Early Jurassic and Late Cretaceous magmatism on Horseshoe Island, Antarctic Peninsula: New U-Pb and microstructural data

Abstract

Early Jurassic U-Pb age is obtained for both foliated and undeformed granites on Horseshoe Island, Antarctic Peninsula. Some microstructures in the foliated granites/orthogneisses indicate high-temperature greenschist or low- to medium-temperature amphibolite facies deformation conditions. Additionally, a Late Cretaceous age is yielded for a gabbro intruding the deformed granitoids.