Combining low-temperature thermochronology with 3-D probabilistic
kinematic modeling of the Bavarian Subalpine Molasse
Abstract
To understand the exhumation history of the Alpine foreland, it is
important to accurately reconstruct its time-temperature evolution. This
is often done employing thermokinematic models. One problem of many
current approaches is that they are limited to 2-D and do not consider
structural or kinematic uncertainties. In this work, we combine 3-D
kinematic forward modeling with a systematic random sampling approach to
automatically generate an ensemble of kinematic models in the range of
assigned geometric uncertainties. Using Markov chain Monte Carlo, each
randomly generated model will be assessed in regards to how well they
fit the available thermochronology data. This is done to obtain an
updated set of modeling parameters with reduced uncertainty. The
resulting, more robust model can then be used to re-interpret the
thermochronological data and find alternative drivers of cooling for
certain samples.We apply this approach to a simple synthetic model to
test the methodology, and then to the Eastern Alps triangle zone in the
Bavarian Subalpine Molasse. Results show that it is possible to
translate low-temperature thermochronology data into a likelihood
function to obtain a 3-D kinematic model with updated, more probable
parameters. The thermochronological data by itself, however, may not be
informative enough to reduce the parameter uncertainty. The method is
useful, however, to study alternative mechanisms of exhumation for the
thermochronological samples that are not respected by the modeling, even
when uncertainty is considered.