Tower Hill
GEOLOGY
Tower Hill is a geological feature formed by a group of scoria volcanic cones within a large lake filled maar volcano crater.
A maar volcano is formed by rising magma comes into contact with shallow sedimentary rocks saturated with ground water. The magma then heats the water into high pressure steam, the resultant pressure then causes explosions, breaking the overlying rock. The ground then collapses allowing the steam to escape. After additional explosions the ground slumps further and a shallow rim is formed by ash deposits around the crater.
At Tower Hill, some time after the maar was formed, heat from the magma dried out the underlying rock, and further volcanic activity formed scoria cones within the base of the maar crater.
Scoria cones are formed, much less violently, but spectacularly, as jets of red hot lava are sprayed high into the air. The frothed up lava is cooled by contact with the air and forms many voids, producing a light rock known as scoria. Scoria falling around the central vent then builds up forming a steeply sided cone.
Tower hill the highest scoria cone, in the formation is believed to have been formed between 25 and 32,000 years ago.
HISTORY
Up until 1850 the forest at Tower Hill was reported to be so dense that people were concerned about getting lost. Unfortunately the area was not managed properly and by 1869 all the usable timber had been removed from the islands. In 1870 there were 11 cottages on the islands and beet, potato and onion crops were grown.
In 1892 Tower Hill was made Victoria's first National Park, controlled by the shire.
During the 1960s, re-vegetation programs were undertaken and in the 1970's native animal species were reintroduced, including emu, kangaroo, koala, echidna and sugar glider.
In 2006, Tower Hill was rated as a geological feature of State and National significance, and added to the Victorian Heritage Register .
OPENING HOURS AND OTHER ATTRACTIONS
The Natural History Visitor's Centre is open Monday to Friday 9am-5pm & Weekends & Public Holidays 10am-4pm
There is a lovely picnic area beside the visitor's centre car park, with wild emus occasionally strolling around on the lawns
The wetland boardwalk is also worth a visit if you have the time.
All Walking trails are sign posted leading out from of the visitor's centre
More information on the Tower Hill State Game Reserve is available on the Parks Victoria Websiteor by calling 13 19 63
To log this Earthcache you need to visit the Natural History Visitors Centre located on the main island, inside, you will find a board, containing information about the geology of Tower Hill, which you will need, in order to answer the following questions. You will also have to walk to the summit of Tower Hill (Peak Climb walk) and photograph yourself and/ or your GPS with a prominent feature in the background.
1. How far below the original surface is the crater floor?
2. How high are the jets of lava from the scoria vents thought to have reached?
3. How far from the crater have debris been found from the blast?
4. In your own words describe how the main features of Tower Hill were formed, be sure to include the feature at the photo location?
Email me your answers to the above questions before logging your visit, obviously do not include your answers in your log.
Log your visit ensuring you post your photo taken at the summit clearing identifying that you visited the site
When logging your visit please describe what you found most interesting about your visit. and feel free to post additional photos of the area
Any logs that do not meet the above requirements will be quietly deleted.
References
Birch William D, Volcanoes of Victoria, Royal Society of Victoria., pp. 1 – 36
Clark Mary Ryllis , Discover Historic Victoria : 60 heritage places to visit pp. 1 – 180