The conventional modeling of crustal temperatures is based on the stea
dy-state approach, which is reliable in tectonically stable regions on
ly. The present work focuses on the assessment of the influence of the
transient effects on the thermal field at regions of ongoing continen
tal collision. In the first part of this study, the thermal effects of
most evident processes operating in collision zones (thickening and f
laking of the crust, frictional heating on the surfaces of flakes, bul
k replacement of mantle lithosphere by hotter rocks, and also uplift a
nd erosion) are estimated on the basis of 1-D time-dependent synthetic
models. The results show that surface heat flow caused by the most of
investigated transient processes may differ from the steady-state one
by quantities of the order of magnitude larger than the uncertainties
of the heat flow measurements, These differences may exist over tens
of millions of years. In the second part, three 2-D time-dependent tem
perature sections gradually including the above assessed effects have
been calculated for the Central Alps, The results show that time-depen
dent models give better agreement of the calculated and measured heat
flow patterns than previously developed for the same region steady-sta
te model (Cermak et al., 1990). Best agreement is achieved when only t
he transient effects of thickening and flaking and increased heat infl
ow from the mantle are taken into account. A poorer coherence of the o
ther versions with the measured heat flow is probably attributable to
uncertain knowledge (and consequently great simplification) of spacing
and time dependence of erosion and/or frictional heating.