Coupes équilibrées à travers le massif subalpin de la chartreuse

Abstract

Kinematical models are proposed for the tectonic of the Chartreuse subalpine massif. They take into account the field observations published at present time and the result of a recent geophysical experiment. The analysis of these data shows that: (1) the structural style of Chartreuse can be describe by folds growing in front of propagating thrusts and/or by folds developed in response to steps in decollement levels. (2) The decollement levels flat in the marly levels of the Berriasian, Callovo-oxfordian and Aalenian, and ramps in the calcareous levels of the Urgonian and Tithonian. (3) The tip lines, the branch lines and the sequence of the thrusts in the Chartreuse are not well documented. Balanced and restored cross-sections are constructed by the use of the Suppe method and of branch-line maps. Three models are consistent with the data and give a bulk shortening in the north of the Chartreuse that ranges between 14 km and 25 km. The minimum value of 14 km is related to 10 km of displacement transfered from the Bomes-Bauges thrust system and 4 km transfered from the Jura thrust system, and the maximum value to 15 km transfered from the Bornes-Bauges, and 8 km from the Jura. © Masson, Paris, 1987.