Hallett Cove

Hallett Cove Conservation Park lies about 22 kilometers south of Adelaide on the Gulf St Vincent coast of South Australia, a 51-hectare site prized as a geological monument of international importance. At Black Cliff it exposes Precambrian metamorphic rock around 600 million years old, folded and faulted, overlain across a marked unconformity by Permian glacial deposits roughly 270 million years old, laid down while Australia was part of the supercontinent Gondwana and experiencing extensive glaciation. That glaciation left behind glaciated pavements marked with crescent-shaped cracks showing the ice once flowed northwestward, along with erratics, rocks dropped by melting glacial ice, some carried from hundreds of kilometers away; one erratic, a tillite, is considered among the earliest evidence of glaciation ever recorded. Later Pliocene and Pleistocene layers add marine and terrestrial deposits reflecting more recent changes in sea level and climate, so the site documents multiple distinct chapters of Earth's history in one small area. This entity documents Hallett Cove specifically as a geological formation.