Polygenetic mélanges: a glimpse on tectonic, sedimentary and diapiric recycling in convergent margins

A significant part of melanges recognized in exhumed convergent margins around the world have been recently documented to be chiefly originated from en-mass transport and subsurface remobilization and disruption (i.e., melanges, from sedimentary and mud-serpentinite diapiric processes and from in-situ fludification-disruption). Tectonic and/or sedimentary processes occurring during subsequent multiple deformational events of convergent margins evolution, commonly overprint and significantly rework the primary (sedimentary or diapiric) melange fabric, forming polygenetic melanges. This ultimately complicates their distinction from true tectonic melanges, masking part of the recorded tectono-sedimentary evolution of the associated convergent margin. The contributions gathered in this thematic collection explore with different methodologies (from field-structural and stratigraphic observations to geophysical analyses) different types of polygenetic melange, at various scales, around the world. The results conclude that the understanding of this type of melange may provide crucial insights for a more detailed interpretation of both the evolution of ancient and modern convergent margins, and of processes-mechanisms triggering potential natural hazards (earthquakes and tsunamis). Case studies include the Apennines in the Central Mediterranean region, the Carpathians in Central Europe, and the Nankai Prism in Japan. Thematic collection: “Polygenetic melanges: a glimpse on tectonic, sedimentary and diapiric recycling in convergent margins” available at https://www.lyellcollection.org/cc/polygenetic-melanges