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all geography including DSDP/ODP Sites and Legs
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Africa
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Mozambique (2)
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North Africa
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Egypt
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Nubian Shield (1)
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wollastonite group
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framework silicates
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nepheline group
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epidote group
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ring silicates
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sheet silicates
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Primary terms
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absolute age (1)
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Africa
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Mozambique (2)
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North Africa
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Egypt
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Safaga Egypt (1)
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Nubian Shield (1)
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West Africa
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Cameroon (1)
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Nigeria (1)
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Arctic region
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Ilimaussaq (7)
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Asia
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Far East
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Burma (1)
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Japan (1)
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Gobi Desert (1)
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Dharwar Craton (1)
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Gujarat India (1)
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Rajasthan India (1)
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Tajikistan (1)
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carbon
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Cenozoic
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Eocene
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Green River Formation (1)
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chemical analysis (1)
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Western Europe
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geochemistry (5)
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igneous rocks
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gabbros (3)
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metamorphic rocks
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metasedimentary rocks
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metasomatic rocks
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metamorphism (3)
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oxygen
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upper Precambrian
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sedimentary structures
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GeoRef Categories
Era and Period
Epoch and Age
Book Series
Date
Availability
arfvedsonite
Magnetic Fabrics in Laminated Rocks of the Ilímaussaq Igneous Complex, Southern Greenland Available to Purchase
Geochemical and Isotopic Constraints on the Origin of Rare-Metal Enriched Alkaline A-Type Granites from the Nubian Shield: Role of Mantle Metasomatism Available to Purchase
Magmatic degassing and fluid metasomatism promote compositional variation from I-type to peralkaline A-type granite in the late Cretaceous Fuzhou felsic complex, SE China Available to Purchase
Illoqite-(Ce), Na 2 NaBaCeZnSi 6 O 17 , a new member of the nordite supergroup from Ilímaussaq alkaline complex, South Greenland. Open Access
Mineralogy and genesis of pyrochlore apatitite from The Good Hope Carbonatite, Ontario: A potential niobium deposit Available to Purchase
Mineralogy of the baotite-bearing Gundrapalli lamproite, Nalgonda district, Telangana, India Available to Purchase
Potassic-magnesio-arfvedsonite, KNa 2 (MgFe 2+ Fe 3+ ) 5 Si 8 O 22 (OH) 2 : mineral description and crystal chemistry Available to Purchase
Mineralogy of the Vattikod lamproite dykes, Ramadugu lamproite field, Nalgonda District, Telangana: A possible expression of ancient subduction-related alkaline magmatism along Eastern Ghats Mobile Belt, India Available to Purchase
Chemical lattice expansion of natural zircon during the magmatic-hydrothermal evolution of A-type granite Available to Purchase
Dyrnaesite-(La) a new hyperagpaitic mineral from the Ilímaussaq alkaline complex, South Greenland Available to Purchase
Chemical Trends in the Meech Lake, QuÉbec, Carbonatites and Fenites Available to Purchase
Lithium-containing Na–Fe-amphibole from cryolite rocks of the Katugin rare-metal deposit (Transbaikalia, Russia) : chemical features and crystal structure Available to Purchase
In-situ infrared spectroscopic studies of hydroxyl in amphiboles at high pressure Available to Purchase
First occurrence of moskvinite-(Y) in the Ilímaussaq alkaline complex, South Greenland – implications for rare-earth element mobility Available to Purchase
REPLACEMENT PROCESSES INVOLVING HIGH FIELD STRENGTH ELEMENTS IN THE T ZONE, THOR LAKE RARE-METAL DEPOSIT Available to Purchase
Barrydawsonite-(Y), Na 1.5 CaY 0.5 Si 3 O 9 H: a new pyroxenoid of the pectolite–serandite group Available to Purchase
3. Neoarchean intracontinental areas of sedimentation, magmatism, and high-temperature metamorphism (hot regions) in eastern Fennoscandia Available to Purchase
Beginning ca. 2.76 Ga, evolution of the Kola-Karelia crust was related to the intracontinental high-temperature metamorphic (up to granulite facies) and magmatic events in combination with formation of the basins related to rifting and infilling with intracontinental volcanic and sedimentary sequences initiated by plume-type processes in the mantle. The geological events corresponding to intracontinental evolution were expressed not only in the formation of new rock associations, juvenile to a significant extent, but also in reworking of previously formed rocks. The age, content, and mode of geological activity are somewhat different in the Kola and the Karelian-Belomorian regions. The Karelian-Belomorian region is oval in plan view. The long axis of this oval extends for 600–700 km in the meridional direction; its maximum width is 400–450 km. The southern part of this oval structure is cut off along the NW-trending boundary with the Paleoproterozoic Svecofennian accretionary orogen. The main constituents of the Karelian-Belomorian region are: epicontinental sequences of greenstone belts (Kostomuksha, Khedozero-Bolsheozero, Gimoly-Sukkozero, Jalonvaara) and paragneiss belts (Hattu, Nurmes); granulite-gneiss complexes and intrusive enderbite-charnockite series; sanukitoid-type granitoid intrusions and lamprophyre dikes, along with migmatization and emplacement of within-plate young granites; and local manifestations of granulite-facies metamorphism superposed on older rocks. Concentric spatial distribution of related geological units is characteristic of the Karelian-Belomorian region. The geometric pattern of the region can be satisfactorily explained assuming initial activity of a mantle plume ca. 2.76 Ga in the central part of the region. A peak of activity was related to the events that occurred ca. 2.74–2.70 Ga. The geochronological data show that a region of high-temperature processes expanded from its center (2.76–2.73 Ga) to the periphery (2.74–2.70 Ga). The concentric character of the tectonic structure was eventually formed as a result of these processes. Widespread high-temperature magmatism and metamorphism in combination with formation of synformal and linear sedimentary basins indicate the setting of anorogenic extension and vigorous influx of extracrustal heat, i.e., a large event related to a mantle plume. In contrast to the Karelian-Belomorian hot region, the coeval Kola region of intracontinental manifestations of high-temperature metamorphism and magmatism is characterized by oval-block geometry. This area, confined to the central part of the Kola Peninsula, extends for 600 km in the northwestern direction, having a width of ~200 km. It is possible that this area extends further to the southeast beneath the platform cover. The main tectonic units are the intracontinental greenstone belts (Sør-Varanger, Titovka, Uraguba, Olenegorsk, Voche-Lambina, Kachalovka, Runijoki–Khikhnajarvi, and Strelna system) in the Inari-Kola microcontinent, the granulite-gneiss Central Kola complex, and the Keivy volcanotectonic paleodepression. Sanukitoid intrusions play a modest role. The Keivy volcanotectonic paleodepression is situated in the eastern Kola Peninsula. Rocks of this tectonic unit are peculiar, and many of them have no obvious analogs in the Fennoscandian Shield or elsewhere. The major Neoarchean amphibolite-gneiss association consists of calc-alkaline to subalkaline garnet-biotite and subalkaline-peralkaline aegirine-arfvedsonite gneisses, as well as biotite-amphibole and amphibole gneisses, amphibolites, and rheomorphic alkali granites. In the western part of the paleodepression, gneisses (metavolcanic rocks) are cut through by small Sakharjok and Kuljok nepheline syenite intrusions. Geochronological estimates characterize two outbursts of magmatic activity separated by a long gap. The early outburst corresponds to magmatic crystallization of calc-alkaline metavolcanic rocks at 2.90–2.87 Ga. The second vigorous outburst documented at 2.68–2.63 Ga corresponds to eruption of subalkaline and subalkaline-peralkaline volcanic rocks, emplacement of alkali and nepheline syenites, and crystallization of gabbro-anorthosite of the Tsaga-Acherjok complex. The duration of the main magmatic phase is ~50 m.y., whereas the preceding gap lasted for ~200 m.y. A model of a volcanotectonic depression largely filled with pyroclastic flows seems plausible to explain pre-metamorphic events. Such manifestations of volcanic activity are inherent to intracontinental domains and related to activity of mantle plumes; similar processes can also develop in the back extensional zone of active continental margins. The synchronism of felsic volcanism and emplacement of the typically intracontinental gabbro-anorthosites form a sound argument in favor of an intracontinental setting for the Keivy paleodepression. The geometry of the Kola region can be satisfactorily explained in terms of mantle-plume activity noted ca. 2.76 Ga in the marginal part of this region; a peak of activity in its central part is related to the events that happened ca. 2.68–2.63 Ga.