Mt Ainslie
Mount Ainslie borders on the inner suburbs of Campbell, Australian Capital Territory & Hackett and is named in honour of James Ainslie, a 19th-century settler who was the overseer on Duntroon, Australian Capital Territory, a large property in the area. The Mount Ainslie tourist outlook, one of Canberra's most popular, provides excellent views of central Canberra and Red Hill, to the south and Black Mountain to the west especially towards sunset.
Mt Ainslie is also the most prominent peak in a range formed as a result of volcanic activity. The range extends from Mt Ainslie, through Mt Majura to Mt Gooroo. Part of its structure is visible in the 50m rock cut on the Horse Park Drive/Federal Highway intersection, there are numerous quarries and other visible elements that have impressive relevance in their own right. This EC will attempt to create a picture of the structure of Mt Ainslie. The questions noted below explore the various distinct layers that the Ainslie Volcanic are made up of.
The EC can be walked on the lower section, but a car would be easier, given the altitude on the climb up the road.
Ainslie Volcanics
Named after Mount Ainslie, Australian Capital Territory, where their type location occurs, the Ainslie Volcanics are composed of Dacite, Ignimbrite and minor volcaniclastic and argillaceous Sediment. The lithology is bluish grey dacitic tuff, which can be massive or foliated, also dacitic agglomerate and shale. These volcanics contain chloritised Cordierite and some have red Almandine, Garnet. Jasper is found on low hills on the north side of the Molonglo River. The thickness is at least 700 metres. The magma was formed by melting an Aluminium Pelitic sediment. The eruption came from a volcano into shallow sea water. The deposits built above sea level as they progressed. The underlying sediments now make up the Canberra Formation. Between Hall and Namina Hill on Spring Range, the Mount Painter Volcanics lie unconformably on top. These rocks date from the Late Wenlock epoch of the Silurian period. They were formed about the same time as the Walker Volcanics and Paddys River Volcanics.
The Ainslie Volcanics occur on Mount Ainslie, Mount_Majura, and in a band extending from Bonshaw and Harman, north to the east of Woolshed Creek, through Majura and at least to Gooroo Hill and Old Joe on the NSW border. On Mount Ainslie the sequence starts with dacitic tuff, banded dacitic tuff, massive dacitic tuff, fifty metres of agglomeratic tuff, massive dacitic tuff, fifty metres of ashstone and topped with massive dacitic tuff.
*Tuff (from the Italian language tufo is a type of Rock consisting of consolidated Volcanic ash ejected from vents during a Volcanic eruption.
Please compile the answers and send them to me, if they check out, you can post. Feel free to photograph the experience, but no spoilers please. The lower section of the EC is based on the "Kokoda" trail, which is based behind the war Memorial. there is ample parking available. The second part would require a drive (recommended) up the main road to Mt Ainslie and each WP is located at an area where there is off street parking available.
Group visits are encouraged, but still will require individual submissions to post.
Area 1 – Banded Dactic Tuff
What colours are the rocks at this area?
Area 2 – Agglomeratic Tuff
There is an information sign at this point. It notes the Sandstones on Black Mountain and Mt Ainslie, are they the same?
There are rock tors (rounded rocks protruding from the ground) visible around this area, what height are they?
Area 3 – Massive Dactic Tuff
Do the rocks here have visible bands or seams?
Area 4 – Ashstone Tuff
What three colours are mostly visible?
Are seams in the rocks visible?
Area 5 – Massive Dactic Tuff
Do the visible seams in the rocks sit in “straight” layer or do they fold and bend?
Area 6 – Upper beds
What is the general colour of the rock?
What is the rocks structural consistency? Is it compact, loose, fractured…?
The summit - take a breather and a photo too!
Please submit your answers as soon as you can. It's ok to post prior, I will check your findings and respond if there are issues. Feel free to add a photo of yourself at the site if you want too. Group visits are encouraged. I hope you enjoy the experience, this is a very special area.