Unit in the Carpathian mountains of SE Poland This article is devoted to the issue of dispersed organic matter present in Menilite shales. A total of 27 samples collected from 8 outcrops, representing various lithological types (mainly shales and mudstones) types, were examined with the use of microscopic (optical microscopy) and geochemical (Rock-Eval pyrolysis) methods. Maceral composition in investigated rocks is relatively monotonous. Liptinite macerals are usually the most numerous, while vitrinite macerals are less common. Inertinite macerals are very rare. The maceral composition suggest brackish environment. Results of both the vitrinite reflectance and the Rock-Eval pyrolysis show that the maturity level of the organic matter changes from the immature to the oil window phase. Maturity increases towards the south-east.Charakterystyka petrograficzno-geochemiczna rozproszonej materii organicznej w łupkach menilitowych z jednostki śląskiej w obrębie polskiej części Karpat Zewnętrznych Artykuł poświęcony jest zagadnieniu rozproszonej materii organicznej. Przy użyciu metod mikroskopowych (mikroskopia optyczna w świetle przechodzącym i odbitym) i geochemicznych (piroliza Rock-Eval) przebadano ogółem 27 próbek pobranych z 8 odsłonięć, reprezentujących różne typy litologiczne, głównie różnego rodzaju łupki i mułowce. Przebadane skały charakteryzują się stosunkowo monotonnym składem macerałowym. Dominują macerały grupy liptynitu, mniej licznie obserwuje się macerały grupy witrynitu, natomiast grupa inertynitu jest obecna jedynie incydentalnie. Skład macerałowy sugeruje środowisko brakiczne. Zarówno wyniki pomiarów refleksyjności witrynitu, jak i pirolizy Rock-Eval wskazują, iż stopień dojrzałości materii organicznej jest zmienny i waha się od stadium niedojrzałego po główne okno ropne, przy czym obserwuje się trend wzrostowy w kierunku południowo-wschodnim.Słowa kluczowe: łupki menilitowe, materia organiczna, refleksyjność witrynitu, liptynit, piroliza Rock-Eval.The Menilite Beds are one of the most interesting formations in the Carpathian Mountains, due to their diverse lithology, occurrence and dispersed organic matter content (its composition and maturity). These features have a great impact when considering them as potential source rocks and for that reason much attention is paid to them [2,4,[6][7][8][9][10][11][12][13][14][15][16][17].The aim of this article is to characterize the organic matter present in the Menilite shales (both its composition and maturity level). Menilite Beds have a complex lithology.Different types of shales (clay, marly, carbonate), as well as siltstones, mudstones, sandstones and cherts occur in the outcrops. This paper investigates whether the lithological character of rocks, influences the variability of the organic matter composition. The relationship of organic matter with basic geochemical parameters obtained from Rock-Eval pyrolysis (TOC, HI, T max ) was also analyzed...

Composition and thermal maturity of organic matter components from Menilite Beds (Skole Unit) were analyzed. Samples (26) were collected from 9 outcrops within the investigated area. Samples represented several lithologies-clay and marly shales, mudstones, sandstones/siltstones, micritic limestones and cherts. Macerals of three groups (vitrinite, inertinite and liptinite) are present in the analyzed samples. Macerals of the liptinite group are the most numerous. Within this group, bituminite is most common, while alginite and liptodetrinite are less often observed. Macerals of the vitrinite (collotelinite, telinite, vitrodetrinite) and inertinite (fusinite, semifusinite, inertodetrinite) groups are also present, but their content is significally lower compared to the macerals of the liptinite group. Organic matter within all the investigated area is clearly immature, which is confirmed by both vitrinite reflectance R o and T max parameters. The composition of organic matter relates mostly to kerogen type II and III (and their mixture). Several relations between Rock-Eval parameters and maceral composition were identified. The obtained results were compared to data from Menilite Beds of the Silesian Unit.

This article is devoted to the characteristics of dispersed organic matter in selected lithostratigraphic divisions of the Skole Unit in the area of the Polish fragment of the Carpathian Mountains. The aim of this research was to broaden the state of knowledge about the Skole Unit by aspects of organic matter petrography. Due to the size of the investigated area and the numerous lithostratigraphic divisions, the presented results should be treated as an introduction to the issue. The main emphasis is placed on microscopic analyses in reflected and UV light. Microscopic observations are enriched with the results of Rock-Eval pyrolytic analysis. The research material consisted of 37 rock samples collected from 3 selected regions. The samples represented various lithostratigraphic divisions -from Spas Shales, through Inoceramian Beds, Hieroglyphic Beds, Variegated Shales, up to Menilite and Krosno Beds. The analysed rocks are characterised by a variable content of organic matter -from trace (Variegated Shales), through low (TOC up to 0.5% -Inoceramian, Hieroglyphic and Krosno Beds), to relatively high (Spas Shales and Menilite Beds). In the maceral composition, macerals from all 3 groups -vitrinite (collotelinite, vitrodetrinite), liptinite (alginite, bituminite, sporinite, liptodetrinite) and inertinite (fusinite, semifusinite, inertodetrinite) -are observed. The group of liptinite macerals dominates in samples within the Spas Shales and Menilite Beds, as well as in some of the shales from the Krosno Beds. In the case of Inoceramian and Hieroglyphic Beds, macerals of the vitrinite and inertinite groups predominate. In the Spas Shales and Krosno Beds, the dominant maceral within the liptinite group is alginite, while in Menilite Beds, bituminite dominates. Alginite is present in nearly all (except Variegated Shales) investigated lithostratigraphic divisions. The content of macerals of the inertinite group is higher than the content of macerals from vitrinite group in the Spas Shales, Inoceramian Beds and in some rocks from Hieroglyphic Beds. The situation is opposite in the case of Menilite and Krosno Beds. The organic matter within all the investigated rocks is in the phase of thermal changes referred to as immature, as evidenced by the T max parameter reaching values lower than 435ºC. The examined rocks clearly differ in terms of the assessment of their hydrocarbon generation potential, which is the poorest for Variegated Shales and slightly better (but still poor) in the case of Inoceramian, Hieroglyphic and Krosno Beds. The best generation potential is observed in rocks collected from Spas Shales and Menilite Beds, with the latter having a generation potential defined as very good and even excellent.

Organic matter from Menilite Beds of the Dukla Unit was studied (optical microscopy, Rock-Eval pyrolysis). In its composition, macerals from vitrinite, liptinite and inertinite groups are observed. Macerals of the liptinite group are dominating (alginite, bituminite and liptodetrinite). Among all invested lithological types, mudstones have the highest average content of these macerals, while in case of marly shales, sandstones/siltstones, micrite limestones and chert the content of individual liptinite macerals is always lower than 1 vol%. The vitrinite group is represented mainly by collotelinite and vitrodetrinite and its average content in all analyzed lithologies does not exceed 1 vol%. Fragments of collotelinite show significant diversity in terms of the reflectance. Macerals of the inertinite group (fusinite, semifusinite, inertodetrinite) are usually limited to single occurrences within the entire investigated sample area. In 41 out of 43 samples, the collotelinite fragments were numerous enough that it was possible to measure the reflectance. For samples in which reflectance of vitrinite fragments was measured, this parameter ranges from 0.25% to 0.56%. Rock-Eval pyrolysis results provided additional information, of which the most important were values of TOC (from 0.47% to 6.04%, average 2.61%), T max (417-449°C), hydrogen (95-502) and oxygen (<133) indices. In the western part of the investigated area, within the tectonic window of Świątkowa, Menilite Beds are in the phase of oil window, while in other locations organic matter is immature. Analyzed samples contain types II, II/III or III of kerogen. Type II dominates in clay shales and mudstones, while type III is most often observed in marly and carbonate shales and also in sandstones/siltstones.

Utwory czerwonego spągowca, ze względu na obecne w nich złoża gazu, są od dziesięcioleci przedmiotem intensywnych badań geologicznych. Współcześnie obszar występowania tych utworów (dotychczas kojarzony ze złożami konwencjonalnymi) budzi zainteresowanie również pod kątem złóż niekonwencjonalnych (ang. tight gas). W artykule przedstawiono wyniki badań petrograficznych i granulometrycznych dla ponad 400 próbek, które przyporządkowane zostały facjom: eolicznej, fluwialnej, plai (jeziornej) oraz tzw. białego spągowca. W celu zbadania relacji pomiędzy składnikami szkieletu ziarnowego, spoiwami a rozkładem uziarnienia dokonano analizy korelacyjnej. Uzyskane wyniki powiązać będzie można z rezultatami analiz petrofizycznych (porowatość, przepuszczalność), co ułatwi stworzenie cyfrowych modeli 3D i umożliwi lokalizację potencjalnych złóż gazu.