21. It is composed of relics of carbonatite intrusion, now appearing as carbonatite ring and subsided central part. 22. It is composed of relics of carbonatite intrusion, now appearing as carbonatite ring and subsided central part. 23. Laterite covers are formed on both sides of carbonatite ring with accumulation of residual ferruginous-manganese minerals. 24. Some of these terrestrial rocks are carbonatite , kimberlite, alkaline syenite, some rocks of sills and anorthosite. 25. Porphyric carbonatite are formed by fast cooling of semi-crystallized magma, or in contact with cool environment. 26. It is a carbonatite -fenite complex of oval outline with a longer axis orientated approximately north-south. 27. The carbonatite has important resources of rare earth elements and is currently managed by ASX-listed Peak Resources. 28. The dikes or sills consist either of phonolite, tinguaite, lamprophyre micromalignite, lamprophyre micromelteigite, or carbonatite . 29. It occurs in an igneous carbonatite sill in Montreal, Canada in the Francon Quarry where it was first discovered. 30. The genesis of this Archaean carbonatite remains contentious as it is the sole example of an Archaean carbonatite in Australia.
