This is an earthcache, there is no container to find, you have to read some geological information, visit the sites and supply the answers below and log the find online. Park in a gravel parking area half way up Mount Stuart Road, it is a steep winding road most suited to a vehicle.
This earth cache is at a boundary between two volcanic rock types - the 'Permian Granites' and 'Julago Volcanics'. Both types date back to the Permian Period (286 to 258 million years ago) and are primarily igneous, having formed from solidification of molten magma, either below the earth (plutonic) or on the surface (volcanic).
Towards the top of Mt Stuart is primarily comprised of granite rocks. These were intially plutonic and cooled slowly at depth to form a coarse grained rock with a larger quartz crystal component. There are also examples of 'microgranites' from the same period, these have a finer texture, medium sized grains and smaller quartz crystals, which formed as magma cooled quickly.
The hard granites have been exposed towards the top of Mt Stuart as the surface volcanic rocks have eroded over more than 250 million years.
Also from the Permian are softer volcanic rocks which are remnants of the 'Julago volcanics' and mainly occur on the lower half of Mt Stuart. They formed from widepread pyroclastics and lava erupting on the surface on the earth. Examples include breccia rocks which contain coarse angular solidified fragments up to around 4 cm and result from a major sustained eruption. While agglomerate rocks are produced from explosive volcanic activity and contain rounder fragments over 6.4cm. The fragments are a lighter coloured rhyolite rock.
Park on the gravel near the tree and head to the listed coordinates by carefully following the bike path eastwards to the big boulder. Stick to the path as there is Siam weed here.
This big boppa and the smaller accompilices are just in the zone of the Julago Volcanics.
Q1a) On close inspection do you think most of the light colours fragments embeded around the base of the big boulder have angular or rounded sides?
1b) Are most of the fragments above or below 6cm long?
1c) Given that do you think the bolders are an agglomerate or breccia rock formed from an explosive or sustained eruption respectively?
Q2) From the path, find an interesting spot for a broad photo of the boulders and send it with the online log.
Carefully head to Hard Rock - waypoint 2. Back up where you parked, on the opposite side of the road (behind the low gear sign) is an example of a granite rock from the Permian period. These pink-red granites are visible along the 'razorback ridge' for the next kilometre in road cuttings up hill. At this waypoint you can see the drill holes for the dynamite when they blasted the road out, the fractures in the rock absorbed a lot of the blast energy.
Q3) Do you think this rock coarse grained granites or fine grained microgranites?
Logging:
Send your answers in the message centre or email and log it online when convenient, online logs with no answers or doubts over attending the site will be queried and may be deleted. We will try and get back to you in a few days with any queries or the typical answers.
A general map of the main geological provenances along Mount Stuart Road is an attached image. It is from the book by Willmot (2009). Information is taken from Parks and Landscapes of the National Parks of North Queensland by W. Willmott (2009) and Rocks and Landscapes of the Townsville District by D.L. Trezise and P.J Stephenson (1990). D. Trezise contributed to the Townsville sections of the book by W. Willmott.