The Limestone Coast is unique in its geology and geography due to the variety of natural features that exist with the area known as the Otway basin. Each feature was formed over a long period of time to be what it is today, a rough timeline of these events are as follows.
- 158 million years ago – Formation of Gondwanaland
- 40 million years ago – Separation of Gondwanaland from Antarctic Continent
- 15-38 million years ago – Laying down of Mt Gambier Limestone Deposits
- 2-5 million years ago – Lifting of Naracoorte Ranges along Kanawinka Fault line Pliocene Era
- 1.5 million years ago – Volcanic eruptions in Mt Gambier
- 1 million years ago – Starting of formation of dunal systems and infilling
- 20,000 years ago – Last dune system formed currently offshore in 50-100m of water
- 4.600 years ago – Last of Volcanic activity around Mt Gambier
Mount Gambier Limestone is a white/cream limestone made up of fine fossil fragments. Mount Gambier Limestone underlies much of the South-East of South Australia and reaches a total thickness of more than 300 m along the coast. The limestone was deposited in a shallow, open sea. The soft limestone is extensively quarried and sawcut into building blocks called ashlars. The building blocks are light weight and have excellent insulation and acoustic properties.
At the listed coordinates you are in a limestone quarry. Please complete the following earthcache tasks
- Do you see any fossil fragments in the rock? Describe them. Additionally, do you see anything artificial carved into the rock?
- Can you scratch the surface? What does this tell you about the stone hardness?
Please send your answers by email or message. Free to log immediately, but you need to follow up with answers within a reasonable time period.