Remarkable Cave, Tasmania

At Remarkable Cave, southern Tasmania, Triasssic sedimentary rocks are intruded by Jurassic dolerite to form a sheet-like body of unknown thickness to the east of and below Remarkable Cave. The sedimentary rocks near sea-level at Remarkable Cave show deformation and flow structures, and are composed of recrystallised predominantly quartz and feldspar with some darker alteration minerals and zeolite in the more massive parts of the recrystallised rock. The deformation was caused by the intrusion of dolerite. At the top of the sheet-like body to the east of Remarkable Cave there is rheomorphic veining into the dolerite following joint fractures. The dolerite is locally transgressive. In Remarkable Cave, dolerite must occur just below the floor of the cave to heat the sedimentary rocks to much higher temperatures than typical contact aureoles in the area, supporting a local feeder geometry, or compositional control.