Wondabyne Unearthed
This is an EarthCache, so there is no physical container to find.
To log this EarthCache, you will need to visit the location, read the information below and send me your answers to four questions about your observations and the type of geology found at this location.
Thousands pass it every day on their daily commute but few barely even notice its existence. The Wondabyne Sandstone Quarry is one of the oldest and most remotely located quarries in Australia.
In its hey-day, the Wondabyne Quarry worked non-stop. It would have had over a hundred employees who lived in houses close to the site and was a major source of building materials for the development of Sydney. In the early days, Wondabyne Quarry had its own railway siding that enabled blocks of cut sandstone to be taken out by train. Rail wagons would be winched into the quarry then loaded. An engine would reverse into the siding and hitch up the wagons to transport the sandstone out. The siding was eventually shut down. The quarry still provides sandstone today but is now on a demand basis. As the only way to get the sandstone out is by barge, the blocks have to be transported across the main north-south rail line. This can only be done a few times a year when the line, in both directions, is shut down for maintenance. Wondabyne Train Station was built to service the quarry and opened on 1st May, 1889.
Many fine buildings used Wondabyne Sandstone in their construction, such as the historic Commonwealth Bank building in Martin Place, the Stock Exchange building in Bond St and the spires of St Mary's Cathedral. The Australian War Memorial in Canberra, considered to be one of the most significant buildings of its type in the world, used Wondabyne Sandstone in its construction.
Commonwealth Bank, Martin Place, Sydney
Old Hawkesbury River Rail Bridge Pylon
The Federation of Australia quite literally rested on Wondabyne Sandstone. The completion of the first Hawkesbury River Railway Bridge in 1886, saw the joining of not just the important Sydney to Newcastle rail line, but also in effect, the railway systems of South Australia, Victoria, New South Wales and Queensland. This vital transport link, with all that it implied about a united Australia, was built on concrete pylons with the beautiful and durable Wondabyne Sandstone surrounding them. The Father of Federation, Sir Henry Parkes, used the bridge as a powerful symbol of national unity when he gave the address at its opening. Many claim this was Parkes’ first Federation speech. The old pylons can still be seen on the eastern side as you travel by train across the current rail bridge.
Earth Science Lesson
Sedimentary rocks are formed by the deposition and subsequent cementation of that material at the Earth's surface and within bodies of water. Sedimentation is the collective name for processes that cause mineral or organic particles to settle in place. The particles that form a sedimentary rock by accumulating are called sediment. Before being deposited, the sediment was formed by weathering and erosion from the source area, and then transported to the place of deposition by water, wind, ice, mass movement or glaciers, which are called agents of denudation. Sedimentation may also occur as minerals precipitate from water solution or shells of aquatic creatures settle out of suspension.
The sedimentary rock cover of the continents of the Earth's crust is extensive (73% of the Earth's current land surface), but the total contribution of sedimentary rocks is estimated to be only 8% of the total volume of the crust. Sedimentary rocks are only a thin veneer over a crust consisting mainly of igneous and metamorphic rocks.
Sedimentary rocks are deposited in layers as strata, forming a structure called bedding. The study of sedimentary rocks and rock strata provides information about the subsurface that is useful for civil engineering, for example in the construction of roads, houses, tunnels, canals or other structures. Sedimentary rocks are also important sources of natural resources like coal, fossil fuels, drinking water or ores.
One type of sedimentary rock is called sandstone. It is composed mainly of sand-sized (0.0625mm to 2 mm) mineral particles or rock fragments.
Most sandstone is composed of quartz or feldspar because they are the most resistant minerals to weathering processes at the Earth's surface. Like uncemented sand, sandstone may be any colour due to impurities within the minerals, but the most common colours are tan, brown, yellow, red, grey, pink, white, and black. Since sandstone beds often form highly visible cliffs and other topographic features, certain colours of sandstone have been strongly identified with certain regions.
Rock formations that are primarily composed of sandstone usually allow the percolation of water and other fluids and are porous enough to store large quantities, making them valuable aquifers and petroleum reservoirs. Fine-grained aquifers, such as sandstones, are better able to filter out pollutants from the surface than are rocks with cracks and crevices, such as limestone or other rocks fractured by seismic activity.
The 250 million year old sandstone that comes out of the Wondabyne Quarry was laid down during the early Triassic period and comes from a rock strata known to geologists as the Narrabeen group. The stone is accessible in only a few spots. It is uniquely stable and durable and this has made it a sought after building material.
1887 - Hand cutting stone at Wondabyne Quarry for the piers of the first Hawkesbury Rail Bridge.
Getting to GZ:
The easiest way to get to this earthcache GZ is by train. Check the timetable as not all trains stop at the unique Wondabyne Station. As you board, let the train guard know that you want to get off at Wondabyne Station, (otherwise, the train won’t stop!) You will need to travel in the last car of the train and exit from the very back door. Don’t forget to push the button to open the carriage door as it doesn’t open automatically. There’s a walking track at the southern end of the station that leads to GZ. The quarry itself is private property so do not enter. GZ will give you a fantastic view into the quarry from above.
To Claim This Earthcache:
Please answer the following questions by going to my public profile (click on my username) and use either the "Send Message" or "Send Email" link. Include the earthcache title in your correspondence. You can log your find immediately, however, I ask that answers to the questions be sent to me as soon as you are able to. I read all emails to verify the answers and will send a confirmation email back to you. There is no need to email me photos. Just upload any photos with your log. Please don't post any photos taken at GZ itself.
Questions:
1. Looking in the direction of ENE from GZ, in your own words, describe the scene in front of you. Please use as much detail as possible in your observations.
2. What processes (both man-made and natural) do you think have caused the surface of the sandstone on the far side to look as it does?
3. In simple terms, describe how sedimentary rock is formed.
4. What geological period does Wondabyne Sandstone come from and how old is the sandstone?
5. Optional - Take a photo of you and/or your geocaching name and/or your GPS device at Wondabyne Station. Brownie Points if you have all three in the one photo. LOL
I really hope you enjoy your adventure getting to this earthcache, observing a unique contributor to our history and learning about the geology of the material excavated from this site.
Cheers, Calypso62
References Consulted:
- Central Coast Express Advocate - Article on Wondabyne Quarry
- Gosford Quarries Website
- Wikipedia - Wondabyne, New South Wales
- Wikipedia - Sedimentary Rock
- Wikipedia - Sandstone
- Dangar Island Historical Society
FTF Honours
Morry9 and JordsAU
Earthcachers Extraordinaire
Did you know that NSW has a geocaching association? Geocaching NSW aims to enhance and improve the activity of geocaching and holds regular events where geocachers meet to enjoy their common interests. Visit the association website here.