Mamelon EarthCache
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Hanging Rock (Mt. Diogenes) is a rare volcanic formation of
solvsbergite, known as a mamelon, situated in the Hesket plains
near the townships of Mount Macedon & Woodend.
A mamelon (from the French mamelon, "nipple") is a rock formation
created by the eruption of relatively thick or stiff lava through a
narrow vent in the bedrock. Because the lava is not fluid, it does
not flow away; instead it congeals around the vent, forming a small
hill or mound on the surface. The outflow from successive eruptions
forms additional layers on top, and the resulting pile of layers
may stand over 100 metres (330 ft) above the surrounding surface.
The term was coined by the French explorer and naturalist Jean
Baptiste Bory de Saint-Vincent, to describe the central peak of the
Dolomieu Crater in the
Piton de la Fournaise volcano on Réunion.
The Hanging Rock mamelon, was created 6.25 million years ago by
stiff magma pouring from a vent and congealing in place. Often
thought to be a volcanic plug, it is not. Two other mamelons exist
nearby, created in the same period: Camels Hump, to the south on
Mount Macedon, and to the east, Crozier's Rocks. All three mamelons
are made of solvsbergite, a form of trachyte only found in two or
three other places in the world. As Hanging Rock's magma cooled and
contracted, it split into rough columns. These weathered over time
into the many pinnacles that can be seen today.
Tasks
- Post a photograph of you and your GPS in a humorous pose under
The Hanging Rock (5)
- Post a photograph of you and your GPS next to the Engraving “T.
Scott 1866” (18)
- Use your GPS to measure the highest point in the vicinity of
King Arthur's Seat and Birdbath (19)
- Use your GPS to calculate the Fall from Lovers Leap (9) S
37°19.836' E 144°35.745', assume the base of Lovers Leap is at the
same altitude as the base of Morgan's Blood waterfall (2)
- What is the earliest date for which evidence of human
occupation of this region has been found?
- What is one of the possible origins for the naming of Morgan's
Blood waterfall?
Note;
All numbers reference
feature listed in the free information brochure available from the
discovery centre.
Please email us with the answers to tasks three through six for
approval to log your find. Please do
not post your answers in your log.
Additional Information
Please be aware that
this reserve is maintained by the Macedon Ranges Shire, who charge
a nominal fee for entry to the park. This fee is used to cover the
cost of maintaining and developing, the Discovery Center, paths and
other facilities within the park.
The park is open Monday to Sunday 09:00 to 17:00 (may open later
during summer weather permitting) Closed Christmas day. Please
ensure that you allow enough time to explore the park and complete
all the tasks.
Additional Hints
(No hints available.)