1992

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Alphabetical by the first author's surname

BAKUN-CZUBAROW, NONNA
Institute of Geological Sciences, Polish Academy of Sciences, Zwirki i Wigury 93, 02-089 Warszawa, Poland
QUARTZ PSEUDOMORPHS AFTER COESITE AND QUARTZ EXSOLUTIONS IN ECLOGITIC OMPHACITES OF THE ZLOTE MOUNTAINS IN THE SUDETES (SW POLAND)
Archiwum Mineralogiczne v. 48, no. 1-2, p. 3-25, 1992

Quartz pseudomorphs after coesite have been found in eclogite-granulite series of the Zlote Mountains in the Polish Sudetes. The polycrystalline quartz inclusions (up to 300 micrometres in length) in eclogitic omphacites are often composed of more or less radial rims and randomly oriented, mosaic aggregates in cores. The inclusions are surrounded by radial microfractures. Moreover, irregularely distributed tiny parallel laths and needles of exsolved quartz (up to 350 micrometres in length) can be observed in some omphacites, often within the grains enclosing inclusions of pseudomorphed coesite. Chemical composition of pre-existing omphacites has been estimated by adding either 3 or 6 wt % SiO2 to the present microprobe analysis of the matrix omphacite and assuming the constant iron oxidation state. Pre-existing nonstoichiometric omphacites contained up to 16 mol % vacancy end-member (CaEs). Most likely vacancies in omphacites were stabilized by pressures over 3.0 GPa. The hypothesis has been put forward that eclogite-granulite series of the Zlote Mountains recorded an ultrahigh pressure Variscan episode during a collisional event that took place in the present northern part of the Moldanubian Gfohl terrane close to the boundary with Moravian terrane within the Bohemian Massif.

A quartz pseudomorph after coesite: a teardrop-shaped inclusion of polycrystalline quartz in big fractured omphacite grain in eclogite from Zlote Mts; inside the inclusion marked radial growth textured rim and mosaic aggregate in the core can be seen; oblique polarizers.
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BARCZUK, ANDRZEJ
Institute of Geochemistry, Mineralogy and Petrography, University of Warsaw, Al. Zwirki i Wigury 93, 00-089 Warszawa, Poland
PETROLOGY OF PRECAMBRIAN CLASTICS AND THE EVOLUTION OF THE MIDCONTINENT RIFT SYSTEM (USA)
Archiwum Mineralogiczne v. 48, no. 1-2, p. 123-203, 1992

Extensive petrological and mineralogical investigations of clastic and volcanoclastic Upper Keweenawan rocks associated with the Midcontinent Rift System (MRS) suggest that structural and temporal evolution of the MRS was similar in its exposed, north-central (Michigan, Wisconsin and Minnesota) and buried, southern (Kansas, Nebraska and southern Iowa) segments. This resulted in the similarity of the lithological and petrological features of the rocks developed along the length of the rift. The only difference between the two segments of the MRS is the absence of a volcanoclastic sequence in the southern part of the rift, whereas in its northern part three sequences, the volcanic, volcanoclastic and clastic ones, are recognized. Petrographical and mineralogical analyses show, that Proterozoic sediments present on the horsts and in the flanking basins consist largely of oxidised arkoses, subarkoses, siltstones or shales, and lesser amounts of conglomerate. The mafic rocks are mainly basalts and some gabbros. Some intermediate or acidic rocks including pegmatites occur. The rocks are altered (mainly albitised and epidotised) to varying degrees. The sediments along the rift show certain similarities, being partly the result of deposition in similar environments. Direct correlation and recognition of distinct stratigraphic sequences in the buried portion of the rift remains still difficult. This study provides petrographical-homotaxial parameters that make some lithostratigraphic correlations of Precambrian sedimentary rocks throughout the Midcontinent trend possible. Based on these parameters the occurrence of a volcanoclastic sequence of the rocks in a drill hole in Minnesota was confirmed and correlated with volcanoclastie rocks at the outcrop in the Lake Superior area. The clastic sequence of the rocks was successfully correlated along the entire length of the MRS. Quartz arenites of the Hinckley Sandstone played a key role in this correlation. They indicate stable cratonic conditions over the whole large area. These mature sandstones could be traced from Michigan, Wisconsin and Minnesota (exposed portion of the rift) to Iowa, Nebraska and Kansas (buried portion of the rift). Petrological studies also helped to solve some problems of diagenesis of rift sediments.
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GAWĘDA, ALEKSANDRA
Department of Earth Sciences, University of Silesia, Mielczarskiego 60, 41-200 Sosnowiec, Poland
MINERAL ASSEMBLAGES AND CRYSTALLISATION CONDITIONS OF THE APLITE-PEGMATITE COMPLEX FROM POLSKA TOMANOWA (WESTERN TATRA)
Archiwum Mineralogiczne v. 47, no. 2, p. 51-67, 1992

Results of studies of the aplite-pegmatite complex from gneisses of Tomanowa Polska are presented. In the studied rock five zones were observed. They differ in textural features and chemical composition. The differences are due to that a part of magma was aplite and the other pegmatite in nature at simultaneous activity of tectonic factors. The occurrence of completely liquid zones made it possible for components to diffuse intensely within the complex.
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GAWĘDA, ALEKSANDRA
Department of Earth Sciences, Silesian University, Bedzinska str. 60, 41-200 Sosnowiec
MINERALOGICAL AND GEOCHEMICAL CHARACTERISTICS OF MICAS, GARNETS AND APATITE FROM THE WESTERN TATRAS PEGMATITES
Archiwum Mineralogiczne v. 48, no. 1-2, p. 101-122, 1992

The group of micas in the pegmatites of Western Tatras has a great rock-forming and classification significance. Primary micas (biotite and microcrystalline muscovite) do not contribute much to the structure of these rocks. A significant component of pegmatites are silvery large-plate muscovites formed by hydrolysis and albitisation of K-feldspars. The garnets are almandines. Primary garnets and postbiotitic garnets have been found. F-apatite is a primary mineral occurring in a strict paragenesis to the biotite. Geochemistry of minerals examined reflects primitive geochemical characters of parent magma. The presence of garnets from the piralspite group in pegmatites allows to conclude the peraluminous character of magma. The geochemistry of micas and muscovite dominance in this mineral group allow to assume that the formation of Western Tatras pegmatites is connected to anatectic processes.
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GIRESSE, PIERRE*; OUALEMBO, PATRICIA*; WIEWIÓRA, ANDRZEJ**; ŁĄCKA, BOZENA**; ZAWIDZKI, PAWEŁ**
*Laboratoire de Recherches de Sédimentologie Marine, Université de Perpignan, Avenue de Villeneuve, 66025 Perpignan, France; ** Institut de Sciences Géologiques, Académie Polonaise des Sciences, Al. Zwirki i Wigury 93, 02-089 Warszawa, Pologne
COMPOSITIONS POLYPHASÉES DES GRAINS VERTS DU BASSIN DU CONGO; COMPARAISON DE DEPOTS RECENTS, HOLOCENES (l0³ - l0⁴ ans) ET MIOCENES (10⁷ ans)
Archiwum Mineralogiczne v. 47, no. 2, p. 17-49, 1992

Les grains verts a la surface du plateau congolais proximal de l'embouchure du Congo-Zaire, ceux d'une carotte holocene du meme secteur et ceux du Miocene de sub-surface (-185 a -520 m) du meme bassin, ont fait l'objet d'analyses diffractométriques aux R.X (transmission), d'observations au MEB et d'analyses chimiques ponctuelles (systemes de dispersion de longuer d'onde et de dispersion d'énergie). Les grains de surface sont composés d'une phase dominante a 7 ou on constate le passage d'une structure dioctaédrique vers une structure trioctaédrique et les premieres néoformations de nontronite. Les grains holocenes, plus magnésiens, ont une phase a 7 sourtout trioctaédriques qui est associée a des nontronites plus abondantes. Les grains miocenes montrent, en parts égales, une phase a 7 dioctaédrique et trioctaédrique transformée et une phase smectitique néoformée. Dans tous les cas, cette composition polyminérale rend artificielle toute définition d'un nouveau minéral (cf. verdine ou odinite). Ces minéraux se développent en fonction de l'environnement (flux de fer et de matiere organique et rythmes du dépôt), ils semblent stables pendant la diagénese (jusqu'a 10⁷ ans). Ils présentent des étapes variées de début de glauconitogénese, évolution minérale qui les différencie donc de celle des minerais de fer a berthierine.
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LASON, KRZYSZTOF
Polish Geological Institute, Upper Silesian Branch Krolowej Jadwigi str.1, 41-200 Sosnowiec, Poland
ZONING OF POLYMETALLIC MINERALISATION IN THE PALEOZOIC ROCKS FROM THE MYSZKOW REGION (NE MARGIN OF THE UPPER SILESIAN COAL BASIN)
Archiwum Mineralogiczne v. 48, no. 1-2, p. 44-59, 1992

Samples of the Paleozoic rocks from six boreholes in the Myszkow region have been analysed. They display a distinct polymetallic mineralisation. Geochemical analyses have pointed to an occurrence of the positive anomaly of Cu, Mo and W in deposit in the whole area investigated, e.g. in the rocks from the Pz-29 borehole — copper content equals to 0.2%, Mo — 0.1%, W — 0.07%. Differentiation in the content of elements has led to determination of zoning of the copper-molybdene-tungsten mineralisation. It was possible to outline zones of the maximum Cu, Mo, W contents and the zones of constant anomalies of Bi, Te, Ag, Ni, Cr, Ba, Sn due to the results obtained. Ore mineralisation in the Myszkow region displays high resemblance to the well-known models of the copper and molybdenum porphyry deposits.
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LORENC, MAREK W.
Polish Academy of Sciences, Institute of Geological Sciences, Laboratory of Geology of the Sudetes, Podwale75, 50-449 Wroclaw, Poland
PETROLOGICAL STUDY OF INTRUSIVE ROCKS FROM NORTHERN SIERRA DE PAIMAN (NW ARGENTINA)
Archiwum Mineralogiczne v. 47, no. 2, p. 70-93, 1992

The northern edge of Sierra de Paiman is composed of (1) granitoid rocks and (2) zonal gabbro-diorite intrusions that pass gradually through tonalites into granodiorite— granite marginal zones. Intermediate rocks of the hybrid character include enclaves of mafic magmatic rocks (MME) xenocrysts, schlieren, and indicate the presence of fluidal structures and other features suggestive of mechanisms of magma mixing and mingling. Within granitoids three kinds were distinguished: Potrerillos with aspects of typical anatectic collision granites; Paiman with pre-collision magma of the arc type; Campanas of the intermediate nature. Some kinds of rocks are cut by synintrusive basic dykes that frequently appear to be a source of enclaves of the MME type. On the basis of tectonic conditions it can be stated that in the Sierra de Paiman region effects of magmatic activity connected with subduction of the ocean-continent type (basic rocks, layered intrusions, basic dykes, metaluminous I-granitoids) as well as results of ensuing collision of the continent-continent type (peraluminous anatectic S-granitoids) are observed.
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MUSZER, ANTONI
Institute of Geological Sciences, University of Wroclaw, Maksa Borna str.9, 50-204 Wroclaw, Poland
NATIVE GOLD FROM THE ZLOTY STOK DEPOSIT (LOWER SILESIA)
Archiwum Mineralogiczne v. 48, no. 1-2, p. 81-98, 1992

Arsenopyrite, pyrrhotite, pyrite and magnetite ores from Zioty Stok have been microscopically and spectrometrically analysed aiming the recognition of the forms of native gold occurrence. Two generations of native gold have been stated in the Zloty Stok deposit. Gold forms submicroscopic inclusions in the ore and rock-forming minerals of the diameter from 0.03 to several tens of micrometers and crystalline grains in the pyrrhotite ore of size up to 1 mm in diameter. Iron sulphides (pyrite, pyrrhotite) contain the highest amounts of gold in contrary to the hitherto existing opinion concerning arsenides and iron sulphoarsenides (loellingite, arsenopyrite) as the main source of gold.
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NEJBERT, KRZYSZTOF; SPECZIK, STANISLAW
Faculty of Geology, Warsaw University, Zwirki i Wigury str. 93, 02-089 Warszawa, Poland
THE SPINELS OF THE SPINEL-HERCYNITE SERIES IN MAGNETITE AND ILMENITE OF THE SUWALKI INTRUSION (NE POLAND)
Archiwum Mineralogiczne v. 48, no. 1-2, p. 62-80, 1992

Microcrystals of spinel-hercynite group found in ilmenite and magnetite of ferrolites and host rocks of Suwatki massif are represented mainly by pleonaste and hercynite. Five morphostructural spinel types were distinguished with varying pleonaste composition and one with composition close to hercynite. Changes in composition and morphology of microspinels correspond to mineral evolution of investigated ores.
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PODHALAŃSKA, TERESA
Institute of Geological Sciences, Polish Academy of Sciences, Zwirki i Wigury 93, 02-089 Warszawa, Poland
PHOSPHATISATION OF THE LOWER-MIDDLE ORDOVICIAN SEDIMENTS FROM THE PODLASIE DEPRESSION (EASTERN POLAND)
Archiwum Mineralogiczne v. 48, no. 1-2, p. 27-41, 1992

A layer several cm thick of biomicrite enriched in calcium phosphate contains phosphatised bioclasts and coated grains. It occurs within a series of biomicrites intercalated by marls Lower-Middle Ordovician in age in the Podlasie Depression in eastern Poland. The phosphatisation is closely associated with a sedimentary discontinuity surface which reflects an inhibited sedimentation at the Lower/ Middle Ordovician boundary. The source of phosphorus should have probably been organic matter that decayed in result of bacteria activity. The phosphatisation had taken place both in the carbonate bioclasts, coated grains including ooids, endolithic filaments as well as in the micritic matrix. This process had probably taken place in early diagenetic phase.
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PUZIEWICZ, JACEK
Institute of Geological Sciences, University of Wroclaw, Cybulskiego 30, 50-205 Wroclaw, Poland
ORIGIN OF THE KOŹMICE GRANODIORITE (NIEMCZA ZONE, LOWER SILESIA, POLAND)
Archiwum Mineralogiczne v. 47, no. 2, p. 95-146, 1992

The Kozmice granodiorite occurring in the Niemcza zone (Sudetes, SW Poland) exhibits weak S-C fabric. The composition of minerals occurring on the S and C planes is magmatic. The S-C fabric was formed at the late-magmatic stage, when the crystallised minerals formed an interconnected network.
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RYKA WACŁAW
Department of Petrography and Mineralogy, Polish Geological Institute, Rakowiecka 4, 00-975 Warszawa, Poland
PSEUDOLEUCITE CARBONATITE FROM MONGOLIAN GOBI DESERT
Archiwum Mineralogiczne v. 47, no. 2, p. 3-16, 1992

Pseudoleucite (Na-rich leucite) has been found in the Lugijn Gol carbonatites. It is the first discovery of this mineral in carbonatites. Structures of breakdown occurring at temperature of about 500°C, composed of K-feldspar (microcline of the triclinity of 0.56) and of low-temperature albite replacing leucite. Albitization of leucite occurred due to hydrothermal alteration at temperature below 200°C and due to an influence of silica-rich solutions. Pseudoleucite displays well developed habit of deltoidal icositetrahedron with dulled edges. It differs a little from pseudoleucites of the nepheline syenite of the Lugijn Gol massif.
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