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 370-380 Ma Khibina and Vuoriyarvi complexes on the Kola Peninsula, Russia, which form part of the Palaeozoic Kola Alkaline Province, contain REE-rich carbonatites with burbankite (Na,Ca) 3 (Sr,Ca,REE,Ba) 3 (CO 3 ) 5 or calcioburbankite (Na,Ca) 3 (Ca,Sr,REE,Ba) 3 (CO 3 ) 5 as the principal primary REE mineral. Within each complex the...
Two empirical garnet-muscovite geothermometers, assuming no ferric iron (Model A) and 50% ferric iron (Model B) in muscovite, respectively, were calibrated under the physical conditions of P=3.0-14.0 kbar and T=530-700 o C. The input temperatures and pressures were determined by simultaneously applying the garnet-biotite thermometer [Am. Mineral. 85 (2000) 881.] and the GASP geobarometer [Am...
The Sierra Chichinautzin Volcanic Field is a key area for understanding the origin of the controversial Mexican Volcanic Belt (MVB). This is due to its recent volcanic activity, which is located at the front of the Central MVB. Although a direct genetic relationship between the volcanism of the MVB and the subduction of the Cocos plate is accepted by most authors, geological, geophysical and geochemical...
In the Higher Himalaya of the region from Cho Oyu to the Arun valley northeast of Makalu, the Miocene leucogranites are not hosted only in the upper High Himalayan Crystallines (HHC); a network of dykes also cuts the lower HHC and the Lesser Himalayan Crystallines (LHC).The plutons and dykes are mainly composed of two-mica (muscovite+biotite+/-tourmaline+/-cordierite+/-andalusite+/-sillimanite) leucogranite,...
During the Neogene, a magmatic change from calc-alkaline to alkaline types occurred in all the regions surrounding the western Mediterranean. This change has been studied in Oranie (western Algeria). In this area, potassic to shoshonitic calc-alkaline andesites (with La/Nb ratios in the range 4-6) were mainly erupted between 12 and 9 Ma. They were followed (between 10 and 7 Ma) by basalts displaying...
Mafic granulite and pyroxenite xenoliths from Cenozoic alkaline basalts at Hannuoba, Hebei Province, North China have been selected for a systematic geochemical and Sr-Nd-Pb isotopic study, which provides a unique opportunity to explore nature of the lower crust and the interaction between the continental crust and lithospheric mantle beneath an Archean craton. The major, compatible and incompatible...
None of the existing models for calc-alkaline ''Late Granite'' (Siluro-Devonian) genesis in the metamorphic Caledonian orogenic belt of Ireland and Scotland fully explains their spatial, age or chemical character. A consistent model must involve the closure of Iapetus Ocean, where slab breakoff is a natural consequence of attempted subduction of continental crust. Expected outcome is a long linear...
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.