Sr Isotopic Age Research Articles

Rb [sbnd]Sr isotopic ages of Precambrian intrusives from Queen Maud Land, Antarctica

Rb Sr total-rock age measurements are reported for the Borg Metamafics and the Jörgen Intrusives of western Queen Maud Land. Pre-Cambrian ages are obtained, and the older Ahlmannrygg sediments can no longer be considered to be of Gondwana age. The position of Antarctica in the reconstruction of pre-Drift Gondwanaland is discussed.

Age of Lundy Granite, Bristol Channel

An unweathered granite specimen of the intrusive phase was collected from the southeast side of Lundy, a small island in Bristol Channel. K-Ar and Rb- Sr isotopic age measurements were made on separate biotite, a representative sample of whole rock, and a slate sample from Lundy. The K-Ar and Rb-Sr ages of the biotite were found to be 52 plus or minus 2 m.y. The problems encountered in the interpretation of the age data are discussed in some detail. It is concluded that the Lundy granite is the most southerly known Tertiary igneous center of the North Atlantic Province. (D.L.C.)