Circum-Superior Belt event in Australia and 1,860 million year old magmatism of the Mashonaland event in Africa. The other questionable suggestion related to the Circum-Superior Belt is the existence of a suggested 1,900 million year old global superplume event. The long Labrador Trough, extending from Ungava Bay through Quebec and Labrador, includes two volcano-sedimentary series, the first ranging from 2,170 to 2,140 million years old and second ranging from 1,883 to 1,870 million years old. This magmatism is considered to have formed as a result of back-arc volcanism. The youngest magmatic series (1883-1870 Ma) contains 1,880 million-year-old carbonatites and lamprophyres. 1,883 to
Circum-Superior Belt indication of the Circum-Superior Belt is also poorly known; either it contains major regional differences or it is the same throughout the magmatic zone. With the discovery of the Pickle Crow dike swarm throughout the western Superior craton, the likelihood of other 1,880 million year old dike groups throughout the Superior craton remains. This is partly because several dike zones in the Superior craton remain undated. The relationship of the Circum-Superior Belt with similar age magmatism throughout the nearby Trans-Hudson belt and elsewhere on Earth is also unknown. This includes the 1,860 million year old magmatism of the East Kimberly