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Alpine exhumation of the central Cantabrian Mountains, Northwest Spain
Author(s) -
Fillon C.,
Pedreira D.,
Beek P. A.,
Huismans R. S.,
Barbero L.,
Pulgar J. A.
Publication year - 2016
Publication title -
tectonics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.465
H-Index - 134
eISSN - 1944-9194
pISSN - 0278-7407
DOI - 10.1002/2015tc004050
Subject(s) - geology , thermochronology , fission track dating , outcrop , paleontology , basement , mountain range (options) , range (aeronautics) , tectonics , zircon , denudation , geomorphology , physical geography , archaeology , geography , materials science , financial economics , economics , composite material
The Cantabrian Mountains extend along the Atlantic coast of northern Spain and are known to have experienced an Alpine phase of deformation, reactivating well‐expressed Variscan structures. They form the westward continuation of the Pyrenean range and were similarly uplifted consequently to the convergence between the Iberian and European plates. Nevertheless, due to the scarcity of syntectonic sediments and structural markers in a large outcrop of Variscan basement, little is known about the precise timing and amount of the Alpine exhumation phase in the Cantabrian Mountains. We present a new low‐temperature thermochronology data set, composed of nine apatite fission track (AFT) and six zircon (U‐Th)/He (ZHe) ages, sampled along structurally well‐constrained N‐S profiles through the central part of the Cantabrian Mountains and complemented by 3‐D thermokinematic modeling. The occurrence of Eocene‐Oligocene AFT and ZHe ages in the center of the profiles allows us to frame the period of Alpine exhumation from 39 to 29 Ma, at a rate of 0.24–0.3 km Myr −1 . Moreover, the reset ZHe ages imply significant burial of the samples, by up to 8–10 km in the center of the range. Therefore, the Alpine exhumation phase was significant, and synchronous to the main phase of exhumation in the central Pyrenees, although exhumation rates were an order of magnitude lower. Three‐dimensional thermokinematic modeling of the data confirms the timing of uplift of this area, but its resolution is limited by the relatively small number of reset ages over a large area.