TY - JOUR
T1 - Conical folding in the core of an orocline. A geometric analysis from the Cantabrian Arc (Variscan Belt of NW Iberia)
AU - Pastor-Galán, Daniel
AU - Gutiérrez-Alonso, Gabriel
AU - Mulchrone, Kieran F.
AU - Huerta, Pedro
N1 - Funding Information:
This paper is part of the IGCP Project from UNESCO No. 574: Bending and Bent Orogens, and Continental Ribbons. Financial support was supplied by Research Project ODRE II (‘‘Oroclines and Delamination: Relations and Effects’’) CGL2009-1367 from the Spanish Ministry of Science and Innovation. DPG is also granted by an ACPI fellowship from the Junta de Castilla and León. We also want to thank Schlumberger for PETREL academic licenses. We also want to thank Gabi Santos, William Dunne, Richard Lisle and an anonymous reviewer for their constructive comments.
PY - 2012/6
Y1 - 2012/6
N2 - The Cantabrian Arc of the Variscan Belt has been recently defined as a true orocline, constraining kinematics and deformation timing. This curved sector of the orogenic belt is characterized by two different fold sets: (1) one runs parallel to the outcrops of the main thrusts and describes a horseshoe shape concave towards the east, and (2) another is radial to the arc. A detailed geometric study of the fold interference patterns in the Cantabrian Arc revealed the conical nature of the folds belonging to the radial set. These conical folds developed with different geometrical characteristics (semi-apical angles and axis attitudes) depending on the initial orientation and geometry of the folded surfaces. They are interpreted to result from a vertical axis rotation during oroclinal buckling of the Variscan Belt in NW Iberia. This study of conical folds in the Cantabrian Arc highlights that conical folds in curved orogenic arcs are a powerful tool for establishing the sequence of tectonic events because interference patterns due to vertical axis secondary differential rotations provide unique geometrical characteristics observed in the Cantabrian Arc that can be extrapolated to other oroclines.
AB - The Cantabrian Arc of the Variscan Belt has been recently defined as a true orocline, constraining kinematics and deformation timing. This curved sector of the orogenic belt is characterized by two different fold sets: (1) one runs parallel to the outcrops of the main thrusts and describes a horseshoe shape concave towards the east, and (2) another is radial to the arc. A detailed geometric study of the fold interference patterns in the Cantabrian Arc revealed the conical nature of the folds belonging to the radial set. These conical folds developed with different geometrical characteristics (semi-apical angles and axis attitudes) depending on the initial orientation and geometry of the folded surfaces. They are interpreted to result from a vertical axis rotation during oroclinal buckling of the Variscan Belt in NW Iberia. This study of conical folds in the Cantabrian Arc highlights that conical folds in curved orogenic arcs are a powerful tool for establishing the sequence of tectonic events because interference patterns due to vertical axis secondary differential rotations provide unique geometrical characteristics observed in the Cantabrian Arc that can be extrapolated to other oroclines.
KW - Cantabrian arc
KW - Conical folding
KW - Ibero armorican arc
KW - Orocline
KW - Vertical-axis rotation
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U2 - 10.1016/j.jsg.2012.02.010
DO - 10.1016/j.jsg.2012.02.010
M3 - Article
AN - SCOPUS:84861005265
SN - 0191-8141
VL - 39
SP - 210
EP - 223
JO - Journal of Structural Geology
JF - Journal of Structural Geology
ER -