Mount Porndon
Encyclopedia
Mount Porndon is a 278 metre high volcano
located 13 kilometres southeast of Camperdown
in western Victoria, Australia
.
Mount Porndon is on private land. There is a fire tower on the summit
. It is a composite volcano of scoria
resting on lava disc and tuff
. The area around Mount Porndon is known as the stony rises. Early settlers use the abundance of rock to build stone fences.
flows, tuff deposits and scoria cones and craters
. The site covers a broad area including the major elements of volcanic sequence. A number of basalt
lava flows extend from Mount Porndon forming rough stony rises, some of which reach Lake Corangamite
. The younger of these flows formed an irregular lava disc roughly 3 km in diameter with a distinct and almost continuous perimeter in places forming a rocky wall 10 to 15 meters high. The stony rise flows have been dated at 300,000 years.
Overlying the lava disc is a thin layer of tuff. The main hills and cones were built from scoria eruptions which succeeded the phreatomagmatic stage after groundwater
had been depleted. Small lava flows from some vents beneath the scoria are the last eruptive activity. The central cone of Mount Porndon has a crater 15 m deep and open to the west.
Volcano
2. Bedrock3. Conduit 4. Base5. Sill6. Dike7. Layers of ash emitted by the volcano8. Flank| 9. Layers of lava emitted by the volcano10. Throat11. Parasitic cone12. Lava flow13. Vent14. Crater15...
located 13 kilometres southeast of Camperdown
Camperdown, Victoria
Camperdown is an historically significant rural town in southwestern Victoria, Australia, south west of the state capital, Melbourne. At the 2006 census, Camperdown had a population of 3,165.-History:...
in western Victoria, Australia
Australia
Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...
.
Mount Porndon is on private land. There is a fire tower on the summit
Summit (topography)
In topography, a summit is a point on a surface that is higher in elevation than all points immediately adjacent to it. Mathematically, a summit is a local maximum in elevation...
. It is a composite volcano of scoria
Scoria
Scoria is a volcanic rock containing many holes or vesicles. It is most generally dark in color , and basaltic or andesitic in composition. Scoria is relatively low in mass as a result of its numerous macroscopic ellipsoidal vesicles, but in contrast to pumice, all scoria has a specific gravity...
resting on lava disc and tuff
Tuff
Tuff is a type of rock consisting of consolidated volcanic ash ejected from vents during a volcanic eruption. Tuff is sometimes called tufa, particularly when used as construction material, although tufa also refers to a quite different rock. Rock that contains greater than 50% tuff is considered...
. The area around Mount Porndon is known as the stony rises. Early settlers use the abundance of rock to build stone fences.
Description
Mount Porndon is the central higher part of a volcanic complex including lavaLava
Lava refers both to molten rock expelled by a volcano during an eruption and the resulting rock after solidification and cooling. This molten rock is formed in the interior of some planets, including Earth, and some of their satellites. When first erupted from a volcanic vent, lava is a liquid at...
flows, tuff deposits and scoria cones and craters
Volcanic crater
A volcanic crater is a circular depression in the ground caused by volcanic activity. It is typically a basin, circular in form within which occurs a vent from which magma erupts as gases, lava, and ejecta. A crater can be of large dimensions, and sometimes of great depth...
. The site covers a broad area including the major elements of volcanic sequence. A number of basalt
Basalt
Basalt is a common extrusive volcanic rock. It is usually grey to black and fine-grained due to rapid cooling of lava at the surface of a planet. It may be porphyritic containing larger crystals in a fine matrix, or vesicular, or frothy scoria. Unweathered basalt is black or grey...
lava flows extend from Mount Porndon forming rough stony rises, some of which reach Lake Corangamite
Lake Corangamite
Lake Corangamite is Victoria’s largest natural lake, located near Colac in south-west Victoria, Australia in the Lakes and Craters region of the Victorian Volcanic Plains. The lake is hypersaline, and salinity levels have increased dramatically as the lake level has dropped in recent decades...
. The younger of these flows formed an irregular lava disc roughly 3 km in diameter with a distinct and almost continuous perimeter in places forming a rocky wall 10 to 15 meters high. The stony rise flows have been dated at 300,000 years.
Overlying the lava disc is a thin layer of tuff. The main hills and cones were built from scoria eruptions which succeeded the phreatomagmatic stage after groundwater
Groundwater
Groundwater is water located beneath the ground surface in soil pore spaces and in the fractures of rock formations. A unit of rock or an unconsolidated deposit is called an aquifer when it can yield a usable quantity of water. The depth at which soil pore spaces or fractures and voids in rock...
had been depleted. Small lava flows from some vents beneath the scoria are the last eruptive activity. The central cone of Mount Porndon has a crater 15 m deep and open to the west.