The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
The Late-Proterozoic Bjerkreim-Sokndal Layered Intrusion (BKSK) consists of andesine anorthosite, leuconorite, troctolite, norite, gabbronorite, jotunite, mangerite, quartz mangerite and charnockite. The sequence of appearance of cumulus minerals and their compositions suggest a parent magma that was evolved, had plagioclase (± olivine) on the liquidus, was sufficiently TiO 2 -rich for hemo-ilmenite...
Migmatitic rocks near Grenville, Quebec, preserve features indicative of reactions at the onset of granulite facies metamorphism. In this area, metapelites and metacarbonates of the classic Grenville Series are spatially associated with granitic gneiss and metabasite, and flank a Paleozoic, Fe-rich syenite stock. Near this intrusion, the metapelite is diatexitic and nearly devoid of biotite, indicating...
The Sputnik kimberlite pipe is a small satellite of the larger Mir pipe in central Yakutia (Sakha), Russia. Study of 38 large diamonds (0.7-4.9 carats) showed that nine contain inclusions of the eclogitic paragenesis, while the remainder contain inclusions of the peridotitic paragenesis, or of uncertain paragenesis. The peridotitic inclusion suite comprises olivine, enstatite, Cr-diopside, chromite,...
Late Devonian (385-370 Ma) granitoid intrusions in the Meguma Zone of southwestern Nova Scotia represent two geographically separate magmatic suites that show subtly different lithological, geochemical and isotopic characteristics. Central intrusions crop out with satellite mafic-intermediate intrusions, range in composition from granodiorite to leucogranite, contain two micas, have exclusively...
The U-Pb and Sm-Nd dating of deep crustal rocks from the Bergen Arcs system helps resolve enigmatic aspects of the tectonic evolution of the Caledonian Orogen in western Norway and yields insights into the arrested stages of eclogite development within the granulites of the area. The U-Pb dating of zircon from one of the eclogite facies shear zones yields an upper intercept age of 945 ± 5 Ma [all...
The Oligo-Miocene volcanics (32-15 Ma), which occur in the Oligo-Miocene Sardinian Rift, were interpreted in the literature as an intracontinental volcanic arc built upon continental crust about 30 km thick. They are characterized by a close field association of dominantly andesites and acid ignimbrites, with subordinate basalts.In this paper we deal with the origin and evolution of recently discovered...
The Seljeneset Meta-anorthosite consists of deformed and metamorphosed anorthosite and mafic rocks, is situated in the high-grade Western Gneiss Region (WGR) of Norway, and is adjacent to the 1.52 Ga Flatraket quartz monzonite (mangerite). The WGR was metamorphosed to eclogite facies during Caledonian tectonism 414 ± 16 Ma ago. The Meta-anorthosite contains 46-57 wt.% SiO 2 and displays...
Quaternary Ceyhan-Osmaniye plain and Hassa graben alkali olivine basalts were erupted along the transtensional depressions of the east Anatolian and Dead Sea left-lateral strike-slip faults in the Adana and Hatay provinces of southern Turkey, respectively. Average values of Ni, Cr, V, Y, Al 2 O 3 , MgO, MnO and SiO 2 in the Ceyhan-Osmaniye (COPB) and Hassa graben basalts (HGB)...
Archean lower crustal granulites are exposed as fault-bounded blocks in the Varpaisjarvi area, central Finland. The prevailing rock types in these blocks are igneous enderbites, tonalitic-trondhjemitic-granodioritic migmatites and mafic granulites. Although metamorphosed at moderate pressures (8-10 kbar), the Varpaisjarvi granulites are not, in a geochemical sense, good representatives of depleted...
The Coldwell alkaline complex is a large (> 350 km 2 ) gabbro and syenite intrusion on the north shore of Lake Superior. It was emplaced at 1108 Ma during early magmatic activity associated with the formation of the Mid-Continent Rift of North America. The eastern gabbro forms a partial ring dyke on the outer margin of the complex and consists of at least three discrete intrusions. The...
The most commonly used tectonic discrimination diagrams for granites were introduced by Pearce et al. [Pearce, J.A., Harris, N.B.W., Tindle, A.G., 1984. Trace element discrimination diagrams for the tectonic interpretation of granitic rocks. J. Petrol. 25, 956–983.]. Since then, many studies have shown that some granites defy classification or their geochemical assignment does not fit with the geodynamic...
The main anatectic granite of the Velay complex is unique among major French Massif Central Hercynian granitoids in that rather than having an entirely lower crustal source, it formed by mixing between partial melts of the meta-igneous lower crust and ‘upper crustal’ country rock schists and orthogneisses. The geochemical variations in the Velay main anatectic granites cannot, however, be explained...
In this paper the first fluid-inclusion data are presented from Late Archaean Scourian granulites of the Lewisian complex of mainland northwest Scotland. Pure CO 2 or CO 2 -dominated fluid inclusions are moderately abundant in pristine granulites. These inclusions show homogenization temperatures ranging from − 54 to + 10 °C with a very prominent histogram peak at − 16 to − 32 °C....
The Pe˜na Negra anatectic complex (central Spain) was formed from a pelitic protolith low in boron (3–80 ppm), by dehydration reactions, melting and fluid loss, which expelled much of the boron; residual B is present in sillimanite and muscovite. Migmatite melanosomes and restites (sillimanite + biotite + ilmenite) are relatively richer in B (mean 29 ppm), while the leucosomes are poorer (13 ppm)...
Microgranitoid enclaves are common in granitic plutons worldwide, occurring individually and in homogeneous or heterogeneous swarms. Three plutons in the central Sierra Nevada batholith contain swarms with mostly heterogeneous suites of enclaves in the intermediate composition range, and occur in a number of two-dimensional shapes, specifically as dikes, small rafts, lenses, pipe/vortices and large...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.