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| Meerbeke, G.L.E. van; Hilgen, J.D.; Floor, P.. |
| Probably Lower Paleozoic quartzo-pelitic schists with bands of feldspathic schists, white and black quartzites, graphite schists and amphibolites have been folded twice. Hercynian regional metamorphism led to porphyroblastic growth of chlorite, albite, biotite, garnet, staurolite mainly between F1 and F2. Andalusite porphyroblasts are related to Hercynian granite intrusions of varying age with respect to F2. An isograd map of biotite, garnet, staurolite and andalusite is presented. Structures elucidating the relations between deformation phases and metamorphic mineral growth are discussed. |
| Tipo: Article / Letter to the editor |
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| Ano: 1973 |
URL: http://www.repository.naturalis.nl/record/505769 |
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| Arps, C.E.S.; Calsteren, P.W.C. van; Hilgen, J.D.; Kuijper, R.P.; Tex, E. den. |
| In Galicia occur several polymetamorphic complexes that contain mafic and ultramafic rocks. Mafic volcanics and gabbros are situated in or near the complexes. An episode of metamorphism and granitization encompassed the generation of the volcanics and gabbros. Gravity surveys revealed the existence of deep roots below polymetamorphic complexes. Geochronological investigations yielded Palaeozoic ages from about 500 Ma for the generation of ultramafic rocks and calcalkaline granite series, till ages of around 300 Ma for postkinematic alkaline and calcalkaline granites. A model involving mantle-plume diapirism and rejuvenation of the lower crust is proposed for the Early Palaeozoic evolution of the continental lithosphere of Galicia. An excursion route is... |
| Tipo: Article / Letter to the editor |
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| Ano: 1978 |
URL: http://www.repository.naturalis.nl/record/505595 |
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