Three New Volcanoes Discovered in Australia
July 8, 2014
Three previously unknown volcanoes have been found in a region of South Australia known as the Newer Volcanics Province (NVP), researchers from Monash University in Australia reported in the Australian Journal of Earth Sciences. The youngest of the three, Cas Maar, is almost 0.6 mile (1 kilometer) wide and is around 300,000 years old. The other two volcanoes are Jays Hill, which is around 2 million years old, and Burgers Hill, which is about 4 million years old.
Mount Gambier in South Australia (at the lower right, near the border with Victoria) is one of around 400 volcanoes in the Newer Volcanics Province. (World Book map).
The NVP is home to approximately 400 somewhat unusual volcanoes. Nearly all volcanoes form along the edges of tectonic plates. Occasionally, however, volcanoes appear above locations called hot spots that can be far from plate boundaries. The NVP volcanoes are of the hot-spot variety. Another hot spot under the Pacific Ocean created a chain of volcanoes that became the Hawaiian Islands.
Cas Maar is an especially unusual type of volcano; it formed when magma heated groundwater, instantly evaporating the water. Such events cause an explosive eruption of steam, ash, and, sometimes, rock, and are known as phreatic eruptions.The other two newly discovered volcanoes are shield volcanoes. The last eruptions at this site occurred around 5,000 years ago, but the area is still considered active.
Additional World Book article:
