TY  - JOUR
A1  - Lescoutre, Rodolphe
A1  - Tugend, Julie
A1  - Brune, Sascha
A1  - Masini, Emmanuel
A1  - Manatschal, Gianreto
T1  - Thermal Evolution of Asymmetric Hyperextended Magma-Poor Rift Systems: Results From Numerical Modeling and Pyrenean Field Observations
JF  - Geochemistry, geophysics, geosystems
N2  - We investigate the thermal and structural evolution of asymmetric rifted margin using numerical modeling and geological observations derived from the Western Pyrenees. Our numerical model provides a self-consistent physical evolution of the top basement heat flow during asymmetric rifting. The model shows a pronounced thermal asymmetry that is caused by migration of the rift center toward the upper plate. The same process creates a diachronism for the record of maximum heat flow and maximum temperatures (T-max) in basal rift sequences. The Mauleon-Arzacq basin (W-Pyrenees) corresponds to a former mid-Cretaceous asymmetric hyperextended rift basin. New vitrinite reflectance data in addition to existing data sets from this basin reveal an asymmetry in the distribution of peak heat (T-max) with respect to the rift shoulders, where highest values are located at the former upper- to lower-plate transition. This data set from the Arzacq-Mauleon field study confirms for the first time the thermal asymmetry predicted by numerical models. Numerical modeling results also suggest that complexities in synrift thermal architecture could arise when hanging-wall-derived extensional allochthons and related T-max become part of the lower plate and are transported away from the upper- to lower-plate transition. This study emphasizes the limitations of the common approach to integrate punctual thermal data from pre-rift to synrift sedimentary sequences in order to describe the rift-related thermal evolution and paleothermal gradients at the scale of a rift basin or a rifted margin.
KW  - Thermal evolution
KW  - Asymmetric rifting
KW  - Numerical model
KW  - Field analogue
KW  - Pyrenees
KW  - Heat flow
Y1  - 2019
U6  - https://doi.org/10.1029/2019GC008600
SN  - 1525-2027
VL  - 20
IS  - 10
SP  - 4567
EP  - 4587
PB  - American Geophysical Union
CY  - Washington
ER  -