Peperite

The term ‘peperite’ or ‘Pépérite’ is most commonly used to refer to breccias, clastic rocks comprising both igneous and sedimentary components, which were generated by intrusive processes, or along the basal contacts of lava flows or hot volcaniclastic deposits with unconsolidated, typically wet, sediments (Skilling et al, 2002). It usually consists of highly irregular fragments of glassy igneous rock within sediments and/or the opposite. The Le Maître et al. (2002) definition is: "A local term for a tuff or breccia, formed by the intrusion of magma into wet sediments” (not a normal use of the word tuff). In contrast with tuffs and pyroclastic rocks, formed by explosive volcanism, it forms essentially in situ by disintegration of magma intruding and mingling with typically wet sediments. It can grade into hyaloclastite and unaltered sediment. Chilled and bleached margins on volcanic clasts are typical, and clasts can vary from blocky to fluidal. The textures may be due to quenching, hydromagmatic explosions, magma-sediment density contrasts, and mechanical stress as a consequence of inflation or movement of the magma.