Silcrete
Silcrete are a group of minerals that arise from hardening silica . They appear as conglomerates in the form of crusts. But it is colloquially understood to mean all silicate crusts. The name is composed of English silica for silica and concrete for concretion . The term was first proposed by Lamplugh in 1902 .
Occurrence
They are common in Australia . One finds it mostly in the arid parts of the continent, also as hardy .
Emergence
Silcrete occur as silicate incrustations when the resulting stable silicic acid silicifies as a result of the reaction of orthosilicic acid with water . This may happen if the subfloor builds up minerally. The silicic acid is initially dissolved and then stiffened to form a hard cement.
The process is similar to that of quartzite .
properties
Silcrete are hard, they can become even harder when exposed to heat. Their color is reddish.
use
In Australia, silcrete are often used as tools by the Aborigines . Two silver tools were found in Africa that are 60,000 and 80,000 years old, respectively.
Silcrete are also used for street design.
Web links
- Article in Nature about stone tools, mentioning the Silcrete.
- Definition of the silcrete at geodz.com
- Entry Silcrete at Britannica
- Explanation together with iron crusts
- Illustration of a blade made of silcrete
- Page about Silcrete in Australia
- Work on Silcrete in St. Peter Sandstone (PDF; 1.3 MB)
- Summary of Silcrete
- Experiments on curing with different methods
literature
- Trevor Langford-Smith: Silcrete in Australia. Department of Geography, University of New England 1978. 304 pages.
Individual evidence
- ↑ http://www.geodz.com/deu/d/Silcrete
- ↑ Archived copy ( Memento of the original from March 21, 2012 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice.
- ↑ http://www.vegvesen.no/_attachment/194998/binary/379719
