Bell Buoy Beach
Access to this cache is only via the beach, please park at the parking coordinates. At high tide this can be tricky to access and will require a lot of rock hoping so please be careful if you attempt at this time. THe return walk should take approx. 1-1.5hours.
Tasmania is renowned for having the world's biggest exposure of the mineral Dolerite. Approximately 50% of the island surface is dolerite. In Tasmania, dolerite dominates much of the landscape. Weathered dolerite forms tall vertical columns throughout the Tasmanian highlands Sea columns are a major part of the Tasmanian coastal scenery. Dolerite is a mafic (oceanic) sub-volcanic rock that intruded beneath the surface of the earth as sills (parallel to the bedding planes) or as dykes (across the bedding planes). The mineral consists of a mixture of silicate compounds including fine plagioclase feldspar silicate crystals (60-65%) set in a finer matrix of clinopyroxene silicate (20–30%), with minor olivine silicate glass (<10%). Depending on the mixture present the colour may range from light brown to dark grey.
Dolerite dikes and sills are typically shallow intrusive bodies and have fine grained features due to rapid cooling. Dolerite is the preferred name for this mineral in most of the world. In North America the mineral is known as Diabase.
To find the EarthCache, you must answer these questions by messaging or emailing me through Geocaching.com or via the Send Answers button in the app. Please do NOT post your answers in your log! You may log the find before you have sent the answers, however please do so within a reasonable timeframe (ie 7-10 days). I will contact you if there are any problems.
1)At the posted coordinates describe what you see, what type of rock is present?
2)At what angle are the layers and how thick are they? Are you looking at a dyke or a sill?
3)At waypoint 2, describe the 2 evident layers that you see, how and why are they different?
4)Describe how you think the top layer is formed.
5)This is a requirement:send a photo of you at GZ or upload a photo of you along the beach with your phone or gps