The Cliffs at the EarthCache Site
The erosion of the coastal cliffs at these co-ordinates, has exposed an excellent section of the Fyansford Formation overlain by the Moorabool Viaduct Sand.
Fyansford Formation – its colour is classed as yellow/brown, to pale orange. It is a mix of sandy to silty marls (from Wikipedia - Marl or marlstone is a calcium carbonate or lime-rich mud or mudstone which contains variable amounts of clays and aragonite.) imbedded in calcareous silty clays. This was formed by an inland sea retreating and depositing sediments as rivers made their way out into the bay area.
Moorabool Viaducts Sands – They are brown to orange brown in colour, and consist of sandy sediments. These are known to consist of calcareous and silty sands, quartzite sandstone, conglomerate and sandy clays. They are a relatively shallow formation and consist of only about 5 meters in this area. You can see some different layers in front of you. The lower section consists of hard white calcrete bands, and the upper layer consists of sandy silty marls.
How it formed – The changing sea level played a major part in shaping the coast line you see before you through landslides and erosion. During the last inter-glacial period, sea levels were generally about 6 metres higher than present. As a new glacial period (ice age) developed, the sea levels trended downward, but with a series of reversals during short warming episodes.
You will learn more about what processes the sea undertook to produce what you see before you while at the site. The co-ordinates take you to an information board from which you can learn more about the sea’s effect on the geology at the site.
To log this EarthCache you must complete the following tasks.
1. Tell us what the dates of the Interglacial Period are when the sea was at its highest.
2. What happened in Corio Bay between 100,000 to 15,000 years ago?
3. Between 14,000 and 6,000 years ago, how much higher were the sea levels than the present?
4. Take a photograph of you (or your GPSr) at the site (please do not include the sign, any photo’s that do will be deleted) and post it with your log.
Note:You can e-mail the questions for 1-3 to us by using the send e-mail feature in our profile. Any logs that do not have an accompanying e-mail will unfortunately be deleted as per the EarthCaching guidelines.
NOTE: As of 1st January 2011 the EarthCache guidelines have changed and you do not have to provide a photo. However if your answers are incorrect your log will be deleted. You are more than welcome to add a photo if you so desire to your log as proof of a visit.
The Western Cliffs are part of the foreshore area which is owned by the City of Greater Geelong. They allow the public to access the boardwalk during times of dry weather only. The boardwalk may be closed for safety reasons if the weather is wet and this will prevent access to the EarthCache.The best access point to the boardwalk close to car parking is at S38 08.046 E144 21.332
References
Bowler, J.M. (1963). Tertiary Stratigraphy and Sedimentation in the Geelong/Maude Area, Victoria. Proc. R. Soc. Vict. 76:69-137. Western Cliff
Whiteway, B. The natural history of the Beaumaris Peninsula and its influence on human activityNatural History
Wikipedia - Marls