by Mario Wipki, GFZ Potsdam, Potsdam, Germany
Orbiculite from W-Australia - can be visited opposite of the holocaust memorial in Tiergarten. Maybe the oldest exposed rock in Berlin - older than 2 billion years. See also www.globalstone.de/ comes from near Mount Magnet in Western Australia. The orbicules occur in a granodiorite matrix. They consist of andesine, plagioclase, hornblende biotite arranged radially around a core of plagioclase or hornblende or less commonly mafic schist.
- Earth Magnetism & Rock Physics (345)
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- Geochemistry, Mineralogy, Petrology & Volcanology (864)
Mario Wipki (distributed via imaggeo.egu.eu)