EDUCATIONAL LOGGING REQUIREMENTS
In order to substantiate your visit and comply with the educational requirement for Earth Caches you have to submit your answers to the following questions to the cache developers via their profile:
For purposes of logging this cache you must answer the following five questions.
1) What are the three major rock types?
2) Which type of rock is marble?
3) What variety of marble is quarried south of Aus?
4) What is the size of the block of marble at the GZ? (Locational question)
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Namibia has vast natural resources. One of the products quarried is marble.
Marble is metamorphic rock. One of the three types of rock, the other being igneous and sedimentary). Marble is composed of recrystallized carbonate minerals, most commonly calcite or dolomite. Marble may be foliated.
Geologists use the term "marble" to refer to metamorphosed limestone; however, stonemasons use the term more broadly to include unmetamorphosed limestone. Marble is commonly used for sculpture and as a building material.
In Namibia marble is quarried mainly in the Karabib area with other quarries near Swakopmund and in the Aus area.
This Earth Cache is near the quarry 100km south of Aus. Access is not permitted to the quarry but the white walls of the marble quarry are visible from the road as you drive the C13 between Rosh Pinah and Aus.
Namibia has a wide variety of marble. At the Aus quarry the Potoro Leonardo variety, a brecciated black marble with a golden yellow matrix is extracted. A calcsilicate marble that contains dark green serpentinite grains within white to cream coloured carbonate matrix (Namibian Green, Namib Harlequin, Desert Green) is exploited just north of Nonidas, 10km east of Swakopmund.
In the Karabib area there are a vast number of varieties quarried. White marble (White Rhino and Karabib White), a greyish- white (African White), a dark grey tightly folded marble with alternating white and grey to dark grey layers (Zebra, Capra Black), hite) and a pink yellowish marble. Also Namibian Rose and Okatji Rose from an off white marble containing various amounts of pink tremolite. There are uni-coloured fine-grained marbles, a white marble with light green schlieren (African Green), a greyish-green marble with occasional light brown streaks (Namib Desert), a light yellowish-brownish banded dolomitic marble (Light Palissandro) which grades into a greyish-brown in- tensely folded variety (Dark Palissandro).
To claim this Earthcache as a find please send us an email with the answers to the four questions, your caching name and your email address through our profile.
You may log your find once you have visited the site and determined the answers to the questions. Logs not supported by the necessary email will be deleted. Please do not reveal the answers in your log but pictures are always welcome!
The information to answer the questions can be found at the GZ and by reading the description of the cache
References
The Geological Survey of Namibia
Wikipedia