strati.ch - Lexique lithostratigraphique de la Suisse

Représentation et statut

Limite inférieure: Erosiver Kontakt über Lias-, Trias- oder Kristallin-Einheiten.

Âge au sommet

Âge à la base

Termes génériques

Type de protolithe

Définition: Masson Henri, Steck Albrecht (2015) : The Maggia-Sambuco nappe : stratigraphy, correlations and tectonic consequences (Central Alps). Swiss Geoscience Meeting, Abstract Volume 13 (Basel), 16–17

p.17: But elsewhere the Cristallina sequence can present a very different aspect, forming narrow bands, tightly pinched into the Sambuco basement, mainly made of calcitic, often conglomeratic marbles. Various types of marbles and breccias are so intimately associated that for practical reasons we group them under the name of Lago Scuro Formation. They have been ascribed by all authors to the Triassic, which is impossble for several reasons. The base of the Lago Scuro Formation is deeply erosive and cuts unconformably the Liassic and Triassic formations, reaching frequently the Paleozoic basement. We interpret the Lago Scuro Formation as the Late Dogger to Malm filling of narrow (half-) grabens generated by very active normal faulting, subsequently strongly deformed by Alpine tectonics. The combination of violent paleofault activity with submarine erosion by channeld débris flows at the foot of the fault scarps peeled the older sediments down to the basement.