The rock is extremely pourous with up to 50% pore space. The high porosity combined with other factors makes the rock a very good water bearing layer and it carries major underground water resources.
Gambier Limestone being very soft, can be sawn for use as a building stone. Major quarries are located 10 kilometres west of Mount Gambier.
Gambier Limestone is Oligocene to Miocene (38–15 million years) in age and comprises cream limestone made up of fossil fragments, mainly bryozoans, foraminifera, and echinoid spines and plates. Dolomite content is variable. Gambier Limestone underlies much of the South-East and reaches a total thickness of >300 m along the south coast. The limestone was deposited in a shallow, open sea that once extended as far north as Renmark in eastern South Australia. The limestone is cut into building blocks called ashlars, which are light in weight and provide high insulation and acoustic properties. The colour is predominantly cream but can range from white to cream to light brown. Dimensions are usually 660 mm long, 240 or 290 mm high, and 100 to 300 mm thick. The ashlars can be supplied as plain face, rock face or bevel edged.
Blocks of Limestone used for building are called ashlars, and are equivalent in area to 10 standard bricks. About 100 can be laid a day.
Sinkholes are important as they provide the best exposures of Gambier Limestone for study. Umpherston Sinkhole is recognised as a Geological Monument, because of its significance for scientific study.
At GZ you will find a sculpture made from Gambier Limestone, You are welcome to log a "Found it" log when you message or email the answers for the following questions.
Unanswered "Found it" logs will be discreetly deleted.
Q1: What does Gambier Limestone comprise of?
Q2: What is the texture of the sculpture as far as how smooth or rough it is?
Q3: What do the different sections of the sculpture represent?
Q4: Limestone is cut into building blocks, these blocks of limestone used for building are called?
Q5: Why are sinkholes important?