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Geologia miejsc niezwykłych : Uluru, Kata Tjuta, Kings Canyon w Australii

Nieć M., Mochnacka K., Sass-Gustkiewicz M.

Przegląd Geologiczny

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2016

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Vol. 64, nr 5

299--305

EN

Uluru, Kata Tjuta and Kings Canyon situated almost at the centre of Australia, on the borders of the Amadeus Basin, are prominent morphological landscape features. Their slopes are sculptured by weathering and erosion producing interesting varied forms. These sites are holy places for Aboriginal population. They provide an exceptional possibility to watch the links between natural phenomena and spiritual experience of the native people and their religious believes. The geographical, geological and cultural values of the sites make them unique geotouristic places.

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Preliminary results of sulphur isotope studies on sulfides from selected ore deposits and occurrences in the Karkonosze–Izera Massif (the Sudety Mts., Poland)

Mayer W., Jędrysek M.O., Górka M., Drzewicki W., Mochnacka K., Pieczka A.

Mineralogia

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2012

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Vol. 43, iss. 3/4

213--222

EN

Preliminary sulphur isotope data are presented for selected ore deposits and occurrences in the Karkonosze-Izera Massif, namely, polymetallic mineralization sites at Budniki, Ciechanowice, Izerskie Garby and Sowia Dolina, and the pyrite deposit at Wieściszowice. The data reveal two populations of δ34S values: from 2.74 to 3.95‰ (pyrrhotites and pyrites in Sowia Dolina, and some pyrites in Wieściszowice) and from 0.79 to 1.8‰ (pyrites in Budniki, Ciechanowice and Izerskie Garby, and some pyrites from Wieściszowice). All of the data are indicative of endogenic sulphur typical of hydrothermal mineralization despite the genetic differences between the sites.

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Ore mineralization in the Miedzianka area (Karkonosze-Izera Massif, the Sudetes, Poland): new information

Mochnacka K., Oberc-Dziedzic T., Mayer W., Pieczka A.

Mineralogia

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2012

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Vol. 43, iss. 3/4

155--178

EN

The Miedzianka mining district has been known for ages as a site of polymetallic ore deposits with copper and, later, uranium as the main commodities. Although recently uneconomic and hardly accessible, the Miedzianka ores attract Earth scientists due to the interesting and still controversial details of their ore structure, mineralogy and origin. Our examination of the ore mineralization from the Miedzianka district was based exclusively on samples collected from old mining dumps located in the vicinity of Miedzianka and Ciechanowice, and on samples from the only available outcrop in Przybkowice. In samples from the Miedzianka field, chalcopyrite, pyrite, galena, bornite, chalcocite, digenite, arsenopyrite, magnetite, sphalerite, tetrahedrite-tennantite, bornite, hematite, martite, pyrrhotite, ilmenite, cassiterite and covellite are hosted in quartz-mica schists and in coarse-grained quartz with chlorite. In the Ciechanowice field, the ore mineralization occurs mainly in strongly chloritized amphibolites occasionally intergrown with quartz and, rarely, with carbonates. Other host-rocks are quartz-chlorite schist and quartzites. Microscopic examination revealed the presence of chalcopyrite, pyrite, sphalerite, galena, tetrahedrite-tennantite, bismuthinite, native Bi, arsenopyrite, löllingite, cassiterite, cobaltite, gersdorffite, chalcocite, cassiterite, bornite, covellite, marcasite and pyrrhotite. Moreover, mawsonite and wittichenite were identified for the first time in the district. In barite veins cross-cutting the greenstones and greenschists in Przybkowice, we found previously-known chalcopyrite, chalcocite and galena. The composition of the hydrothermal fluids is suggested to evolved through a series of consecutive systems characterized, in turn, by Ti-Fe-Sn, Fe- As-S, Fe-Co-As-S, Cu-Zn-S and, finally, Cu-Pb-Sb-As-Bi compositions.

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Isotopic Re-Os age of molybdenite from the Szklarska Poręba Huta Quarry (Karkonosze, SW Poland)

Mayer W., Creaser R. A., Mochnacka K., Oberc-Dziedzic T., Pieczka A.

Geological Quarterly

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2012

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Vol. 56, No 3

505--512

EN

New Re/Os isotopic data for molybdenite from the Szklarska Poręba Huta Quarry provide ages of 307 ± 2 Ma and 309 ± 2 Ma, respectively. The quarry is dominated by the porphyritic (“central”) and equigranular (“ridge”) varieties of the Karkonosze granite. Ore mineralisation hosted in aplogranite includes an assemblage of sulphides, sulphosalts, oxides and various rare phases. The molybdenite ages obtained are consistent with a previously published isotopic age of leucogranite (aplogranite?) from the same quarry and are only slightly older than a recently published, refined 2 6Pb/238U age of untreated zircons from the Szklarska Poręba Huta porphyritic granite. The age of the molybdenite corresponds moderately well to the younger stage of post-magmatic, pneumatolitic/hydrothermal activity of the Karkonosze granite (about 312 Ma).

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Studies on magnetite and pyrite mineralization, and on their early Palaeozoic ocean-floor host-rocks from the Leszczyniec Unit (West Sudetes, Poland)

Oberc-Dziedzic T., Mochnacka K., Mayer W., Pieczka A., Creaser R. A., Góralski M.

Annales Societatis Geologorum Poloniae

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2011

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Vol. 81, No 2

133-160

EN

The Leszczyniec Unit extends along the eastern margin of the Karkonosze-Izera Massif. It comprises the Early Palaeozoic, MORB-like Leszczyniec complex composed of metabasites, metagranites and metasedi- ments. The metabasites host magnetite mineralization encountered in Jarkowice, whereas near Wieściszowice village the pyrite deposit occurs in metasediments and metabasites. The common feature of both sites is the almost complete absence of the accompanying ore minerals. Basing on petrographic, mineralogical, geochemical and microstructural studies, it was found that the metabasic rocks, which host magnetite mineralization, were lava flows, whereas the protoliths of pyrite-bearing schists were basic and acid tuffites accompanied by ocean-floor basalts. The igneous rocks from the Leszczyniec Unit were subjected to the ocean-floor metamorphism, whereas the accompanying sediments were altered by hydrothermal fluids enriched in sulphur ions, which reacted with iron derived from the sediment and promoted crystallization of pyrite. The sources of hydrothermal fluids were adjacent magmatic centres. The estimated age ~480 Ma for pyrite (Re-Os method) is similar to the previously known ~500 Ma age of metabasites (U-Pb, zircon method) from the Leszczyniec Unit, which establishes a temporal link between pyrite accumulation and the ocean-floor environment. The rocks of the Leszczyniec Unit, first altered by the ocean-floor metamorphism and the hydrothermal fluids, were subsequently subjected to the regional metamorphism at 360–340 Ma and the two-stage deformations of various intensities, followed by the third stage of deformations which caused the reorientation of the regional foliation. The zones of ductile and brittle deformations connected with the second deformation event host the accumulations of magnetite formed at the expense of Fe-bearing rock-forming minerals or from iron supplied from adjacent sources. In the pyrite-bearing schists, mineral assemblages formed during the hydrothermal alteration have been subjected to recrystallization and were included into domains defining foliation and lineation, which formed during the first stage of deformation. Pyrite crystals were affected by both deformation stages. At the end of the second stage, the invasion of fluids led to the dissolution of pyrite crystals and to the filling of cracks in pyrite crystals with chalcopyrite and tennantite. This process was followed by the formation of quartz veins with minor amounts of ore minerals.

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The Orthogneiss and Schist Complex of the Karkonosze-Izera Massif (Sudetes, SW Poland): U-Pb SHRIMP zircon ages, Nd-isotope systematics and protoliths

Oberc-Dziedzic T., Kryza R., Pin C., Mochnacka K., Larionov A.

Geologia Sudetica

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2009

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Vol. 41

3-24

EN

Many basement units of the Variscan orogen that are exposed in the Sudetes, SW Poland, comprise widespread ~500 Ma orthogneisses and associated mica schists, the latter often of unknown age and derivation. Our new U-Pb sensitive high resolution ion microprobe (SHRIMP) zircon ages from two samples of the Izera metagranites, both around 503 Ma, are in a good agreement with the well established late Cambrian-early Ordovician magmatism in the West Sudetes. An Archean inherited zircon age of ~ 3.4 Ga is one of the oldest zircon ages reported so far from the Bohemian Massif. The orthogneisses of the Karkonosze-Izera Massif (KIM) have calculated TDM ages of between 1.50 and 1.93 Ga, but these ages are not necessarily evidence for a Mid-Proterozoic crustal derivation: more probably, they reflect the average of several detrital components mixed into the granitoid magma sources. In spite of likely age differences, the Lusatian greywackes, which outcrop to the west, and the mica schists of the KIM display similar geochemical characteristics, suggesting that both could have been derived from similar sources. However, the presence of lower Ordovician products of within-plate volcanism - intercalations of quartzofeldspathic rocks and amphibolites within the mica schists - supports an idea that the mica schist protoliths, derived mainly from crustal rocks, could have also contained an admixture of contemporaneous volcanic materials. The age spectra of inherited zircons from the KIM orthogneisses and their Nd-isotopic signatures are comparable to the Lusatian greywackes: this suggests that the Lusatian greywackes, or very similar rocks, could have been the source material for the granitic protoliths of the KIM orthogneisses.

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New insights into the mineralization of the Czarnów ore deposit (West Sudetes, Poland)

Mochnacka K., Oberc-Dziedzic T., Mayer W., Pieczka A., Góralski M.

Geologia Sudetica

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2009

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Vol. 41

43-56

EN

This paper provides new data on the mineralogy and mineral chemistry of the Czarnów ore deposit, a polymetallic vein that occurs within the eastern envelope of the Karkonosze Pluton (West Sudetes). New data are also provided on the deposits' geothermometry, mineral succession, and origins. The Czarnów ore vein is about 500 m long, strikes SW-NE, dips 80° SE and continues to a depth of 200 m. It is hosted within the albite-mica schists, quartzofeldspathic rocks and striped amphibolites that comprise the Czarnów Schist Formation (CSF); its western part is composed of almost monomineral arsenopyrite, whereas the southwestern part locally contains a pyrrhotite lens that extends downwards. Although many types of sulphides, sulphoarsenides, sulphosalts and native phases accompanied by oxides and arsenates have been previously reported, this paper describes four minerals that have not been previously identified from the Czarnów deposit: ferrokësterite, ikunolite, bismite and pentlandite. Geothermometry data suggest formation temperatures of arsenopyrite between 551 °C and 420 °C and that of sphalerite between about 400 °C to about 200 °C. Fluid inclusion data from vein quartz gave homogenization temperatures between 430 °C and 150 °C. Integrat on of textural and other data suggests the following primary mineral succession: early arsenopyrite and cassiterite as the high-temperature phases; then combinations of pyrrhotite, pyrite, chalcopyrite and sphalerite, all of which formed over a wide temperature range; finally, low temperature galena and Bi phases. Secondary weathering products overprint the primary sequences. Cataclasis of the first-formed arsenopyrite imply that mineralization was related to at least one tectonic event in the region. The Czarnów ore deposit probably resulted from hydrothermal activity associated with the near Karkonosze granite.

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Ti remobilization and sulphide/sulphoarsenide mineralization in amphibolites: effect of granite intrusion (the Karkonosze–Izera Massif, SW Poland)

Mochnacka K., Oberc-Dziedzic T., Mayer W., Pieczka A.

Geological Quarterly

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2008

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Vol. 52, No 4

349-349

EN

Our studies focus on ore mineralization in a contact-metamorphic aureole, using the Variscan Karkonosze Granite pluton as an example. The Karkonosze in trusion is enveloped by an Early Palaeozoic (about 500 Ma) metamorphic complex of the Izera–Kowary Unit composed of a diverse assemblage of gneisses, granitic gneisses, schists, amphibolites and marbles. The Budniki ore mineralization site was discovered in the early 1950's at the SE margin of the pluton. The uneconomic Ti-ox ide/sil i cate, Fe-Cu-Ni-Co-sulphide-sulphoarsenide, and uranium mineral deposits are hosted within amphibolites which were subjected to regional metamor phism fol lowed by contact meta - morphism. The Ti mineralization includes an ilmenite-titanite assemblage that originated from regional-metamorphic transformation of igneous Ti-bearing minerals, such as ilmenite and tschermakite, of the basic protoliths of amphibolites. During subsequent contact metamorphism, ilmenite was decomposed and, after wards, Al-rich titanite and rutile were formed. The Ti remobilization was coeval with an early stage of superimposed Fe-Cu-Ni-Co-sulphide/sulphoarsenide mineralization (pyrrhotite, pyrite, pentlandite, arsenopyrite, chalcopyrite, sphalerite and Fe-Ni-Co-As-S phases), related to the activity of the Karkonosze Granite hydrothermal system. The ore minerals formed successively within a wide range of temperatures (625–250gradeC).

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Occurrence and genetic relationships of uranium and thorium mineralization in the Karkonosze Izera Block (the Sudety Mts, SW Poland)

Mochnacka K., Banaś M.

Annales Societatis Geologorum Poloniae

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2000

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Vol. 70, No. 2

137-150

EN

The paper summarizes available data on uranium and thorium deposits and occurrences in the Karkonosze-Izera Block (the Sudety Mts, SW Poland). The following types were distinguished: 1. Mineralization in the Karkonosze granite and its pegmatites: 1.1 disseminated broeggerite in granite, 1.2 uranium minerals filling the cracks in granite, 1.3 disseminated uranium and U-Th minerals in pegmatites, 2. Mineralization in the metamorphic cover: 2.1 uranium and thorium mineralization in nests, 2.2 pitchblende-fluorite mineralization in veins and nests, 2.3 pitchblende mineralization in veins and nests, 2.4 pitchblende-polymetallic mineralization in veins and nests, 2.5 vein- and nest-type secondary uranium mineralization, 2.5.1 secondary accumulations with traces of primary mineralization, 2.5.2 secondary accumulations without trace of primary mineralization. The origin of these accumulations is mostly related to the Karkonosze Granite and its hydrothermal activity.

PL

W pracy przedstawiono informacje dotyczące występowania złóż i przejawów mineralizacji uranem i torem w bloku Karkonosko-Izerskim. Wyróżniono następujące typy okruszcowania: 1 Mineralizacja w granicie Karkonoszy i w pegmatytach 1.1. broeggeryt rozproszony w granicie, 1.2. mineralizacja uranowa wypełniająca szczeliny w granicie, 1.3. mineralizacja uranowa i uranowo-torowa w pegmatytach, 2. Mineralizacja w osłonie metamorficznej: 2.1. mineralizacja uranowa i torowa w postaci gniazd, 2.2. smółkowo-fluorytowa mineralizacja w formie żył i gniazd, 2.3. smółkowa mineralizacja w formie żył i gniazd, 2.4. smółkowo-polimetaliczna mineralizacja w formie żył i gniazd, 2.5. wtórna mineralizacja uranowa w formie żył i gniazd, 2.5.1 ze śladami mineralizacji pierwotnej, 2.5.2. bez mineralizacji pierwotnej. W większości przypadków są to wystąpienia genetycznie związane z granitem Karkonoszy i jego działalnością hydrotermalną.