The effect of hydrothermal alteration and metamictisation on the U-Th-Pb- distribution and U-Pb-systematics of pyrochlore of the Sokli carbonatite complex, N-Finland

March 26th, 2012  Posted by jmwarnsloh

Pyrochlore is a common accessory mineral in granite pegmatites, nepheline syenites and carbonatites. Its ability to accomodate many different elements lead to a wide range of pyrochlore varieties. This is obvious for the U- and Th- contents. The Sokli carbonatite complex is part of the Kola alkaline province (KAP) in the northern Baltic Shield. The complex is situated in the area of Savukoski, Finish Lapland, close to the border to Russia. The emplacement age of 360 – 370 Ma falls in

Pyrochlore Composition As Indicator For The Carbonatite Evolution Stages At Sokli?

March 26th, 2012  Posted by jmwarnsloh

Pyrochlore is a common accessory mineral in granite pegmatites, nepheline syenites and carbonatites. The general chemical formular is A2-mB2X6-wY1-n • pH2O where A includes Na, Ca, U, Th , Pb, REE, Ba and Sr; B includes Nb, Ta, Ti, Zr and Fe; X = O and OH; Y = O, OH and F. The ability to accomodate many different elements leads to a wide range of pyrochlore varieties.
In Sokli (Finland) pyrochlore composition

U-Th-Pb- elemental and isotopic distribution of pyrochlore minerals from the Sokli carbonatite complex, N-Finland

March 26th, 2012  Posted by jmwarnsloh

Pyrochlore, ideally (Ca,Na)2(Nb5O6)(OH,F), is a relatively common accessory mineral in many rock-types including carbonatites. In the Sokli carbonatite, N. Finland, pyrochlore concentrates to economically important amounts, where it forms the ore mineral of niobium.