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Depositional environment of Paleogen amber-bearing quartz-glauconite sands from Zdolbuniv (Rivne region, NW Ukraine): mineralogical and petrological evidences

Natkaniec-Nowak L., Dumańska-Słowik M., Naglik B., Melnychuk V., Krynickaya M. B., Smoliński W., Sikorska-Jaworowska M., Stach P., Kubica D., Ładoń K.

Gospodarka Surowcami Mineralnymi

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2017

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T. 33, z. 4

45--62

EN

Amber-bearing sands from Zdolbuniv mine are Paleogene fine-grained (0.6–0.12 mm) clastic rocks. The material is poorly rounded and moderately sorted out. It mainly consists of quartz, glauconite, and subordinately, feldspars (K-feldspars and plagioclases), mica, carbonates, zircon, epidote, fossil resins (Baltic amber) and ore minerals such as hematite, rutile, anatase, ilmenite. The presence of glauconite in the sands proves that sedimentation basin had to be marine reservoir. The variable composition of individual glauconite grains suggests the environmental conditions had to change during the sedimentation of clastic rocks. The occurrence of minerals, assembly such as zircon, epidote, ilmenite, rutile, anatase in the sands as well as the brown CL color of quartz grains, may suggest that majority of clastic material originated from metamorphic rocks, most probably coming from the Ukrainian Shield. Together with metamorphic material the fragment of fossil resins, i.e. Baltic amber, from the Paleogene off-shore forests could be transported to the sedimentation basin. Nowadays the bottom part of the analyzed profile is the most promising for the recovery of glauconite, whereas the exploration of Baltic amber may be initiated from the top of the profile.

PL

Piaski bursztynonośne z kopalni Zdolbuniv (obwód rowieński, NW Ukraina) to paleogeńskie, drobnoziarniste (0,6–0,12 mm) skały klastyczne. Materiał ziarnisty tych piasków jest słabo obtoczony i średnio wysortowany. Stanowią go głównie kwarc i glaukonit oraz występujące w podrzędnych ilościach: skalenie (K-skalenie i plagioklazy), miki, węglany, cyrkon, epidot, żywice kopalne (bursztyn) i minerały rudne, takie jak: hematyt, rutyl, anataz, ilmenit. Obecność glaukonitu wskazuje na środowisko morskie sedymentacji tego materiału. Duże zróżnicowanie składu chemicznego poszczególnych osobników glaukonitu sugeruje, że w trakcie sedymentacji materiału ziarnowego dochodziło do zmian warunków środowiskowych w samym basenie. Obecność w przedmiotowych piaskach takich minerałów, jak np. cyrkon, epidot, ilmenit, rutyl, anataz, jak i barwy ziaren kwarcu na obrazach CL wskazują, że większość materiału ziarnowego pochodzi ze skał metamorficznych, najprawdopodobniej budujących podłoże Tarczy Ukraińskiej. Wraz ze wspomnianym materiałem do basenu sedymentacyjnego mogły być transportowane fragmenty paleogeńskiej żywicy (bursztynu), pochodzące z pobliskich lasów. Analizowany profil piasków jest w dolnej części wzbogacony w glaukonit, podczas gdy górna jego część jest wzbogacona we fragmenty żywic kopalnych.

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Charakterystyka mineralogiczno-petrograficzna utworów klastycznych Gór Pieprzowych (Wyżyna Sandomierska) i produktów ich wietrzenia

Naglik B., Heflik W., Natkaniec-Nowak L.

Przegląd Geologiczny

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2016

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Vol. 64, nr 5

338--343

EN

Clay shales and mudstones from the Pieprzowe Mts. Shale Formation and their weathering cover were investigated for mineralogy and petrography in order to reconstruct weathering processes that led to crystallization of secondary sulphates. White crusts occurring on Cambrian pyrite-bearing rocks are a product of hypergenic alteration in low pH conditions and Al-rich environment. They are composed of pickeringite [MgAl2(SO4)4*22 H2O] accompanied by alunogen [Al2(SO4)3*17 H2O] and small amounts of epsomite [MgSO4*7H2O].

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Węgiel cenniejszy niż diament? – występowanie diamentów marmaroskich w południowo-wschodniej części Górnośląskiego Zagłębia Węglowego

Musiał A., Naglik B., Sermet E., Wyrobek P.

Górnictwo Odkrywkowe

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2016

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R. 57, nr 5

53--57

PL

Praca przedstawia wstępne wyniki badań kryształów kwarcu, które potocznie nazywane są „diamentami marmaroskimi”. W badaniach wykorzystano okazy pochodzące z południowo - wschodniego obrzeżenia Górnośląskiego Zagłębia Węglowego. Opisywane kryształy kwarcu występują w skałach płonnych, prawdopodobnie w warstwach siodłowych. Wykorzystano metodę spektroskopii ramanowskiej (RS), która pozwoliła na identyfikację minerałów kwarcu oraz poznanie charakteru inkluzji w nim występujących. W pracy po raz pierwszy przedstawiono dowody naukowe na występowanie diamentów marmaroskich w obszarze Górnośląskiego Zagłębia Węglowego.

EN

This paper presents the preliminary research of the quartz crystals commonly known as “marmarosh diamonds”. The area of the research is in the south-east part of the Upper Silesian Coal Basin (USCB). Raman spectroscopy method was used to identification the quartz crystals and recognision of the character of inclusions.

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Mineral assemblages as a record of the evolutionary history of the Pepper Mts. Shale Formation (the Holy Cross Mts.)

Naglik B., Natkaniec-Nowak L., Heflik W.

Geology, Geophysics and Environment

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2016

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Vol. 42, no. 2

161--173

EN

The Pepper Mts. Shale Formation, consisting of: clayey shales, mudstones and sandstones, as one of the oldest unit of the Holy Cross Mts., was subjected to mineralogical and petrographical studies. In order to reconstruct the geological history of the succession, mineral assemblages were characterized from the genetic point of view. Pyrite and goethite taking a form of bacterial-cell pseudomorphoses, crystallized during sedimentation and/or diagenesis, while quartz, kaolinite, goethite and chlorite prove subsequent alteration due to the hydrothermal fluid circulation. Secondary sulphates occurring on the pyrite-bearing rock outcrops mark the way of weathering processes. According to the presented results, Cambrian sediments were affected by hot fluids, which caused mineral recomposition and maturing of organic matter. Under the hypergenic conditions sulphate crust precipitate with pickeringite [MgAl 2 (SO 4 ) 4 ∙ 22H 2 O], as a dominant phase accompanied by alunogen [A l 2 (SO 4 ) 3 ∙ 17H 2 O] and small amount of epsomite [MgSO 4 ∙ 7H 2 O].

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Pickeringite from the Pieprzowe Mts. (the Holy Cross Mts., Central Poland)

Naglik B., Natkaniec-Nowak L.

Geology, Geophysics and Environment

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2015

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Vol. 41, no. 1

114--115

EN

The Pieprzowe Mts., which constitute the eastern part of the Holy Cross Mts. (Central Poland), are considered a large complex of mid-Cambrian strata (Alexandrowicz 1972). In a 2-km long exposure of the Pieprzowe Mts succession, along the Vistula River bank near the town of Sandomierz, shales, quartz-mica shales, quartzites, sandstones, mudstones and conglomerates are outcropping. All shaly facies are enriched in pyrite. The occurrence of secondary minerals in the weathering zone of the mid-Cambrian shale formation in the Pieprzowe Mts. is known for an extended period of time. Differences in color eff lorescence observed on the weathered surface were considered as alum incrustations; hence, the term “alum shale” has been used with reference to these rocks. The phase composition of fine-crystal aggregates was determined by Kuhl (1931). Based on observations under polarizing microscope, he interpreted them as a composition of mirabilite, epsomite and alunogen, thus contradicting his earlier hypothesis about pickeringite occurrence. Pickeringite is a sulphate mineral owing its origin to oxidation of pyrite in low pH conditions (Kruszewski 2013) and is a member of the halotrichite group with theoretical formula MgAl2(SO4)4 ∙∙ 22 H2O. However, chemically pure pickeringite is rare as most of its occurrences form transitional phases between pickeringite and halotrichite (Parafiniuk 1991). This mineral is usually observed in aggregates with other sulphates; the most common association consists of alunogen and epsomite. Crystallization and preservation of pickeringite depend on air humidity, which results from its high solubility in water (Balcerzak et al. 1992, Parafiniuk 1991). The aim of this study is to describe conditions of pickeringite crystallization in the weathering zone of the Pieprzowe Mts. shale formation. SEM-EDS analysis made it possible to detect three types of sulphide minerals occurring within aggregates. The most common is pickeringite forming elongated crystals with smooth surfaces, which demonstrate absence of dissolution processes. Fibers of pickeringite are associated with a mineral of tabular shape named alunogen – Al(SO4)3. Epsomite was detected in subordinate quantities. XRD analysis confirmed the polymineral character of efflorescenes. The main ref lex for pickeringite (ca. 4.80 Å) is fragmented into two peaks: (1) 4.8061 Å and (2) 4.7958 Å. These values are reduced as compared to ICDD data, which could result from admixtures of other sulphates, alunogene and epsomite. Another options is that this reduction means that pickeringite is forming transitional phase into halotrichite, which has its maximum reflex at 4.81 Å. This could be confirmed by chemical composition (Fe impurities). The Pieprzowe Mts. shale formation presents specific conditions favouring evaporation of pickeringite. The elements required for pickeringite crystallization originate from the host rocks. The source of Al3+could be kaolinite, which is common as a product of alteration processes as well as an authigenic compound. Processing of micas transformation causes environmental enrichment in Mg2+. The published sources indicate that the presence of pyrite is a key-factor for pickeringite crystallization. However, this mineral is also typical for shales present in the Carpathian rock units, where as a product of pyrite oxidation jarosite and gypsum are common. This suggests that some other initiator is required for the formation of pickeringite. It has been suggested that surface evaporation of groundwater causes the precipitation of sulphates (Cody & Briggs 1973 vide Parnell & Roderic 1982). The Pieprzowe Mts. shale formation contains dense network of veins so it is possible that waters from deeper layers are able to migrate into the subsurface. Some documented occurrences of pickerigite are related to arid regions. Certainly, an important role is played by humidity – southern exposure and poor plant cover of the Pieprzowe Mts. could be the reason why pickeringite may not only crystalize but also exist there. Most of the pickeringite occurrences in Poland are associated with rocks of old units (mid-Cambrian in age in the Pieprzowe Mts., Proterozoic in Wieściszowice and in Krobica quarry). Older rocks are poor in carbonates so it could mean that pH is a more important factor conditioning pickeringite crystallization than pyrite occurrence. Pickeringite was found also on burning coal-mining dumps in the Upper Silesian Coal Basin (Kruszewski 2013), what confirm that pH determines crystalization of this mineral. Correlation between pickeringite and other sulphates is also interesting. Alunogen associated with pickeringite crystalize when the delivery of Mg2+is reduced. Paragenesis consisting of alunogene, epsomite and pickeringite could be a result of different solubility of these phases or changing of Mg2+and Al3+ions during evaporation processes. The following sequence of crystallization is proposed: alunogene-pickeringite-epsomite.

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Preliminary results of mineralogical investigations of Cambrian rocks from the Pieprzowe Mts. (Sandomierz Upland, Poland)

Naglik B., Heflik W., Natkaniec-Nowak L.

Geology, Geophysics and Environment

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2014

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Vol. 40, no. 1

112--113

EN

The mid-Cambrian rocks exposed in a topographic scarp adjacent to the Vistula River within the Pieprzowe Mts. (Sandomierz Upland, South East Poland) were the subject of preliminary petrological and mineralogical studies. The Pieprzowe Mts. are a unique geological feature because of their unusual pepper-like coloured weathering cover. The Pieprzowe Mts. are a stratotype area for the Pieprzowe Mts. Shale Formation (mid-Cambrian) defined by Orłowski (1975). This formation consists of the following sedimentary and meta-sedimentary rocks: clay shale, quartz-mica schist, quartzite and conglomerate. Despite over 150 years of research on this formation some geological and mineralogical problems are still awaiting explanation (for example the origin of phosphate nodules in conglomerate layers). The scarcity of fossils and complicated tectonic structure of the formation are the reasons why its sequence stratigraphy is especially difficult to detect. Trilobites characteristic for the mid-Cambrian were found only at one locality within the conglomerate layers, and this age was extrapolated to other units of the Pieprzowe Mts. Shale Formation. Michniak (1969) claims that the same age cannot be ascribed to the whole rock succession because of petrographic diversity of the constituting rock types. Kowalczewski (1995) suggests that the age of the formation should be extended from the Early Cambrian to Early Ordovician (Early Tremadocian). Majority of research devoted to the Pieprzowe Mts. strata focused on stratigraphy, sedimentology and tectonic analysis. Petrographic descriptions of those rocks were given by Samsonowicz (1916, vide Orłowski 1964) but mineralogical analyses were done rather sporadically (Kuhl 1931a, b, Michniak 1969). This paper is devoted to the preliminary mineralogical description of quartz-mica schists and quartzites. The analysis involved observations under transmitted light polarizing microscope. In addition, scanning electron microscopy (SEM) equipped with Energy Dispersive Spectroscopy detector (EDS) was used. During preliminary studies of quartz-mica schists, it was found that quartz, which is a dominant component of this rock occur as both, terrigenous grains and authigenic filling of veins. Quartz is also present within the lithic grains of quartzites that are common in the quartz-mica schists. Kaolinite appears in two genetic forms: (1) as a product of mica transformations, and (2) as an authigenic mineral. Accessory mineral assemblage consists of zircon, framboidal pyrite and Ti-oxides. The Fe-oxides result from chemical weathering. In the mineral composition of quartzites angular, xenomorphic, nonundulatory quartz prevails, which is locally impregnated with phosphates. A single grain of apatite was encountered. Very fine veins composed of secondary carbonates occur within the rock. Accessory minerals are represented dominantly by piryte, which does not have the framboidal character typical for sedimentary rocks. In the light of the aforementioned preliminary results, it is inferred that these rocks were subjected to strong diagenesis and bear traces of hydrothermal processes. Presence of apatite in quartzites sheds a new light on the problem of the origin of phosphate nodules within the conglomerates. According to the present study, the authors suggests that the quartzites may be older than the quartz-mica schists, based on the presence of quartzite lithic grains within them. This paper informs about the research project aiming to characterize the weathering products occurring within the Pieprzowe Mts. It can be observed that a lot of secondary minerals is present here such as: kaolinite, alunite (Kuhl 1931a, b), Fe and Mn-oxides. It seems that weathering processes and theirs products are still not sufficiently explained. There is a hypothesis that jarosite could also form here. Further research will be carried out using various analytical techniques to improve our understanding of these processes.