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The Liiliang Mountains,located in the North China Craton,is a relatively stable block,but it has experienced uplift and denudation since the late Mesozoic.We hence aim to explore its time and rate of the exhumation by the fission-track method.The results show that,no matter what type rocks are,the pooled ages of zircon and apatite fission-track range from 60.0 to 93.7 Ma and 28.6 to 43.3 Ma,respectively;all of the apatite fission-track length distributions are unimodal and yield a mean length of～13μm;and the thermal history modeling results based on apatite fission-track data indicate that the time-temperature paths exhibit similar patterns and the cooling has been accelerated for each sample since the Pliocene(c.5 Ma).Therefore,we can conclude that a successive cooling,probably involving two slow(during c.75-35Ma and 35-5Ma) and one rapid(during c.5 Ma-0 Ma) cooling,has occurred through the exhumation of the Liiliang Mountains since the late Cretaceous.The maximum exhumation is more than 5 km under a steady-state geothermal gradient of 35℃/km.Combined with the tectonic setting,this exhumation may be the resultant effect from the surrounding plate interactions,and it has been accelerated since c.5 Ma predominantly due to the India-Eurasia collision.
The Liiliang Mountains, located in the North China Craton, is a relatively stable block, but it has experienced uplift and denudation since the late Mesozoic. It therefore aims to explore its time and rate of the exhumation by the fission-track method. Results show that, no matter what type rocks are, the pooled ages of zircon and apatite fission-track range from 60.0 to 93.7 Ma and 28.6 to 43.3 Ma, respectively; all of the apatite fission-track length distributions are unimodal and yield a mean length of ~ 13 μm; and the thermal history modeling results based on apatite fission-track data indicate that the time-temperature paths show similar patterns and the cooling has been accelerated for each sample since the Pliocene (c.5 Ma). conclude that a division cooling, probably involving two slow (during c.75-35Ma and 35-5Ma) and one rapid (during c.5 Ma-0 Ma) cooling, has occurred through the exhumation of the Liiliang Mountains since the late Cretaceous The maximum exhumation is mor e than 5 km under a steady-state geothermal gradient of 35 ° C / km. Combined with the tectonic setting, this exhumation may be the resultant effect from the surrounding plate interactions, and it has been accelerated since c.5 Ma predominantly due to the India-Eurasia collision.