کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
6428717 | 1634748 | 2014 | 11 صفحه PDF | دانلود رایگان |
- Detrital zircon grains are analyzed through low-temperature thermochronology.
- The Mauléon basin's thermal history is compared to a thermo-kinematic modeling.
- The thermal anomaly recorded at onset of shortening is inherited from rifting.
The extent to which heat recorded in orogens reflects thermal conditions inherited from previous rift-related processes is still debated and poorly documented. As a case study, we examine the Mauléon basin in the north-western Pyrenees that experienced both extreme crustal thinning and tectonic inversion within a period of â¼30 Myrs. To constrain the time-temperature history of the basin in such a scenario, we provide new detrital zircon fission-track and (U-Th-Sm)/He thermochronology data. The role of rift-related processes in subsequent collision is captured by inverse modeling of our thermochronological data, using relationships between zircon (U-Th-Sm)/He ages and uranium content, combined with thermo-kinematic models of a rift-orogen cycle. We show that the basin recorded significant heating at about 100 Ma characterized by high geothermal gradients (â¼80â°C/km). Our thermo-kinematic modeling and geological constraints support the view that subcontinental lithospheric mantle was exhumed at that time below the Mauléon basin. Such a high geothermal gradient lasted 30 Myr after onset of convergence at â¼83 Ma and was relaxed during the collision phase from â¼50 Ma. This study suggests that heat needed for ductile shortening during convergence, is primarily inherited from extension rather than being only related to tectonic and/or sedimentary burial. This should have strong implications on tectonic reconstructions in many collision belts that resulted from inversion of hyper-extended rift basins.
Journal: Earth and Planetary Science Letters - Volume 408, 15 December 2014, Pages 296-306