[ 1] Temperature-time histories of rocks are often used to constrain
the kinematics of tectonic events, the evolution of landforms, erosion
rates, and/or amount of faulting in tectonically active areas. However,
interpretations based on thermal histories are not always
straightforward as they rely on several interdependent mechanisms such
as heat conduction, heat advection, or the presence of transient
topography that must be taken into account. Using a three-dimensional
finite element code recently developed by one of the authors, we have
calculated temperature-time histories to interpret an existing
thermochronological data set ( K-Ar and FT) complemented by new low-T
thermochronometer data ((U-Th)/He and FT) from the Southern Alps of New
Zealand. Combined with inversion methods ( Genetic Algorithm and
Neighbourhood Algorithm), the model is used to derive from the data
information on the tectonomorphic development of the orogen during the
Pliocene and Pleistocene epochs. Assuming a quasi-geomorphic steady
state, we can constrain the rate of tectonic horizontal advection and
vertical uplift as well as the geometry of the main structural boundary,
i.e., the Alpine Fault. We can also explain the along-strike geometry of
the metamorphic isograds and thermochrons in relationship to surface
topography. Furthermore, we show that if one assumes that the landscape
has not been horizontally transported by tectonic movement, the relief
on the west coast of the Southern Alps has increased. This relief
increase could have been initiated at any time between 1.5 Ma and 100
ka. Any relief reduction during this period is ruled out by our
modeling. Alternatively, if the landscape is advected horizontally in
the direction normal to the trace of the Alpine Fault, a relief increase
is not required to explain the thermochronological data.