Lava Blister : Point Gellibrand, Williamstown
Along the Point Gellibrand foreshore near the suburb of Williamstown on the western side of Port Phillip Bay is this remarkable geological feature called a Lava Blister.
These Blisters form when fluid Lava crosses a shallow body of standing water or swampy ground causing the water to boil. As a result, the confined steam pressure raises the surface of the Lava into a dome formation which then slowly cools.
At Point Gellibrand - easily accessible by foot being not far from Williamstown Railway Station and the famous Timeball Tower - the Blister is Kidney shaped measuring 4.8 meters (near 16 feet) by 3.4 metres (near 11 feet) with a rim between 30 and 40 centimetres (about 12 to 16 inches) deep. The upper part of the Blister's dome has been eroded by tide and time into its present formation. Lava Blisters generally are considered rare throughout the world and especially in the volcanic rocks of Victoria.
At times of low Tide, this Blister can be seen in its entirety, carousing with the endless waves seeking its ruin. At other times it is partially or fully submerged.
Victoria, (the southernmost mainland State in Australia) has the world's third largest volcanic field, though all tumult is long dormant (note not extinct, as the Geologists will quietly inform). Within an hour's drive or so of Melbourne (roughly 100 kilometres or just over 60 miles) there are at least four once prominent, though long inactive, Volcanoes - Mounts Blackwood, Buninyong, Macedon and Cottrell - and a host of smaller volcanic outlets and features. This is not well known generally, let alone considered by most Melbournians.
For me, the Lava Blister at Point Gellibrand is an astonishing geological treasure; a real time capsule when you imagine all those tens of thousands of years ago Lava flowed from eruptions into Port Phillip Bay. Such time travellers can be seen not only in this Blister but across the strewn fields of Granite that feature along the foreshore here and at nearby places.
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- Canon PowerShot G10
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