Petrology of the Suvasvesi granitoid intrusion
The Paleoproterozoic (1870 ± 4 Ma) Suvasvesi intrusion belongs to the
Heinävesi granitoid suite that intrudes the Paleoproterozoic Ylä-Kaleva
metasedimentary rocks (migmatitic paragneisses) of the Karelian domain
(Viinijärvi suite). The Suvasvesi intrusion is ca. 10 x 30 km in size
and majority of its areal extent is located under and south of lake
Suvasvesi in Northern Savonia. The Heinävesi suite has previously been
associated with the Svecofennian post-kinematic (1.88–1.87 Ga)
granitic–quartz monzonitic magmatism mostly present within the Central
Finland granitoid complex (CFGC). The Heinävesi suite, however, intrudes
clearly older (>1.92 Ga) country rocks east of the CFGC area and,
based on Nd isotope composition (εNd@1880 -6.6 to -1.9), taps a
significantly more enriched crustal source than the post-kinematic
intrusives within the CFGC (εNd@1880 -1.1 to +0.5).
The
mineralogy, petrology, and lithology of the Heinävesi suite are in
general rather poorly studied and this project aims to enhance the regional geological framework by unraveling the petrogenesis of the Suvasvesi granitoid. In
order to do this, a reconnaissance-scale mapping project including
petrographic, geochemical, and mineral chemical analysis to describe the
Suvasvesi granite intrusion and to study its relation to the regionally
widespread pegmatitic dykes intruding the Viinijärvi suite, is to be
conducted.
The project is realized as a MSc thesis project and will include mapping of the Suvasvesi intrusion and
the surrounding mica gneisses,
petrographic and geochemical analyses, and thermodynamic partial melting modeling based on the acquired
data set in order to constrain the source components, geochemical
evolution, and possible enrichment processes related to the Suvasvesi
intrusion magmas.
Much of the field-work and regional geological studies in this project are conducted in close collaboration with the Geological Survey of Finland.
More info here.
No comments:
Post a Comment