Two- and three-dimensional thermal modeling of a low-angle detachment: Exhumation history of the Simplon Fault Zone, central Alps

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Serval ID
serval:BIB_66AB6DB9A8E8
Type
Article: article from journal or magazin.
Collection
Publications
Title
Two- and three-dimensional thermal modeling of a low-angle detachment: Exhumation history of the Simplon Fault Zone, central Alps
Journal
Journal of Geophysical Research - Solid Earth
Author(s)
Campani M., Herman F., Mancktelow N.
ISSN-L
0148-0227
Publication state
Published
Issued date
2010
Peer-reviewed
Oui
Volume
115
Pages
B010420
Language
english
Abstract
Two alternative models have been proposed to explain footwall exhumation
along major low-angle detachments: (1) crustal-scale exhumation along a
detachment fault that maintained a low dip angle or (2) exhumation along
a high-angle fault passively rotated by isostatic rebound (''rolling
hinge model''). These proposed models were tested against a
well-documented example of a low-angle detachment fault in the European
central Alps, the Simplon Fault Zone (SFZ). An extensive
thermochronological data set provides the basis for 2- and 3-D
thermokinematic models (Pecube), coupled with a stochastic inversion
algorithm (the Neighbourhood Algorithm). Model results establish that
the thermochronological pattern is better reproduced by a low-angle
detachment that maintained a 30 degrees dip, rather than by a rolling
hinge model. Although a range of histories involving either steady state
or variable exhumation rates is possible, the preferred model of highest
probability is for a variable rate, with the fault zone initiated at
18.5 +/- 2.5 Ma and active until the present day. Footwall exhumation
was relatively fast until 14.5 +/- 1.5 Ma (similar to 1.4 mm yr(-1)).
This enhanced SFZ footwall exhumation is similar in timing and
kinematics to orogen-parallel extension reported throughout the Alpine
orogen. After 14.5 Ma, SFZ footwall exhumation continued at a reduced
rate (similar to 0.7 mm yr(-1)) until 4 Ma. The subsequent increase (to
similar to 1 mm yr(-1)) reflects enhanced regional erosion rates across
both footwall and hanging wall after circa 4 Ma (from 0.35 +/- 0.15 mm
yr(-1) to 0.70 +/- 0.15 mm yr(-1)), probably in response to climate
changes during the Pliocene.
Open Access
Yes
Create date
07/10/2012 19:46
Last modification date
20/08/2019 14:22
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