Fundamental Minerals

Sialic Minerals

Feldspars

Feldspathoids

Quartz

Femic Minerals

Spodumene

Accessory Minerals

Rare Accessory

Alteration Products

Microstructures

Rocks

Jacupiranga complex

Sövite

The carbonatites within the main intrusion on Alnö island are mainly Ca-carbonatites with only minor Mg-carbonatite. They are intruded as dykes with widths from several tens of meters to only a few centimeters and cross-cut all major igneous rocks of the main intrusion, i.e. pyroxenite, ijolite series rocks and nepheline syenite.

It has not been possible to establish if there are different generations of Ca-carbonatites within the Alnö complex. Most Ca-carbonatite appears to have been intruded at more or less the same time as no cross-cutting relationships have been observed. However, it has been observed that Mg-rich carbonatites, which only occur as smaller dykes (< 50 cm in width), in general cross-cut the Ca-carbonatite dykes. Silicate minerals are ubiquitous in Ca-carbonatite. These are primarily clinopyroxene (diopside-aegirineaugite), phlogopite and titanite, but olivine, alkali feldspars, wollastonite and quartz have also been observed. It should be noted however, that some of the silicate minerals present in the Ca-carbonatites are derived from surrounding wall-rock and thus did not crystallize within the carbonatite magma.

Bibliography

• Andersson, M. (2015). 3D Structure and Emplacement of the Alnö Alkaline and Carbonatite Complex, Sweden: Integrated Geophysical and Physical Property Investigations.
• Kresten P (1980): The Alnö complex: tectonics of dyke emplacement. Lithos 13:153–158.
• Brueckner H.K, Rex DC (1980): K-A and Rb-Sr geochronology and Sr isotopic study of the Alnö alkaline complex , northeastern Sweden. Lithos 13:111–119.

Calcite, biotite (green) and monticellite (elongated and fractured crystals) in a Sövite from Alnö complex, Sweden. PPL image, 2x (Field of view = 7mm)	Calcite, biotite (high interference colors) and monticellite (elongated and fractured crystals) in a Sövite from Alnö complex, Sweden. XPL image, 2x (Field of view = 7mm)	Calcite and biotite (green) crystals in a Sövite from Alnö complex, Sweden. PPL image, 2x (Field of view = 7mm)
Calcite and biotite (high interference colors) crystals in a Sövite from Alnö complex, Sweden. XPL image, 2x (Field of view = 7mm)	Calcite and biotite (high interference colors) crystals in a Sövite from Alnö complex, Sweden. XPL image, 2x (Field of view = 7mm)	Calcite, biotite (green), magnetite (black) and monticellite (elongated and fractured crystals) in a Sövite from Alnö complex, Sweden. PPL image, 2x (Field of view = 7mm)
Calcite, biotite (green) and monticellite (elongated and fractured crystals) in a Sövite from Alnö complex, Sweden. PPL image, 2x (Field of view = 7mm)	Calcite, biotite (high interference colors) and monticellite (elongated and fractured crystals) in a Sövite from Alnö complex, Sweden. XPL image, 2x (Field of view = 7mm)	Calcite, biotite (green) and monticellite (elongated and fractured crystals) in a Sövite from Alnö complex, Sweden. PPL image, 2x (Field of view = 7mm)
Calcite, biotite (green) and monticellite (elongated and fractured crystals) in a Sövite from Alnö complex, Sweden. PPL image, 2x (Field of view = 7mm)	Calcite, biotite (high interference colors) and monticellite (elongated and fractured crystals) in a Sövite from Alnö complex, Sweden. XPL image, 2x (Field of view = 7mm)	Calcite, biotite (high interference colors) and monticellite (elongated and fractured crystals) in a Sövite from Alnö complex, Sweden. XPL image, 2x (Field of view = 7mm)
Calcite, biotite (green) and monticellite (elongated and fractured crystals) in a Sövite from Alnö complex, Sweden. PPL image, 2x (Field of view = 7mm)	Calcite, biotite (high interference colors) and monticellite (elongated and fractured crystals) in a Sövite from Alnö complex, Sweden. XPL image, 2x (Field of view = 7mm)	Calcite and biotite (green) crystals in a Sövite from Alnö complex, Sweden. PPL image, 2x (Field of view = 7mm)
Calcite and biotite (high interference colors) crystals in a Sövite from Alnö complex, Sweden. XPL image, 2x (Field of view = 7mm)	Calcite, biotite (green) and monticellite (elongated and fractured crystals) in a Sövite from Alnö complex, Sweden. PPL image, 2x (Field of view = 7mm)	Calcite, biotite (high interference colors) and monticellite (elongated and fractured crystals) in a Sövite from Alnö complex, Sweden. XPL image, 2x (Field of view = 7mm)
Calcite and biotite (high interference colors) crystals in a Sövite from Alnö complex, Sweden. XPL image, 2x (Field of view = 7mm)	Calcite and biotite (high interference colors) crystals in a Sövite from Alnö complex, Sweden. XPL image, 2x (Field of view = 7mm)	Calcite and biotite (high interference colors) crystals in a Sövite from Alnö complex, Sweden. XPL image, 2x (Field of view = 7mm)
Calcite and biotite (green) crystals in a Sövite from Alnö complex, Sweden. PPL image, 2x (Field of view = 7mm)	Calcite and biotite (high interference colors) crystals in a Sövite from Alnö complex, Sweden. XPL image, 2x (Field of view = 7mm)	Calcite and monticellite (elongated and fractured crystals) in a Sövite from Alnö complex, Sweden. PPL image, 2x (Field of view = 7mm)
Calcite and monticellite (elongated and fractured crystals) in a Sövite from Alnö complex, Sweden. XPL image, 2x (Field of view = 7mm)	Cristalli di calcite, biotite (alti colori di interferenza) e monticellite (cristalli allungati e fratturati) in una Sövite di Alnö, Svezia. Immagine a NX, 2x (lato lungo = 7mm)	Calcite and biotite (high interference colors) crystals in a Sövite from Alnö complex, Sweden. XPL image, 2x (Field of view = 7mm)
Calcite and monticellite (elongated and fractured crystals) in a Sövite from Alnö complex, Sweden. PPL image, 2x (Field of view = 7mm)	Calcite and monticellite (elongated and fractured crystals) in a Sövite from Alnö complex, Sweden. XPL image, 2x (Field of view = 7mm)	Calcite and monticellite (elongated and fractured crystals) in a Sövite from Alnö complex, Sweden. XPL image, 2x (Field of view = 7mm)
Calcite and monticellite (elongated and fractured crystals) in a Sövite from Alnö complex, Sweden. XPL image, 2x (Field of view = 7mm)	Calcite, biotite (green) and monticellite (elongated and fractured crystals) in a Sövite from Alnö complex, Sweden. PPL image, 2x (Field of view = 7mm)	Calcite, biotite (high interference colors) and monticellite (elongated and fractured crystals) in a Sövite from Alnö complex, Sweden. XPL image, 2x (Field of view = 7mm)
Calcite and biotite and monticellite (elongated and fractured crystals) in a Sövite from Alnö complex, Sweden. PPL image, 2x (Field of view = 7mm)	Calcite and biotite and monticellite (elongated and fractured crystals) in a Sövite from Alnö complex, Sweden. PPL image, 2x (Field of view = 7mm)	Calcite and biotite and monticellite (elongated and fractured crystals) in a Sövite from Alnö complex, Sweden. XPL image, 2x (Field of view = 7mm)
Calcite and biotite and monticellite (elongated and fractured crystals) in a Sövite from Alnö complex, Sweden. PPL image, 2x (Field of view = 7mm)	Calcite and biotite and monticellite (elongated and fractured crystals) in a Sövite from Alnö complex, Sweden. XPL image, 2x (Field of view = 7mm)	Calcite and biotite and monticellite (elongated and fractured crystals) in a Sövite from Alnö complex, Sweden. PPL image, 2x (Field of view = 7mm)
Deformed biotite crystal in a Sövite from Alnö complex, Sweden. PPL image, 2x (Field of view = 7mm)	Deformed biotite crystal in a Sövite from Alnö complex, Sweden. XPL image, 2x (Field of view = 7mm)	Deformed biotite crystal in a Sövite from Alnö complex, Sweden. PPL image, 2x (Field of view = 7mm)
Deformed biotite crystal in a Sövite from Alnö complex, Sweden. XPL image, 2x (Field of view = 7mm)	Deformed biotite crystal in a Sövite from Alnö complex, Sweden. XPL image, 2x (Field of view = 7mm)	Deformed biotite crystal in a Sövite from Alnö complex, Sweden. XPL image, 2x (Field of view = 7mm)
Deformed biotite crystal in a Sövite from Alnö complex, Sweden. XPL image, 10x (Field of view = 2mm)	Deformed biotite crystal in a Sövite from Alnö complex, Sweden. XPL image, 10x (Field of view = 2mm)	Deformed biotite crystal in a Sövite from Alnö complex, Sweden. XPL image, 10x (Field of view = 2mm)