Kinzigite
“High-grade paragneiss with garnet and sillimanite”
Kinzigite is a high-grade metamorphic rock (paragneiss) containing garnet, biotite, and sillimanite derived from the metamorphism of clay-rich sediments. Named after the Kinzig Valley in the Black Forest of Germany, it represents pelitic sediments that reached temperatures exceeding 650°C.
garnet, biotite, sillimanite, quartz, feldspar, cordierite, graphite (from organic matter)
Black Forest (Germany — type locality), Ivrea Zone (Italy), Calabria (Italy), Madagascar, Kerala (India)
6-7
Graphite flakes in kinzigite are derived from organic matter in the original muddy sediment — they prove that the carbon from ancient organisms can survive burial to depths of 20+ km and temperatures above 700°C.
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What does the presence of graphite in kinzigite reveal about the nature of its protolith (parent rock)?
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