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| Titel: |
On the acid volcanigs and the ore formation in the skellefte district, northern Sweden |
| Auteur: |
Vessby, Erik |
| Verschenen in: |
GFF |
| Paginering: | Jaargang 90 (1968) nr. 2 pagina's 272-301 |
| Jaar: |
1968-06-28 |
| Inhoud: |
The oldest Precambrian formations of the Skellefte District, usually called the “Skellefte volcanites”, consist largely of acid and intermediate Na-rich rocks — in the upper parts of which the most important sulphide ores of Sweden are situated — and are overlain by the Phyllite Formation. The present writer finds it likely that the characteristic appearance of the acid Skellefte volcanites was developed principally by metamorphic-metasomatic processes. A model is suggested for the way in which the sulphides, considered to have been confined originally to black shales of the Phyllite Formation, could have concentrated in the sheared upper parts of the underlying rocks by mobilization and mainly gravitational differentiation during regional metamorphism. Simultaneously the most mobile components of these latter rocks could have migrated towards the zones of ore formation developing “alteration aureoles” of sericite-quartz-schists and leaving Na-rich acid rocks behind, farther away from the ores. Certain observed variations in the apparent metamorphic facies of the mineral assemblages are attributed to the above-mentioned processes, which are fit into a tentative scheme for the geological evolution of the Skellefte District. |
| Uitgever: |
Taylor & Francis |
| Bronbestand: |
Elektronische Wetenschappelijke Tijdschriften |
Details van artikel 11 van 19 gevonden artikelen
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