Approximately 260 million years ago, in the Permian age this area was part of a massive volcano that had its origin some 40km SE of Jervis Bay. The resulting flows make up an area of the south coast that geologists often refer to as the ‘Gerringong Volcanics’.
The blowhole latite (Igneous rocks which are formed by solidification of cooled volcanic rock) is the oldest of several flows that comprise this area. Other features in the area include the Wandrawandian Tuffs (sth of Nowra), Saddleback Mountain and north towards Bombo headland.
The latite which makes up this headland has many flow features evident including flow banding, parallelism of crystals and elongated vesicles (spherical cavities in the rock). The rock is also strongly jointed with the shore platform being a mosaic of regular five to eight sided blocks.
Cache requirements have recently been updated, please be aware of changes: 26th Oct 2010
To log a find for this Earthcache take a photo of you & or your GPS in front of the blowhole and answer the following questions. (Email answers via gc.com profile) Please fulfil all requirements of this cache or your log may be deleted.
- What is the softer rock which erodes faster called?
- What wind direction is best for the “blowhole” to work?
- This volcanic extrusion is known as a?
- Where is the air compressed? (2 word answer)
- Who was the mayor who opened the “Endeavour Lookout”?
Please be careful when in the area as the ocean can be very unpredictable. It is possible to stand right up close to the opening (if you don’t mind getting wet).
I hope you enjoy my first Earthcache.