noun
rare GeologyA brecciated volcanic material in marine sedimentary rock, regarded by some as being formed by the intrusion of lava or magma into sediment under water, and by others as a product of the mixing of volcanic ejecta with such sediments.
Origin
Mid 19th century; earliest use found in The Civil Engineer and Architect's Journal. From peper- + -ite, after French pépérite.
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