Sandra L. Kamo, Charles F. Gower, Thomas E. Krogh; Birthdate for the lapetus Ocean? A precise U-Pb zircon and baddeleyite age for the Long Range dikes, southeast Labrador. Geology ; 17 (7): 602–605. doi: https://doi.org/10.1130/0091-7613(1989)017<0602:BFTLOA>2.3.CO;2
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Mafic dike swarms represent direct evidence of early tensional environments that may have eventually led to ocean formation. The first precise U-Pb zircon and baddeleyite age of 615 ±2 Ma for a Long Range southeastern Labrador, could mark the beginning of Iapetus Ocean formation. Baddeleyite (ZrO2) is more widespread than previously recognized. It is ideal for use with the U-Pb system because it has low initial common lead and sufficient uranium levels, and it does not lose significant radiogenic lead with time. Baddeleyite therefore provides a unique opportunity for dating dikes associated with rift-related events with un-precedented accuracy.