Subsurface structures in the Chablais Prealpes: New tectonic interpretations of the Prealpes Medianes nappe based on palinspastic lengths

Citation
Gd. Borel et J. Mosar, Subsurface structures in the Chablais Prealpes: New tectonic interpretations of the Prealpes Medianes nappe based on palinspastic lengths, ECLOG GEOL, 93(3), 2000, pp. 307-314
Citations number
33
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Earth Sciences
Journal title
ECLOGAE GEOLOGICAE HELVETIAE
ISSN journal
0012-9402 → ACNP
Volume
93
Issue
3
Year of publication
2000
Pages
307 - 314
Database
ISI
SICI code
0012-9402(2000)93:3<307:SSITCP>2.0.ZU;2-9
Abstract
In an intergrated approach based on palinspastic reconstruction of basin wi dth at the latest Liassic, on present-day surface structure, and on knowled ge of the depth of the basal decollement, we propose a new solution for the structural geology of the Chablais Prealpes south of Lake Geneva. Applied to the whole nappe, this combined approach allows to construct qualitative balanced cross sections and to overcome the inconsistencies between cross-s ections proposed in the past. Our approach results fi om sedimentological i nvestigation and basin analysis of the Prealpes Medianes realm. Comparing t he ideal basin width with the observed bed length, the importance (length) of hidden imbricates at depth call be deduced. In the Cornettes de Bise are a of the swiss Chablais, we propose to introduce two important, so far unkn own, imbricates which are necessary to fill the space between the basal dec ollement and the subsurface structures. This new solution is consistent wit h palinspastic basin width and structural geology, and proposes a mechanism explaining the high structural/topographic relief.