The Scotia metamorphic complex at Cape Bowles, Clarence Island, South Shetland Islands, western Antarctica.

Samples of phyllite and schist from Cape Bowles have a relatively simple structure related to isoclinal folding, with an axial cleavage. A series of arenaceous sediments derived from an acid igneous terrain appears to have been metamorphosed to greenschist-facies conditions. XRF analyses for 7 rocks are accompanied by probe analyses for white mica, epidote, chlorite and albite, together with minerals from the higher-grade rocks of Elephant Island, some 40 km west (M.A. 83M/1025). Rb/Sr data for 9 rocks from Cape Bowles give an isochron age of 71 + or - 40 m.y., i.e. the same Late Cretaceous (70-100 m.y.) event recorded elsewhere in the Scotia complex; initial ⁸⁷Sr/⁸⁶Sr ratios (0.7094 + or - 0.0005) are consistent with a Mesozoic rather than a Precambrian source area.-R.A.H.