'The Arch' is located near Kilcunda on the George Bass walking trail which is a cliff top walk that stretches from the outskirts of San Remo at Punchbowl Road, to the Bass Highway (just opposite the hall at Peppermint Road) in Kilcunda. The walk is approximately seven kilometres long and takes an average of 2 hours to walk one way. The walk offers spectacular views of the coastline and follows the route of the explorer George Bass' epic voyage of discovery along the southern edge of the Anderson Peninsula, over 200 years ago.
Sea Arches- A sea arch is a natural opening eroded out of a cliff face by marine processes. Some arches appear to have developed from surge channels, which are created by wave refraction causing the focussing of wave fronts on the side of a headland. More generally, arches develop where waves attack a plane of weakness which cross-cuts a promontory. Caves produced on either side of a promontory may become joined over time to become a tunnel and, finally, an arch.
The supporting roof of the arch is known as the keystone. The architecture of an arch is a reflection of its lithology and structure. Sea arches have been regarded as ephemeral forms tending to survive over periods of just few decades or centuries. The term sea tunnel can be used to describe a hole in the cliff line where the arch itself is considerably longer than the width of the entrance.
Types Of Coastline Arches- On coasts two different types of arches can form depending on the geology.
On Discordant Coastlines rock types run at 90° to the coast. Wave refraction concentrates the wave energy on the headland, and an arch forms when caves break through the headland, e.g., London Bridge in (Victoria, Australia). When these eventually collapse, they form stacks and stumps.
London Bridge, Port Campbell, Victoria
On Concordant Coastlines rock types run parallel to the coastline, with weak rock (such as shale) protected by stronger rock (such as limestone) the wave action breaks through the strong rock and then erodes the weak rock very quickly. Good examples of this are at Durdle Door and Stair Hole near Lulworth Cove on the Dorset Jurassic Coast in south England, although these are on an area of concordant coastline. When Stair Hole eventually collapses, it will form a cove.
Stair Hole, Dorset Jurassic Coast, South England
To log this cache you need to send us an email with the answers to the following questions-
1- What is your team name and the name of this cache
2- Is this a Discordant or Concordant coastline arch?
3- Which type of beach can be found to the right of the arch?
Optional- Include a photo of your adventure, but nothing that will give away the answers.
Have fun! :)
References-
http://www.basscoast.vic.gov.au/Leisure/Bicycle___Walking_Tracks/George_Bass_Coastal_Walk
http://www.landforms.eu/shetland/arches.htm
https://en.wikipedia.org/wiki/Natural_arch