Welcome to
Clifton Springs "The Dell" - EarthCache
A simple EarthCache to bring you here and to highlight this natural amphitheatre on the coast of the Bellarine Peninsula
Clifton Springs Foreshore is a stunning coastal reserve with exquisite scenery and beaches. The reserve boasts tremendous views, as well as a plethora of rotundas and walking tracks. The Dell is truly sensational reserve.
The Dell is also an environment under constant change. The natural amphitheatre was created by a series of landslips in the foreshore escarpment at Clifton Springs, helped by the natural movement of groundwater towards the coast
The local Wathaurong people inhabited the area up to 30,000 years ago and you may find traces of shell middens along this part of the coast.
Mineral springs are naturally occurring springs that produce water containing minerals, or other dissolved substances, that alter its taste or give it a purported therapeutic value. Salts, sulfur compounds, and gases are among the substances that can be dissolved in the spring water during its passage underground.
In 1870 the "discovery" of mineral springs on the property of Thomas Bates who had named his residence "Clifton". Analysts described the spring water as bright and sparkling with many health benefits and superior to imported varieties. The medicinal value of the waters was submitted to rigid chemical examination, and summarised as containing magnesia, seltzer, sulphur, soda and iron and the groundwater discharges through a number of points and may amount to a total discharge of up to one mega litre per week
The Dell became popular with picnickers and day-trippers. At that time there is approximately 20m of dry land at the base of the cliff and the spring water bubbled up in several locations in this foreshore land area. The high water mark was protected by a continuous 600 mm high deposit of shell grit.
The 600 mm high deposit of shell grit at the high water mark, which nature had built up from time immemorial, was in 1933 the source of a short term industry. It was systematically bagged up, by teams of up to 50 men, and sent away to a Melbourne company for use in the manufacture of glass. This action plus the dredging of the Bay exposed the foreshore to erosion.
In 1984 the Dell mineral water is deemed unsafe to drink due to the use of septic tanks by residential development in the area and it wasn't until 2008 it was deemed safe to drink again.
Formation & Geology
About 40000 years ago the Dell was formed when, presumably after heavy rain, a large volume of land slid down towards the bay. This landslip would probably have occurred over days or weeks. Nature and time then created a sheltered and picturesque north facing dell.
Landslides occur when the downward force of gravity acting on slope materials exceeds the cohesive force that holds the soil particles together, or the frictional force which holds the material to the slope (i.e. ‘shear strength’). The failure of slope materials can be related to a number of contributing factors and trigger factors.
The steep coastal cliffs are structurally controlled by the Curlewis Monocline and the upper plateau is generally flat before falling some 25 to 30 m to the coast. (A monocline is a step-like fold in rock strata consisting of a zone of steeper dip within an otherwise horizontal or gently-dipping sequence).
The Dell comprises a large basal landslide which generally comprises much of the gentle lower slopes. A number of medium to small slides are located around the steep amphitheatre flanks.
Site geology contains the presence of the Older Volcanics as basalt overlain by tuff, intercalated sands and gravels, the presence of limestone and marl and the Pliocene sands.
On the eastern side of The Dell, the Older Volcanics are exposed as basalts overlain by tuffs, which are disconformably overlain by the Moorabool Viaduct Formation. On the coastal platform immediately in front of the cliffs near the old bath jetty, there is sporadic presence of remnant fossiliferous marls (presumably the Fyansford Formation) on top of the Older Volcanic tuff. West of The Dell, on the coastal platform has mapped the Fyansford Formation dipping from 70° NW to 30° NNW. Mapping also shows the Older Volcanics either side of The Dell, with sand and alluvium in between.
Current Day
The Dell represents an erosional feature formed by continuous mass wasting through geological time. The present day landslide is a continuation of the erosion process.
In 2002 a crack appeared in the access road to The Dell after a truck is driven down to the foreshore. Subsequent geotechnical investigations indicate a landslide risk and the Council closes the Dell.
In 2007 The Dell is reopened but access is only available from along the foreshore until 2009 a staircase was constructed and the Dell is re-opened to the public.
Ground travel rates are generally very slow and of the order of 15 to 20mm per annum although much accelerated rates have been noted in the past.
By installing relief wells the reduction in groundwater pressure has been extremely effective at slowing the rates of movement.
Ongoing monitoring is a critical part of the management strategy and detailed monitoring programs have been planned every 6 months. in addition the establishment of a real-time monitoiring station provides near real time access to some monitoring results
Questions to log this EarthCache
Q1 What are "mineral springs" and how do they occur?
Q2 In your own words desribe what has/is happed/happening here
Q3 What else could be the cause of erosion and what steps can you see that are being implemented to slow it down?
Q4 Standing at GZ, looking towards the west, describe the cliff edge just below the lookout.
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