The Svartliden granite: Petrography, whole rock geochemistry and stable isotope composition
Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
In this MSc thesis a characterization of the field appearance, petrogeochemistry, mineralogy, and oxygen/hydrogen isotope composition of the Svartliden granite was done. The Svartliden granite is a fine to medium grained two mica leuco granite (weakly mineralized by pyrrhotite) containing metasedimentary xenoliths and is intensely varying in character; granular-aplitic-pegmatitic. The Svartliden granite belongs to the Skellefte-Härnö granitic suite and is of S-type character. The protholith is most probably metasedimentary rocks belonging to the surrounding Bothnian Basin. Normally immobile elements such as Y, Ho, Zr and Hf have possibly been mobile in the fluid-rich magmatic Svartliden granite system. This makes the Svartliden granite interesting from a prospecting point of view because other normally immobile elements also possibly could have been mobile and concentrated. A spatially close Skellefte-Härnö pluton shows similar characteristics based on field appearance, deformation style, modal and nominal mineralogy; whole rock geochemistry, aluminum saturation, REE-signatures and oxygen/hydrogen isotope composition. Two spatially Svartliden-related Revsund plutons have been characterized for comparison. The Revsund granites are white to reddish, medium grained, equigranular-porphyritic biotite granites (s.s.) containing hornblende, titanite, and magnetite. It is possible to distinguish the Revsund granites from the Skellefte-Härnö granite (including the Svartliden granite) in the study area by the means of the above mentioned characteristics. The Revsund granites are of I-type character but show S-type affinities. The latter is probably caused by assimilation of metasedimentary material from the Bothnian Basin giving rise to for instance high A/CNK ratios and δ18O-values. The reddish colour of one of the Revsund plutons is caused by hematite alteration of magnetite and pyrite. This study provides further data in support of a sedimentary protholith generating the Skellefte-Härnö granite, and also data valuable for a continued discussion of the genetic aspects of the Revsund granitoid.
Place, publisher, year, edition, pages
2012. , 78 p.
Life Earth Science
Bio- och geovetenskaper, Svartliden, granite, S-type, I-type, whole rock geochemistry, petrography, stable isotope chemistry
IdentifiersURN: urn:nbn:se:ltu:diva-55280Local ID: c29247a3-8ada-4c8a-bbae-9076dbe14955OAI: oai:DiVA.org:ltu-55280DiVA: diva2:1028662
Subject / course
Student thesis, at least 30 credits
Geosciences, master's level
Validerat; 20120521 (anonymous)2016-10-042016-10-04Bibliographically approved