- GeoRef, Copyright 2004, American Geological Institute. Reference includes data from Bibliography and Index of Geology Exclusive of North America, Geological Society of America, Boulder, CO, United States
The Manx slate series, the ancient and complex bedrock of the Isle of Man, has been affected by three pre-Carboniferous phases of deformation. The oldest, designated F 1 , produced the large-scale Isle of Man syncline and acute folds with steep axial planes; F 2 refolded the earlier system with more open folds and axial planes with a gentle northwest dip; F 3 is a suite of open cross flexures, with axial planes dipping steeply east-northeast, developed on the flanks of previous structures. Distinct metamorphic textures characterize the F<1) and F<2) phases. The low-grade F<1) fabric was controlled by both flexural slip along bedding and planar slip parallel to axial planes of the folds. The F<2) fabric is characterized by the growth of porphyroblasts of leucoxene, muscovite, chloritoid, cordierite, garnet, biotite, and tourmaline along the hinge of the F<2) synform and it appears in an elongate belt in the middle of the island.