Results 141 to 150 of about 479 (172)

Rapakivi Granite of Ezhimala Complex and its Significance

Journal Geological Society of India, 1982
Abstract The field characters, chemistry and the spatial association of the 678 m.y. old Rapakivi granite with gabbros and anorthosites suggest that these litho-units have developed through bimodal magmatic processes whereby heat derived from basic magma parental to the anorthositic rocks caused partial melting at or near the base of the
M. M. Nair, K. T. Vidyadharan
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The genesis of the Gaborone rapakivi granite complex in southern Africa

Journal of the Geological Society, 1982
The Gaborone Granite is a mushroom-shaped intrusion with a surface area of over 5000 km 2 . The intrusion is layered, consisting of a central core of rapakivi granite (Thamaga Granite) surrounded by successive shells of an equigranular leucocratic granite (Kgale Granite), a porphyritic granophyre or microgranite ...
R. M. Key, E. P. Wright
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Rapakivi granites in the geological history of the earth. Part 1, magmatic associations with rapakivi granites: Age, geochemistry, and tectonic setting

Stratigraphy and Geological Correlation, 2009
Rapakivi granites characteristic practically of all old platforms are greatly variable in age and irregularly distributed over the globe. Four types of magmatic associations, which include rapakivi granites, are represented by anorthosite-mangerite-charnockite-rapakivi granite, anorthosite-mangerite-rapakivi-peralkaline granite, gabbro-rapakivi granite-
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Rapakivi granites from Brazil and adjacent areas

Precambrian Research, 1999
Abstract A review of the rapakivi magmatism in Brazil and adjacent areas demonstrates that the dominantly felsic anorogenic complexes of the Amazonian craton can be considered as rapakivi suites. They are found in almost all provinces of the craton and are concentrated in the timespan covering the end of the Palaeoproterozoic until the beginning of ...
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Granitoids of rapakivi granite-anorthosite and related associations

Precambrian Research, 1991
Abstract Mid-Proterozoic anorthosite-mangerite-charnockite-rapakivi granite (AMCG) magmatic suites have commonly intruded Proterozoic orogenic belts within 100 Ma or less to as much as 600 Ma after cessation of calc-alkalic crustal generation processes. High FeO (FeO+MgO) , high Na2O+K2O, low Al2O3, and reduced redox condition of the granitoids
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Acoustic Logs in the Structural Interpretation of the Hästholmen Rapakivi Granite Site

61st EAGE Conference and Exhibition, 1999
Geological and geophysical borehole data from the site investigation programme for nuclear waste disposal in Finland are integrated to analyse the main engineering geological structures of the rock mass.
O. Okko, K. Front
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Tectonic setting and origin of the Proterozoic rapakivi granites of southeastern Fennoscandia

Earth and Environmental Science Transactions of the Royal Society of Edinburgh, 1992
ABSTRACTThe 1·65–1·54 Ga rapakivi granites of southeastern Fennoscandia represent the silicic members of a bimodal magmatic association in which the mafic members are tholeiitic diabase dykes and minor gabbroic-anorthositic bodies. They are metaluminous to slightly peraluminous A-type granites and occur as high-level batholiths and stocks in an E-W ...
Ilmari Haapala, O. Tapani Rämö
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Geology, Petrography and Petrology ofthe Rapakivi Granites; The Rapakivi Granites of Finland

İri alkali feldispatm plajiyoklas tarafından çevrelenmesiyle oluşan dokuyu gösteren granitler "Rapakivi Granitleri" olarak adlandırılmaktadır. Çoğunlukla Proterozoyik 1.8-1.0 milyar yıl yaşlı olan rapakivi granitleri, Ukrayna, Baltık ülkeleri, güney Grönland, orta-kıtasal ve batı ABD, Venezüella, Brezilya, Bostwana ve diğer birçok ...
ARSLAN, Mehmet, ASLAN, Zafer
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Charnockite-granite association in SW Nigeria: rapakivi granite type and charnockitic plutonism in Nigeria?

Journal of African Earth Sciences (1983), 1987
Abstract A plutonic complex containing both charnockitic and non-charnockitic granite rocks (Older Granites) occurs within the amplhibolite facies rocks of gneisses and migmatites in the Ado Ekiti-Akure region of southwestern Nigeria. This complex comprises three petrographic types of charnockitic rocks and three of granitic rocks.
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Origin of rapakivi granites by stochastic modeling: Vyborg and Salmi Massifs

Mathematical Geology, 1987
Grain sequences of Precambrian rapakivi granites of the Vyborg and Salmi Massifs have been compared with the stochastic model for ideal granite. These sequences show that classical rapakivi granites correspond to metasomatically weakly altered granites with a simple loss of Markov transitions from quartz and plagioclase.
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