Cathodoluminescence p trography of Middle Proterozoic extrusive carbonatite from

• Main Authors: Qasiarsuk South Greenland, Christopher L. Hayward, Adrian, P. Jones
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Subjects: cathodoluminescence petrography; carbonatite; Qasiarsuk; Greenland
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.606.782; http://www.minersoc.org/pages/Archive-MM/Volume_55/55-381-591.pdf

The amygdaloidal carbonatite lavas at Qasiarsuk have a primary phenocryst assemblage of calcite, fluor-apatite and magnetite set in a groundmass ofcalcite, apatite and iron oxides, and minor dolomite. Cathodoluminescence reveals a complex history, both for the major minerals which show zonal growth, and for important Nb and REE accessory phases which include pyrochlore and perovskite. The REE reside in fluor/hydrous-carbonates included exclusively in apatite. These REE minerals are similar to synthetic phases from hydrothermal experiments, but probably crystallised in equilibrium with a late-stage volatile-rich carbonate melt. Apart from low-temperature alteration, the rocks have been little disturbed since their extrusion during the earliest phase of development of the Gardar