HENTY GLACIAL ERRATICS STATE RESERVE
Location: 14km from Queenstown near the Anthony Main Road intersection | Google Maps Reference
Key facts about this geosite:
• The area has been affected by multiple periods of glacial activity.
• Huge volumes of rocky detritus was entrained in ice and deposited as glacial till.
• Boulders were sourced from the elevated West Coast Range in the Mt Julia – Mt Tyndall area.
• The glacial deposits overlie the Mt Read Volcanics.
Geosite Description: The oldest bedrock visible in this area shows Cambrian rocks comprising ash-rich volcaniclastic siltstones and sandstones of the Mount Read Volcanics, deposited during a period of volcanism about 500 million years ago. These rocks host important copper-lead-zinc-gold mines at Mt Lyell, Rosebery, Henty and Hellyer. The volcanic rocks were subsequently largely eroded and partly deposited beneath the ocean, prior to being exhumed during a Devonian mountain building episode.
During the Pleistocene epoch, Tasmania was affected by multiple periods of glacial activity with large ice sheets covering much of the mountainous central and western Tasmania. The Henty Glacial Erratics State Reserve is located near what was the western limit of ice during the Henty glacial event approximately 34,600 years ago. As the ice sheet melted, rock debris (including large boulders called glacial erratics) and clay that were once entrained in the ice were deposited as glacial till.