Tweed Volcano
Tweed Volcano was an early Miocene shield volcano in northeastern New South Wales, Australia. In the course of about three million years, Tweed Volcano was formed over the East Australia hotspot when this part of the continent passed over it around 23 million years ago.[1] Mount Warning, Lamington Plateau and the Border Ranges between New South Wales and Queensland are among the remnants of this volcano that was originally over 100 km in diameter and nearly twice the height of Mount Warning today (1,156 m). Despite its size, Tweed Volcano was not a supervolcano; other shield volcanoes - such as on Hawaii - are much larger. In the 23 million years since the volcano was active, erosion has been extensive, forming a large erosion caldera around the volcanic plug of Mount Warning. Its erosion caldera is the largest in the Southern Hemisphere.[2]
[edit] Volcanic Stratigraphy
Lavas from the Tweed Volcano are recognised as part of the Lamington Volcanics.[3]
The volcanic stratigraphy of the Tweed Volcano is similar to many other hot spot volcanoes around the world. Eruptions of tholeiitic and some alkaline basalts are the oldest recognised units derived from the volcano. These are named the Lismore/Beechmont Basalt in New South Wales and Queensland respectively. There are numerous flows recorded which may have been erupted erreguarly as soil profiles and lacustrine type rock units are occasionally found within the rock unit.
Following eruption of the Lismore/Beechmont Basalt a period of eruption of rhyolite lavas took place. Eruptions occurred in lava and some pyroclasic forms. These rhyolites are known in New South Wales as the Nimbin Rhyolite and Queensland as the Binna Burra Rhyolite. Following eruption of this rhyolite a period of basaltic volcanism resumed (or continued) with the eruption of the Blue Knob(NSW)/Hobwee(QLD) Basalt.
[edit] See also
[edit] References
- ^ Knesel K. M., Cohen B.E., Vasconcelos P. M., and Thiede D.S. (2008) Rapid change in drift of the Australian plate records collision with Ontong Java Plateau, Nature vol 454, pages754-757.
- ^ the Caldera of the Tweed Volcano.
- ^ Geoscience Australia Lamington Volcanics Stratigraphy
- Mount Warning
- Records in the Rocks. A relatively simple account of the creation of the Tweed Volcano
- Green Mountains, Lamington National Park
Coordinates: 28°23′44.71″S 153°16′0.19″E / 28.3957528°S 153.2667194°E
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