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Unraveling the Mesozoic and Cenozoic Tectonothermal Evolution of the Eastern Basque‐Cantabrian Zone–Western Pyrenees by Low‐Temperature Thermochronology

DeFelipe, I. ; Pedreira, D. ; Pulgar, J.A. ; van der Beek, P. ; Bernet, M. ; Pik, R., Tectonics

Unraveling the Mesozoic and Cenozoic Tectonothermal Evolution of the Eastern Basque‐Cantabrian Zone–Western Pyrenees by Low‐Temperature Thermochronology

DeFelipe, I. ; Pedreira, D. ; Pulgar, J.A. ; van der Beek, P. ; Bernet, M. ; Pik, R.

Tectonics, 2019, 38, 9, 3436-3461

Abstract :

Low‐temperature thermochronology studies have increased our knowledge of the orogenicprocesses along the Pyrenean‐Cantabrian mountain belt by placing time constraints on the exhumationhistory of its rocks. However, a significant gap in the data existed between the western Pyrenees and thecentral Cantabrian Mountains, hampering a comprehensive view of the tectonothermal evolution along thebelt. We present a new apatitefission track and zircon (U‐Th)/He (ZHe) data set for the easternBasque‐Cantabrian zone–western Pyrenees. Apatitefission track central ages cluster in theEocene‐Oligocene. ZHe samples can be separated into two groups : Group 1 depicts clustered ZHe ages‐eUconcentration (Cinco Villas massif) and Group 2 depicts dispersed ZHe ages‐eU concentration (Alduidesmassif and a Paleozoic rock pinned along the Leiza thrust). A sample from the Oroz‐Betelu massif showsintermediate behavior. Inverse modeling suggests that samples from Group 1 reached 240–280 °C in theLate Cretaceous, implying deep sedimentary burial of the Cinco Villas massif before its major exhumationphase, most probably in the early to middle Eocene, postdating the phase of rapid exhumation of thewestern part of the Leiza thrust. The sample from the Oroz‐Betelu massif, far from the Mesozoic exhumedmantle domain, experienced maximum temperatures close to 200 °C by burial beneath the Jaca‐Pamplonabasin. It was later exhumed in the hanging wall of the Gavarnie thrust in the Bartonian‐Priabonian. Thiswork provides new insights into the tectonothermal evolution of the Basque massifs and the inversion of ahyperextended margin.

Voir en ligne : https://doi.org/10.1029/2019TC005532




publié mercredi 15 janvier 2020