Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
Results
Showing 1 to 6 of 6 for “"nepheline syenites"”.
-
Fluid evolution in the nepheline syenites of the Ditrău Alkaline Massif, Transylvania, Romania
… nappe system of the Mesozoic crystalline zone. Nepheline syenites are the most abundant rocks occurring in the central and eastern part of the Massif, and represent the youngest intrusion of the complex. Petrographic observations and fluid inclusion studies were performed on nepheline syenites …
-
Petrogenesis of hybrid porphyry pipes and evolution of alkaline magmas in the Kanabeam Igneous Complex, Southern Namibia
… in the province are represented and include nepheline syenites, quartz syenites as well as granites. In addition to these plutonic phases a number of late stage, xenolith rich porphyry pipes were emplaced, exploiting contact zones between earlier plutons. Xenolith types include gabbro …
-
Alkaline igneous rocks of the coastal belt, south of Luderitz, South West Africa : a petrological study
… be recognised. The first phase produced chilled nepheline syenites beneath the roof of the intrusion. These chilled rocks grade downwards into coarse-grained foyaites. The second phase was the emplacement of the Inner Foyaite which crystallized as a cylindrically zoned plug, capped by a zone of …
-
Petrology and Geochemical Evolution of the East Hill Suite of the Mont Saint-Hilaire Alkaline Plutonic Complex
… Hill suite, an assemblage of several distinct nepheline syenites and evolved syenitic rocks. Whole-rock analysis of the East Hill suite reveals two fractionation trends, one which is described by the syenitic lithologies and one by the evolved syenites and syenoids. A lamprophyric unit stands …
-
Oxygen and radiogenic isotope constraints on the generation of coexisting silica-undersaturated and oversaturated felsic magmas of the Ditrau Alkaline Massif (Romania)
… mantle origin of hornblendites, diorites and nepheline syenites. The Nd and O isotope variations imply the involvement of 20-65% upper crustal melts into the re-injected camptonite magma to generate the Ditrău syenites, quartz syenites and granites. The isotope results of the DAM require the …
-
Geochemical and isotopic constraints on the source regions of phanerozoic carbonatites and associated alkaline rocks from the Zandkopsdrift complex of Namaqualand, South Africa, and the Marinkas Quellen, and Dicker Willem complexes in Namibia
… and alkaline lamrophyre at Zandkopsdrift, nepheline syenite and trachyte at Marinkas Quellen, and ijolite and trachyte at Dicker Willem. At both Marinkas Quellen and Dicker Willem, the trachytes appear to be derived primarily from fenitised country rock. The major and trace element …