ISSN:
1476-4687
Source:
Nature Archives 1869 - 2009
Topics:
Biology
,
Chemistry and Pharmacology
,
Medicine
,
Natural Sciences in General
,
Physics
Notes:
[Auszug] Petroglyphs in arid and semi-arid lands are frequently etched into a dark coating called rock varnish, composed of oxides and hydroxides of manganese and iron, clay minerals, and minor and trace elements that accrete on rock surfaces2'3. After pecking the petroglyph element through the varnish, the ...
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1038/302816a0
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