Temat: magmatism - Prolib Integro

Skocz do pozycji: 1.

Tytuł:: Petrographic characteristics of the north-western part of Kosovo
Autorzy:: Kutllovci, F.
Tematy:: magmatism
metamorphism
microscope properties; Pokaż więcej
Wydawca:: Politechnika Wrocławska. Wydział Geoinżynierii, Górnictwa i Geologii. Instytut Górnictwa
Powiązania:: https://bibliotekanauki.pl/articles/88922.pdf Link otwiera się w nowym oknie
Opis:: In the north – western part of Kosovo, the next lito stratigraphic units were separated: Palaeozoic (gneiss, mica schists, leucogneiss, amphibolite, quartzite), Jurassic (Serpentinised hazburgit, Schist serpentines with granitic intrusion, Basalts with dacite dykes, Dacite, Metamorphic sole (amphibolites), Supra ophiolite sedimentary mélange), Cretaceous (Valanginian basal conglomerates, Valanginian–Hauterivian silty – sandstone turbidity’s, Barremian–Aptian basal conglomerates, Barremian–Aptian silty – marl turbidity’s, Albian–Senomanian sandy – phillitic turbidites, Santonian sedimentary ophiolitic melange) Quaternary (alluvium, proluvium, slope wash, lower river terrace, higher river terrace, lacustrine, gravel and sand). The samples were taken from those rocks for chemical, geo-chemical and for the preparation of petrographic microscope properties. The analyses were completed at the certified laboratory of Geology-Mining Faculty (Polytechnic University of Tirana) – Geosciences Institute.
Dostawca treści:: Biblioteka Nauki

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Tytuł:: Overview of magmatism in Northwestern Vietnam
Autorzy:: Khuong, H.
Tematy:: Vietnam
plate tectonics
magmatism
Palaeozoic
Mesozoic
Cenozoic; Pokaż więcej
Wydawca:: Polskie Towarzystwo Geologiczne
Powiązania:: https://bibliotekanauki.pl/articles/191922.pdf Link otwiera się w nowym oknie
Opis:: Amalgamation of tectonic plates of Southeast Asia occurred in northwestern Vietnam. Six groups of magmatic rocks are related to the tectonic events. The first group corresponds to the major episodes of crustal formation in the South China block, or is linked with the formation of Gondwana. The second group includes granitoids in connection with the collision and formation of the Caledonian-Hercynian folding event. The third group contains Upper Permian ophiolites, as well as the Permian extrusives, formed in intraplate setting, related to back-arcs spreading. The fourth group is related to Triassic Indosinian orogeny, the fifth group comprises Jurassic-Cretaceous intraplate granitoids. Finally, during Cenozoic times, magmatic rocks were represented by alkaline granitoids - the effect of strike-slip faulting related to the collision of India and Eurasia plates.
Dostawca treści:: Biblioteka Nauki

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Tytuł:: Cretaceous magmatic evolution in the Deylaman igneous complex, Alborz zone, Iran : change from extensional to compressional regime
Autorzy:: Akmali, Sheida
Asiabanha, Abbas
Haghnazar, Shahrooz
Tematy:: back-arc magmatism
Cretaceous
Neotethys
Alborz
Iran; Pokaż więcej
Wydawca:: Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Powiązania:: https://bibliotekanauki.pl/articles/2058637.pdf Link otwiera się w nowym oknie
Opis:: The Deylaman igneous complex, as a part of the Late Cretaceous rock unit that lies behind the Paleogene Alborz magmatic arc, in the northern Alborz zone, is composed of basaltic sheet lavas alternating with the pelagic calcareous sediments, basaltic pillow lavas, felsic lavas and gabbroic-monzodioritic intrusions. The pelagic calcareous deposits contain microfossils representing the Santonian-Maastrichtian ages. Furthermore, petrographic textures such as the hyalomicrolitic texture and swallow-tail plagioclase crystals in the pillow lavas, and also segregation vesicles in the basaltic sheet lavas, imply high external (hydrostatic) pressures as the magma was extruded in a deep-water environment. The rock samples show both compositional bimodality and characteristic trends in the variation diagrams. Also, some geochemical characteristics imply that the basaltic lavas originated from the partial melting of an undepleted deep mantle source containing spinel lherzolite: the enrichment patterns of LREE/HREE ratios of the samples [(La/Yb)n = 3.93-4.16 for basaltic lavas and 10.92 for felsic lavas] lying between those characteristic of OIBs [(La/Yb)n = 12.92] and EMORBs [(La/Yb)n = 1.91]; similarities between the patterns of multi-element spider-diagrams; LILE bulges in the basaltic samples compared with those of OIBs. Moreover, the samples show influence from two geotectonic environments: supra-subduction zone (SSZ) settings and plume-type within-plate magmas. Therefore, because of the deep submarine environment inferred for the effusive volcanic eruptions in Santonian-Maastrichtian time, it seems that the Deylaman igneous complex evolved through two stages: first, a tensional regime in a supra-subduction zone (farther from the Mesozoic magmatic arc) and formation of an embryonic rift-related oceanic basin in the Late Jurassic-Early Cretaceous; secondly, a compressive regime in the Late Cretaceous-Early Paleocene and inland migration of the magmatic arc. Consequently, the Cretaceous magmatism can be interpreted as a prelude to the Eocene magmatic flare-up in the magmatic arcs of Iran.
Dostawca treści:: Biblioteka Nauki

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Tytuł:: Alkaline rocks of the Ukrainian Shield: Some mineralogical, petrological and geochemical features
Autorzy:: Ponomarenko, Aleksandr N.
Kryvdik, Stepan G.
Grinchenko, Aleksandr V.
Tematy:: Ukrainian Shield
alkaline magmatism
Proterozoic
Devonian kimberlites; Pokaż więcej
Wydawca:: Polskie Towarzystwo Mineralogiczne
Powiązania:: https://bibliotekanauki.pl/articles/127598.pdf Link otwiera się w nowym oknie
Opis:: The Ukrainian Shield (USh) is a typical province of Proterozoic alkaline magmatism where about 50 massifs and occurrences of alkaline rocks and carbonatites have been found. In spite of the wide distribution of Devonian basaltic- and alkaline magmatic rocks in the Dnieper-Donetsk depression adjacent to the USh, and in a marginal zone of the USh adjacent to folded Donbass, only alkaline rocks of Proterozoic age (1.8-2.1 Ga) that have been identified in the central interior of the USh. Some discrete bodies of 2.8 Ga subalkaline rocks also occur in Bogdanivka massif (Azov area). Occurrences of both Proterozoic (prevailing) and Phanerozoic (Devonian) alkaline rocks and kimberlites are only found in the eastern part of the USh (Azov area). Kimberlites in the central part of the Ukrainian Shield (Kirovograd region) are also of Proterozoic age (ca 1.8 Ga). It is this predominance of Precambrian rocks that makes the USh so different from other alkaline provinces where Phanerozoic alkaline rocks and kimberlites commonly prevail over Precambrian rocks. The lack of Phanerozoic alkaline magmatism on USh is poorly understood. Two main complexes of alkaline rocks - alkaline-ultrabasic (carbonatitic) and gabbro- syenitic - are distinguished in the USh. There are also rare occurrences of rock types such as alkaline- and alkaline-feldspar granites that may represent one separate alkaline-granite complex. Alkaline rocks present in the Eastern (Azov) province and in the Western province display essentially different geochemical character. Those of the Eastern province show characteristics typical of alkaline-ultrabasic rocks (e.g. high contents of incompatible rare elements 116 such as Nb, REE, Zr, Y, Sr, whereas those in the Western province are characterized by low contents of Nb and Zr, and REE in some cases. This fact is interpreted as reflecting different geodynamic conditions of their origin. The Eastern rocks were formed in rift settings, the Western rocks in crustal compressional settings (collision, subduction). Various mineral deposits of phosphorus (apatite), niobium, REE, yttrium and zirconium, including unusually rich ores of REE, Y and Zr (Azov and Yastrybetsky) are associated with the alkaline rocks and carbonatites of the USh.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 5.

Tytuł:: The Variscan Orogen in Poland
Autorzy:: Mazur, S.
Aleksandrowski, P.
Kryza, R.
Oberc-Dziedzic, T.
Tematy:: Bohemian Massif
Sudetes
Palaeozoic
terranes
metamorphism
magmatism; Pokaż więcej
Wydawca:: Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Powiązania:: https://bibliotekanauki.pl/articles/2058949.pdf Link otwiera się w nowym oknie
Opis:: The structure and evolution of the Polish part of the Variscan Orogenic Belt is reviewed, based on published data and interpretations. The Sudetic segment of the Variscides, together with adjacent areas, experienced multi-stage accretion during successive collisional events that followed the closure of different segments of the Rheic Ocean. In SW Poland, Variscan tectono-stratigraphic units are tectonically juxtaposed and often bear record of contrasting exhumation/cooling paths, constrained by palaeontological and geochronological data. This points to the collage-type tectonics of this area. A three-partite subdivision of the Sudetes is proposed that reflects timing differences in deformation and exhumation of the respective segments. The Central,West and East Sudetes were deformed and amalgamated during the Middle/Late Devonian, at the turn from the Devonian to Carboniferous and during Early Carboniferous times, respectively. Problems in extending the classical tectono-stratigraphic zonation of the Variscides into the Sudetes are discussed and attributed to activity along Late Palaeozoic strike-slip faults and shear zones, disrupting and dispersing the initially more simply distributed tectono-stratigraphic units into the present-day structural mosaic. Relationships between the Variscan Externides and the foreland basin are explored. Sediments of the foreland basin locally onlap the external fold-and-thrust belt that had undergone an earliest Carboniferous partial tectono-thermal overprint. During the Late Carboniferous, the SW part of the foreland basin was heavily affected by thrusting and folding and incorporated into the Externides. DuringWestphalian C to Early Permian times, localized folding and thrusting affected the distal parts of the foreland basin, probably in response to dextral transpressional movements along NW–SE trending basement faults.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 6.

Tytuł:: Late Devonian magmatism in the Pripyat Palaeorift: a geodynamic model
Autorzy:: Aizberg, R. Y.
Beskopylny, V. N.
Starchik, T. A.
Tsekoyeva, T. K.
Tematy:: Pripyat palaeorift
Devonian
ultrabasic-alkaline magmatism
geodynamics
palaeovolcanoes
diatremes; Pokaż więcej
Wydawca:: Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Powiązania:: https://bibliotekanauki.pl/articles/2059320.pdf Link otwiera się w nowym oknie
Opis:: Late Devonian magmatism in the Pripyat Trough, Belarus was associated with the development of the intraplate Pripyat-Donets Palaeorift. Magmatic rocks belong to an alkali-ultrabasic-alkali-basaltoid suite. These are represented by explosive, effusive, subvolcanic and volcanic facies. The magmatic activity and rock composition changes from the periphery to the axial part of the Pripyat Trough, corresponding to the general trend of destructive processes in the rifting zone. Geodynamically, the Pripyat alkali-ultrabasic rocks represent a series of magmatic suites of the Pripyat-Donets palaeovolcanic region coinciding with a zone of disappearance of Late Devonian divergence processes in the south-west of the East European Craton.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 7.

Tytuł:: Late Silurian–Early Devonian tuffites from the Małopolska and Łysogóry blocks reflect arc-back-arc magmatic activity on the southern margin of Laurussia
Autorzy:: Wójcik, Emil
Tematy:: zircon ages
geochemistry
late Silurian magmatism
Holy Cross Mountains
Sudetes; Pokaż więcej
Wydawca:: Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Powiązania:: https://bibliotekanauki.pl/articles/58907120.pdf Link otwiera się w nowym oknie
Opis:: Zircon U-Pb dating of tuffites within the upper Silurian greywackes in the southern part of the Holy Cross Fold Belt gives a result of 419.91 ±1.7 Ma, which indicates they are of Přídolí age. Geochemical studies of Přídolí tuffites from the Małopolska Block, an Emsian tuffite from the Łysogóry Block in the Holy Cross Fold Belt and a Přídolí tuffite from the Bardo Unit in the Central Sudetes indicate that they were formed in a similar tectonic setting related to post-orogenic, continental arc-back-arc magmatism, developed along the southern margin of Laurussia, correlated with the Rhenohercynian Zone. In terms of their geochemical pattern, the tuffites are similar to the upper Silurian–Lower Devonian igneous rocks in Germany, Ukraine (Podolia) and Moldova, which were probably formed along the same subduction zone, during an early stage of the continental arc-back-arc magmatic activity.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 8.

Tytuł:: Niemcza diorites and moznodiorites (Sudetes, SW Poland) : a record of changing geotectonic setting at ca. 340 Ma
Autorzy:: Pietranik, A.
Storey, C.
Kierczak, J.
Tematy:: Variscidies
Niemcza Zone
diorites
LA-ICP-MS zircon age
potassic magmatism; Pokaż więcej
Wydawca:: Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Powiązania:: https://bibliotekanauki.pl/articles/2059736.pdf Link otwiera się w nowym oknie
Opis:: Granites sensu lato in the Sudetes intruded in several episodes during the Variscan orogeny recording different stages of crust and mantle evolution. Correlating precise ages with geochemistry of the Variscan granites provides information on the evolution of these sources within the Variscan orogen. The Variscan intrusive rocks from the Niemcza Zone (Bohemian Massif, Sudetes, SW Poland) include undeformed dioritic to syenitic rocks and magmatically foliated granodiorites. In this study we analysed low SiO2 (48–53 wt.%) monzodioritic rocks from Przedborowa and Koźmice. The monzodiorites contain late-magmatic zircons with ages of 341.8 ± 1.9 Ma for Przedborowa and 335.6 ± 2.3 Ma for Koźmice, interpreted as emplacement ages of the dioritic magmas. Older Przedborowa rocks are lower in K, Mg, Rb and Ni than the Koźmice rocks and similar compositional trend is also observed in the Central Bohemian Plutonic Complex. The implication is that the mantle underlying the Niemcza Zone became more enriched from ca. 342 to ca. 336 Ma, probably following the collision of the Saxothuringian and Moldanubian/Lugian domains. The magmatism related to the collision occurred ca. 12 Ma later than that in the Central Bohemian Plutonic Complex, but was accompanied by a similar change in magma chemistry from high-K (Przedborowa) to shoshonitic (Koźmice, Kośmin enclaves) and probably to ultrapotassic (Wilków Wielki).
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 9.

Tytuł:: Neogene calc-alkaline intrusive magmatism of post-collisional origin along the Outer Carpathians: a comparative study of the Pieniny Mountains and adjacent areas
Autorzy:: Pécskay, Z.
Gméling, K.
Molnár, F.
Benkó, Z.
Tematy:: Outer Carpathians
Pieniny Klippen Belt
Neogene intrusive magmatism
K-Ar ages
boron concenrations; Pokaż więcej
Wydawca:: Polskie Towarzystwo Geologiczne
Powiązania:: https://bibliotekanauki.pl/articles/973597.pdf Link otwiera się w nowym oknie
Opis:: A petrographical and geochemical analysis was carried out on intrusive rocks from the Pieniny and Moravian areas, with special attention to boron content and K-Ar radiometric ages. The intrusions form medium- to high-potassium calc-alkaline andesitic suites, which are compositionally slightly different from each other and from the other calc-alkaline sequences in the Carpathian-Pannonian Region. No significant geochemical differences were observed within the different phase intrusions in the Pieniny areas. However, there is a slight difference in major and trace element composition between the Moravian and Pieniny intrusions. The andesitic rocks in the Pieniny and Moravian area are enriched in large ion lithophile elements and light rare earth elements and depleted in high field strength elements, indicating a metasomatized mantle source of the parent magmas. The low boron concentration of the andesitic rocks in the Pieniny area is in the range measured in back-arc, intraplate basalts of the Bakony-Balaton Highland volcanic field, whereas the higher boron content of the Moravian rocks overlaps with that of the Western Carpathian andesites. This may indicates the heterogeneity of the mantle lithosphere below the areas, or indicates different magma evolution histories. On the basis of the systematic geochronological study, the intrusive rocks along the Outer Carpathians can be divided on three groups, which overlap with each other temporally. The oldest magmatism occurred from 14.8 Ma to 11.0 Ma in the Uhersky Brod area, Moravia, which was followed by the emplacement of andesitic dikes and sills in the Pieniny Mts., south Poland (13.5–10.8 Ma). In the Pieniny area, two intrusive phases were distinguished. Partly overlapping with this area, but generally younger than this magmatism, the emplacement of the youngest intrusions is referable to the Poiana Botizei-Ţibleş-Toroiaga-Rodna-Bârgâu intrusive area, Romania, where magmatic activity started at ~11.8 Ma and terminated at 8.0 Ma.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 10.

Tytuł:: Wczesnokarboński wiek intruzji platformowych w podłożu krystalicznym NE Polski
Early Carboniferous age of the cratonic intrusions in the crystalline basement of NE Poland
Autorzy:: Krzemińska, E.
Wiszniewska, J.
Williams, I.S.
Tematy:: zircon
U-Pb SHRIMP geochronology
closure temperature
mafic-alkaline magmatism
Early Carboniferous
NE Poland; Pokaż więcej
Wydawca:: Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Powiązania:: https://bibliotekanauki.pl/articles/2074482.pdf Link otwiera się w nowym oknie
Opis:: Three mafic-alkaline intrusive bodies in NE Poland: Ełk, Pisz and Tajno, have been dated recently with U-Pb SHRIMP method. An earlier Rb-Sr whole rock isochron of Ełk syenites pointed to an age 355š4 Ma, while K-Ar age estimates suggested a Late Paleozoic age of Pisz and Tajno rocks, however, in a wide range between 349-291 Ma and 327-289 Ma, respectively. In the paper, we present new geochronological results and discuss the problem of the closure temperatures for different minerals and different isotopic systems used in previous age determinations. Much of the early dating works has been done using K-Ar method. Biotite and K-feldspar retain radiogenic Ar quantitatively below 280 -200şC. Only if magmatic bodies cooled quickly and remained unmetamorphosed, K-Ar and Rb-Sr ages estimate accurately the intrusion emplacement. Zircon used for U-Pb datings has a closure temperature over 800şC, that is comparable to the temperature of magma’s solidus. Therefore U-Pb magmatic zircons dates could be interpreted as an intrusion emplacement ages. The obtained U-Pb results of 347.7 š8 Ma (Ełk) and 345.5š5 Ma (Pisz) have shown very consistent Early Carboniferous age of platform mafic-alkaline magmatic activity. This new U-Pb SHRIMP dating indicates that Ełk and Pisz intrusions are coeval and together with the Tajno alkaline-carbonatite massif could be affined with the Late Devonian Kola Alkaline Carbonatite Province (KACP).
Dostawca treści:: Biblioteka Nauki

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