The structure of the Lavagna Nappe in the region of Monte Ramaceto and Val Graveglia (Ligurian Apennines, Italy)

Abstract

Detailed structural analysis and mapping in the Lavagna Nappe reveals the effect of various phases of deformation on a regional scale. The earliest phase produced large isoclinal, originally SW-facing folds (F1). A second phase led to the development of open folds (F2). The vergence of the younger folds (F3, F4) is NE. Thrusting occurred in two stages: postF2-preF3 and synF4. Hereafter the previously stacked thrustsheets, together forming the Lavagna Nappe, were emplaced on top of the Mélange Nappe by NE-directed thrusting. A final phase of gentle folding (F5) caused an undulation of all older structures.