The geology of the Snug Cove area, north west coast Kangaroo Island, South Australia

This item is only available electronically.On the north west coast of Kangaroo Island in the vicinity of Snug Cove a major shear - the Snug Cove Shear Zone (SCSZ) has been recognised. The Snug Cove Shear Zone trends east-west in the area but is believed to strike inland to the east. The lithologies in the area were highly foliated and recrystallised in the shear zone but are gently folded outside of it. The lithological descriptions of Daily & Milnes (1971, 1973) were used to determine the stratigraphic position of the Snug Cove rocks; they are most likely to be within the Tapanappa Formation. Flattening strains in the area were low and the strain ellipsoid was oblate to spherical - a result of high recrystallisation. Kinematic indicators indicate a top to the north sense of shear throughout the shear zone. Strain variations in the shear zone are illustrated by the presence of high strain mylonitic zones in between lenticular relatively less deformed zones and the anastomosing nature of the mylonitic foliation. The relationship between the SCSZ and the nearby West Bay Syncline is due to the reactivation of a preexisting fault such that the SCSZ is located on the normal limb of the fold and not on the overturned limb as expected. The localisation of stress to create a ductile to semi-ductile shear zone is attributed to the buttressing effect of the Gawler Craton. Regionally, more than one deformation can be proposed on the basis of foliation relationships in porphyroblast schist. D1 was folding and cleavage development; D2 was crenulation and metamorphism; D3 was shear zone development.Thesis (B.Sc.(Hons)) -- University of Adelaide, School of Earth and Environmental Sciences, 199